Survey of Swine Disease, Management and Biosecurity Practices of Hawai‘I Swine Farms

SURVEY OF SWINE DISEASE, MANAGEMENT AND BIOSECURITY PRACTICES OF HAWAI‘I SWINE FARMS

A THESIS SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI‘I AT MĀNOA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF

MASTER OF SCIENCE

ANIMAL SCIENCE

DECEMBER 2018

Brittany Amber Castle

Thesis Committee:

Halina Zaleski, Chairperson

Jenee Odani

Rajesh Jha

Keywords: Swine, Hawai‘i, agriculture

ACKNOWLEDGEMENTS

I would like to express my deepest gratitude to Dr. Zaleski, my advisor and chair, for her patient guidance and earnest encouragement. Also, thank you for asking for the hard questions which helped me widen my research and thinking. I could not have imagined a better advisor and mentor during my master’s program.

I would like to offer my special thanks to the rest of my thesis committee, Dr. Odani and Dr. Jha, for their insightful comments, encouragement, and useful critique of this research.

I would like to thank Naomi Ogasawara, the previous graduate student who started this project and who helped lay the groundwork for everything I did.

I am particularly grateful for the assistance given to me by Travis Heskett, Laura Ayers, and all the employees of the Hawai‘i Department of Agriculture that provided endless knowledge and my samples for this project.

I would like to thank Dr. Fabio Vannucci and the University of Minnesota Veterinary Diagnostic Laboratory their support and sample analysis.

Finally, I wish to thank my family and friends for their support, love, and encouragement throughout my study.

ABSTRACT

Although swine diseases and parasites cause significant losses to producers in Hawai‘i, limited information is available on changing disease patterns and related farm practices. The objectives of this study were to identify practices used on Hawai‘i swine farms and to determine if there is a relationship between those practices and the absence or presence of a disease. A management and biosecurity practices survey was administered to farmers (n=27). Survey questions were analyzed by region, sow population, and disease presence. Most common practices included cooking food waste (94% of farmers feeding food waste), feral pig exclusion (74%), and administering an anthelmintic (63%). Challenges faced by farmers include biosecurity concerns of on-farm sales, limited access to veterinary specialists, and excluding vermin from the production area. In addition, serological samples (n=414) from swine farms

(n=57 out of 200 farms) were tested and found positive for antibodies against Porcine Circovirus Type 2b

(PCV ELISA; 98% positive), Senecavirus (SVA IFA; 58%), Porcine Epidemic Diarrhea (PED IFA; 33%) and Porcine Reproductive and Respiratory Syndrome (PRRS ELISA; 16%). Fecal flotation detected coccidia oocysts (63%) on every island; Oesophagostomum dentatum (26%), Ascaris suum (18%),

Strongyloides (11%), Metastrongylus spp. (8%), and Trichuris suis (8%) ova were on a subset of islands.

Analysis indicates that disease prevalence is regionally distributed. Kaua‘i, which is protected by a quarantine order, has remained negative for PED, and Moloka‘i, which sees less interisland traffic, is negative for PRRS, PED, and SVA. Geographical patterns in disease distribution assist biosecurity and management practice recommendations, the design of vaccination protocols, and the judicious use of antibiotics.

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TABLE OF CONTENTS

Acknowledgements ...... ii Abstract ...... iii List of Tables ...... v List of Figures ...... vi Abbreviations ...... vii Chapter I: Literature Review ...... 1 Swine in Hawai‘i ...... 1 Management Practices ...... 3 Food Waste ...... 6 Biosecurity Practices ...... 8 Disease Introduction and Impact ...... 14 Viral Transmission ...... 16 Seroprevalence and morbidity rates for PCV2, PEDv, SVA, and PRRS ...... 18 Virus Control Through Vaccination ...... 19 Parasites and Their Control ...... 20 Parasitic and Viral Interactions ...... 24 Objectives ...... 25 Chapter II: Materials and Methods ...... 27 Study Approval ...... 27 Study Population...... 27 Survey Creation and Testing ...... 28 Data Collection ...... 29 Feces and Ear Swab Collection and Testing ...... 29 Sera Collection and Testing ...... 31 Survey Statistical Analysis ...... 33 Biosecurity Score ...... 33 Disease Score ...... 34 Reporting ...... 34 Chapter III: Results ...... 35 Research Participation ...... 35 Producer Demographics ...... 36 Farm Performance ...... 38 Farm Practices ...... 38 Open-Ended Survey Questions ...... 42 Serology ...... 43 Parasite Detection ...... 45 Disease and Biosecurity Scores ...... 49 Chapter IV: Discussion ...... 50 Limitations and Future Opportunities...... 56 Appendix ...... 58 Literature Cited ...... 72

LIST OF TABLES

Table 1.1. Guidelines for swine farm visitor risk assessment ...... 10

Table 1.2. Herd morbidity rates and seroprevalence of selected viral diseases ...... 19

Table 1.3. Dewormers and medications for endo- and ectoparasites of swine ...... 23

Table 2.1. Inventory of Hawaiʻi counties in the 2012 USDA Census ...... 28

Table 2.2. Submission of sera to UMN VDL for testing ...... 32

Table 3.1. Producer demographics of the surveyed farmers ...... 37

Table 3.2. Demographics of the participating farms ...... 37

Table 3.3. Herd performance of surveyed farms ...... 38

Table 3.4. Products farmers reported using on their farm in the 12 months prior to farm visit and survey completion...... 40

Table 3.5. Feed and feed delivery on surveyed farms ...... 41

Table 3.6. Reports of vermin and their control methods on surveyed swine farms ...... 41

Table 3.7. Symptoms producers reported observing on their farms in the 12-month period before survey date ...... 42

Table 3.8. Number of tested swine and farms that were serologically positive for the four viral diseases of interest ...... 43

Table 3.9. Endoparasites and ectoparasites identified on surveyed farms ...... 46

Table 3.10. Disease and biosecurity scores by region and by number of sows ...... 49

LIST OF FIGURES

Figure 1.1 Hawai‘i swine inventory and farm totals from 1959-2010 ...... 3

Figure 3.1. Producer participation in project elements...... 36

Figure 3.2. Map of serologically positive farms by region ...... 44

Figure 3.3. Collective viral antibody presence on surveyed farms ...... 45

Figure 3.4. Collective endoparasite presence on farms ...... 46

Figure 3.5. Map of detected endoparasites by region ...... 47

Figure 3.6. Map of detected ectoparasites by region ...... 48

ABBREVIATIONS

ADAP-Agricultural Development in the American Pacific APHIS-Animal and Plant Health Inspection Service AID-Animal Industry Division AI-artificial insemination ADG-average daily gain CDC-Centers for Disease Control and Prevention CTAHR-College of Tropical Agriculture and Human Resources DNA-deoxyribonucleic acid ELISA-enzyme linked immunosorbent assay EPA-Environmental Protection Agency FMD-food and mouth disease ft-feet HDOA-Hawai‘i Department of Agriculture HPIA-Hawaiʻi Pork Industry Association IACUC-Institutional Animal Care and Use Committee IRB-Institutional Research Board IFA-indirect immunofluorescence assay km-kilometer lb-pound NASDA-National Association of State Departments of Agriculture NASS- National Agricultural Statistics Service NIFA-National Institute of Food and Agriculture NPPC-National Pork Producer’s Council PCR-polymerase chain reaction PCV1-porcine circovirus type 1 PCV2-porcine circovirus type 2 PED-porcine edidemic diarrhea PEDv-porcine epidemic diarrhea virus PDNS-porcine dermatitis and nephropathy syndrome PMWS-postweaning multisystemic wasting syndrome PRRS-porcine reproductive and respiratory syndrome PRRSv-porcine reproductive and respiratory syndrome virus rRT-PCR-real-time reverse-transcription polymerase chain reaction RT-PCR-reverse-transcription polymerase chain reaction SVA-senecavirus A SOP-standard operating procedure SIV-swine influenza virus TGEv-transmissible gastroenteritis virus UMN-University of Minnesota USDA-United States Department of Agriculture VDL-Veterinary Diagnostic Laboratory

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CHAPTER I LITERATURE REVIEW

Swine in Hawai‘i

The Hawai‘i swine industry has a rich history that continues to impact the islands today. Pigs were one of the three mammal species brought to the Hawaiian Islands by the Polynesians in 300 AD

(Kirch, 1982; Maresca, 2006). Pork was an important food source for the Polynesians in addition to having cultural and religious roles (Quentin, 1986; Kolb, 1999). Boar tusks and bones served as material for jewelry, as well as used for other ornamental objects and tools (Quentin, 1986).

Pigs also play an important role in traditions and celebrations in modern times. Major milestones in Hawaiian culture include a child’s first birthday, graduations, housewarmings, weddings, and death

(George Kahumoku Jr., personal communication). A child’s first birthday is important to many of the ethnic groups that reside in Hawai‘i, and a baby lū‘au is often held to celebrate the event. Traditionally, roasted pork is always found at a baby lū‘au, and “the pig and its preparation is a focal point of today’s

Baby Lū‘au, gathering family and friends in a cooperative celebration.” (Clarke, 1994; pg. 28-29). Other celebrations, such as weddings, also feature pork dishes: lechon (Vietnamese), kālua pig (Hawaiian), and

Kau yuk (Chinese). Some of these dishes are symbolic, such as Kau yuk, which symbolizes prosperity and good luck in Chinese culture (Clarke, 1994).

For a large portion of history, Hawai‘i swine were free roaming. They were fed agricultural crops and food scavenged from settlements and the forest, creating a loosely domesticated relationship with humans (Diong, 1982; Bay-Petersen, 1983). On February 1, 1778, Captain James Cook brought breeding stock to Ni‘ihau, the first recorded introduction of a European swine breed in Hawai‘i (Kuykendall, 1938).

The Hawai‘i swine industry grew during the 1800s, bolstered by trading voyages and the

California gold rush (Hugh et al., 1986). Honolulu on O‘ahu and Lahaina on Maui were significant ports of commerce for Pacific trading vessels. Fur, sandalwood, and whale oil traders would stop to replenish their supplies and food stores, especially perishable foods such as vegetables and pork (Kuykendall, 1938). As journeys lengthened from a few months to several years throughout the 1800s, Hawaiian ports became indispensable for ship repairs and supplies. The effect was not only felt at the ports, but throughout the islands, as pigs, vegetables, and other supplies were grown or raised before being sent to the port for

1 market (Kuykendall, 1938). The North West Company, which later joined with the Hudson Bay Company in 1921, were fur traders that frequented Honolulu for supplies. Mackle (1997) noted that in one trip in

1817-18, “they [North West Company] went to buy, slaughter, and pickle 100 barrels of pork” to support their voyages and bases of operation (pg. 29). At Hilo, records for 1853-1854 showed 10,000 pounds of live hogs were sold to the 80 ships that docked during a 12-month period (Kuykendall, 1938). In the mid-

1800s, hogs were exported to California during the Gold Rush to supply the rapidly expanding industry

(Hugh et al., 1986). The Mahele in 1848 divided the land and allowed for private land ownership in the

Hawaiian Kingdom, impacting agricultural practices. Fences sprung up between land plots to control livestock and to prevent them from damaging crops (Kuykendall, 1938).

During the early to mid-1900s, swine production on O‘ahu was centered in and around Honolulu.

After World War II, farms began relocating to the Koko Head area as urbanization and zoning pushed them away from commercial areas (Hugh, 1984). As Honolulu expanded in the mid and late 1900s, hog producers were once again relocated to the Leeward area. Kalama Valley, one of the last areas of piggeries near Honolulu, saw the remainder of its farms moved in the 1970s. This continuing forced relocation of small farmers caused many to stop raising pigs and find other ways to support their families

(Trask, 1987).

Presently, a standard Hawai‘i swine farm is a farrow-to-finish, continuous-flow operation. These are confinement farms with hogs raised in pens or small lots (Hugh, 1984). The land available for farming is limited. According to Sharma (1996), farms with fewer than 25 sows had on average 2.3 acres of farmland. This number increased as sow numbers increased, with 25-75 sow farms having 3.4 acres and farms with more than 75 sows using 6.9 acres of land (Sharma, 1996). The small-scale of many farms and land constraints makes it impracticable for most farmers to construct separate buildings for different age groups (Sharma, 1996; Maresca, 2006).

In the 2015 United States Department of Agriculture (USDA) National Agricultural Statistics

Service (NASS) report for Hawai‘i, hogs were ranked the 19th top agricultural commodity valued at approximately $2,742,000 USD (USDA, 2017a). As of December 2016, there were an estimated 10,000 pigs in the state of Hawai‘i (USDA, 2017b). This is a decrease from previous years, as can be seen from the compiled data in Figure 1 from the USDA Census of Agriculture. The Hawai‘i swine industry has seen

2 a continual decline in swine inventory since WWII ended, originally owing to the decrease in military food waste as a feed source in addition to the cost of importing grain-based feeds (Vollrath, 1956). More recent declines are attributed to urbanization, high production costs, environmental concerns, the increasing price of land, and competition with mainland pork imports (Hugh, 1984; Sharma, 1996).

Total Reported Farms and Hogs in Hawai‘i (1959-2012)

90,000 2000 80,000 1800 70,000 1600 60,000 1400 1200 50,000 1000 40,000 800 30,000 600

20,000 400 TotalNumber of Head 10,000 200 TotalNumber of Farms 0 0 1955 1965 1975 1985 1995 2005 2015 Year

Hogs Farms

Figure 1.1. Hawai‘i swine inventory and farm totals from 1959 – 2012. Declining swine numbers are representative of the challenges the industry has faced, including economic constraints, environmental regulations, and competition from imported pork. Data adapted from the USDA 2012 census (USDA, 2012) and USDA Census of Agriculture Historical Archive (USDA, 2017c).

Management Practices

In order to adapt to these challenges, Hawai‘i swine producers have developed management practices to create more efficient farms and decrease production costs. An important aspect of this is disease prevention and management, which presents additional challenges to producers. Specific practices that relate to prevention and herd health include new animal quarantine, artificial insemination

(AI), housing decisions, vaccination protocols, record keeping, and feed preparation.

New animal quarantine has long been practiced in Hawai‘i. Before swine can be imported into the state of Hawai‘i, a permit is required from the Hawai‘i Department of Agriculture (HDOA). Swine must be

3 tested negative for pseudorabies, brucellosis, and swine enteric coronavirus disease, which includes porcine epidemic diarrhea (PED). If the imported swine are not being sent directly to slaughter, they must undergo a 30-45 day quarantine period after arrival (HDOA, 2017a). However, this quarantine is done on the receiving farm, thus limiting its effectiveness. Any swine being shipped to Kaua‘i must be tested and declared free of porcine reproductive and respiratory syndrome (PRRS) within 30 days of shipment

(HDOA, 2017a). Regarding the movement of swine around the state, there are fewer policies. On-farm quarantine of new animals has long been recommended to farmers as a way to minimize the risk of disease introduction (Krauss, 1923; Stokes et al., 2010).

More recently, AI allows farmers to introduce new genetics without bringing new animals onto their farm. Artificial insemination is a common practice in many commercial farms worldwide as it quickly became a widespread assisted reproductive technology (Maes et al., 2008; Althouse and Rossow, 2011).

The first formal AI workshop in Hawai‘i occurred in 1995, although AI was used by several farmers before then (Halina Zaleski, personal communication; Hugh et al., 1986). In 2000, the Agricultural Development in the American Pacific (ADAP) project released a guide for AI outlining the basic procedures and encouraging farmers to work with their local Cooperative Extension Service for trainings and to develop their own programs (Ioanis et al., 2000). Farmers who wish to import swine semen into the state of

Hawai‘i must acquire an import permit from HDOA Animal Industry Division (AID). The imported semen must originate from a boar-stud that has been certified to be free of brucellosis, pseudorabies, and PRRS, and the boar stud must be approved by the HDOA AID (Laura Ayers, personal communication).

Benefits of AI include potentially introducing superior genetics, decreasing the number of boars needed on the farm, and decreasing the risk of disease transfer between animals (Maes et al., 2008;

Althouse and Rossow, 2011). Am-in et al. (2010) showed natural service was less expensive than AI, but the benefits offset this cost through larger litter sizes and higher conception rates. Successful AI programs require creating a breeding schedule to minimize costs and to increase profits, in addition to being proficient in estrus detection and maintaining records (Ioanis et al., 2000; Lamberson and

Safranski, 2000).

Due to the tropical climate in Hawai‘i, swine barns have adapted to take advantage of the favorable weather. Open-sided barns allow wind to keep pigs cool, but they also allow birds and insects access to the herd. Hawai‘i farmers have also adopted mainland trends, such as elevated farrowing pens, slatted floors, lagoons, and earlier weaning practices (Hugh et al., 1986). In Hawai‘i, many farms house all the animals in one building or a divided pasture due to the high cost of land (Maresca, 2006).

Good piglet management practices are vital to decrease preweaning mortality and illness. Hugh

(1984) recommended several practices to Hawai‘i farmers, including cross-fostering, providing supplemental heating when needed, creating an protected area to prevent piglet crushing, administering a form of iron in the first week of life, and providing access to creep feed. Other common preventative practices can include tail docking, treating the umbilical cord, clipping needle teeth, deworming, and administering vaccinations (Reese et al., 2015, Zaleski et al., 2009). Some piglet practices are implemented to serve other purposes, such as castrating male piglets to prevent boar odor and assigning individual identification for record keeping (Hugh, 1984; National Animal Health Monitoring System,

1992).

Vaillancourt, et al. (1990) reported the principal causes of the preweaning deaths were trauma and low viability, which was defined by low birth weight and starvation. This is also in agreement with

Muns, et al. (2016), who stated that crushing and low viability were the main causes of preweaning mortality, often with starvation and chilling as underlying contributing factors. The above piglet management practices can be used to prevent or decrease causes of preweaning mortality.

Vaccines are used as tools to reduce the impact of a disease on a population or to prevent the introduction of a particular pathogen altogether (Rose and Andraud, 2017). Vaccination programs are herd or area dependent, as it is more relevant to vaccinate for diseases that are of concern in a farm’s area. In 2009, the University of Hawai‘i’s College of Tropical Agriculture and Human Resources (CTAHR) released a publication to assist Hawai‘i swine farmers in creating a herd vaccination plan. It outlined a vaccination program that addressed common pathogens seen at varying stages of production, and this publication is the current recommendation for Hawai‘i farmers (Zaleski et al., 2009).

The first step in creating a vaccination program is identifying what diseases are a threat to a farm’s herd. This can be done through serological testing, necropsies of symptomatic swine, and examining production records for changes and trends (Janisko, 1994). The current recommendations were partially created in response to the serological surveillance findings from a 2006-2011 National

Institute of Food and Agriculture (NIFA) project (Project No. HAW00263-A). Porcine circovirus type 2

(PCV2), PRRS, and Mycoplasma hyopneumoniae were found throughout the state, and thus vaccine recommendations were created to help farmers combat these pathogens (NIFA, 2017).

In addition to record keeping’s role in vaccination programs, it is also a valuable tool to determine farm productivity, list what medication was given and when, and record litter information. Furthermore, detailed record keeping allows the producer to track trends, such as the number of animals treated year to year or the average litter size of each sow (National Pork Board, 2016). Keeping sow and litter records allows farmers to compare sows based on reproductive performance indicators like litter size and weight, farrowing rate, and number weaned per sow (Dewey et al., 1995; The Pig Site, 2013b).

The practice of record keeping on Hawai‘i pig farms is not new. Krauss (1923) listed that in a report submitted by Kamehameha School that they maintained a “complete system of records” (p. 39) for all their pigs. Examples of record keeping sheets were published by Cooperative Extension to help farmers establish their own records (Hugh, 1976). More recently, producers have the ability to use software programs have been developed to assist record keeping and management, such as

PigCHAMP®, which is offered to farmers free of charge by University of Hawai‘i Cooperative Extension

Service (PigCHAMP.com, 2017; Halina Zaleski, personal communication). However, producers who prefer can easily create and maintain written records. The National Pork Board (NPB) and Cooperative

Extension Service provide numerous free record templates available to farmers (NPB, 2016).

Food Waste

Using food waste as a swine feed has a long history in Hawai‘i (Krauss, 1923; Willett et al., 1948).

Hawai‘i is geographically isolated and has limited land for crops, restricting the amount of grains that can be grown for animal consumption. Due to this, most livestock grains and feeds are imported, leading to higher costs for the producers (Zaleski, 2007). Food waste can offset this cost because it is locally

6 produced and abundant. Food waste is considered to provide acceptable levels of nutrients and calories, although some studies have reported highly variable levels of calcium, copper, zinc, and iron (Westendorf et al., 1998; Westendorf et al., 1999). Heitman et al. (1956) suggested that supplementing food waste diets with a complete grain-based ration can provided a better nutrient balance and faster growth. Kjos et al. (2000) evaluated the effects of feeding waste products to grower-finisher pigs, finding that the composition of the meat varied between pigs fed food waste and those fed a grain-based diet. As the percentage of waste to grain in the diet increased, they reported a decrease in fat firmness and an increase in polyunsaturated fatty acids. Another study found similar results with dehydrated food waste mixed with a grain blend (Myer et al., 1999).

Before 1980, there were no national regulations on who could feed food waste or if it could be fed raw or cooked. Public law 96-468, commonly known as the Swine Health Protection Act, was passed in

1980 and began the regulation of food waste as a swine feed (House Report, 1980), although some states had regulations on food waste feeding before then and others adopted stricter regulations afterwards (Zimmerman and Brandly, 1965; Office of the Federal Register; 1985). All food waste fed to swine in the United States must be heated to 100°C for a minimum of 30 minutes, or equivalent, which is a sufficient length of time to eliminate swine and human pathogens from the mixture (House Report,

1980).

According to the City and County of Honolulu Ordinance, Chapter 9, businesses that generate high amounts of food waste, like some restaurants, hotels, and grocery stores, must dispose of food waste in a way to prevent it from entering a landfill, such as through recycling, composting, and energy generation (Revised Ordinances of Honolulu § 9-1.1, 1990). One option presented was for the food waste to be used as swine feed. Additionally, businesses pay fees for this disposal, which in turn becomes income for farmers who collect and utilize the food waste. O‘ahu farmers can collect food waste from sites directly, or sites can sell their food waste to a distribution company, such as Eco-Feeds, Inc. (Department of Environmental Services, 2005). Farmers who collect food waste benefit from lower feed costs due to a reduced need for grain and by income from the collection fee less the cost of transportation and cooking.

This ordinance is only on the island of O‘ahu; producers on other islands do not benefit from this and in some instances may have to pay to collect food waste (Halina Zaleski, personal communication).

Biosecurity Practices

While the word biosecurity is relatively novel, the concept is not. It has been defined by countless agencies and organizations, and one such definition is from the National Association of State

Departments of Agriculture (NASDA).

Biosecurity itself is more than a buzzword; it is the vital work of strategy, efforts, and planning to

protect human, animal, and environmental health against biological threats. The primary goal of

biosecurity is to protect against the risk posed by disease and organisms; the primary tools of

biosecurity are exclusion, eradication, and control, supported by expert system management,

practical protocols, and the rapid and efficient securing and sharing of vital information.

Biosecurity is therefore the sum of risk management practices in defense against biological

threats. (NASDA, 2001).

In Hawai‘i, biosecurity concerns were spurred by the 1996 PRRS outbreak on O‘ahu. Biosecurity practices that were implemented in response to the outbreak included sourcing all 4-H pigs locally, making all 4-H pig shows terminal, and replacing the practice of importing breeding stock with artificial insemination (Halina Zaleski, personal communication). More recently, worry over porcine epidemic diarrhea virus (PEDv; HDOA, 2014a) and PCV2 (NIFA, 2017) have prompted additional biosecurity concerns.

As research is constantly being published on disease transmission and routes of infection, biosecurity recommendations are ever changing. Additionally, novel disease threats require biosecurity plans that can be updated and implemented quickly. An effective biosecurity plan requires the farmer to know what diseases risks are present in their area, possible transmission routes, disease prevention strategies, and what disease management practices should be implemented if a disease is introduced onto the farm or in the area (Levis and Baker, 2011; Neumann, 2012). When creating a biosecurity plan, there are several key areas that can be included: visitor/personnel policies, vehicle and delivery policies,

8 feral pig control, rodent/pest management, waste handling and disposal, and cleaning and disinfecting procedures (Stokes et al., 2010).

People can unknowingly introduce pathogens onto a farm when biosecurity protocols are not present or sufficient. On-farm sales are common on Hawai‘i farms. Buyers benefit from purchasing locally-raised live hogs by obtaining fresh, hot pork, the entire carcass, and blood and offal that is normally disposed of during slaughter (Zaleski, 2007). To combat the high foot traffic, Extension agents recommend creating a sales pen near the entrance of the farm away from the main herd. This minimizes contact between visitors and the herd (Halina Zaleski, personal communication).

Several diseases have been shown to spread through contaminated fomites, including PRRS

(Otake et al., 2002a), PEDv (Lowe et al., 2014), and PCV2 (Madson et al., 2009b). These pathogens can be carried on contaminated footwear, clothing, vehicles, and equipment (Dalrymple and Innes, 2016).

Farmers are recommended to ask visitors either change to on-farm footwear or wear disposable booties, to ask for no contact with pigs or a slaughterhouse for a set amount of time before visiting the farm, to wear clean clothes, and to enter information in a visitor log (Stokes et al., 2010; NPB, 2016). Additionally, biological transmission can occur with zoonotic pathogens. One such example is influenza, where H1 and

H3 strains are transmissible between humans and swine (Webster et al., 1992).

The risk a visitor poses to the biosecurity of a farm is summarized in Table 1. By knowing the risk presented by the average visitor or buyer to the farm, the producer is better equipped to create a visitor biosecurity plan appropriate for his or her farm (Dalrymple and Innes, 2016).

Table 1.1 Guidelines for swine farm visitor risk assessment. Table adapted from Dalrymple and Innes, 2016.

Low Risk Moderate Risk High Risk Number of farm visits No other farm contact One or occasionally Routinely visits many per day more than one farm per farms or auctions day Protective clothing Wears sanitized shoes Wears sanitized shoes Does not wear clean or or boots. One pair of or boots. If clean, may protective clothing clean coveralls per site not change coveralls Contact with animals No animal contact Minimal or no direct Regular direct contact contact – exposure to with animals housing facilities Animal ownership Does not own and/or Owns and/or cares for Owns and/or cares for care for livestock a different species a similar species and production type Biosecurity knowledge Understands and Aware of basic Little appreciation or promotes biosecurity biosecurity principles understanding of for industry but is not an advocate biosecurity principles Foreign travel Does not travel outside Limited travel outside of Travel to foreign of country country without animal countries with animals contact contact in those countries

Not only can personnel pose a biosecurity risk, personal and industry specific vehicles (e.g. feed delivery trucks and animal trailers) can be potential sources of disease introduction onto a farm. The risks a vehicle carries are dependent on where it has been recently, although most biosecurity guides caution farmers against letting any vehicle enter the farm regardless of its origin (Stokes et al., 2010; Levis and

Baker, 2011). The National Pork Board recommends that any vehicle visiting a farm be parked away from the barns, preferably in a specified visitor area, and delivery trucks should not drive onto the farm.

Preferably, all vehicles should be cleaned and disinfected before driving on the premises (NPB, 2016). In

Hawai‘i, customer movement among farms can transport pathogens. Additionally, feed trucks, such as those used by Eco-Feeds, Inc., visit multiple farms and are a high risk of disease transmission

(Department of Environmental Services, 2005; Stokes et al., 2010). Drivers, if they exit their vehicle, should change into farm-specific footwear or disposable plastic boot covers as they can carry disease onto the farm (Levis and Baker, 2011). These suggestions also apply to vehicles of farm employees or owners. The importance of cleaning and disinfecting farm-specific vehicles should not be understated

(Levis and Baker, 2011; Agralytica, 2015).

Until 2017, thousands of swine were shipped to Hawai‘i each year for consumption as local pork production could not meet market demand (USDA, 2017b). This practice stopped on September 27,

2017, due to rising costs, competition, and perceived welfare concerns (Halina Zaleski, Personal

Communication; Hawaii News Now, 2017). Imported swine were held under quarantine at the slaughterhouse, preventing contact with local swine and farmers. However, it is possible that the pigs were still a disease risk for pathogens that could be spread by vectors such as birds or flies (Halina

Zaleski, personal communication).

Slaughterhouse biosecurity is an important issue facing the industry. Arruda et al. (2017) showed specific strains of PRRS were spread to Canadian farms that used the same trucks to send swine to market, although the exact mode of transmission from the vehicles was not identified. Another study showed trailers used to transport PRRS-positive pigs to market had the ability to infect sentinel pigs when the trailers were not effectively cleaned and disinfected (Dee et al., 2004). Lowe et al. (2014) associated the possibility of PEDv spread with transportation vehicles, calling for a multi-front effort from producers, drivers, regulators, and slaughter facility owners to increase biosecurity efforts at slaughter facilities.

Biosecurity practices extend beyond minimizing the disease introduction and transmission from human activities. Animals, including imported and feral swine, can also be a source of disease spread

(Stokes et al., 20). The benefits of new animal quarantine cannot be over-emphasized and were included in the management practices section of this literature review. However, there is a threat from non-herd animals, specifically feral pigs, which present one of the largest risks of disease introduction for Hawai‘i swine farmers (Wyckoff et al., 2009; Stokes et al., 2010). Feral swine have been shown to be infected with brucellosis, PRRS, PCV2, pseudorabies, and swine influenza virus (SIV) in Hawai‘i (Hahn et al.,

2010; Stephenson et al., 2015). One study sampled 229 feral swine on O‘ahu and found 33 to be positive for Brucella spp., the highest prevalence rate of the thirteen states sampled (Pedersen et al., 2012).

These diseases can be transmitted to domestic herds in a variety of ways, including direct and indirect contact, including oral/nasal, venereal, and oral-fecal routes (Müller, et.al, 1996; Pospischil et al., 2002;

Stokes et al., 2010; Aparicio, 2013). A 1989 study on Moloka‘i identified numerous parasites present in feral swine, including Metastongylus spp. and Trichuris suis (McKenzie and Davidson, 1989).

Preventing feral swine from accessing a domestic herd does not require complex materials or protocols. A fence or double fence preventing feral swine from being able to physically touch or access areas where domestic swine live may be enough to thwart disease transmission (Wyckoff et al., 2009;

Stokes et al., 2010). Large-scale control of feral swine has been approached by several different methods: hunting, shooting, fencing, trapping, poisoning, and habitat manipulation (Diong, 1982). Feral pig control is a divisive topic in Hawai‘i, where residents are polarized by their view on whether feral pigs should be controlled, let alone the control method. Diong (1982) listed reasons why residents of Hana,

Maui, did not want to control feral pigs, including “Hawaiians lived with pigs; it’s part of the heritage” and

“The need to enter the forests for medicinal or food plants no longer exists, so pig control is not necessary.” (pg. 367). Those in favor of feral control often discuss the damage feral animals have caused to the Hawaiian ecosystem by destroying native forests and spreading invasive plant species (Stone et al., 1992).

Other animals can introduce disease to a herd, including birds, rodents, cats, and dogs, to name a few. Mechanical disease transmission appears to be the main cause of concern with many of these species. Any animal can theoretically carry infectious material such as feces from pen to pen or even between two farms. For example, brucellosis has been shown to be transmittable through mechanical transmission from infected people and animals (Olsen et al., 2012). In an experimental setting, infected mosquitoes have been shown to transmit the porcine reproductive and respiratory syndrome virus

(PRRSv) between pigs, although its status as a biological vector was not assessed (Otake et al., 2002b).

Flies have been shown to be mechanical vectors of PRRS (Otake et al., 2004), and cattle egrets, a common bird found across Hawai‘i, also have the potential to be mechanical vectors of PRRS (Maresca,

2006).

Unwanted animals can also act as biological vectors for disease introduction. McNeil et al. (2016) found that 14% of dogs used for feral hunting on O‘ahu were positive for B. suis, which suggests hunting dogs could potentially transmit B. suis to domestic pigs and humans. Rodents are notorious vectors for several diseases, including leptospirosis. Since many swine herds in Hawai‘i are housed in open-sided barns, preventing vermin from accessing the herd and barn area is difficult. However, there are measures that can be taken to reduce the incidence rate. Creating an open, grass and debris-free area around

12 swine pens uses the natural inclination of rats to not cross open area (Levis and Baker, 2011).

Additionally, proper feed storage deters vermin by eliminating a food source (Stokes et al., 2010).

When controlling disease spread on a farm, waste management plays a key role. Several viruses, including PRRSv (Madson et al., 2014; Song et al., 2005), PEDv (Pospischil et al., 2002), and PCV2

(Segalés et al., 2005), have been shown to be present in feces and/or urine of infected animals. The majority of endoparasites excrete their eggs through the feces (Laber et al., 2002; Greve, 2012). Thus, proper waste handling and management is important to minimize disease spread and break the transmission cycle. Due to the small size of many Hawai‘i swine farms, several farmers do not have an extensive waste management system as is commonly found on large, concentrated farms. Instead, as with the housing systems, Hawai‘i farms use manure collection and disposal systems that are adapted to small-scale production. Several papers have been published on anerobic waste handling systems for land-limited farms and waste management for swine farms in Hawai‘i. However, the number of hogs needed to financially break-even with anaerobic digestors is several thousand, much greater than the average producer has in Hawai‘i (Yang and Gan, 1998; Yang and Wang, 1999). Deep litter systems and inoculated deep litter systems are also being used across the state on some farms as a cost-effective practice that complies with Environmental Protection Agency (EPA) policies (Duponte and Fischer, 2012).

Stokes et al. (2010) suggests removing manure from the pens on a daily basis will assist in maintaining good herd hygiene. For pasture-raised animals, scheduled pasture rotation along with a deworming program will assist in breaking the infectious cycle of parasites (Levis and Baker, 2011).

Cleaning and disinfecting go hand in hand with waste management. Since many pathogens and parasites are found in feces, urine, and other bodily secretions, proper cleaning can remove the potentially infectious organic matter. This should be done before disinfection as many disinfectants are not effective in the presence of organic material (Food and Agriculture Organization, 2010). In Hawai‘i, feeding food waste makes keeping pigs and pens clean challenging. However, in addition to decreasing the presence of pathogens on a farm, farmers have an incentive to maintain clean and presentable farms to appeal to customers during on-farm sales (Halina Zaleski, personal communication).

Following the labels on disinfectants is important as products need varying contact times to work

(Levis and Baker, 2011; Neumann, 2012). A list of disinfectants currently recommended to Hawai‘i swine farmers can be found in Zaleski et al. (2009).

There are numerous components necessary to create a biosecurity plan. This literature review highlighted some of those practices. For in-depth guides on creating a farm-specific biosecurity plan, more information is available at Food and Agriculture Organization (2010), Levis and Baker (2011), and

Stokes et al. (2010).

Disease introduction and Impact

Porcine reproductive and respiratory syndrome virus is an RNA virus of the order Nidovirales, family Arteriviridae (Zimmerman et al., 2012) that has been present in Hawai‘i since 1992 (LeaMaster and

Zaleski, 1996). There are two strains of the virus. Type 1 is known as the Lelystad strain or the European strain while type 2 is referred to as the North American strain. The North American strain is prevalent on

O‘ahu and considered the more virulent strain, while the European strain found on Maui presents a milder form of the disease. This was confirmed by the University of Minnesota in 2001 (Maresca, 2006). In 2007, a study of North American strains of PRRSv found a viral isolate from Hawai‘i was phylogenetically separated from the 19 mainland strains characterized, possibly indicating at least one Hawai‘i strain has divergently evolved since introduction (Fang et al., 2007).

The impact of PRRS on Hawai‘i swine production in 1996 was felt across the state. During the original O‘ahu outbreaks, routes of PRRS transmission were not fully known, but the movement of infected animals and aerosol transmission were the main suspects (Maresca, 2006). Viral introduction was attributed to imported infected breeding stock (LeaMaster and Zaleski, 2006). Limiting spread between farms was difficult in pig-dense areas, and despite adopting strict biosecurity practices many farms broke with PRRS (Maresca, 2006). The 1996 O‘ahu outbreak was estimated to directly cost producers $2.75 million; the indirect costs were not calculated (Maresca, 2006). PRRS continued to circulate in the state, and HDOA conducted a 2000-2001 PRRS surveillance to establish seroprevalence.

O‘ahu, Maui, and West Hawai‘i showed 59%, 42%, and 36% farmers tested to be seropositive, respectively. Antibodies were detected on Moloka‘i and East Hawai‘i but at a much lower rate. Kaua‘i was

14 serologically negative, which prompted the implementation of the previously mentioned quarantine order

(Maresca, 2006).

In the 2006-2011 NIFA project (NIFA, 2017), Hawai‘i swine farms were tested for PRRS, initially finding 28% of the farms tested were serologically positive. During the second project year, the number of seropositive farms decreased to 9%. However, the results of this project may be biased as farms were not randomly sampled. Instead, farms experiencing what appeared to be pathogen related losses at the time of the study were chosen (NIFA, 2017). PRRS has proven itself to be a continuing cause of concern for the Hawai‘i swine industry.

In the same NIFA project, PCV2 was officially identified for the first time in the state. At the beginning of the project, 88 of the 100 samples tested were positive for PCV2, prompting the implementation of a vaccination protocol for suckling and weaned pigs on seropositive farms. On the farms where PCV2 symptoms were reported, the vaccination program was successful in minimizing or eliminating symptoms (NIFA, 2017). Current recommendations for Hawai‘i swine farmers include vaccinating pigs for PCV2 if it is suspected or diagnosed (Zaleski et al., 2009).

In 1999, multiple Wai‘anae area farms began experiencing symptoms consistent with a coronavirus. By March of 2000, the farms had been tested for common diarrhea-causing pathogens, such as transmissible gastroeneritis, and the results were negative. Porcine epidemic diarrhea was suspected but never confirmed (Halina Zaleski, personal communication). The virus was first formally recognized in

Hawai‘i in the November of 2014 on a Wai‘anae farm. The farm experienced a 25% mortality rate with the majority of losses being piglets (HDOA, 2014a). This outbreak resulted in a quarantine order that halted the movement of pigs off O‘ahu and restricted the movements of swine around the island (HDOA, 2014b).

Another PEDv outbreak occurred in December of 2014 when PEDv was detected on four additional Wai‘anae farms near the original outbreak, although no losses were reported. (HDOA, 2014c,

2017b). It was concluded that the strain responsible for the Hawai‘i outbreak was a milder strain then the one circulating in the continental United States during that time period (HDOA, 2017b). It is possible this milder PEDv strain is the same that caused symptoms in 1999 in Wai‘anae. Wai‘anae saw another PEDv

15 outbreak in 2017, and the affected farm experienced heavier losses than what was seen on the previously infected farms (HDOA, 2017b).

Senecavirus A (SVA), previously Seneca Valley Virus before 2015 (Adams et al., 2015), is an emerging disease of swine despite being sporadically noted in U.S. swine herds since 1988 (Knowles et al., 2006). In 2015, there were several positive SVA swine identified in Hawai‘i from market hogs imported from the mainland (Travis Heskett, personal communication; Schulz, 2015). These imported pigs were shipped directly to the slaughterhouse on O‘ahu where the inspector noticed vesicles. Additionally, hogs from another Hawaiian Island had been shipped to the O‘ahu slaughterhouse at that time, and those pigs developed similar vesicular lesions. Senecavirus A was confirmed in both sets of pigs, although testing to determine if the viral strains matched was not done (Travis Heskett, HDOA AID, personal communication). Subsequent testing revealed SVA was found on other islands, although the strain(s) appear to be asymptomatic (Halina Zaleski, personal communication).

As a member of the genus Senecavirus in the family Picornaviridae, SVA is related to several foreign animal diseases that are a concern to pork producers, including Foot and Mouth Disease (FMD;

Montiel, 2016). While FMD is not present in U.S. swine herds, it is clinically indistinguishable from SVA, which is a cause of concern for the industry as FMD is a highly contagious disease with the ability to disrupt both domestic and foreign animal and animal product trade (Knight-Jones and Rushton, 2013;

Leme et al., 2015). Due to this, there is a high level of awareness and concern surrounding SVA.

Viral Transmission

Since the wide-spread PRRS outbreaks, there has been a plethora of research on PRRS transmission. Transmission can occur through direct contact between infected animals (Prickett et al.,

2008), through semen (Yaeger et al., 1993; Mortensen et al., 2002), indirectly through fomites and vehicles (Otake et al., 2002a; Arruda et al., 2017), through insect vectors such as Aedes vexans mosquitoes (Otake et al., 2002b), from dam to offspring via the placenta and in milk (Wagstrom et al.,

2001; Rowland et al., 2003), and through aerosol transmission (Mortensen et al., 2002; Kristensen et al.,

2004). The range for aerosol transmission has been debated. Dee et al. (2009) reported infectious viral particles were collected 4.7 km from the infected study herd, although if there were significant quantities

16 to infect another pig is unknown. A follow-up study by the same authors indicated some strains maintained their infectious status over 9 km while others did not (Otake et al., 2010). If PRRS can be readily transmitted through aerosols, this may have played a key role in the PRRS outbreak on O‘ahu.

Feral swine are reported to not be an important source of transmission to domestic herds as it was found that only 3% of the feral swine on O‘ahu and Hawai‘i were positive for the virus (Stephenson et al., 2015).

Additionally, PCV2 has been identified in feral swine on O‘ahu, which indicates a potential route of infection for domestic herds not practicing proper biosecurity measures (Stephenson et al., 2015).

Infection can occur from direct contact between infected and noninfected swine, and indirectly through fomites such as clothes, boots, and equipment (Phaneuf et al., 2007; Prickett et al., 2008). Transmission through semen and AI is still debated. Madson et al. (2008) detected PCV2 viral DNA in semen collected from infected boars, prompting concerns about if it can be transmitted through semen. However, further research indicated that PCV2 positive semen was unable to infect sows experimentally (Madson et al.,

2009b). However, that same research team went one step further. They inseminated sows using PCV2 spiked semen, which caused reproductive failure and seroconversion, showing that sows can be infected through semen (Madson et al., 2009a).

For PEDv, oral-fecal transmission is the main route of infection for this virus, although other transmission routes have been identified or suspected (Pospischil et al., 2002). Viral genetic material was intermittently detected in semen collected from infected boars, although its infectivity was not determined

(Gallien et al., 2018). The virus can be spread through contaminated boots, personal, trailers, feed bags, and any other surface commonly accepted as a fomite in disease transmission (Lowe et al., 2014). The spread of PEDv on feed bags led to discontinuing the use of reusable feed bags in Hawai‘i (Halina

Zaleski, personal communication). This highlights the need for good biosecurity protocols on swine farms, including manure disposal, animal movement, adequate cleaning and disinfection, and awareness of the disease (Bertasio et al., 2016).

SVA transmission is still largely unknown, but it is suspected to be similar to other Picornaviridae viruses. Canning et al. (2016) hypothesized that vermin and visiting personal were the most likely origin of

SVA introduction onto the study farm. Baker et al. (2017) assigned risk levels to different management

17 and biosecurity practices, with indirect transmission via people or vehicles carrying the virus onto the farm being the highest risk. Viral shedding has been reported in oral/nasal secretions and feces up to 28 days post infection, up to 21 days post infection in oral secretions, and up to 10 days post infection in nasal secretions and feces (Joshi et al., 2016a).

Seroprevalence and Morbidity Rates for PCV2, PEDv, SVA, and PRRS

Porcine reproductive and respiratory syndrome morbidity and seroprevalence are strain dependent. Two of the strains reported in the United States were associated with 35% (Zemen et al.,

1993) and 50% (Gauger et al., 2012) herd morbidities, and both are presumed to be North American strains. In Minnesota herds suspected to be experiencing an outbreak of North American PRRS, seroconversion of the sows was reported to range from 57-86% (Morrison et al., 1992). Desrosiers and

Boutin (2002) found 36% of the PRRSv (strain unidentified) infected sows were still seropositive after 20 months post infection. Terpstra et al. (1992) reported that once a European PRRSv strain was introduced onto a farm, 85-95% of the animals seroconverted within 3 months.

Morbidity of PCV2 is ill-defined as animals may not present clinical symptoms, leading to a lack of farm-wide testing. However, PCV2-associated diseases are associated with morbidities of 5-30% when clinical symptoms of PMWS and/or PDNS are present (Segalés, 2012). In a Belgian field trial, 86%

(31/36) of pigs sampled were seropositive for PVC2 by 14 weeks of age (Mesu et al., 2000), although it is widely accepted that seroprevalence in infected herds is typically 100% (Gillespie et al., 2009).

SVA morbidity ranges widely in naïve herds, with a viral prevalence of 5-30% in most finishing and breeding pigs, although an outbreak in Brazil reported sow morbidity from 20-90%. In an experimental setting, morbidity rates were reported as 66% (8/12) (Joshi et al., 2016a). In one study where swine were experimentally inoculated with SVA, 100% (4/4) of the pigs seroconverted by day 6 and remained seropositive for 57 days post infection (Yang et al., 2012). Joshi et al. (2016a) detected

SVA-specific antibodies starting at 5 days post infection and all animals were seropositive on day 10; seropositive status for every animal was maintained through 38 days post infection. For both studies, monitoring ended before researchers saw animals converting to seronegative status. It is currently unknown how long circulating SVA-specific antibodies persist in the bloodstream at detectable levels.

For PEDv, sow morbidities vary, but research has shown high morbidity of sows when the litter was challenged by a high virulence U.S. strain (Leidenberger et al., 2017). Nursing piglets typically experience 100% morbidity (Gao et al., 2013). In one study, seroprevalence has been shown in sows to persist for a minimum of 180 days (Leidenberger et al. 2017), and in another study seroprevalence in piglets and sows was 100% for 80 days before the herds saw animals slowly converting to seronegative status (Bertasio et al., 2016). In both studies, the animals were challenged with a PEDv once during the trails. It was thought that continued exposure would increase the length of seropositive status. Table 1.2 summarizes the above information.

Table 1.2. Herd morbidity rates and seroprevalence of selected viral diseases.

Disease Reported Herd Morbidities Herd Seroprevalence Porcine Reproductive and 50%A; 35%B 57-86%K; 36% after 20 Respiratory Syndrome monthsM; 100% after 8 monthsN; 85-95%P

Senecavirus A 4-70% & 5-30%C, 20-90%G; 66%R 100% for 38 daysR; 100% for 57 daysQ Porcine Circovirus Type 2 4-30%D 86%L, Near 100%E Porcine Epidemic Diarrhea 100%F 180 daysH; 100% until 80 daysJ

Sources: AGauger et al., 2012; BZeman et al., 1993; CLeme et al., 2017; DSegalés, 2012; EGillespie et al., F G H J 2009; Gao et al., 2013; Leme et al., 2015; Leidenberger et al., 2017); Bertasio et al., 2016; KMorrison et al., 1992; LMesu et al., 2000; MDesrosiers and Boutin, 2002; NYoon et al., 1995; PTerpstra et al., 1992; Q Yang et al., 2012; RJoshi et al., 2016a

Virus Control Through Vaccination

Some viral diseases of swine can be controlled by vaccination and management protocols, as antiviral medication is not readily available. While there are PRRS vaccines approved for use in US swine herds that are reviewed in Charerntantanakul (2012), studies have shown modified-live virus vaccines have the potential to revert to virulence and spread through horizontal and vertical transmission (Bøtner et al., 1997; Beilage et al., 2009). In the CTAHR swine health management recommendations for Hawai‘i farmers that were current at the time of this study, PRRS vaccination is only recommended after consulting with a veterinarian (Zaleski et al., 2009). The vaccine for PCV2 is based on a PCV2a strain of

19 the virus (Kekarainen et al., 2010; Han et al., 2012), and has been shown in infected pigs to improve average daily gain (ADG), reduce viral loads, decrease mortality rate, and reduce the incidence of lesions

(Cline et al., 2008; Segalés et al., 2009; Han et al., 2012).

A PEDv vaccine by Zoetis is under a conditional license while it undergoes continuing potency and efficacy studies (Zoetis, 2017). This vaccine, unlike the PRRS and PCV2 vaccines, relies on passive immunity through colostrum. Sows are vaccinated during gestation, stimulating IgA production and secretion to piglets in the sow’s colostrum. Leidenberger et al. (2017) found piglets receiving maternal antibodies shed less virus, had a lower mortality rate, and were clinically healthier than piglets who did not receive maternal antibodies. Finally, there is no approved vaccine or medication for SVA in pigs

(Leme et al., 2017).

Parasites and Their Control

Endoparasites and ectoparasites are not new concerns for Hawai‘i swine farmers. Farmers have long been advised that gastrointestinal parasites and external parasites are widespread concerns for hogs (Gantt, 1938; Krauss, 1923). Several gastrointestinal parasites have been specifically listed as concerns for swine farmers, including Ascaris suum (Gantt, 1938; Vollrath, 1956), coccidia, Hyostrongylus rubidus, Metastrongylus spp., Oesophagostomum dentatum, Stephanurus dentatus, Strongyloides spp.,

Trichuris spp. (Alicata, 1964; Vollrath, 1956), and many others (Alicata, 1964).

Pigs have the ability to develop protective immunity against some parasites, such as A. suum, once they are infected continuously for several weeks. The immune system will mount a response of eosinophils, goblet cells, and mast cells against the hatched larvae, preventing the majority of larvae from penetrating the intestinal lining, although successful infection still occurs at a low level (Mejer and

Roepstorff, 2006; Masure et al., 2013). This allows for eggs to be continuously introduced into the environment, infecting newborns and any newly introduced pigs.

An intestinal nematode of swine is Trichuris suis, commonly called whipworm. Pasture production systems are associated with persistent infections of T. suis. Eggs can remain infective for up to eleven years (Roepstorff and Nansen, 1998) and require consistently warm temperatures to develop.

Hawai‘i's climate presents a challenge in parasite control. T. suis and A. suis require warm temperatures and moisture for embryonation, which can delay the time it takes for the eggs to become infectious in locations that experience a cold season (Roepstorff and Murrell, 1997; Roepstorff and

Nansen, 1998). The optimal temperature range for the development of Metastrongylus spp. larvae is 22-

26°C (Roepstorff and Nansen, 1998). Areas of the state below 1,000 ft do not typically see temperatures under 10°C at any time of the year, and the relative humidity of lowlands average between 60 and 70 percent (Western Regional Climate Center, 2017). This creates an ideal environment for egg maturation.

Due to this, it is important to maintain a parasite control program year-round in tropical production systems such as Hawai‘i.

Metastrongylus spp., unlike the before mentioned endoparasites, require the earthworm as an intermediate host for their life cycle. Because of this, the lungworm is commonly seen only in swine raised with access to dirt or on pasture (The Pig Site, 2013a). Metastronglyus spp. can be controlled with the same methods as A. suum. Frequent pen cleaning and disinfecting in addition to preventing contact with earthworms will break the transmission cycle (Laber et al., 2002). Infection for pigs raised on concrete or slatted floors without access to pasture is unlikely (The Pig Site, 2013a).

Sarcoptic mange, caused by a burrowing mite known as Sarcoptes scabiei, is considered the most important swine ectoparasite in herds worldwide (Greve and Davies, 2012). Haematopinus suis, also known as the hog louse, is a suckling louse ectoparasite of swine (Greve and Davies, 2012).

Transmission of the hog louse is only through direct animal-to-animal contact as the ectoparasite’s entire life cycle is on swine (Greve and Davies, 2012). These two ectoparasites are historically common across the state, often reported in Extension publications where they are described from mildly irritating to growth retarding (Vollrath, 1956).

Mange is considered to be a result of poor management and/or an inadequate diet, which indicates that management changes in addition to treatment are recommended (Greve and Davies,

2012). Ivermectin has been shown to be effective at controlling Sarcoptes scabiei and hog louse infestations in pigs (Mock, 1997). Giving an injection of ivermectin to gestating sows one week before farrowing has been shown to minimize the risk of infection of the neonatal pigs (Arends et al., 1990).

Breeding animals should be treated as they can transfer lice and mange during mating (Mock, 1997). For both mange and lice, it is important to treat every infected animal to break the infection cycle (Greve and

Davies, 2012; The Pig Site, 2013a). Humans can be mechanical vectors of mites, so good biosecurity protocols for visitors and workers are important to reduce the transmission of mites between herds (Mock,

1997; Greve and Davies, 2012). There are several products which can be used to treat mange, lice, or both. They can be found in Table 1.3.

Control measures for all the internal parasites listed include maintaining a regular deworming program for the entire herd, rotating pastures if pasture raised, and for pigs raised on concrete or slatted floors, cleaning and disinfecting stalls between groups and before farrowing (Roepstorff and Nansen,

1998). A specific control program can be developed once the parasites present on a specific farm are identified. All previously mentioned gastrointestinal parasite species can be diagnosed by a fecal flotation as the parasite eggs will be excreted in the feces (Roepstorff and Nansen, 1998; Greve, 2012). The Food and Agriculture Animal Health Manual provides several different fecal examination procedures appropriate for quantification and identification of the parasites listed in this literature review (Roepstorff and Nansen, 1988).

Identification of parasites present in a herd is critical to developing an effective deworming program. There is no one antiparasitic medication effective against all parasites of swine, thus what each herd requires will vary based on parasites present. Antiparasitic medications and their targeted parasite(s) are included below in Table 1.3. However, a strict cleaning and sanitation program for the herd has been shown to be the most effective at decreasing infection rates. Thorough cleaning of pens, especially farrowing crates, where all organic material is removed before the pens are disinfected can help break the transmission cycle and prevent reinfection of herd animals (Laber et al., 2002; Lindsay et al., 2012).

Migrating Eggs Withdrawal Active Trade Ascarids T. M. Sarcoptic Presentation worm Coccidia* Lice Period Medicine Names A. suis suum spp Mange larvae (days) Amitraz Taktic® Topical 7 (12.4%) Dichlorvos Atgard® Feed

Doramectin Dectomax® Injection 15

Febantel Bayverm® Feed Pellet 4

Fenbandazole Panacur®, Feed Pellet 1 Flexadin® Safe- Guard® Flubendazole Flubenol®, Feed Powder 2 Flubenvet® Ivermectin Ivomec ® Injection 15 (1%) Ivermectin Ivomec® Feed Premix 10 (0.6%) Levamisol Levacide®/ Injection 3 Levadin® Oxibendazole Loditac® Feed Pellet 4

Permethrin Atroban® Topical 5

Phosmet Porect® Topical 5 (20%) Thiophanate Nemafax Feed Powder 3 (22.5%) 14® Table 1.3. Dewormers and medications for endo- and ectoparasites of swine. Modified from Zaleski et al., 2009, and The Pig Site, 2013a. *Baycox (toltrazuril) is approved for extra label drug use treatment of coccidia in pigs. However, use is only recommended when consulting a veterinarian as the product has a 70-day withdrawal time. Depending on the age/weight of marketing, this withdrawal time may not be fulfilled

(Drugs.com, 2017). 23

Parasitic and Viral Interactions

Not only do viruses and bacteria have the ability to interact during concurrent infections, parasite interactions with viruses, bacteria, and other parasites have also been studied. Several examples of viral and bacterial interaction have already been discussed in this literature review.

In addition to PRRS being a challenging disease on its own, the virus attacks alveolar macrophages, leading to an increase in secondary infections from opportunistic bacteria (Done and

Paton, 1995; Cancel-Tirado et al., 2004). The immunosuppressive effects of PRRSv can increase the severity of both PRRS and the concurrent infection (Dwivedi et al., 2012). Van Reeth et al. (1996) described a concurrent infection of PRRSv and SIV in ten-week-old pigs, which resulted in exacerbated symptoms such as growth retardation, fever, and respiratory symptoms. It is interesting to note that each of the three groups infected with PRRSv-SIV exhibited varying severities of clinical signs, leading the authors to suggest influence from underlying physiological parameters (Van Reeth et al., 1996).

Typically, PCV2 presents mild clinical signs unless there is a coinfection with another pathogen.

Severe wasting disease has been seen in swine infected with PCV2 and porcine parvovirus simultaneously (Allan et al., 1999a). In pigs infected with PRRS and PCV2, the viral load was enhanced when compared to pigs inoculated with PCV2 alone (Allan et al., 2000). Porcine circovirus can also increase the severity of other diseases, as with Mycoplasma hyponeumoniae. Pneumonia symptoms were shown to have an increase in severity, and PMWS incidence was greater in a herd coinfected with

M. hyponeumoniae and PCV2 (Opriessnig et al., 2004). In one trial, PCV2 infected swine were given

RespiSure®, a vaccine used to prevent pneumonia caused by M. hyponeumoniae, and 49.2% of the treated swine presented PMWS clinical signs as opposed to only 10.7% of the PCV2 infected control group (Kyriakis et al., 2002). In the above studies, it was suggested that PCV2 infection has immunosuppressive actions due to its replication in immunological cell lines, leading to the susceptibility of the infected pig to a concurrent infection (Allan et al., 2000; Kyriakis et al., 2002; Opriessnig et al.,

2004).

One example of a parasite-virus coinfection is a study by Núñez et al. (2003) regarding

Cryptosporidium parvum and PCV2. In that particular study, the heavy infestation was suggestive of a

24 failure to trigger an immunological response against the parasite. As PCV2 is suggested to be immunosuppressive, it is thought to be the cause of the suppressed immune response (Núñez et al.,

2003). Another study suggests that Isospora suis infections effect the gastrointestinal tract, which may result in an increased susceptibility to enteric infections, such as Escherichia coli and transmissible gastroenteritis virus (Chae et al., 1998).

Parasite-parasite coinfections are more complex as some parasites have been suggested to compete for the same area of the digestive tract, creating an antagonistic relationship. Frontera et al.

(2005) reported that while overall parasite loads were less in pigs coinfected with A. suum and M. apri., the number of white spots found during the trial was higher in coinfected swine than those solely infected with A. suum. Additionally, the number of M. apri larvae and adults in the lungs was lower in mixed infection pigs than in the M. apri only infected pigs. This antagonistic relationship was also found between

A. suum and Oesophagostomum dentatum coinfected pigs (Helwigh et al., 1999).

Objectives

The current biosecurity and management practices related to disease spread and prevention have not been surveyed in depth. The surveys completed in 1996 by K.R. Sharma (Dissertation, UH

Mānoa) and 2006 by B.T. Maresca (Master’s thesis, UH Mānoa) were focused studies that did not fully evaluate the broad range of practices used by Hawai’i swine farmers. Additionally, the ADAP project completed an animal health survey involving swine in 1999. However, the ADAP survey focused on disease prevalence on several Pacific islands, not on farm management and biosecurity practices and diseases of Hawai‘i farms (ADAP, 2000).

The Hawai’i swine industry is a valuable contributor to the state’s local food production, in addition to contributing 2-3 million dollars to the state’s economy each year. By determining management and biosecurity practices and their relationship to disease presence, recommendations can be made to better control swine diseases, leading to improved pig performance and a safer supply of pork.

The first objective of this research is to determine the management and biosecurity practices currently being used on Hawai‘i swine farms. Second, I wish to determine if there is a relationship

25 between management and biosecurity practices and the absence or presence of a disease. Finally, I want to update current guidelines for farmers to minimize disease spread, increase animal welfare, increase the effectiveness of vaccination protocols, and to decrease antibiotic use.

CHAPTER II MATERIALS AND METHODS

Study approval

The University of Hawaiʻi at Mānoa Institutional Animal Care and Use Committee (IACUC)

(Protocol ID 99-041-14) approved all experimental procedures. The survey’s content and use were approved by the University of Hawaiʻi at Mānoa Institutional Review Board (IRB) (Protocol ID 2017-

00324).

Study population

The target population for this study was swine producers in the state of Hawaiʻi, specifically on

Oʻahu, Maui, Hawaiʻi, Molokaʻi, and Kauaʻi. Eligible producers were English speaking and over eighteen years of age. Producers were required to own at least one hog that was not a 4-H show hog at the time of the survey. Farms that raised other animals or crops were not excluded from this study.

Contact information for farmers was obtained from HDOA or University of Hawaiʻi Cooperative

Extension. Farmers were contacted by email, followed with a phone call if needed. The following informatin was provided to farmers during the initial contact: a brief program description, its importance, the protocol, and their rights should they choose to participate. The IRB approved consent form was attached to the email for their convenience.

At the time of this project, the last published information on the number of swine farms and animal inventory was done by the 2012 USDA agricultural census (USDA, 2012). There were 231 swine farms reported in Hawaiʻi, with a varying number of farms and animals per island (Table 2.1). In order to detect statewide prevalence of a practice that is being used on 15% of farms with 95% confidence, 25 farms would have to be surveyed.

Table 2.1. Inventory of Hawaiʻi counties in the 2012 USDA Census. While Maui and Hawaiʻi counties had more farms per county, Honolulu county had the majority of hogs in the state.

Location Total Number of Number of Animals Farms Hawai‘i County 70 931 Honolulu County 60 6,265 Kauaʻi County 20 1,480 Maui County (includes the islands of 81 2,765 Maui, Molokaʻi) State Totals 231 11,441 Data adapted from the 2012 Census of Agriculture (USDA, 2012).

Survey Creation and Testing

The survey was based on current industry biosecurity and management practices recommended by the USDA (USDA 2015, 2016) and NPB (NPB, 2016) with emphasis on Hawai‛i specific challenges

(Zaleski, 2007). It was reviewed by three University of Hawaiʻi at Mānoa CTAHR faculty members, each of which is knowledgeable about the Hawai‛i swine industry. Survey layout was rearranged so that management specific questions were grouped according to production group while biosecurity specific questions were clustered according to topic. Furthermore, the survey was modified to include an area to list all medications present on the farm in addition to their purposes.

After survey revision was completed, it was pre-tested at a 2017 annual meeting of the Hawaiʻi

Pork Industry Association (HPIA) where local swine farmers, Cooperative Extension personal, and HDOA employees were in attendance. Comments and concerns were collected and used in the final survey revision. Farmer demographic questions were added before the survey was submitted for IRB approval.

The final survey contained eleven sections: (1) inventory, (2) farmer demographics, (3) suckling pigs, (4) weaned pigs, (5) growing-finishing pigs, (6) breeding – females, (7) breeding – males, (8) disease indicators, (9) biosecurity, (10) free response, and (11) wrap-up/media release form. Sections 3-7 deal with management practices, medications, and vaccinations for each production group of pigs.

Section 8 assesses common clinical symptoms farmers have noticed on their farms and the medications used for treatments. The biosecurity section contains practices directly related to disease transfer. The free response section was created so that participants could express concerns and questions about

28 biosecurity and management anonymously. Full survey and waivers are available in Appendices A and B.

The answers provided are intended to guide future industry workshops and demonstrations.

The front and last pages of each survey contained identifying information, including name, address, premise ID, media release form, etc. Each page of the survey received an island specific, non- identifying code. After data collection, the first and last page were detached and kept in a locked drawer that was accessible only to the lead researcher.

Data collection

Survey responses were collected from June, 2017 until July, 2018 at a time convenient to the participant. Participants were asked to sign the consent form and were given a physical copy for their records. Each survey was administered during a 30 – 45 minute interview. In accordance with current biosecurity recommendations (Levis and Baker, 2011; Stokes et al., 2010), as far as possible only one farm was visited per day and all supplies were either disinfected or disposed of to minimize risk of disease transmission between farms. However, due to time and budget constraints, some farms were visited back to back on Kauaʻi, Hawaiʻi, Molokaʻi, and Maui. Between farms, the researcher’s outer clothing or disposable coveralls was changed, and the car and supplies were disinfected. The full farm visit biosecurity standard operating procedure (SOP) is presented in Appendix C.

Feces and Ear Swab Collection and Testing

Hawaiʻi swine farms are divided into four lists by the HDOA for mandated routine brucellosis and pseudorabies testing on a four-year rotating basis. Farms that were visited during the 2017 and 2018 years were informed of the disease surveillance and asked if they wished to participate. Each farmer that opted-in was asked to read and sign the IACUC-approved waiver before sample collection began.

Fresh fecal samples were collected from the animals’ pens. Each sample’s weight fell in the range of 25 – 75 g. From each farm, samples from three age groups were collected: suckling, grower- finisher, and adult breeding. Farms that did not possess all three age groups or farms where the pens had been recently cleaned had samples taken where possible. All collected samples were stored under refrigerated conditions (4°C) until laboratory analysis (University of Hawaii, 2017). A minimum of three fecal samples were taken from each participating farm to allow for the detection of a 10% or greater

29 prevalence with a 95% confidence interval. The required number of samples was adapted from Pittman et al. (2010).

Fecal flotations were performed using Fecalyzers® and Fecasol® solution (Vétoquinol USA, Inc.,

Fort Worth, TX). Feces were collected in the inner chamber and placed into the housing. Fecasol® solution was added before mechanical force was applied to mix feces with solution. The container was filled with Fecasol® and a glass coverslip was placed on top. After 10 minutes, the coverslip was removed and placed on a glass slide for viewing under 100x magnification. Magnification was increased to 160x when identifying parasite ova. Ova counts were recorded semi-qualitatively as “+” (<10 ova), “++”

(10-50 ova), and “+++” (>50 ova).

Ear swabs were collected from adult animals. Five animals were sampled per farm when possible; on farms with fewer than five adult animals, samples were collected from each adult animal present. This number was chosen based on the ability of HDOA employees to collect the samples.

Samples were gathered by swabbing the inner pinna with a cotton-tipped swab at sites with crust build- up. Swabs were then placed in a sealed container for transport at ambient temperature before storage under refrigerated conditions (4°C).

To determine if ectoparasites were present in the ear swab samples, two to three drops

(approximately 100 µl) of mineral oil was placed on a glass slide. The ear swab was rolled through the mineral oil to transfer sample onto the slide. Large clumps of debris were broken up by pressing with the swab. Slides were immediately viewed at 40x and then 100x magnification to determine if ectoparasites were present.

After analysis was completed, all glass slides and coverslips were disinfected in Virkon S® solution for a minimum of 20 minutes in before being disposed of in a sharps container. Equipment and counters were disinfected with 70% alcohol solution. Fecalyzer® contents were discarded in the laboratory sink before the Fecalyzer® itself was disposed of in the regular waste. All untested sample material and the original collection containers were autoclaved before disposal (University of Hawaii,

2017).

Sera Collection and Testing

To determine the number of samples taken per farm, an EpiTools (Ausvet, Australia) online free statistical software, was used (Sergeant, 2017). Sample sizes were calculated using hypergeometric distribution without replacement. The formula used for calculations was

1 (퐷 − 1) 푛 = (1 − 훼 ⁄퐷) − (푁 − ) 2 where n is sample size, N is the herd size, D is expected number of diseased animals in the population, and α is one minus confidence, or 0.05 (Fosgate, 2009). A sample size of 10 serum samples per farm provides a 95% degree of confidence for detecting a prevalence of at least 30% for all farms under 2000 animals. Morbidity and seroprevalence of the four viral diseases are such that if one was present in a tested herd, its detection is expected (see table 1.2., pg 22). Results were compiled to show disease presence and absence by area and by island.

Blood samples was collected by HDOA employees from the external jugular vein or vena cava.

The blood was transferred to uncoated, evacuated glass tubes (BD Vacutainer®, Franklin Lakes, NJ) and stored at room temperature until centrifugation to separate serum. Serum was removed to a test tube and stored under refrigerated conditions (4°C) for mandatory brucellosis and PRV testing by an HDOA veterinarian. Afterwards, sera were stored at -20°C until being packaged for shipping (Storch, 2000).

Sera were sent to University of Minnesota (UMN) Veterinary Diagnostics Laboratory (VDL; St.

Paul, MN) in insulated polystyrene foam coolers with ice packs using a secure 2-day shipping service.

The samples were shipped when it was convenient for the researchers, but all samples were sent in a timely manner so that individual results could be provided to each participating farm. The shipping schedule can be found in Table 2.2. Each sample underwent diagnostic testing for SVA (IFA screen, two dilutions), PRRS (ELISA), PEDv (IFA screen @ 1:40), and PCV2 (ELISA). These techniques are used to determine the presence or absence of antibodies in the blood sera; antibodies can be present from a current infection, a recent infection, or in response to vaccination

Table 2.2. Submission of sera to UMN VDL for testing.

Sample Number of Samples Submission Date Results Received Submission Submitted (n) Date 1 161 3/28/2017 04/07/2017 2 59 06/06/2017 06/12/2017 3 20 06/13/2017 06/29/2017 4 9 8/09/2017 8/16/2017 5 66 3/06/2018 3/13/2018 6 99 6/27/2018 7/3/2018 Total 414

The PRRS enzyme linked immunosorbent assay (ELISA; IDEXX PRRS) is an indirect assay in which serum is placed into antigen-coated wells on an ELISA plate (Devi Patnayak, UMN VDL, personal communication; Fabio Vannucci, UMN VDL, personal communication). Any antibodies present in the serum bind to the antigen, creating an antibody-antigen complex. After washing the plate, an enzyme labeled secondary antibody is added that will bind to any primary serum antibodies present. The plate is washed again before a colorimetric reporter enzyme is added that will bind to the secondary antibody.

The color intensity developed correlates with the antibody levels of the serum sample (Kemeny and

Callacombe, 1988). Test specificity and sensitivity were reported as 99.9% and 98.8%, respectively.

Positive samples were confirmed by IFA. Those samples that were positive by ELISA but negative by IFA were considered negative.

The PCV2 ELISA is a competitive, or blocking, ELISA (SERELISA PCV2, Zoetis) ran in-house at

UMN VDL (Devi Patnayak, UMN VDL, personal communication; Fabio Vannucci, UMN VDL, personal communication). Similar to the indirect assay, an antigen is fixed to the ELISA plate before adding a serum sample. Any antibodies present in the serum will bind to the antigen. After washing, a labeled antibody is introduced, binding to any exposed antigens present. This creates a competition between the two antibodies to bind to the plate antigens. The more labeled antibodies bound to the plate, the greater the color change intensity once the reporter enzyme is added, and the less antibodies present in the serum (Duncan, 1988). Test sensitivity and specificity were reported as 86% and 85%, respectively

(Fablet et al, 2017).

For the SVA diagnostic test, an indirect immunofluorescence (IFA) screen developed by the UMN

VDL was used. SVA antigen was isolated and fixed to wells in a 96-well microtiter plate. Serum was added in two dilutions and incubated. After washing, a secondary anti-porcine antibody was added.

Counterstaining the wells before observing them causes positive wells to fluoresce under a fluorescence microscope. Test sensitivity and specificity were reported as 90.3% and 100%, respectively (Patnayak et al., 2015).

Finally, the PEDv IFA screen is an in-house test that is performed in the same manner as the

SVA IFA. An antigen is fixed to a plate, serum is added and incubated, the plate is washed before a secondary antibody is added, and the sample is examined for fluorescence. Test specificity and sensitivity were reported as 100% and 92%, respectively (Storch, 2000; Devi Patnayak, personal communication).

Results for the PCV2 and PRRS ELISAs were considered positive if the sample-to-positive ratio was ≥ 0.40. For the SVA and PED IFA, samples were considered negative if fluorescence was not detectable at a 1:40 dilution. For the both IFAs, the sample was positive if fluorescence was detected at a

1:40 dilution. Positive SVA samples were also screened at a 1:80 dilution, although all samples positive at

1:40 dilution were considered positive regardless of the outcome of the 1:80 dilution screen.

Survey statistical analysis

Once the farm visit was complete, survey responses were processed using Microsoft Excel.

Responses were binarily recorded as 1 (yes), 0 (no), and blank (not applicable/not present) when possible. Non-binary responses were recorded verbatim in either list format (e.g. medications and vaccines) or numerically with units (e.g. average age at weaning). Results were compared among farm size groups and regions by t-tests in R statistical software.

Biosecurity Scoring System

Survey questions were divided into seven categories for analysis: (1) new animal introduction, (2) vaccinations and preventative care, (3) visitor policies, (4) nutrition and delivery, (5) general management,

(6) vermin and feral control, and (7) symptoms (see Appendix D for full list of questions per section).

Scores were normalized on a 10-point scale, with higher scores representing a higher level of biosecurity.

Biosecurity scores were analyzed individually, by region, and by farm size by ANOVA, ‘cor.test’, and the

‘pairwise.t.test’ function in R statistical software.

Disease Scoring System

A numerical score was assigned to each viral disease based on the potential impact of the disease should it be introduced onto a farm. Factors included disease severity, prevalence (spread), and the potential impact of an outbreak: PRRS and PED were assigned a score of 3.5, PCV2 was assigned a score of 2, and SVA a score of 1. Farm disease scores were calculated based on the absence or presence of viral antibodies detected. Farms could score between 0 and 10, with a score of zero signifying no viral antibodies detected and a score of 10 signifying antibodies against all four viral diseases were detected. Disease scores were compared with biosecurity scores and among farm size groups and regions by ANOVA, ‘cor.test’, and the ‘pairwise.t.test’ function in R statistical software

Reporting

An individual report was sent to each participant stating what was found on his or her farm, which included viral results, endoparasites, and ectoparasites. Results were deidentified for all other reports.

Deidentified aggregated blood sera results were sent to the HDOA, reported to industry, and are compared to survey results in this thesis.

CHAPTER III RESULTS

Research Participation

Of the approximately 230 swine operations in the state of Hawai`i, 63 participated in at least one part of the project, although not all farmers participated in all components of the project (Figure 3.1). All farmers who wished to participate in the project met the inclusion criteria.

Surveys were collected from 27 farmers from July, 2017 to June, 2018. Sample collection occurred from January to June, 2017 (Ogasawara, 2017) and from July, 2017 to July, 2018. Farmers were asked to answer questions pertaining to their farm based on practices that occurred during the previous 12 months. Farm records were consulted when present; otherwise all survey answers were based on farmer recollections. With 27 farmers participating, the detectable prevalence of a practice being used statewide was 10% with 95% confidence (Sergeant, 2017).

Serology

n= 57 Total Hawai‘i Swine Farms N=231 (USDA, 2012)

21 5

Parasite 1 3 Survey n= 41 1 n=27

Figure 3.1: Producer participation in project elements.

Producer Demographics

Twenty-seven swine producers participated in the management and biosecurity survey. The average participant’s swine farming experience ranged from 0.25 – 50 years (Table 3.1). Farm demographics also varied among farms (Table 3.2).

Table 3.1. Producer demographics of the surveyed farmers

Survey Participant Demographics Number of Percentage of farmers farmers EducationA,B Some High School 2 8% High School Diploma/GED 8 31% Some College 2 8% Associates or Technical Degree 5 19% Bachelor’s Degree 7 27% Graduate Degree 2 8% Years Swine FarmingB 0-9 10 37% 10-19 5 19% 20-29 4 15% 30-39 4 15% 40+ 4 15% Average 18.6 ± 15.7 Pork Quality Assurance Certification Yes 6 22% No 21 78% AOne farmer declined to disclose education level, n=26 B Values not add to 100% due to rounding

Table 3.2. Demographics of the participating farms

Farm Demographics Number of farms Percentage of farms Country Hawai‘i 3 11% O‘ahu 10 37% Kaua‘i 4 15% Maui 10 37% Farm Size (by sow) 0-9 13 48% 10-49 11 41% 50+ 3 11% Average 21.8 29.1 ± sows Farm Size (by acre) < 1 7 26% 1-5 14 52% 6-10 2 7% 11+ 4 15% Average 3.9 ±4.3 acres Land Ownership Own 18 67% Lease 9 33% Farm Type Farrow to Finish 24 89% Farrow to Wean 1 4% Wean to Finish 2 7%

Farm Performance

For all surveyed farms, the average number born alive per litter was 10.8 pigs, and the average number weaned per litter was 8.4 pigs (Table 3.3). Preweaning mortality was calculated to be 21.1%. The average weaning age was 38.8 days. There was no correlation between farm size and preweaning mortality (r= -0.26, p<0.05).

Table 3.3. Herd performance of surveyed farmers.

Farm Size < 10 Sows 10-50 Sows > 50 Sows All Farms Mean SDA Mean SDA Mean SDA Mean SDA Number of sows 3.4 2.5 26.4 11.2 89.0 33.8 22.3 29.0 Average number 11.0 2.6 10.5 2.1 11 1.6 10.8 2.2 born alive per litterB Average number 8 1.3 8.3 1.7 9.5 0.9 8.4 1.5 weaned per litterB Preweaning 24.5 12.6 20.2 13.8 12.8 7.5 21.1 12.8 mortality (%)B Average weaning 41.5 14.8 39.5 10.2 25.7 4.0 38.8 12.7 age (days)C ASD denotes standard deviation B These values are calculated based on 24 farms as 3 farms did not produce piglets at the time of the survey CThese values are calculated based on 25 farms as 2 farms did not wean piglets at the time of the survey.

Preweaning mortality of piglets is often associated with management related issues. In this study, there was no relationship between the use of a farrowing crate and preweaning mortality (p>0.05).

Furthermore, there was no relationship between age at weaning and preweaning mortality (p>0.05).

Farmers were not asked the causes of piglet mortality on their farms, nor did farmers report the average number of stillborns and mummies per litter.

Additionally, the data collected was compared with Sharma (1996), and there were no significant differences in average number born per litter, average number weaned per litter, and preweaning mortality (p>0.05).

Farm Practices

Record keeping, which ranged from electronic software programs to written notes on a calendar, occurred on 14 farms; breeding herd records were kept on all 14 farms, 7 farms kept suckling pig records,

38 and 5 farms kept grower-finisher records. Sixteen farmers reported that they had contacted Extension agents and/or HDOA veterinarians for assistance with management and biosecurity practices.

Introduction of new pigs onto a farm occurred on 14 of the 27 farms in the surveyed year, and of those, 4 (27%) practiced on-farm quarantine. Quarantine lengths were reported as 30 days (1 farm), 45 days (1 farm), and over 180 days (2 farms). Of those two farms, one confined all introduced pigs to market pens away from the main herd until sold, and the other farm did not have pigs on the premise before the new animal introduction. Farmers reported introducing breeding animals (8 farms), growing or finishing pigs (2 farms), and recently weaned pigs (5 farms).

Artificial insemination was performed on 10 farms, and 6 farms had closed herds with no animal or semen introduction. O‘ahu, Maui, and Hawai‘i island farmers only bought swine from other farms on their own island or from Kaua‘i. Surveyed farmers on Moloka‘i bought swine from other Moloka‘i farmers or from Maui and/or Kaua‘i. Only 2 farmers reported importing swine from the continental United States, and only one of those farmers imported animals during the study period.

Twenty-three farmers reported 115 vaccine or medicinal products used on their farms; four farmers reported that they did not used any products (Table 3.4). Most farmers that used antimicrobials

(12 of the 15 farmers) used penicillin, and 8 of the 15 reported using more than one antimicrobial compound. The two main vaccines used were Farrowsure Gold+B (9 farmers; Zoetis) and RespiSure-

ONE (9 farmers; Zoetis). Ivermectin products were the main antihelminth medication used (10 farmers), followed by Dectomax and Safegaurd (4 farmers each; Zoetis and Intervet, respectively). While only 17 of study participants provided supplemental iron to their piglets, piglets on 7 of the remaining 8 farms were pasture raised and had access to dirt; the last two farms did not have piglets at the time of the study.

Table 3.4. Products farmers reported using on their farm in the 12 months prior to farm visit and survey completion.

Product Total % Farmers that have % Farmers that follow Farms used at least 1 in past all CTAHR year RecommendationsA,B Antimicrobial 15 56% C Vaccine 14 52% 11% Anthelmintic 17 63% 11% Wound Care & Topical 9 33% C MedicationD Iron 17 63% 63% Reproductive Hormones 4 15% C OtherE 7 26% C A Zaleski et al., 2009. BSeveral farmers almost follow all the listed CTAHR recommended practices. For example, five farmers reported deworming their herd according to recommended practices with the exception of deworming at weaning. C No recommendations D Topical medication included iodine-based sprays, scarlet oil, Mistral powder, and topical antimicrobial wound ointments EOther includes diarrheal medication, carob syrup, and vitamin supplements

On-farm sale of pigs was a common practice among the surveyed farmers, with 23 farmers (85%) having done at least one on-farm sale in the year they were surveyed. Of those 23, 6 farms had a market animal pen away from the rest of the herd, and 8 required buyers to either change into farm provided footwear or to use a footbath before entering the animal area.

Food waste was used as a source of feed on 20 of the 27 surveyed farms (Table 3.5). When asked, some participants stated that food waste was the more economical choice for their farms. On those farms that solely fed commercial grain-based rations, several participants indicated that their costumers and/or market contracts preferred pigs fed grain-based rations. Most farms that fed both a commercial diet and food waste would feed the commercial diet to the lactating sows and wean-offs while feeding the food waste to boars and market pigs.

Table 3.5. Feed and feed delivery on surveyed farms.

Number of Farms Percentage of Farms Main Source of Feed Grain-based ration 7 26% Food Waste 2 7% BothA 18 67% Feed Delivery to Farm Yes 5 19% No 22 81% ABoth denotes that both food waste and a commercial grain-based ration were fed to swine on that farm

Due to the nature of the open-sided barns found on farms, both farms that pasture-reared and those that confined their animals were unable to exclude all vermin (Table 3.6). Chickens, particularly feral, were the main vermin contact with domestic swine herds, as they were reported or observed on all islands except Moloka‘i. Additionally, while 5 farmers reported their herd had contact with feral swine, 8 farmers had observed feral swine near their farm. Three farmers reported that dogs present on their farm were used to hunt feral swine.

Table 3.6. Reports of vermin and their control methods on surveyed swine farms.

Type of animal contact with herd Number of farms Percentage of farms Rodents 12 44% Dogs 15 56% Cats 16 59% Chickens 17 63% Feral Swine 5 19% OtherA 19 70% Rodent Control Method Poison 9 33% Traps 5 19% OtherB 13 48% Feral swine control Fencing 16 59% Firearms 5 19% Snares 2 7% OtherC 8 30% AOther included cattle, sheep, goats, deer, ducks, turkeys, and other avian species BOther includes cats, mesh wire, and firearms COther includes guard dogs and motion activated lights

Flooring type varied among farms, and 15 farms had more than one type of flooring present. Slats or woven wire flooring was found on 14 farms, predominantly in the farrowing area. Concrete was the most common type of flooring as it was found on 22 farms. Pasture, defined as dirt, grass, and deep litter

41 flooring, was present on 13 farms, mainly used for open sows, boars, and market animals, although four farms solely pasture raised. Farrowing crates/pens were present on 19 farms, and 16 farmers reported cleaning and disinfecting them between use. Market animal pens were cleaned and disinfected between groups on 10 of 23 farms that had concrete or slats present. Daily manure removal from pens occurred on 12 farms. Six farms shared equipment with other farms, and three of those cleaned and disinfected before allowing the equipment back onto their farms.

Farmers were asked to list all symptoms seen on their farm in the 12 months prior to the date of the survey. Both participant-reported symptoms and those observed at the time of the farm visit were recorded (Table 3.7).

Table 3.7. Symptoms producers reported observing on their farms in the 12-month period before survey date.

Classification Symptoms Number of Surveyed Farms Reporting Symptoms Gastrointestinal Diarrhea 15 (56%) Vomiting Reproductive Reproductive failure 6 (25%)A Mastitis Respiratory Sneezing 6 (22%) Coughing Cutaneous Scratches/Abrasions 6 (22%) Sunburn General Lethargy 13 (48%) Off-feed Lameness Management/Other Management relatedB 5 (19%) OtherC AThree farms did not produce litters. n=24 farms BManagement related symptoms include mouth wounds due to overgrown tusks (1 farmer), high incidence of hernias (1 farmer), and irritated eyes due to air quality (1 farmer). COther includes neurological symptoms (2 farmers)

Open-Ended Survey Questions

When asked to rank “How important is biosecurity to you” (question 72) on a 5-point scale where 5 represented very important and 1 represented not very important, the mean response was 4.6 ± 0.7.

When asked to rank “How effective do you perceive your biosecurity practices to be” (question 73) on that same scale, the mean response was 3.4 ±1.0.

Answers given to question 74, “What is your most pressing farm concern”, were placed into 7 categories: disease management and biosecurity (10 farmers), farm maintenance and utilities (7 farmers), feed cost and supply availability (6 farmers), labor (5 farmers), a lack of knowledge (3 farmers), and marketing (2 farmers). A few participants (6 farmers) declined to comment. Farmers were allowed to give more than one response. Participant responses to questions 75 and 76 were specific to each individual farm and could not be generalized into categories. A full list of farmer responses to questions 75 and 76 can be found in Appendix E. Details that could lead to identification of individual farms were omitted.

Serology

Fifty-seven farms participated in the serology surveillance (Table 3.8). Serological samples were collected from 57 farms on all 5 study islands: Hawai‘i (9 farms), O‘ahu (26 farms), Kaua‘i (8 farms), Maui

(8 farms), and Moloka‘i (6 farms).

Serology results were mapped by region (Figure 3.2). Antibodies again PCV2 were found on all tested farms except one, and 34 farms were seropositive for both PCV2 and SVA (Figure 3.3). Of the 56 farms positive for PCV2, 4 reported using a circovirus vaccine at the time of testing. Only one PRRS positive farm reported using a PRRS vaccine at the time of testing, and no farms reported any vaccination for PED or SVA. Despite being present on 58% of farms tested, there were no clinical cases of SVA reported or noticed on any of the study farms. Clinical symptoms of PED, PRRS, and PCV2 were reported and observed on several farms that were found to be serologically positive.

Table 3.8. Number of tested swine and farms that were serologically positive for the four viral diseases of interest.

Viral Antibodies Seropositive serum Farms with at least one samples seropositive animal Porcine Circovirus Type 2 282 (68%) 56 (98%) Porcine Epidemic Diarrhea 78 (19%) 19 (33%) Porcine Reproductive and 22 (6%) 8 (16%) Respiratory Syndrome Senecavirus 164 (40%) 33 (58%) Total 414 samples 57 farms

Figure 3.2. Map of serologically positive farms by region. Based on Ogasawara, 2017. Map of Hawai‘i by Erik Gauger.

19 Farms 7 Farms: SVA: 18 SVA: 3 PCV2: 19 PCV2: 7 PRRS: 6 PEDv: 13 6 Farms PCV2: 5 8 Farms 8 Farms SVA: 4 SVA: 4 PCV2: 8 PCV2: 8 PEDv: 1 PEDv: 2 PRRS: 1

5 Farms SVA: 2 PCV2: 5 PRRS: 2 PEDv: 2

Abbreviations:

Senecavirus A (SVA)

Porcine Circovirus Type 2 (PCV2) 4 Farms Porcine Reproductive and Respiratory SVA: 2 Syndrome (PRRS) PCV2: 4 PEDv: 1 Porcine Epidemic Diarrhea Virus (PEDv)

Total Farms Surveyed: 57

Figure 3.3. Collective viral antibody presence on surveyed farms.

Parasite Detection

Forty farms participated in the parasite surveillance (Table 3.9). Samples were collected from 41 farms for endoparasite surveillance from all 4 counties: Hawaii (7 farms), Honolulu (19 farms), Kauai (7 farms), Maui (6 farms). Additionally, 27 farms provided samples for ectoparasite: Hawaii (1 farm),

Honolulu (15 farms), Kauai (6 farms), Maui (7 farms).

Twenty-seven farms (66%) had at least one endoparasite oocyst detected. Coccidia was the most widespread as it was detected on each of the 5 islands surveyed. Ascaris suum oocysts were found on 4 of the 5 islands. Ectoparasites were detected on 5 farms (19%) on O‘ahu, Maui, and Moloka‘i

(Figure 3.4). Endoparasite and ectoparasite results are mapped by geographical area (Figures 3.5 and

3.6, respectively).

Table 3.9. Endoparasites and ectoparasites identified on surveyed farms

Farms with at least one Oocysts detected Endoparasite positive animal (farms (total samples = 82) surveyed =38) Coccidia (Isospora suis, 38 (44%) 24 (63%) Eimeria spp.) Ascaris suum 8 (10%) 7 (18%) Metastrongylus spp. 3 (4%) 3 (8%) Strongyloides 7 (9%) 4 (11%) Trichuris suis 3 (4%) 3 (8%) Oesophogostomum spp. 17 (21%) 10 (26%) Farms with at least one Parasites detected Ectoparasite positive animal (farms (total samples = 45) surveyed = 29) Sarcoptes scabiei 1 (2%) 1 (3%) Haematopinus suis 3 (7%) 3 (10%) Unidentified mite species 1 (2%) 1 (3%)

Figure 3.4 Collective endoparasite presence on farm

Figure 3.5. Map of detected endoparasites by region. Based on Ogasawara, 2017. Map of Hawai‘i by Erik Gauger.

12 Farms Coc: 8 3 Farms Tri: 1 Asc: 1 Osp: 1 Coc: 1 Met: 1 Osp: 1 Tri: 1 7 Farms Asc: 2 3 Farms Coc: 5 Coc: 3 Osp: 2 Str: 1

7 Farms: 5 Farms Asc: 3 Asc: 1 Coc: 2 Coc: 3 Osp: 1 Osp: 5 Str: 1 Str: 2 Tri: 1 Met: 2

Abbreviations: 2 Farms Coc: 2 Ascarids (Asc)

Coccidia (Coc)

Metastrongylus (Met)

Oesophogostomum (Osp)

Strongyloides (Str)

Trichuris (Tri)

Total Farms Surveyed: 38 4

Figure 3.6. Map of detected ectoparasites by region. Based on Ogasawara, 2017. Map of Hawai‘i by Erik Gauger.

5 Farms: Neg 10 Farms Lice: 2 Mites: 1 2 Farms Lice: 1 6 Farms Unidentified Mite 5 Farms Species: 1 Neg

1 Farms Neg

Abbreviations:

Haematopinus suis (Lice)

Sarcoptes scabiei (Mites)

Total Farms Surveyed: 29

Disease and Biosecurity Scores

Disease score varied significantly among the 7 regions (ANOVA, n=57, p<0.001), with scores ranging from 0 to 10 (Table 3.10). Upon comparing the individual regions, there are significant differences between West O‘ahu and East O‘ahu (p<0.001), West O‘ahu and Maui (p<0.001), and West O‘ahu and

Moloka‘i (p<0.01). Additionally, there is a positive correlation between farm size by number of sows and disease score (r= 0.420, p=0.051).

Farms that were seropositive for PCV2 that vaccinate their animals against the disease were included in the disease score calculations. The disease score is not a measure of what was circulating on the farm at the time of sample collection, but instead it is a measure of exposure and risk. Farmers vaccinated because they observed symptoms associated with PCV2 and/or they were concerned about the disease.

Producer biosecurity scores not are correlated with farm size by number of sows (r=0.40, p>0.05) nor by region (ANOVA, n=27, p>0.05). Additionally, biosecurity score and disease score are not correlated (r=0.194, p>0.05).

Table 3.10. Disease and biosecurity scores by region and by number of sows.

Disease score Biosecurity score Number of Mean SD Number of Mean SD Farms Farms By Region East Hawai‘i 5 5.2 4.4 2 5.8 1.4 East O‘ahu 7 2.4 0.5 3 5.6 2.1 Kaua‘i 8 3.8 1.8 4 4.9 1.4 Maui 8 2.9 1.1 7 5.8 1.0 Moloka‘i 6 1.7 0.8 3 3.4 0.2 NW Hawai‘i 4 3.4 2.1 2 7.7 0.0 West O‘ahu 19 6.4 2.3 7 5.7 1.4 Overall 57 4.3 2.7 27 5.4 1.4 By Number of SowsA 0-10 11 2.6 1.6 11 4.9 1.6 11-50 9 4.7 2.6 9 5.9 1.2 >50 2 4.8 2.5 2 7.0 0.2 Overall 22 3.7 2.3 22 5.5 1.5 AThis calculation only includes farms that participated in both the disease surveillance and the management/biosecurity survey

CHAPTER IV DISCUSSION

The diversity of the study farms make it difficult to define a typical Hawai‘i swine farm. The wide array of farm sizes, management and biosecurity practices, and resources available to farmers have influenced each farm. One unifying factor is that Hawai‘i swine farms are individually owned; this is in stark contrast to most swine farms found in the continental United States. This absence of central control allowed farmers to manage their farms and personalize them to best fit their needs, resources, and ideal markets. Additionally, it influenced the diverse management and biosecurity practices recorded in this study.

Despite worry over aging farmers and declining farm numbers, a third of the survey participants had been farming for nine years or less. This aligns with the latest USDA census, which reported that

33% of Hawaii principal farm operators were beginning farmers with 0-10 years on their farm (USDA,

2014). Zaleski (2007) listed “bringing in new farmers” as a concern for the Hawai‘i swine industry, and noted land constraints and start-up costs as barriers for new producers. However, the large percentage of study participants that had entered the industry in the last nine years may indicate that individuals are overcoming these factors.

Surveyed farmers expressed that farm biosecurity was important to them, but farmers were inconsistent in implementing biosecurity practices on their farms. The causes behind this varied. Several farmers commented on this in the free response section. One reason is the variable market weights of pigs in Hawai‘i. Farmers sell pigs at the weight their customers desire, which ranges from small, 30 lb suckling pigs to adult animals. When asked, some farmers that had an earlier market weight decided not to vaccinate and/or deworm their animals because they either could not justify the monetary costs of buying vaccines for younger animals due to smaller profit margins, or their primary markets were for weights before a withdrawal time could be met. This was especially true on O‘ahu, as farmers are paid to pick up food waste; the more food waste they could pick up and feed to growing animals, the greater their profit. By selling young, vaccinated and dewormed animals, farmers lost income from food waste while concurrently increasing their costs.

Several farmers were also worried about alienating customers by imposing stricter biosecurity practices on their farm. As many farms rely on on-farm sales as the main way to market their animals, there was concern about customers going to farms where there were fewer “hoops to jump through”. To combat this, Cooperative Extension advocates constructing a market pen away from the main herd. This minimizes animal-customer interactions and limits the area where customers are allowed on a farm.

Additionally, farmers have been facing difficulties acquiring certain materials. As the number of swine farms have decreased in Hawaii, local feed stores have discontinued carrying several products for swine. If a needed vaccine is no longer available in local feed stores, farmers who want to vaccinate will either (1) not vaccinate, or (2) pay increased costs to ship the product from a supplier. One solution to this problem that was discussed involved developing a list of core products that farmers want and present it to local feed stores. Farmers will have a consistent supply of the products they need, and feed supply stores are able to provide products that farmers want and will buy.

Finally, farmers commented that while some of the practices were potentially valuable, many practices were not perceived as necessary. For example, most farmers believe in maintaining farm- specific footwear, but considerably fewer farmers held their clothing to that same standard. One farmer commented that several practices were “good ideas” and “should be done but [I] hadn’t gotten around to yet”. Casal et al. (2007) also reported this inconsistency between awareness and application of biosecurity and management practices on Spanish swine farms.

When asked what their most pressing concern was, farmer answers were spread over several categories. ‘Disease Biosecurity and Management’ received the most farmer comments; however, farmers responses might be biased as the survey highlighted management and biosecurity practices and could thus influence the farmers’ answers. There is overlap between this study’s farmer concerns and

Zaleski (2007). The task force listed marketing, costs, herd health, and producer education as industry weaknesses to be addressed.

Utilizing food waste as a feed source was common throughout the state, although attitudes varied between O‘ahu and the neighbor islands. On O‘ahu, county regulations mandate recycling food waste for some establishments (Revised Ordinances of Honolulu § 9-1.1, 1990). Farmers are paid to pick up food

51 waste for use on their farms, providing an economic incentive to utilize food waste as a feed instead of buying grain-based rations. The other islands do not have such ordinances, and several farmers reported that they had to pay for food waste. For many, there was still an economic advantage to buy and process food waste due to it being cheaper than commercial grain diets. Other farmers fed only grain-based diets due to customer demand.

Preweaning mortality of suckling pigs did not show any change between this study and Sharma,

1996, and both studies found the preweaning mortality rate to be double the 2012 USDA reported national value (USDA, 2015). In addition to being a welfare concern, preweaning mortality is an economic issue, as a decrease in pigs produced per sow can decrease potential profit, especially in operations that feed food waste. The high cost of grain-based diets that is typically fed to lactating sows is not offset by the income of picking up food waste to feed to growers and finishers.

It is generally accepted that by improving management practices, farmers can decrease their farm’s preweaning mortality (Vaillancourt et al., 1990; Muns et al., 2015). Farrowing crates/pens were prevalent on study farms, and although there was no significant relationship between farrowing crates/pens and preweaning mortality, other studies have shown that farrowing crate/pen usage decreases preweaning mortality rates (Muns et al., 2015). Other sources of preweaning mortality include infectious causes. Scours, or baby pig diarrhea, was widely reported throughout the islands, although farmers did not explicitly associate scours with high piglet loss; one exception to this was a PEDv-positive farm that participated in the study.

Animal movement between the study farms and islands was uncommon except for the movement of animals, typically breeding stock, from Kaua‘i to other islands. Farmers reported being aware of the associated risks of new animal introduction. However, approximately half (14/27) brought new animals onto their farm during the study period, but few (4/14) practiced on-farm quarantine. Some farmers that bought animals from a Kaua‘i farm felt that on-farm quarantine was unnecessary as Kaua‘i is accepted as being PRRS-negative and is therefore considered lower-risk. This could be due to the large-scale PRRS education and vaccination campaign that occurred in the mid-1990s during the initial PRRS outbreaks

(LeaMaster and Zaleski, 1994). This program raised awareness about the impact PRRS could have on a

52 farm while educating farmers on PRRS prevention practices. Future farmer education should include a more comprehensive approach to disease prevention and farm biosecurity. Heavy emphasis has been placed on PRRS education, and while PRRS is a potentially devastating disease that has a well- documented impact on the swine industry (Pejsak et al., 1997; Johnson et al., 2004), introduction of other bacteria, viruses, and parasites can also impact farmers.

Introduction of animals to Moloka‘i was limited to the occasional breeding animal or 4-H project.

Moloka‘i is a rural island with a small market, and the farmers that participated in the survey were focused on raising pigs for personal use or providing fresh pork for celebrations. This low rate of introductions from other islands and the low concentration of pigs present on Moloka‘i may have contributed to the low seroprevalence of antibodies against the study viruses even though the average biosecurity score for

Moloka‘i was the lowest of the seven regions.

By looking at the regional differences in disease detection across the state, the idea of island or regional biosecurity versus individual farm biosecurity comes to light. This can be seen in the disease score difference between West and East O‘ahu. There is very little movement of swine from West O‘ahu to East O‘ahu as Wai‘anae is considered by many to be a high disease risk area. That belief is supported by the difference in diseases scores. Additionally, East and West O‘ahu is separated by two mountain ranges, which may decrease the risk of aerosol and vector transmission between the regions. This natural barrier is a geographical boundary between the regions that may also influence disease transmission.

Regional biosecurity practices are often associated with disease eradication efforts (Olsen et al.,

2012; Arruda et al., 2017; Rathkjen & Dall, 2017) where surveillance testing and eradication of seropositive animals is employed. In Hawai‘i, regional control is associated with disease prevention. The main example of this is seen in the quarantine order that restricts animal movement to Kaua‘i until the animal’s PRRS seronegative status is established (HDOA, 2017a). The efficacy of the quarantine order is highlighted by the PRRS-negative samples submitted from Kaua‘i. This lends credibility to the quarantine order’s benefit in targeted disease prevention. In this case, a quarantine order for Moloka‘i could prove valuable in maintaining its PRRS and PEDv status.

PCV2 antibodies were detected on every study farm except one. This is a higher percentage of seropositive farms than detected in NIFA (2017). Coupled with the lack of reported symptoms, this could indicate that PCV2 circulates at low levels in pig dense areas across the state. Widespread seroconversion of swine maintains a low naïve population, thus mitigating large outbreaks which tend to be noticeable and reported quickly. Due to this, implementing large scale vaccination and control methods would be ineffective. Alternatively, maintaining herd seroconversion and immunity could control and minimize PCV2 spread (Maresca, 2006).

Unlike the circulating strands of Senecavirus in the North and South America, there have been no reported symptoms associated with the strain or strains present in the domestic swine on the study islands. Throughout this study, no farmers described the traditional snout or foot vesicles, nor were any symptoms noted by the researcher during farm visits. Moreover, HDOA has not recorded SVA vesicles or lesions from pigs on local hog farms, although SVA lesions were identified on swine shipped to O‘ahu from another island for slaughter (Travis Heskett, personal communication). This could indicate that the strain(s) present in Hawai‘i may be a different, lower pathogenicity strain than what is present in other areas where SVA positive pigs have been identified. Additionally, it is possible that clinical symptoms may only occur after a period of high stress, such as animal movement, as vesicles were noted after swine from a neighbor island arrived at the O‘ahu slaughterhouse and mixed with mainland imported hogs. As imported hogs may reside at the slaughterhouse for a week, it is possible that the SVA symptoms noted in the Hawai‘i origin pigs resulted from the SVA strain present in the imported hogs as the virus has a 4-5 day incubation period (Leme et al., 2017). Isolation and sequencing of the Hawaiian SVA strain(s) would be beneficial in determining the origin of the strain as well as providing insight on its relationship with other circulating SVA strains.

It would be difficult to determine if other known SVA symptoms, such as the increased preweaning mortality described by other researchers (Baker et al., 2016; Canning et al., 2016), were present due to the high preweaning mortality rates found across most study farms regardless of their SVA serological status. As many of the study farms did not keep records for breeding animals, an increase in

54 preweaning mortality may be overlooked or ascribed to other causes. This complicates accurately identifying SVA specific symptoms.

As the year and method of SVA and PCV2 introduction into Hawai‘i is unknown, the actual transmission path around the islands is uncertain. It is possible that SVA and PCV2 spread was assisted by asymptomatic animals. Asymptomatic animals and herds can decrease concerns over potential disease introduction, thus leading some farmers to believe on-farm quarantine of new animals is unnecessary.

In pig-dense areas, such as in West O‘ahu, the spread of disease is aided by the close proximity between farms. Many farms share a fence, and instances of pig to pig contact did occur among several study farms. Additionally, open-sided barns increase the changes that diseases that can be transmitted through aerosol or vectors, such as mosquitoes and flies, can be introduced onto a farm. Finally, transmission through fomites is an important concern that has been reported in several previous studies regarding PRRS, PEDv, and PCV2 (Otake et al., 2002b; Lowe et al., 2014; Madson et al., 2009). In these pig-dense areas, locations such as local feed and supply stores and their parking lots are potential areas for infectious fomites to move between farmers. This is one of the reasons that farmers are encouraged to use on-farm specific footwear.

In this study, all the tested Maui farms were serologically negative for PRRS. There was a sufficient number of samples taken from each farm to detect antibody presence if at least 30% of the tested herd was seropositive. As infected herds are reported to seroconvert at a rate greater than 30%, this was adequate to identify seropositive farms. However, Maui has been historically positive for PRRS as the European PRRS strain was detected on Maui in 1992 (LeaMaster and Zaleski, 1996). As only 8 farms were tested, it is possible that there are PRRS-positive farms that went undetected, especially if the

PRRSv only present in a small subset of Maui farms.

The majority of farms either had no parasite oocysts detected or only coccidia (22/39 farms). This may be indicative of effective anthelmintic use on Hawai‘i farms, as FDA approved dewormers can assist in controlling common gastrointestinal parasites of swine except coccidia. However, it cannot be determined if specific deworming practices on the tested farms are related to oocyst incidence as only 19

55 of the 41 tested farms participated in the management and biosecurity survey. Additionally, the tested breeding animals can build up immunity against endemic parasites (Roepstorff and Nansen, 1998), which could lead to negative samples and farms being false negatives.

Limitations and Future Opportunities

As this study was designed using convenience sampling, farmers that underwent HDOA surveillance in 2017 and 2018 became the main pool of participants. HDOA attempts to sample 25% of swine farmers throughout the state each year on a rotating basis. Therefore, approximately 50% of

Hawai‘i swine farmers were directly informed. Farmers that wanted to opt-in to the study that were not on the HDOA lists were encouraged to participate, but it is possible that some farmers throughout the state remained unaware of this project. Future studies should attempt to reach all Hawai‘i swine farmers in order to prevent sampling bias and increase the pool of potential participants.

Additionally, there were few farms that participated in all three components, leading to insufficient statistical power in some areas. This is partly due to monetary and time restraints. The researcher was able to accompany HDOA officials to farms during surveillance and administer the survey to willing farmers on O‘ahu and Kaua‘i. On Maui, Moloka‘i, and Hawai‘i, HDOA surveillance occurred at different times than the survey administration, and farmers appeared less willing to complete the survey portion after sample collection. If a similar project is done in the future, it is recommended to coordinate all components of the research into one farm visit.

The ear swab used in ectoparasite surveillance was determined to be an inadequate tool for diagnostic testing. Mange mites and lice were observed on several farms that were diagnosed as negative for either ectoparasite. For sarcoptic mange, the primary method for sample collection is a skin scraping that removes mite lesions from the ear (Greve & Davies, 2012). As mange mites burrow into outer skin layers, scrapings allow for better sample collection as swabbing only removes the outermost layer of exudate. Only one mite or louse was observed per positive farm, and in each instance the parasite was dead at the time of collection. As samples were collected by HDOA officials, an ear swab was the agreed upon method due to the low cost of supplies and the willingness of the officials to perform it.

There is an opportunity in Hawai‘i to create and implement regional biosecurity practices. Based on survey responses, it is evident that many farmers already consider disease risk to vary by region and have adjusted their farm practices accordingly, i.e. buying breeding stock from PRRS-negative Kaua‘i or using AI instead of purchasing replacement breeding stock. By formalizing regional biosecurity plans, such as implementing a quarantine order for Moloka‘i, new disease introduction can be minimized between regions. This is significant as disease presence appears to be spread evenly throughout each region. Creating region specific biosecurity plans is an important recommendation for future work.

Appendix A

2017-2018 Swine Health Survey

Farm Owner:

Premise ID:

Farm Address:

Email: ______

Phone Number:

Farm Code:

Date:

Appendix B 2017-2018 Swine Health Survey Consent Form

University of Hawaii’s College of Tropical Agriculture and Human Resources (CTAHR) Swine Extension Specialist (Dr. Halina Zaleski) and Veterinary Extension Associate Specialist (Dr. Jenee Odani) will be working with their graduate student (Brittany Castle), in coordination with the Hawaii Department of Agriculture’s (HDOA) Division of Animal Industry (DAI), to begin the development of a state-wide surveillance program to assess swine health and management practices in Hawai‘i. Information will be collected through a voluntary biosecurity and management survey during the Summer of 2017.

Project Description: Vaccination, treatment, and biosecurity recommendations must be based on knowledge of the severity and prevalence of diseases. A clear picture of swine disease patterns will enable the development of management and vaccination recommendations that can better target prevalent diseases, including:

1) Porcine Epidemic Diarrhea Virus 2) Seneca Valley Virus 3) Porcine Respiratory and Reproductive Virus 4) Porcine Circovirus 2 5) Internal and External Parasites

Activities and Time Commitment: If you choose to participate in this survey, it will be conducted at a time and location that is convenient for you. The survey is planned to take 30 – 45 minutes to complete. The majority of questions require yes/no answers, and questions will pertain to management practices, biosecurity practices, disease presence on your farm, and vaccinates and medications that are commonly used. Participation is voluntary, and you may refuse to participate at any time.

Benefits and Risks: There is no direct benefit to you for participating in this survey. The results of this project may help improve current management, biosecurity, and vaccination/deworming recommendations. There is no known risk involved in taking this survey, and you can be stopped at any point if you decide you do not want to complete the survey.

Confidentiality, Privacy, and Media Release: The surveys will be coded for confidentiality and the results will not be linked to you or your farm. All surveys and pictures containing participant information will be stored in a locked drawer that only Dr. Zaleski will be able to access. At the end of the project, the hard copies will be destroyed, and the digital copies will be password protected and kept for five years to assist in responding to farmer requests for farm improvement. Confidentiality will be maintained, unless disclosure is required by law.

Attached to the survey is a media release form concerning picture taking on your farm. You have the ability to agree to or deny independent of survey participation. If you agree, pictures taken will be used in industry publications, UH Mānoa classrooms, and in the graduate thesis defense. Pictures that could be used to identify you or your farm will not be taken, and you have the ability to review any pictures that may be chosen for use. The University of Hawai'i Human Studies Program has the right to review research records for this study.

Your cooperation in this study may help the University Extension faculty/agents understand the current state of swine health in Hawai‘i. This information may enable us to create herd health management programs that are sensible and effective and improve the health of Hawaii’s livestock. Any questions about this study can be directed to Brittany Castle at [email protected] or to Dr. Halina Zaleski at [email protected]. You may contact the UH Human Studies Program at (808) 956-5007 or [email protected] to discuss problems, concerns and questions; obtain information; or offer input with an informed individual who is unaffiliated with the specific research protocol. Please visit https://www.hawaii.edu/researchcompliance/information-research-participants for more information on your rights as a research participant. Please keep a copy of the informed consent for your records. Are you willing to be photographed: Yes / No

If you are willing to participate in this program, please sign below:

______Signature/date ______Printed Name

Appendix C

1. Introduction and Purpose: Biosecurity is the practices employed to prevent or minimize the introduction of infectious diseases onto a farm. It is also the steps taken to control the spread of pathogens within a specific farm. The procedures outlined in this document are intended to minimize the risk of disease transmission during swine farm visits in the state of Hawai‘i. These procedures apply to all Hawai‘i Department of Agriculture (HDOA) and University of Hawai‘i – Mānoa employees and students that make visits to swine farms. 2. General Requirements/Definitions: 2.1. Clean clothes, coveralls, and boots 2.2. Disposable coveralls (Tyvek®, DuPont™) and plastic boot covers (“booties”) 2.3. Virkon™ S Disinfectant or other approved, farm safe disinfectant 2.4. Disposable gloves (e.g., nitrile or vinyl) 2.5. Water container(s) for potable water 2.6. Pump sprayer for disinfecting large items 2.7. Long handle brush and bucket 2.8. Trash bag(s) – large and small 2.9. Disinfected container(s) for storage and transport 2.10. Hand Sanitizer 2.11. First aid kit 3. Policy or Procedure: 3.1. Before Farm Visit 3.1.1. Place small plastic trash bags under or beside each seat, one for each person that is performing the farm visit. 3.1.2. When farm gate is in sight, stop at a non-muddy area of the road. Place feet into plastic booties before stepping out of the vehicle. Spray vehicle tires with disinfectant that was premade in the pump sprayer. To get back into the vehicle, remove one foot from disposable bootie and place into car. Sit in the car. Remove the other foot from plastic bootie and place that foot into car. Dispose of the booties into trash bag. Try to perform this when there is no traffic. 3.2. During Farm Visit 3.2.1. Vehicle will be parked outside of farm gate when possible. If not possible, the vehicle should be parked away from pens and feed storage in a non-muddy area. 3.2.2. Open vehicle door. Place feet into disposable plastic booties before stepping out of the vehicle. Remove clean boots from vehicle. In one motion, remove one foot from plastic bootie, step into Tyvek® coveralls, and place foot into the clean boot, never allowing the foot to touch the ground. Repeat for other foot. 3.2.3. Finish putting disposable coveralls on and zip the suit up. Double glove hands. 3.2.4. Create disinfectant solution using Virkon™ S (or other farm safe disinfectant) and water. Disinfect boots and all applicable equipment (e.g. snares, sorting boards, etc.). 3.2.5. Perform farm visit. 3.2.6. Clean all supplies to remove all visible manure and other debris. Apply disinfectant to the items. Place the decontaminated item in a clean container or clean location inside vehicle. 3.2.7. When removing boots and disposable coveralls, unzip coveralls to remove arms and torso. In one motion, remove one foot from boot, pull that leg out of the coveralls, and place foot into the disposable bootie containing the original footwear. Repeat with other leg. Dispose of coveralls in trash bag along with the outer layer of gloves. Boots should be scrubbed with the long-handled brush with disinfectant before placing into the vehicle. 3.2.8. Clean and disinfect any containers that came into contact with the ground or gloved hands before placing into the vehicle.

3.2.9. To enter the car, see 3.1.3 3.2.10. Remove gloves from hands and dispose into trash bag. Sanitize hands. Close vehicle door. 3.3. Post Farm Visit 3.3.1. When leaving farm, the vehicle tires should be sprayed with disinfectant. Repeat procedure 3.1.3. 4. Other Related Policies/Forms: N/A 5. Revision History: N/A 6. References: 6.1. Levis, D.G., and R.B. Baker. 2011. Biosecurity of pigs and farm security. University of Nebraska- Lincoln Extension EC289. Lincoln, Nebraska, U.S. 6.2. Morley, P., Burgess, B., Van Metre, D., and B. Ouyang. 2015. Infection control and biosecurity standard operating procedures (SOP). James L. Voxx Veterinary Teaching Hospital. http://csu- cvmbs.colostate.edu/vth/diagnostic-and-support/biosecurity-and-infection- control/Pages/default.aspx. (Accessed 1 June 2017) 6.3. Zimmerman, J.F., Karriker, L.A., Ramirez, A., Schwartz, K.J., and G.W. Stevenson. 2012. Diseases of Swine 10 ed. Wiley-Blackwell, West Sussex, UK.

Appendix D

Categories Number Question Animal Movement/ 2 Have any of the following been introduced to the farm in the Introduction previous 12 months? 71 Quarantine questions (5 parts) Vaccinations/ 15 What piglet processing is done? (6 parts) Preventative Care 16 Are the nursing pigs vaccinated for anything 19 Are any vaccinations/medications given at weaning 20 Are pigs treated for worms or mange/lice? 21 Are any vaccinations given? 22 Are pigs dewormed? 23 Are pigs treated for mange/lice? 24 Are any vaccinations given prebreeding 25 Are any vaccinations given to pregnant sow? 26 At any point are breeding females dewormed? 27 At any point are breeding females treated for mange/lice? 30 Are any vaccinations given? 31 Are pigs dewormed? 32 Are pigs treated for mange/lice? Visitors/Sales 45 Do you allow visitors/buyers on the farm? 46 Are visitors/buyers asked to park off farm? 47 Are visitors/buyers asked to stay in a designated area when on farm? 48 Do visitors/buyers change to on-farm specific footwear? 49 Are visitors/buyers required to have a pig free period before they can enter the farm? 50 Are visitors/buyers asked to change into farm coveralls? 51 Do market hogs have their own area away from the main herd for sale? Nutrition/Delivery 55 If garbage feeding is done, is the garbage cooked for a minimum of 30 minutes at a full boil, or equivalent? 58 Is feed delivered to the farm? 60 Are delivery vehicles that come onto the farm disinfected before they enter? 61 Are deliver vehicles that come onto the farm disinfected after they leave? 62 Does the delivery driver exit the vehicle and walk on farm property? Management 7 Are you PQA plus certified? (Cleaning, record keeping, manure) 8 Does this farm have written vaccination and medication records? 29 Are sows washed before farrowing? 34 If a pig gets sick, is there someone that is regularly called? 35 Have you received help related to biosecurity or management from an extension agent or a veterinarian? 39 Are pens cleaned and disinfected between groups? 40 Is the farrowing crate/pen (if present) cleaned between groups? 41 What type of flooring is present in pens? 42 Is manure removed from the pens daily? 44 Do you have farm specific boots and clothes you wear when working with the pigs?

53/54 If farm equipment is shared with another farm? If yes, does the equipment get disinfected before it leaves and/or reenters your farm? Vermin 63 Are rodents regularly seen on the farm? 64 What rodent control methods are used? 65 Do other animals (pet or stray) have access to pigs or barn? 66 IF dogs are present, are they used to hunt feral swine? 67 Have any feral pigs been seen on the farm since 1/1/2017 68 What methods are used to deter feral swine? 69 Have any feral pigs come into contact or been suspected to have come into contact with farm pigs? Disease/Illness Gastrointestinal (diarrhea, vomiting) Symptoms 33 Reproductive (reproductive failure) 33 Respiratory (sneezing/coughing) 33 Cutaneous (excessive scratching/abrasions) 33 General (Lethargy, Off-feed) 33 Management/Other (lameness, other)

Appendix E

Farm Code Question 75: Workshops Question 76: General Comments General knowledge and disease Other farmers are the main source of K-001 information PQA plus Requested literature on hernias and K-004 guidance on hernia management More individual farm visits and by No comment M-002 Extension and Veterinarians None Questions about farm flooding M-005 management M-008 Anything No comment General knowledge and management Concerns on piglet care and processing. M-009 Expressed interest in literature M-010 No comment No comment M-011 General knowledge No comment M-007 None OmittedA O-001 No comment OmittedA Farm employee training and management; OmittedA O-003 general biosecurity planning with focus on practical applications O-004 No comment OmittedA O-005 Open to anything No comment Anything Requested updates from Hawaii pork O-019 industry O-012 General knowledge and disease OmittedA O-017 No comment OmittedA Farm Management and training on simple Requested information on dewormer MO-001 on-farm treatments properties of papayas MO-002 Anything No comment MO-003 Artificial insemination No comment O-022 Small scale health management No comment General knowledge and disease No comment O-023 management O-024 None; no interest in attending No comment H-008 Artificial insemination No comment H-009 No comment Food waste regulations H-010 Parasite identification No comment No comment Expressed interest in individual farm visits K-008 and by Extension and Veterinarians Marketing for small scale producers; No comment K-005 discussion of management styles and application on farms of varying sizes AOmitted responses are removed to prevent disclosing identifiable information that could link a specific farm or farmer to a study ID.

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