Zoonotic Risks of Agricultural Occupations

Principles and examples

 Julie Smith, DVM, PhD, University of Vermont Extension Dairy Specialist

 Used by permission of: Kelley J. Donham MS, DVM, DACVPM Department of Occupational and Environmental Health College of Public Health, University of Iowa Danelle Bickett-Weddle, DVM, MPH, PhD, DACVPM Associate Director, Center for Food Security & Public Health, Iowa State University

Kelley Donham 2009 What is your experience with zoonotic diseases?

Kelley Donham 2009 How do you say it?

1. Zoonosis (a) zō-ˈä-nə-səs (b) zō-ə-ˈnō-səs 2. Zoonoses (a) zō-ˈä-nə-ˌsēz (b) zō-ə-ˈnō-ˌsēz 3. Zoonotic ˌzō-ə-ˈnä-tik

Kelley Donham 2009 Overview

 What are zoonoses?  Who is at risk?  How are zoonoses transmitted?  How can workers protect themselves?  A few examples  Wrap up  Quickie quiz

Kelley Donham 2009 Zoonoses are diseases common to animals and humans.

There are over 200 zoonoses in the world.

About 40 are risks for agricultural workers in the US.

Kelley Donham 2009 Names can be deceiving!

Common Human Animal Term Dysentery Shigella spp. Brachyspira (swine) Typhoid S. typhi S. gallinarum Erysipelas Str. Erysipelothrix pyogenes Measles Host-specific Taenia virus saginata

Kelley Donham 2009 Zoonoses can be classified by major reservoir.

People (zooanthroponosis)

Vertebrate animal (anthropozoonosis)

Either (amphixenosis)

Kelley Donham 2009 Who is at risk for zoonotic diseases?

Photo by Julie Smith recreational occupational

Kelley Donham 2009 How many Vermonters have exposure to livestock? Livestock census (USDA NASS 2007)

10,000 beef cows 2700 pigs + 140,000 cows hobby farms

7000 farms

Few large production units; many backyard 50% of operators 14,000 flocks full-time sheep Kelley Donham 2009 What populations are at greatest risk?

Kelley Donham 2009 Populations at greatest risk . . .

Kelley Donham 2009

Vulnerable Populations: • Children • Lower immunity • Women • Abortion risk for Brucella, Q Fever, Listeria • Those lacking “herd

immunity” Kelley Donham 2009 Zoonotic risks depend on exposure

BEEF CATTLE: DAIRY CATTLE: POULTRY: Anthrax Brucellosis Histoplasmosis Rabies Q Fever Ornithosis Staph infection Ringworm

SHEEP: SWINE: RURAL ENVIRONMENT: Contagious ecthyma Leptospirosis Blastomycosis Q-fever Erysipeloid Viral encephalitis Toxoplasmosis Streptococcus suis Lyme Disease Tularemia Swine influenza Tetanus MRSA

Kelley Donham 2009 Emerging diseases are often zoonotic.

West Nile fever

Lyme disease

Hanta virus Bovine Spongiform Encephalopathy

Kelley Donham 2009 Humans are often dead end hosts for zoonoses.

West Nile fever

Lyme disease

Hanta virus Bovine Spongiform Encephalopathy

Kelley Donham 2009 An emerging swine zoonosis

 Hepatitis E  A human disease of concern primarily to pregnant women  There is a Hepatitis E virus of swine that can be isolated from the feces of infected swine  It can also be found in the environment in such places as surface waters  The importance of this disease and the risk of transmission from swine is not yet known

Kelley Donham 2009 Another emerging swine zoonosis

 Nipah Virus  In the spring of 1999, 100 rural persons died in a period of 4-5 days in Malaysia  The virus thought to cause the disease is called Nipah virus  The virus is transmitted through urine to humans  The true importance of the disease is not known at this time

Kelley Donham 2009 How often are zoonoses identified?

• Often they are not diagnosed • Sporadic rather than epidemic • Are maintained by aymptomatic carrier animals • Someone has to know to ask the right questions

Kelley Donham 2009 How are diseases transmitted?

 Inhalation  Ingestion  Direct contact  Animal-inflicted trauma  Vector-borne  Iatrogenic

Kelley Donham 2009 Diseases transmitted by:

 Ingestion

Many dairy farm owners and employees consume raw milk

Vermont dairies can sell up to up to 160 quarts per day (2-tiered system since 2009)

Kelley Donham 2009 Diseases transmitted by:

 Bacteria found in unpasteurized milk:  Listeria monocytogenes  Salmonella spp.  Campylobacter jejuni  Yersinia enterocolitica  E. coli O157:H7, Shiga-toxin E. coli  Other potential bacterial contaminants:  Brucella (Bang’s), Mycobacteria, Staphylococcus, Coxiella (Q fever)

Kelley Donham 2009 Diseases transmitted by:

 Fecal-oral route  Hand-washing facilities limited  Abundant exposure to manure  Salmonella, E. coli, Cryptosporidia, etc.  Diarrhea, nausea, vomiting  Abdominal pain and cramping  Dehydration, fever

Kelley Donham 2009 Diseases transmitted by:

 Direct contact  Ag workers rarely wear PPE  MRSA, contagious ecthyma (orf), dematophytosis, erysipeloid

Kelley Donham 2009 Diseases transmitted by:

 Bite wounds or wound infections  Rabies, Tetanus, other bacteria

Kelley Donham 2009 What steps can workers take to protect themselves?

Kelley Donham 2009 Steps workers can take to protect themselves.

 Understand the risks  Use appropriate PPE  Wash hands  Change clothes  Stay up-to-date with vaccines like tetanus and flu (rabies, in some cases)

Kelley Donham 2009 A sampling of zoonotic diseases

 Rabies  Leptospirosis/Weil’s Disease  Zoonotic Influenza  MRSA  Erysipelas/Erysipeloid  Q Fever  Lyme Disease

Kelley Donham 2009 Rabies (hydrophobia)

 Drooling  Convulsions, Excitability  Exaggerated sensation at the bite site  Loss of feeling in an area of the body  Loss of muscle function  Low-grade fever (102 F or lower)  Muscle spasms, Numbness and tingling  Pain at the site of the bite  Swallowing difficulty (drinking causes spasms of the voicebox)

Kelley Donham 2009 Rabies  Lyssavirus  Rhabdoviridae  Enveloped, bullet shaped RNA viruses  Viral amplification in brain, spinal cord  Destroyed by disinfectants, UV light, heat  Viable in carcass less than 24 hours  Longer if refrigerated  Does not survive in dried saliva

Center for Food Security and Public Health Iowa State University 2009 Kelley Donham 2009 Rabies worldwide (2013)

Kelley Donham 2009 Distribution of major rabies virus variants by reservoir animals, US and Puerto Rico, 2010

Blanton, et al. 2011 JAVMA: 239 (6) 773-783 Kelley Donham 2009 Reported cases of rabies in raccoons by county, 2010

Blanton, et al. 2011 JAVMA: 239 (6) 773-783

Kelley Donham 2009 Reported cases of rabies in bats by county, 2010

Blanton, et al. 2011 JAVMA: 239 (6) 773-783

Kelley Donham 2009 Rabies in cattle

 Separation from herd, aggression  Bellowing, hypersalivation, seizures  Anorexia  Pharyngeal paralysis often mistaken for “choke”, resulting in human exposure  Progressive paralysis, beginning with hindquarters

Kelley Donham 2009 Rabies in Vermont

 71 confirmed animal cases in 2009, 7 were cows or calves, 1 horse  63 confirmed animal cases in 2012, 1 cow and 1 sheep  Most cases skunks and raccoons, also bats and a few cats

Kelley Donham 2009 Rabies in Vermont

 56 confirmed animal cases in 2014, 1 cat, 2 bobcats  50 confirmed animal cases in 2013, 1 cow, 1 calf, 1 horse, 1 cat, 1 dog  Most cases skunks and raccoons, also a few foxes and bats

Kelley Donham 2009 How can workers avoid infection with rabies?

Kelley Donham 2009 Rabies questions?

 1-800-640-4374 (Vermont only) or 802-863-7240 Dr. Bob Johnson, State Public Health Veterinarian Monday through Friday, 8:00 a.m. to 4:30 p.m. Health Care Providers may contact Dr. Johnson 24/7 as needed.  The Department of Health is also responsible for the management of animals that may have exposed humans, assesses human and animal rabies exposure, coordinates rabies specimen testing and provides vaccination guidelines.  Rabies Hotline 1-800-472-2437 (800-4-RABIES) or 1-802-223-8697

Kelley Donham 2009 Leptospirosis

 Weil disease; Icterohemorrhagic fever; Swineherd's disease; Rice-field fever; Cane-cutter fever; Swamp fever; Mud fever; Hemorrhagic jaundice; Stuttgart disease; Canicola fever  Worldwide distribution in domestic livestock and wild animals  Spirochete bacteria, often present in surface water

Kelley Donham 2009

Kelley Donham 2009 Risk factors

 Reservoirs: Animals hosts, moist soils, streams and ponds  Mechanism of transmission: Direct or indirect contact with urine from infected animals, or handling an aborted fetus  Route of entry: Mucous membranes  Time/season: Mid to late summer

Kelley Donham 2009 Symptoms

 Usually asymptomatic  Range of symptoms: high fever, severe headache, chills, muscle aches, vomiting, jaundice, red eyes, abdominal pain, rash  Severe, acute, icteric form with liver and kidney damage: Weil’s disease

Kelley Donham 2009 How can workers avoid infection with leptospirosis?

Kelley Donham 2009 Influenza Virus

 Family Orthomyxoviridae  “myxo” means mucus  Three main types  Type A  Multiple species  Type B  Humans  Type C  Humans and swine

Center for Food Security and Public Health Iowa State University 2007 Kelley Donham 2009 Influenza A is the principal zoonotic strain

 Infects multiple species  Humans, pigs, birds, horses, others  Most virulent group  Classification by surface antigens into subtypes

Center for Food Security and Public Health Iowa State University 2007 Kelley Donham 2009 Influenza A

Center for Food Security and Public Health Iowa State University 2007 Kelley Donham 2009 Center for Food Security and Public Health Iowa State University 2007 Kelley Donham 2009 Interspecies transmission

Kelley Donham 2009 Novel H1N1 of 2009 aka “Swine Flu”

Kelley Donham 2009 Kelley Donham 2009 Kelley Donham 2009 Epidemiological aspects of swine influenza

 Swine influenza describes important respiratory pathogen of pigs  Type A, H1N1, H1N2 and H3N2 circulate in pigs  Component of “porcine respiratory disease complex”  Seasonal pattern overlaps with human influenza  As host to both avian and human strains, as well as swine strains, pigs can serve as “reassortment vessels”  Pigs CAN contract influenza from humans and humans from people (relatively close contact required)

Kelley Donham 2009 Epidemiological aspects of avian influenza

 Wild birds are the natural reservoir of all subtypes of influenza A viruses  Most infections subclinical in birds  Highly pathogenic strains (e.g., H5 or H7) can cause serious disease (death) in wild and domestic birds  2014-2015 US Avian Influenza outbreak  H5N2 and H5N8 (also found in captive falcons)  12/19/2014 – 6/17/2015 48 million birds affected  Many turkeys flocks, also pullets and laying hens  This influenza subtype considered a low risk to public health BUT CAUTION IS WARRANTED

Kelley Donham 2009 How can workers avoid infection with zoonotic influenza?

Kelley Donham 2009 Methicillin-Resistant Staphylococcus aureus (MRSA)  S. aureus typically causes skin and soft tissue infections

Kelley Donham 2009 Methicillin-Resistant Staphylococcus aureus (MRSA)  MSRA: resistant to penicillins and related beta-lactam antibiotics, cephalosporins  Modified penicillin-binding protein (PBP2a)  First reported as nosocomial pathogens  Rising prevalence, now considered “community associated”

Kelley Donham 2009 Genetics of MRSA

 PBP2a is encoded by mec2 gene  Carried by one of six Staphylococcus chromosomal cassettes (SCCs)  SCCs may carry genes for multiple antibiotic resistance as well as for Panton-Valentine leucocidin (PVL)

Kelley Donham 2009 Transmission of MSRA between humans and animals

 Companion animals tend to carry human-associated MRSA strains  “humanosis”  Strains associated with livestock  1972, Belgian milk cows www.thebellamossfoundation  Multiple reports since in pigs, sheep, chickens, rabbits, horses, cattle  As in humans, often associated with poor skin condition

Kelley Donham 2009 MRSA in swine

 Isolates found to be shared between swine and human caretakers  ST398 transmitted from pigs to pig farmers in Netherlands  Recent report estimates 70% prevalence in one Iowa swine unit while a 2nd unit in Illinois had no positive samples  Prevalence in sampled workers 64% at farm with colonized swine

Kelley Donham 2009 MRSA in cattle

 Reported MRSA isolated from cows with subclinical mastitis  27 of 375 SA isolated were MRSA  Throat sampling of 12 workers on farm found 1 MRSA  Human strain indistinguishable from that isolated from several cows  Direction of transfer not established

Juhász-Kaszanyitzky, et al. EID 2007: 13(4) 630-632 Kelley Donham 2009 How can workers avoid infection with MRSA?

Kelley Donham 2009 Erysipelas: “Diamond Skin Disease”

Kelley Donham 2009 Erysipelas / Erysipeloid  Erysipelothrix rhusiopathiae  Relatively common pathogen of swine, poultry (turkeys), fish  Commercial herds vaccinate or exclude  Survives well in environment: soil, fecal material, world-wide distribution  Erysipeloid in humans

Kelley Donham 2009 Infection in people typically on hand or foot

 Typically contracted by direct contact (occupational disease)  Swelling, painful  No suppuration  Violet-colored zone of erythema surrounding lesion  Joints of phalanges, tender limited movement  Axillary lymph nodes, swollen and tender

Kelley Donham 2009 More severe infections possible

 Also acute septic, chronic cardiac and arthritic forms  Confirmation: blood cultures  Endocarditis rare, but case- fatality rate reported >30%

Kelley Donham 2009 How can workers avoid infection with erysipeloid?

Kelley Donham 2009 Q Fever

 Coxiella burnetii  Rickettsia-like bacterium  Obligate intracellular parasite  Stable and resistant to heat, drying & many disinfectants  Killed by pasteurization  Bioterrorism agent: reportable in U.S. since 1999

Kelley Donham 2009 Historical  1935  1st described in Queensland, Australia  Found in ticks in Montana  Outbreaks  Among military troops when present in areas with infected sheep, goats or cattle  Cities and towns  Downwind from farms  By roads traveled by animals  50 – 60 cases/yr in U.S. (probably under- reported)

Kelley Donham 2009 Transmission

 Aerosol  Parturient fluids  Urine, feces, milk  Wind-borne  Direct contact  Fomites  Ingestion  Arthropods (ticks)  Person-to-person (rare)

Center for Food Security and Public Health Iowa State University 2009 Kelley Donham 2009 Case study

 Male dairy farmer, 46 years of age  Sudden onset of fever, chills, cough, weight loss  Initially thought it was influenza  Symptoms persisted for 2 weeks  Presented to emergency room  Again influenza was the diagnosis

Center for Food Security and Public Health Iowa State University 2009 Kelley Donham 2009 Case study (continued)  Referral to infectious disease specialist  Tested positive for Q fever  Antibiotics for 5 days  Resolved in 2 weeks  Epidemiology  No recent births on his farm  Two beef cattle herds across the road  2 out of 14 tested positive for Q fever

Center for Food Security and Public Health Iowa State University 2009 Kelley Donham 2009 Dairy survey

 EID April 2005  Evaluated bulk tank milk samples for prevalence  3 year period  316 samples; 19 states (most northeast)  >90% prevalence in bulk tank milk  No human disease information

Center for Food Security and Public Health Iowa State University 2009 Kelley Donham 2009 Milk transmission questioned

 Epidemiology and Infection 2006  Reviewed literature establishing pasteurization conditions effective against Coxiella burnetii and patterns of cases vs exposure

Kelley Donham 2009 How can workers avoid infection with Q fever?

Kelley Donham 2009 Small ruminants and human health concerns

 Coxiella  Brucellosis (Brucella ovis and melitensis)  Chlamydiosis (Chlamydia and Chlamydophila)  Toxoplasmosis (Toxoplasma gondii)  Vibriosis (Campylobacter spp.)

Kelley Donham 2009 Small ruminants and human health concerns: Brucellosis

 Brucellosis (Brucella ovis and melitensis)  Gram negative bacteria  Transmitted in placenta, fetus, fetal membranes, semen, milk  Consider if abortions and stillbirths seen  Rev-1 B. melitensis vaccine can cause disease in people

Kelley Donham 2009 Small ruminants and human health concerns: Chlamydiosis

 Chlamydiosis (C. abortus)  Considered Gram negative but difficult to stain  Transmitted by ingestion, aerosols, direct contact with mucous membranes  Consider if abortions and stillbirths seen  Recovered animals immune (or don’t abort) for several years

Kelley Donham 2009 Small ruminants and human health concerns: Toxoplasmosis

 Toxoplasmosis (Toxoplasma gondii)  Intracellular protozoan parasite  Life cycle: oocyst, tachyzoite, bradyzoite, tissue cyst  Animal (or human) becomes infected when eats un- or under-cooked meat or tissues containing tissue cysts  Can cross placenta in sheep and goats  Cats are the definitive host, generally asymptomatic

Kelley Donham 2009 Small ruminants and human health concerns: Vibriosis

 Vibriosis (Campylobacter spp.)  Gram negative curved or spiral rods  C. jejuni is predominant cause of sheep abortion in US  C. fetus also causes abortions, stillbirths, weak lambs in sheep  C. jejuni causes enteritis in humans; C. fetus is opportunistic pathogen in humans, causes septicemia

Kelley Donham 2009 What protective actions should people take?

Kelley Donham 2009 Steps workers can take to protect themselves.

 Understand the risks  Use appropriate PPE  Wash hands  Change clothes  Avoid needle sticks when vaccinating animals for Brucella

Kelley Donham 2009 Wrap Up

 What is a zoonosis?  A disease common to humans and animals.  We classify zoonoses by:  Etiologic agent  Associated human activity  Groups of animals involved  Direction of transmission

Kelley Donham 2009 Take home points

 General features of zoonoses:  Vague symptoms, may evade diagnosis  Often resolve spontaneously, seldom fatal  Animals are often subclinically infected (appear “healthy”)  Humans often an incidental host

Kelley Donham 2009 Take home points

 Prevention worth a pound of cure  Risk communication  Risk management

Kelley Donham 2009 Now a quick quiz

Kelley Donham 2009 Zoonoses are diseases common to animals and humans.