AFRICAN SWINE FEVER (ASF) ERADICATION CHANGE PROJECT IN SONGEA
MUNICIPAL, RUVUMA REGION OF TANZANIA
BY
SERIA MASOLE SHONYELA
2018
DR.SERIA MASOLE SHONYELA
Date
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ACKNOWLEDGEMENT Although this is not the end of the project, I am thankful to God for giving me wisdom and direction to start doing this change project. Thanks to Swedish government as the international training was supported by the Swedish International Development Cooperation Agency (SIDA) through International Training Program (ITP) to be the initiative of the change project and for the training they provided for us. I am very grateful to the Songea Municipal livestock professionals for their collaboration in this project. Thank you doesn’t seem sufficient but it is said withappreciation and respect for your collaboration. My special thanks to the municipal director and head of livestock department for allowing me to use the office for meetings and to let the training happen. I owe a great deal of appreciation and gratitude to Dr. Erika Chenais For her good coordination on the training in Sweden, friendly environment to work with us on training period in Sweden I pay tribute to my mentor Magdalena Jacobson I warmly thank for her valuable advice and her extensive discussions when I was in Sweden for the training. I am also very grateful for her scientific advice and pig knowledge and many insightful suggestions. It’s my pleasure to acknowledge all teachers/instructors for their constant moral support, teaching and providing the good knowledge to carry out for disease control some part of myresearch work. I am much indebted to the chair person and assistant chairperson of the ITP program. I wish to thank our respectable brother in Sweden, for caring and guiding us during the training, Uweis Nassor
I would also like to thank my colleagues from different countries in the region. The whole time of training was made happy, smooth, comfortable and easier with their presence and their questions.
Last but not least, I would like to pay high regards to my three children, my mother, sisters, for their sincere inspiration and taking care of my children.
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TABLE OF CONTENTS
ABSTRACT ...... Fel! Bokmärket är inte definierat.ii
ACKNOWLEDGEMENT ...... iiiii
TABLE OF CONTENTS ...... iiiiv
LIST OF TABLES ...... Fel! Bokmärket är inte definierat.vi
LIST OF FIGURES ...... Fel! Bokmärket är inte definierat.vi
CHAPTER 1 ...... Fel! Bokmärket är inte definierat.1
1.1. Introduction ...... Fel! Bokmärket är inte definierat.1
1.2. Objective ...... Fel! Bokmärket är inte definierat.5
CHAPTER 2 ...... Fel! Bokmärket är inte definierat.6
2.1. Materials and Methods ...... Fel! Bokmärket är inte definierat.6
2.1.1. Change projectstudy Area ...... Fel! Bokmärket är inte definierat.6
2.1.2. Subject 1 Coordination and management ...... Fel! Bokmärket är inte definierat.10
Outline of official arrangements ...... Fel! Bokmärket är inte definierat.11
2.1.3. Subject 2 Prevention, control and eradication models for ASFFel! Bokmärket är inte definierat.12
2.1.4. Subject 3Training and knowledge transfer ....Fel! Bokmärket är inte definierat.16
2.1.5. Subject 4 Pig and wild boar interactions relevant for ASF epidemiology ...... Fel! Bokmärket är inte definierat.38
2.1.6. Subject 5 Development of vaccine against ASFFel! Bokmärket är inte definierat.39
3. CHAPTER 3 ...... Fel! Bokmärket är inte definierat.20
3.1. Project Results: ...... Fel! Bokmärket är inte definierat.20
3.1.1. Subject 2 - Prevention, control and eradication models for ASFFel! Bokmärket är inte definierat.20
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3.1.2. Subject 3 Training and knowledge transfer ...Fel! Bokmärket är inte definierat.30
CONCLUSION ...... Fel! Bokmärket är inte definierat.35
RECOMMENDATIONS ...... Fel! Bokmärket är inte definierat.36
LIST OF APPENDICES ...... Fel! Bokmärket är inte definierat.42
Consent form ...... Fel! Bokmärket är inte definierat.42
Questionnaire ...... Fel! Bokmärket är inte definierat.43
REFERENCES ...... Fel! Bokmärket är inte definierat.51
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LIST OF TABLES Table 1. Pig population inSongea municipal from the years 2013 to 2018 ...... 710 Table 2 Results of the Questionnaire response symbolized as percentage on ASF Questions concerning: knowledge, awareness, preventive measures and disease guideline YES (green bars), DON’T KNOW (light green bars) and NO (red bars) as described in Table below ...... 2427 Table 3 Predictors of ASF on Questionnaire were pig management system, sex and Location 2428
LIST OF FIGURES Figure 1. A map showing the study area ...... 710 Figure 2. Songea Municipality ...... 711 Figure 3. Structure and the political organization of Songea municipal ...... 813 Figure 4. Administrative Organization structure ...... 1014 Figure 5. Pig management systems ...... 1317 Figure 6. Administration of questionnaires to the farmers ...... 1619 Figure 7. Interaction and training on control of ASF to the pig farmers and butcheries ...... 1922 Figure 8.practical training for meat inspectors and animal health professionals on how to do thorough meat inspections and on how to collect blood samplesfor laboratory testing...... 2023
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CHAPTER 1
1.1.Introduction
African Swine Fever (ASF) is a shocking disease affecting pigs caused by a complex virus member of the Asfarviridae family[1]. Disease transmission is maintained under different and complex epidemiological settings involving domestic and wild swine and arthropod vectors. Due to the fact that no vaccine has been obtained so far, prevention, control, and eradication of the disease is mainly based on the early detection and the implementation of strict sanitary measures. The disease is endemic in Sub-Saharan countries of Africa [2]. Since 1997, ASF was acknowledged in
Tanzania, Kenya, Zambia, Mozambique, Malawi and many other African countries where the spreading is out of control, causing a serious threat to African countries [1]. African swine fever is since 2012 the most important threat to pigs in the Ruvuma region (official unpublished documented). ASF outbreaks have been continuing in the different districts in Ruvuma region, causing severe economic losses for many pig farmers and pork producers (slaughters/ butcheries; official unpublished documents). In addition, the number of ASF cases in Ruvuma region has dramatically increased over the past few years and is at the moment present in four districts.
Evidence supports direct contact with infected pigs imported for slaughter that are kept in free- range management, and consumption of contaminated feed (i.e. uninspected pig offals and game meat), as the main transmission routes of ASF virus (ASFV) to domestic pigs. On the other hand, significant awareness gaps emphasize the vital need for research to investigate the importance of indirect transmission from the environment.This will provide an improved basis of knowledge on how to optimize current interventions and develop new strategies to reduce the risk of ASFV transmission to domestic pigs.
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ASFV can be preserved in domestic pigs through a pig-to-tick cycle, which does not involve warthogs, and a pig-to-pig cycle through direct contact between infected and susceptible animals
[3, 4]. Whilst the acute form of the disease is oftenseen in domestic pigs [5].
The importance of training and knowledge transfer of a devastating disease like ASF in domestic pigs has been recognized for many years since its first description in 1921 and was appreciated
1957 in Africa [6, 7]. Since acceptable circumstances concerning the control and prevention of
ASF is not yet accomplished in Africa, there is still spread of the disease in many countries. In this situation, the Songea municipality is at high risk of introduction of the disease by legal or illegal movements of animals and animal products, particularly through imported pigs (abattoirs). In order to design a rational eradication model that takes into account different risk situations, knowledge about the pig farming systems / pork meat production and contact pattern is mandatory.
Although ASF occurs mostly in Songea municipal, Songea district council, Mbinga district, in the
Ruvuma region it has recently spread in the Nyasa district (ITV news November 2018). The most important limitations in the control of the disease is the lack of disease reporting from the farmers to the professionals becauses of financial issues (compensation), insuffient biosecurity and the lack of an efficient vaccine to protect the pigs. For that reason, at present the control, prevention, and eradication of ASF is mostly depending on its timely detection and the achievement of strict hygienic measures. At the beginning of 2018, the pig population in the Songea municipality was estimated to almost 102870 (official document). High proportions are held at household’s backyards and in smallholder farms, which are more likely to have difficulties in accepting biosecurity measures. Ruvuma region are heavily reliant on pig as a monetary source and as a source of animal proteins because people living there are mostly Christians. The consumption of
2 pork accounts for 40 per cent of the meat consumed in the Ruvuma region and small-scale pork- meat production provides an important income for many young. The achievement of the campaign against ASF mainly rely on additional complementary actions and effective disease surveillance, for example raising awareness among small-holder farmers, permitting farmers and pork-meat producers to replace pigs with other animals, or shifting from animal husbandry to other kinds of farming such as the production of food or cash crops, and the achievement of social programs to counteract household losses.
1.2.Outbreak of ASF in Ruvuma regional
The first mortalities in what turned out to be the most shocking outbreak of African swine fever
(ASF) ever recorded in Ruvuma regional, with high mortality rates in Songea Municipal, Songea
District council, and Mbinga district, occurred in November 2017 to March 2018 among pigs that were free-range /tethered and/or housed indoors in small-holder pig farms. The disease killed at least 40% of the domestic pigs in Ruvuma region (in Songea Municipal, Songea district council,
Mbinga district, Nyasa and Madaba district; approximating 47,000 animals), resulting in the collapse of the pig farming and livestock sector. This outbreak in 2018 was not the first in the
Ruvuma region, and the presence of ASF had been diagnosed many times before. In each district, technical assistance from Tanzania ministry of livestock and fisheries had been requested to control the outbreak to make sure that it did not happen again, but usually this did not work as expected because of financial problems. Because of these previous experiences, hopefully this
“change project” on training pig farmers and butchery/middlemen in the region on how to report and control the diseases will help to eradicate the disease from the area. Aided by training, the
Songea municipality livestock sector is taking further steps to improve the diagnosing and control
3 of AFS. In the year 2018 the spread of ASF in Ruvuma region, including the Songea Municipality, has already led to serious socio-economic consequences to the pig farmers and livestock sector in the region; while the Ministry of livestock and fisheries has not taken serious steps to eradicate the disease. For that reason, pig meat markets are being negatively affected. The coverage of the spread of ASF in Ruvuma region remains doubtful due to the inadequate capacities of the official veterinary services and financial issues to quickly identify and confirm the disease.
The eradication of ASF will be achieved by designing more cost-effective surveillance programs and control strategies in different risk situations and by identifying risk factors for disease spread, such as infection by pig offals from the abattoirs, or by uninspected pig meat from neighboring regions or countries. Therefore the results of the project will help to prevent costly outbreaks, by advising farmers as stakeholders, and providing policymakers with valuable tools for decision- making, to better prevent and control ASF in the region.
1.3.Objective
In response to the threat of African swine fever spreading in the Ruvuma region, posed by its presence in Songea municipal and other three districts, the “ASF change project” aim to provide pig farmers, hunters, veterinarians and policy makers with practical answers and prevention knowledge to help control the disease. This “change project” will provide help to require the knowledge (reporting) that will support in the rapid control of the disease before spreading, and with other measures that allow for the early recognition and eradication of the disease. The aim of the “change project” is to develop prevention and control strategies of African swine fever in the
Songea Municipality and if possible also for the whole of the Ruvuma region.
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This “change project” will therefore contribute to estimate the patterns, causes and effects of the disease by developing control and biosafety measures by training and providing information on meetings concerning surveillance and control to farmers, butcheries and hunters on how imported pigs or game meat may transmit the disease during interaction with farmed pigs, and the potential role of ticks in spreading the disease.
The “change project” efforts developed and contributed to provide knowledge for preparedness in this evolving situation, including the gathering of i) Important knowledge to design new, cost-effective surveillance and control strategies for
ASF into different risk settings. ii) Data necessary to identify risk factors for designing new control strategies including
inspection of imported animals, wildlife considerations and inspections at the boarder.
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CHAPTER2
2.1.Materials and Methods
2.1.1. Change project study area
The change project was started in November 2018 and will continue to January 2023 or infinite until the eradication of the ASF in the Ruvuma region of Tanzania (Fig. 1 and 2), with the administrative structure as seen in (Fig 3 and 4). This district is one of the seven administrative districts of the Ruvuma region in Tanzania. It is the regional headquarter. It is situated in the middle of the region, with the Mbinga district and the Songea district council to the southern, Namtumbo and Tunduru districts to the eastern, the Madaba and Njombe districts to the northern, and the
Rudewa district to the western part of the region. The district lies between latitude-10.676803° S with GPS coordinates of (10° 40' 36.4908'' S), and longitude 35.655785° E with GPS coordinates of (35° 39' 20.8260'' E) and has an area of 3,811 km2, whereof 1,532 km2 is land and 2,279 km2 is water area such as e.g. rivers. Of the total land area, 961 km2 is used for agricultural activities.
The major economical activities in the Songea municipality are agriculture, livestock, and business, fishing in rivers and wells and small-scale mining. Most parts of the district receive between 1119.5 and 18000 mm mean annual rainfall, suitable for both food and cash crops. The number of livestock is considered among the highest in the Ruvuma region. Pig keeping is practiced by almost every household. The pig-human ratio, calculated as the proportion of pig farmers divided by the total number of households in the district, was 1:3, a point estimate for the year 2018 (Table 1). Pigs reared are mainly of the local breed, and the majorities are kept under tethering and/or a free-range condition depending on the season.
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Table 1. Pig population in the Songea municipality from the years 2013 to 2018
Year 2013 2014 2015 2016 2017 2018 Pig population 61984 49786 53213 63123 57234 57896
Other livestock kept include cattle, sheep, goats, donkeys, rabbits, and poultry.
Figure 1. A map showing the study area
Figure 2. Songea Municipality
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Source:Songea Municipal Planning Department.
Figure 3. Structure and the political organization of the Songea municipality
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Figure 4. Administrative Organization structure
2.1.2. Subject 1. Coordination and management
Coordination and management of the activities are carried out under the leader Dr. Seria Masole.
The scientific, non-scientific and technical work-plan of the “change project” was further divided into four subjects that were subdivided into work packages each with particular objectives to achieve the overall goals of the change project, as described below:
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2.1.2.1.Outline of official arrangements
Sufficient requirements for the “change project” may be estimated to a cost of about USD
($) 193500, which is not available at the moment. The project began in November 2018 and may end after 5 years or more, i.e. in October 2023. The Department of livestock and fisheries in the
Songea Municipality is responsible for the starting-up and for the first steps in the project, to attract financial support from outside the district, and will also be responsible for the execution under the project leader Dr. Seria Masole. Meetings ( i.e. meetings with farmers, butchery, and livestock professionals, municipal and regional meetings, and also reports to the Tanzania veterinary association workshop) were arranged to discuss on how to control the disease in the implementation of the programme. Awareness of ASF were improved at different levels by trainings and meetings, targeting pig farmers, hunters, animal health professionals/veterinarians, governmental and non-governmental agencies in the Songea Municipality. Knowledge developed within the project was disseminated through multiple information channels (posters, mass media i.e. churches, markets, and events i.e. funerals, wedding ceremonies). Outputs of this project provided policy makers with knowledge to better prevent and control ASF. Training and knowledge transfer on relevant aspects of ASF was conducted through:
i) The organization of meetings attended by around 60 farmers, 25 Butchery man’s, 22
animal health professionals including ward extension officers
ii) The distribution of posters and leaflets on ASF at different occasions i.e. markets,
churches, and other events i.e. funerals and ceremonies
iii) Production of an interactive training on ASF and pig posters on “ASF awareness” for
wide dissemination.
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2.1.3. Subject 2. Prevention, control and eradication models for ASF
Research work developed under this subject aimed to provide necessary information to plan for further cost-effective surveillance and control strategies of ASF in the municipality. This would reduce the economic losses in the different risk situations, by providing valuable information for policy-makers, administrations, veterinarians and pig farmers/producers.
The specific objectives of the work developed aimed to:
• gather data on pig farming and pork meat production systems in the Songea Municipality
and neighboring districts (i.e. Mbinga, Nyasa etc), as well as data of presence of risk factors
that could facilitate ASF introduction and/or spread, by administering a questionnaire to
the farmers and meat inspectors.
• replicate observed pig-trade networks to understand the mechanisms underlining the
organization of these networks, and to highlight the key differences between the pig
farming systems and pork-meat production in the Ruvuma region.
• evaluate /assess and accomplish cost-benefit analysis of the existing surveillance and
control strategies for ASF in the Songea municipality and on other districts namely in
Mbinga, Nyasa, Tunduru, Madaba and Namtumbo as endemic areas, and Njombe, Mbeya
and Iringa as regions at risk, and neighboring Mtwara region as free regions.
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Figure 5. Pig management systems
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2.1.3.1.House-hold questionnaire
A questionnaire with both closed and open-ended questions was administered to a member of the selected household after a given oral or written consent (Appendix 1) as shown in figure 6.
Questions included aspects of pig management and husbandry practices, possible transmission factors (e.g. source of feeds for pigs and awareness of ASF), the house-hold living conditions in terms of economical issues, backyard slaughter of pigs, inspection of slaughtered pigs,
14 consumption of pork, the presence of carcasses and slaughter waste for antemortem and postmortem inspections. Latitude and longitude coordinates of each household were recorded using hand-held global positioning system (GPS) receivers. During the interview, farmers who were present at the visit were educated on the main risk factors for infection and prevention measures for ASF (Fig 6).
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Figure 6. Administration of questionnaires to the farmers
2.1.4. Subject 3. Training and knowledge transfer
The work plan of this subject aimed to improve awareness of ASF at different levels and included training activities for pig farmers, hunters, butchery and animal health/veterinarians as shown in
16 figure 7 and 8. Comprehensive knowledge on ASFV, including understanding of the epidemiology, the pathology and clinical presentation of the disease is crucial for stakeholders of the Songea municipality but depends on the financial support. The training will continue in the other districts of the Ruvuma region at risk and in regions recently affected by ASF. They all need to be aware of their responsibilities and their role in preventing and combating the disease, as well as their options for effective prevention and control.
The project includes training for meat inspectors and butchery/middlemen on procedures preparing animal for transports, for example training on decontamination of vehicles, motorcycles, and bicycles prior to entering the animal house. People involved in pig transport and slaughter should not come in contact with animals or with farmers. If there is a need to be close to the domestic pigs, footwear should be changed, cleaned and disinfected, and the vehicles, motorcycles, and bicycles have to be cleaned and disinfected before and after every use. New animals from other places for keeping or for slaughter should be kept at different rooms for quarantine between 10 and 20 days. Animals should be ear-tagged and all animal activities recorded. Animal records such as births and deaths, and animal census should be recorded to allow follow-ups if there is an outbreak. To be put into effect, biosecurity-measure training, registration of visits, cleaning and disinfection procedures should be appropriately registered in an animal record book. Good disposal of manure in addition to dead animals, and no contact with domestic pigs from other places or neighboring pigs should be ensured.
The specific objectives of the work were:
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• to increase preparedness for ASF among animal health professionals/veterinarians, in
particular professionals working in the villages, boarders and with meat inspection in the
Songea municipality, the Songea district council and in the recently affected districts in
Nyasa and Mbinga.
• to organize and call for meetings/workshops and provide training for animal-health
professionals/veterinarians on the eradication of the diseases by referring to European
countries such as Sweden and some African countries such as Mozambique, to increase
risk awareness and capacity of incident response.
• to provide representatives of different governmental and none-governmental agencies in
the Songea municipality and in other districts at risk, through their participation in different
trainingoccasions and meetings/workshops, a stage to argue and apprise their current
prevention strategy and to modify contingency strategies / policies.
• to increase the awareness for ASF through investigations on the arrogance of all pig
farmers, butchery’s/middlemen and hunters concerning disease-reporting.
• to prepare and distribute material for disease knowledge/promotions concentrating on
farmers, butchery’s/middlemen and hunters in the Songea municipality and neighboring
districts like the recently affected Nyasa and Mbinga, and other districts at risk.
• Additionally, we distributed learning materials on different aspects about ASF (leaflets,
training meetings and posters on mass media such as in church, markets etc.) see the
appendix.
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Figure 7. Interaction and training on control of ASF to the pig farmers and butcheries
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Figure 8. Practical training for meat inspectors and animal health professionals on how to do thorough meat inspections and on how to collect blood samples for laboratory testing.
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3. CHAPTER 3
3.1.Change Project Results:
3.1.1. Subject 2. Organization of the project
3.1.2. Subject 2 - Prevention, control and eradication models for ASF
The investigations were developed in eight work packages, subdivided in several assignments aiming at the accomplishment of the subject objectives as described below:
3.1.2.1.Work package 1 - Characterization of the pig farming systems in the Songea
Municipality and other ASF-affected districts in the Ruvuma region
i. Summary of the objectives in work package 1
The aim of WP1 was to describe, evaluate and map the existing pig farming / pork meat production within all areas of the Songea municipality and the neighboring Songea district council.
ii. Summary of objectives and results of the assignments
The main objective was to gain better understanding of the factors that influence patterns and changes in pig trade in varying environments
• Assignment 1 included the collection and evaluation of data on pig husbandry farming with
indoor management system farms, especially in Songea town.
• Assignment 2 included the collection and evaluation of data on pig farming under free-
range and tethering management system farms, especially outside/surrounding the Songea
town
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• Assignment 3 included the assessment of pig husbandry management systems and
comparing of the productivity of the different management systems, price differentials as
driving force for trade and evaluation of ASF-potential risk factors for each
management/production types.
• Assignment 1 and 3 aimed at describing the pig farming and pork meat production
(benefits) in the Songea municipality and neighboring districts. In order to achieve this, the
Songea municipality, Songea DC, Nyasa DC and Mbinga DC, were selected as
representative examples of pig producers in the Ruvuma region.
• Assignment 1 was focusing on indoor pig husbandry management farms (backyard
farming) while “Assignment 2” was focusing on free-range and tethering management
farms. Assignment 3 aimed to evaluate the motivating forces in pig trade by conducting
systemic questionnaires to the pig farmers about pig husbandry management systems,
productivity, price differentials and other related factors.
Based on data collected by administering questionnaires, including questions about information on pig ownership, on pig holding and management, information on breeding management, bush pigs contact, trade issues and participation in exhibitions and auctions was also collected along with the questions asked by farmers during the training and farmers on site. The result showed that pig farming husbandry is characterized with regards to the municipality/district proximity, proximity to crop farmers, to forest, distance to other pig holdings, and aside to town (township).
The study further revealed that in the Ruvuma region, farmers have three types of pig management systems, free range (including tethering) and confinement as shown in figure 5; they alternate these systems depending on the season. Also the study showed that free-range husbandry system, age,
22 sex and location of the pig were significant determinants for ASF as shown in table 3. In addition the study showed that farmers, hunters, butcheries and politicians lack the knowledge about the disease spread/transmission especially with regard to the transmission dynamics of the virus, farmers do not see the need to keep pigs indoor as one way of preventing the disease in pigs as shown in table 2.
Concerning motivating forces in pig trade, outcomes indicated that driving forces significantly differed, depending on the pig-farming husbandry system and pork-meat production. In indoor pig-farming husbandry systems, animal trade was economically profitable good compared to free- range and tethering management systems because some customer butcheries were scared of porcine cysticercosis for free-range pigs.
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Table 2. Results of the Questionnaire response symbolized as percentage on ASF Questions concerning: knowledge, awareness, preventive measures and disease guideline YES (green bars), DON’T KNOW (light green bars) and NO (red bars) as described in the table below
Table 3. Predictors of ASF as given by the questionnaire were pig management system, sex, and location
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Predictors Point or rank Odds ratio (95% CI) P-value
Pig manag. F.r./T. 11.925 6.539 to 22.549 0.000
Conf. -
Sex Female 0.247 0.102 to 0.599 0.002
Male -
Divisions Songea town near the 10.207 5.091 to 22.472 0.000
city abattoir
Msamala 2.423 0.870 to 6.750, 0.09
Mateka out of the city -
centre
3.1.2.2.Work package 2 (WP 2). Characterization of contact between pig
populations through social network analysis
i. Summary objectives of the work package
The objective of WP2 was to evaluate the pig movements, and the structure of pig trade networks, and make a comparison of indoor and free-range or tethering farming.
ii. Summary of objectives and results of assignments
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• The first objective of assignment 1 and assignment 2 was to investigate the commodity
chain in order to evaluate pig exports and imports (consignment) between pig farming
areas, to the auction, or to the abattoir with the view to suggest possible factors that
would explain the observed choices of trading points.
• Assignment 1 commodity chain analysis evaluated the pig husbandry and movements
within and between pig farming in areas with indoor or backyard farming and free-range
or tethering farming.
• Assignment 2 aimed to understand the pig movements in areas with indoor/backyard
farming related to trade, with the vision to set hypotheses on probable factors that would
explain the observed options of trading.
Details of data collected by the questionnaire from all towns allowed the intense exploration of pig trade patterns and to describe the entire trade patterns between different farming systems.
3.1.2.3.Work package (WP 3) - Update on the epidemiological situation of ASF in
the Songea municipality
i. Summary of the objectives in the work package
The aim of WP3 was to update the epidemiological situation of ASF in the Songea municipality.
ii. Objectives and results of assignment
• Assignment 1 includes the description of the epidemiological situation in the Songea
municipality and to the neighboring districts based on sampling and identification of the
geographical spatial-temporal patterns (official documented data). In order to increase the
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knowledge about the epidemiological situation assignment 1 was focused on
epidemiological data obtained from official sources.
Due to the responses from the questionnaire, ASF is spreading from outside the Ruvuma region through the import of affected pigs from Mbeya and Malawi. Regarding the temporal patterns, the highest incidence of cases occurred from August to December. The lowest incidence was observed during the period from January to May. A low level of officially documented data on the association between bush pigs and domestic pig cases was found. A possible way to spread the disease could be by infected bush pig meat, since there was no evidence of interactions between bush pigs and domestic pigs in Songea or in neighboring districts, but hunters may bring bush pig meat into the area; however, the importance of this route of transmission in the spread of ASF in the Songea municipality is uncertain. Bush pigs has been involved in the spread of ASF both at local and trans-boundary levels in different areas of Africa, but in the Ruvuma region the spatial association for the relation between cases in domestic pigsis insignificant. In the Ruvuma region, the results showed that imported domestic pigs are the source of 95% of the outbreaks, as the response of the questionnaires shows that the disease usually starts in areas located close to abattoirs. Also, it was revealed from the responses obtained from the pig farmers that some animals did survive for more than a month and were able to recover from the infection. Taking this into consideration, endemic villages/towns have historically been located in the Ruvuma region where nearly 80% of the total outbreaks were concentrated. Areas where the virus is persistent, especially in recovered pigs, have been identified. The second way of ASF transmission could be as the result of certain socio-economic factors, mainly the illegal selling of uninspected meat, free-range pig breeding or the mingling of herds.
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3.1.2.4.Work package 4 (WP 4). Evaluation and cost-benefit analysis of existing
surveillance, contingency plans and control strategies in the municipality
i. Summary of the objectives in the work package
The aim of WP4 was to review and evaluate the historical and current surveillance and control
programs in the Songea Municipality
ii. Summary of objectives and results of assignments
• Assignment 1. Review and cost-benefit analysis of the surveillance and control
strategies for ASF in Songea
• Assignment 2. Review and cost-benefit analysis of the surveillance and control
strategies for ASF in the neighboring, affected districts i.e. Mbinga, Nyasa, an Songea
district council (official documents)
Assignment 1 and 2 reviewed the surveillance and control strategies for ASF in the Songea municipality and in neighboring, affected districts, and cost-benefit analyses were performed. The area is considered to be affected and at risk at any time point, thus the comparison of the surveillance and control programs were applied. Control measures gave detailed information about the situation in Songea and the neighboring, affected districts. A high number of farmers in
Ruvuma lacked knowledge on ASF, since the Ruvuma authorities have not invested efforts and resources for combatting ASF during the current years, and the results revealed a rapid spread of the disease in the region.
On the other hand, the legislation on ASF in the country is more stringent regarding the slaughter of animals in case of outbreaks and the postponement area for animal movement restrictions. The
28 effective implementation of these measures is always inadequate because of financial issues which leads to offences of the laws with severe consequences. There is a need for well-equipped veterinary services, and it is the necessary to compensate the pig farmers for the economic losses, as an incentive to enhance the prompt reporting of the disease.
• Assignment 3. Assessment of existing surveillance strategies and contingency plans in
Songea
The goal of the assignment 3 was to evaluate the existing surveillance strategies and contingency plans in Ruvuma region, since uniform and standardized disease-control requirements are difficult to achieve, since the livestock sector is heterogeneous. From a legal point of view, all livestock professionals (animal health professionals, non-animal health professionals such as animal scientists, agronomists) are equal and have to fulfil the same requirements related to ASF control and eradication. However, non-professional farmers or pork meat producers are often not under the full control of authorities. A great identified problem is wild animal meat-inspection since hunters sell and consume uninspected bush-pig carcasses, mainly those with invisible lesions. In
Ruvuma, the Veterinary Service does not perform any effective active or passive surveillance; furthermore, the number of veterinarians is insufficient, encountering less than 5 for all seven districts. Disease prevention and control is challenging due to the low levels of ASF awareness, low biosecurity, poor compliance of animal regulations, and lack of animal identification and traceability systems. There are no funds to investigate suspected outbreaks, neither any compensation.
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According to the official documents, during the outbreak Mbinga and Nyasa followed a similar early-detection program, mainly focusing on sampling of pigs located in high-risk areas.
Differences were found in terms of program coverage and techniques employed.
3.1.2.5.Work package 5 (WP 5). Dynamic disease modelling to identify key spread
mechanisms and quantify potential local spread.
i. Summary of the objectives in the work package
The aim of the WP5 was to develop an active model of the spread of ASF in the network of
pig trade (from WP2). Another objective was to better identify appropriate parameters related
to ASF epidemiology, counting transmission speeds and ASFV survival.
ii. Summary of objectives and results of assignments
• Assignment1. Improvement of disease spread model
• Assignment 2. Assessment of control measures
The work undertaken as part of assignment 1 aims at increasing the understanding of the
transmission process of ASF, in order to update simulation models that can be used to
standardize intervention measures. A second goal of this assignment was to investigate the
major local routes of transmission in outbreaks from 2016 to 2018 in the Ruvuma regions. The
objectives of assignment 2 was to summarize the epidemiological outputs of different
transmission simulations in the Songea municipality in order to be able to perform an economic
analysis, to approximate and associate the efficiency of different mitigation strategies for ASF
for each type of case, and to provide recommendations on how to modify the present
justification strategy, to maximize its effectiveness.
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The results suggested that spatial proximity to an infected farm was a strong risk factor for
infection of a susceptible farm because of poor biosecurity. Furthermore, occurrence of ASF
outbreaks in Songea was found to be positively associated with free-range management that
allow pigs to meet pigs from neighboring areas and the occurrence of uninspected meat from
neighboring countries i.e. Mozambique and Malawi, for example on funerals. Through the
development of disease-spread models, a risk-based surveillance strategy targeting farms that
are under free-range management could be considered as the most effective moderation
strategy.
3.1.2.6.Work package 6 (WP). Economic evaluation of different alternative for
disease spread and control scenarios.
i. Summary of the objectives of the work package
Work package 6 aims to develop a decision-support tool for the Ruvuma region, to identify
appropriate and cost-effective ASF prevention and control strategies under different scenarios
at risk.
ii. Summary of objectives and results of assignments
• Assignment 1. Cost-effective model for the assessment of different disease spread and
control situations
• The main objective of assignment 1 is to develop a cost-effective module to be combined
with the different economic outputs obtained.
By combining this work and all the knowledge that was generated as part of the project, assignment
1 also aims to make a decision that will allow identifying appropriate control strategies including
31 both surveillance and intervention strategies optimized for specific ASF risk situations, effective inspection of imported and on-transit pigs, good pig husbandry training and follow-up strategy. It was also shown that implementation of the alternative control strategies would be beneficial.
3.1.2.7.Work package 7 (WP).Guidelines for a cost-effective control and
prevention, including communication.
i. Summary of the objectives of the work package
The goal of WP7 is to produce a set of guidelines for cost-effective prevention and control of ASF, by incorporating the results obtained in the previous work packages (from 1 to 6).
ii. Summary of objectives and results of assignments
• Assignment 1.Guidelines for cost-effective prevention and control of ASF, including
communication.
The main goal of assignment 1 is to establish guidelines to prevent and control ASF, in view of two risk situations (free area and area at risk) in order to be cost-effective. Cost-effective strategies included a brief introduction about ASF, as well as a description of the current situation in Ruvuma.
Furthermore, main relevant results obtained from subject 1, which was focused on epidemiology, were gathered in these guidelines. Outcomes such as “pig farming system in Ruvuma”, “pig trade services in Ruvuma districts”, and “preventing and control strategies” were identified as the most effective and practical for the two risk scenarios (ASF-free setting and ASF-infected setting)
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3.1.3. Subject 3. Training and knowledge transfer
The work plan was developed under three work-packages subdivided in several assignments, aiming at the accomplishment of the subject objectives as described below:
3.1.3.1.Work package 1 (WP 1). Training and disease awareness of pig farmers,
butcheries and hunters in the Songea municipality
i. Summary of the objectives of the work package
The aim of this work package was to improve preparedness for ASF among pig farmers/producers in the Songea municipality, in particular in areas at risk, and in other recently affected districts in the Ruvuma region.
ii. Summary of objectives and results of the assignments
• Assignment 1. Investigate the attitude of pig farmers, butcheries/middlemen and hunters
towards disease reporting in the Songea municipality and in other districts in the region
recently affected or at risk. A questionnaire survey was developed by animal health
professionals / veterinary officers, to investigate the attitude and beliefs of pig farmers,
butcheries and hunters in Songea and other districts in the region towards reporting
suspected cases of ASF. The questionnaire results showed that most farmers would not
immediately report suspected cases because they believe that their reputation would be
negatively affected if they were to report it. Further, as no compensation is available, they
try to control the losses and outbreaks without the involvement of veterinary services.
Some also said that the laboratory confirmation would take too much time.
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• Assignment 2. Material for disease-awareness campaigns were developed in the Swahili
language and distributed in villages/areas at risk in the Songea and other neighboring
districts. the following topics were included:
- The etiological agent
- Geographical distribution
- Clinical signs and disease progress
- Virus transmission, dynamics and cycle
- What to do when facing a potential case, why and how.
The leaflet was prepared in English and translated into Swahili language (see appendix).It was distributed to all villages and abattoirs.
Further, a poster was designed and produced with key information on the “Change project”, and was presented at the municipal meetings, as well as all the trainings, meetings/workshops, and different scientific and nonscientific events across the municipality, that happened during the year.
3.1.3.2.Work package 2. Training and disease awareness of animal health
professionals
i. Summary of the objectives of the work package
The aim of this work package was to enhance the preparedness for ASF among animal health professionals / veterinarians, in particular in affected areas and areas at risk in the Songea municipality and in recently affected districts in the region. The objectives were to organize meeting/workshops, and to provide training for animal health professionals/veterinarians to increase the responsiveness and capacity of incident response.
34 ii. Summary of the objectives and results of the assignments
• Assignment 1. Training workshops on ASF was organized for pig animal health
professionals/veterinarians in the Songea Municipality and in the neighboring districts
(Mbinga, Nyasa and Madaba), recently affected by ASF.
The initially planned three workshops were organized as follows:
- Training workshop in Songea town held in November 10th 2018.The training aimed at
gathering animal professionals (livestock and wildlife), to review and discuss fundamental
and practical aspects of the disease namely those related to its prevention, control and
eradication. Twenty-four participants attended this workshop, all of them being livestock
and wildlife professionals. Twenty-four participants also attended the training meeting.
The participants were from all towns in the municipality and also veterinarians from the
neighboring districts Tunduru, Nyasa, Songea district council, and Madaba were invited.
- Training workshop in Songea town held on December 4th 2018. The participants consisted
of forty (40) pig farmers from different towns and 12 trainers’ (animal health professionals
and 2 veterinarians from Mbinga and Nyasa) attended the workshop.
- Training workshop in Songea town held on December 29th 2018. The participants included
12 Butcher/middlemen that attended the workshop. In total, more than 24 livestock and
wildlife professionals, >12 butcheries / middlemen and>40 farmers were trained during
these workshops. Each workshop consisted of a similar program with modifications
according to the professions of the participants.
By the end of the trainings, the invited animal health professionals / veterinarians were expected to:understand the pathogenesis and transmission routes of ASF; be familiar with risk factors for
35 the spread of ASF; be able to recognize a possible ASF case; have a broad idea on how the laboratory diagnosis is carried out and to be able to understand laboratory results; have an understanding of the risk for failure in the control of an ASF outbreak and its economical impact; and to be responsive to the overall epidemiological circumstances present, with particular focus on Tanzania.
The Speakers included “Change Project” coordinator (Dr. Seria Masole) as well as other trained experts from the department. All PowerPoint slides/presentations were made in the Swahili language, and translated into English (see below; appendix). Translation was available during the workshops whenever needed, for example concerning some untranslatable words. Feedback from participants indicated a successful dissemination to the Animal health professionals / veterinarians in the targeted regions, including practitioners as well as official animal health professionals / veterinarians from different administrative levels (village, district wards). The participants did not receive any certificate on completion of the training.
- Assignment 2. Advertisements type material on ASF was prepared and made available
through all mass-participation events (churches, markets, mosque, and funerals), allowing
farmers to learn more about disease outbreaks.
In this work package, the pig farming within the Ruvuma region and in ASF-affected areas in
Ruvuma was characterized by collected data on pig-farming systems and pork production.
Management systems and their impact on productivity and price differences were assessed. The imported pig movements within the municipality were estimated. This information was incorporated and used to determine the corresponding risk factors and to develop models to replicate the possible spread of ASF within and between the districts.
36
SUMMARY AND CONCLUSION
In summary, the following aims was set up:
All accomplishments mentioned above comprise significant advances in the knowledge on ASF situations and constitutes a basis for the development of further consistent control measures to fight ASF.
- To make necessary information, design additional cost-effective surveillance and control
strategies for ASF in different risk situations available and provide tools for policy makers,
administrations, pig producers and animal health professionals/veterinarians. The final
goal would be to prevent and control ASF to minimize the economical loses in endemic
areas.
- To provide the information necessary to recognize key points for designing innovative
control strategies. This will be accomplished by gaining more knowledge and
understanding of the transmission of ASF virus with its hosts.
- To improve the knowledge on the vector in particular the role of Ornithodoros soft ticks as
a secondary vector in the spread of the disease to domestic pigs in Poor, small-holder pig
farm farms.
In conclusion, Subject 2 aimed: to train farmers, hunters, and butcheries on how to control and eradicate diseases and transfer knowledge to improve awareness of ASF at different levels.
- To enhance the awareness of ASF among pig farmers, pork producers and hunters in the
Songea municipality and other districts in the Ruvuma region.
37
- To increase the preparedness for ASF among animal health professionals/veterinarians, in
the Songea municipality and in other, recently affected districts in Ruvuma region through
the organization of meetings/workshops and through the provision of training for animal
health professionals / veterinarians to increase risk awareness and capacity of event
response.
- To provide a platform for representatives of different non-governmental and governmental
agencies in the Songea and in neighboring districts at risk, to discuss and update their
prevention strategies and to adjust contingency plans.
To complete these objectives, a number of training workshops have been prepared to increase the risk awareness and capacity of immediate actions by pig farmers, hunters, butcheries, animal health professionals/veterinarians and representatives of the governmental agencies in response to incidents. This was coordinated by Dr. Seria Masole and other participants in the project, including members of the department of Livestock and fisheries in the Songea Municipality. Materials for disease awareness were developed and distributed in areas at risk in the Songea, in collaboration with animal-health government workers. In general and due to the results gained in the above mentioned areas, the “Change project” contributed with an appropriate approach to the sustainability and competiveness of the agri-food sector, and the Songea municipality added value in diverse features.
Overall, the “Change project” will contribute to a better awareness of ASF, by aiding to decrease the present and future socioeconomic consequences of the disease in the region.
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RECOMMENDATIONS
This project, requiring considerable expenses as well as technical input, is most unlikely to be achieved by the Songea Municipality alone. On the other hand, there are a number of other regions in the country that are confronted by the same problems related to ASF which are unique. There is therefore good reasons for the whole country to cooperate in finding a solution, ideally in association with international agencies able to assist e.g. SIDA, involving international donors and others with the potential to assist in ASF control. Tanzania Veterinary Laboratory Agency (TVLA) should have competence and capacity in the diagnosis and surveillance of viral diseases. If financial support is available, Restriction fragment-length polymorphism (RFLP) analysis at
Sokoine University of Agriculture or at Tanzania veterinary laboratory on some representative isolates of ASF virus will be conducted, to determine what genotypes are present.
An ASF outbreak in the region is limited and laboratory confirmations are performed outside the region. However, effective and efficient laboratory diagnosis of ASF is relatively complicated and this situation prevails in most African countries; it was therefore not in itself an indictment against the abilities of the virus laboratory within the Tanzania Veterinary Laboratory (TVL). In order to equip TVL to handle the present and future ASF outbreaks as well as to maintain effective surveillance, the laboratory will need to focus on optimizing the existing direct fluorescent antibody (FA) test for the detection of ASF viral antigens in tissues from infected animals, and on an indirect enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to ASF virus in the sera of pigs. To achieve this, there will be a need for financial support for salaries of laboratory staff and possibilities to train some of the existing staff in the department, because most of them are diploma holders and don’t know how to collect blood samples and lack knowledge on
39 proper storage. Financial support is also needed for one person to attend to the international training program in Sweden. Additionally, some equipment, such as -20°C freezer and -80°C freezer, as well as reagents and other laboratory equipment are needed, but for the moment no financial support is available for this purpose.
The training still remaining should be completed, including the drafting of a booklet on ASF for field workers; whoever does this should obtain the assistance of the project's national consultant.
The need for and objective of the envisage poster on ASF needs to be carefully considered, so that the outbreak may come to an end.
Funds for the equipment and reagents for ASF diagnosis and surveillance should be provided by funds from the government or any other source. At the moment there are no funds available. In the longer term, some arrangements should be reached with an international reference laboratory, ideally involving a range of strategically important animal diseases.
There is an increased requirement for knowledge concerning the epidemiological and molecular features of the currently circulating strains of ASFV in the Ruvuma region, with special regards to those present in the Songea, Mbinga and Nyasa districts. To address this need, funds for molecular typing of isolates is needed to integrate and to investigate the dynamics of the infection.
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LIST OF APPENDICES
Consent form
Title: An epidemiological survey of African swine fever, in Songea Municipal, Tanzania
Dr. Seria Masole Shonyela, a project coordinator, P. O. Box 14, Songea Municipal, Tanzania.
The study on learning how to do the project was sponsored by Swedish government under SIDA.
The continuation of the project is not financially sponsored. The participation of the study is non- payable but there will be an offer of bus fare and soft drinks to the seminar, ASF posters, and knowledge on good husbandry for your pigs.
The purpose of this questionnaire is to determine the factors of re-occurrences/prevalence of
African swine fever, also to assess how best you are aware of the disease, and to educate you the effect of the disease. If you have question feel free to ask as this is a discussion between me and you.
❖ I confirm that I have read and understood the information sheet for the above
research and I have had the opportunity to ask questions ( )
❖ I appreciate that my participation is helpful and that I am free to leave at any time
with no reason ( )
❖ I have the same opinion to take fraction in the above study ( )
❖ I agree to the interview consultation being in the audio recorded agree ( )
❖ I agree to the interview consultation being video recorded ( )
❖ I agree to the use of anonymised quotes in publications ( )
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Name of Participant Date Signature
Name of investigator at the area Date Signature
Questionnaire
Respondent (Interviewer) number ______house number/small town______
Date: ______
Division______Village______
Latitude ______Longitude ______No. of pig died for ASF: ______
Address
______
______
Phone number______
SECTION A: SOCIO-DEMOGRAPHIC
1. Name………………………………………………………………
2. Sex:
a) Male
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b) Female
3. Age in years:
a) 18-19
b) 20-30
c) 31-40
d) 41-50
e) Over 51
4. Educational status
a) Degree holder
b) Diploma holder
c) High School
d) Primary
e) No education
5. Occupation
a) Farmer
b) Student
c) No particular job
d) Employed
e) Daily Wage Earner
f) Others specify ______
SECTION B: FACILITIES OF RESPONDENTS HAVE
YES NO DON’T KNOW
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6. Do you own any Livestock? ( ) ( ) ( )
7. Do you keep pigs ( ) ( ) ( )
8. If your household does not have a pig, is there a reason ( ) ( ) ( )
If yes, please explain______
9. What other livestock do you keep Give the number Cattle____, Goat ____, Sheep ____,
Poultry _____, pigeon ______, Other specify______
10. Give the current number of pigs in the household by age and sex
Male Female TOTAL
Breeders
Piglets
Glowers
Fatteners
TOTAL
11. What management system do you use to keep your livestock
TICK WHERE APPROPRIATE
MANAGEMENT SYSTEM
LIVESTOCK Zero grazing Restricted grazing Free range Tethering
Pigs
Cattle
Shoats
Other specify
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YES NO DON’T KNOW
12. Do you ever purchase replacement pigs? ( ) ( ) ( )
13. If yes, from where?
______
14. Why are you keeping pigs (mark all those that apply)
a) Home consumption
b) Commercial
c) Security (as a bank)
d) Other (specify) ______
15. What is the source of your pig’s feeds
a) House hold left over (waste)
b) Neighbor left over (waste)
c) Scavenges around
d) Other specify______
16. What is the period of slaughtering or selling for butchery of your pigs______
SECTION C: HEALTH PROBLEMS OF PIGS, KNOWLEDGE, DISEASE AWARENESS,
AND WAYS OF TRANSMISSION AND PREVENTION
17. What are the most important troubles come across through pig rearing managing or disease
45
a) ______
b) ______
c) ______
d) ______
e) ______
18. How do you manage______
YES NO DON’T KNOW
19. Have you ever heard of disease called African Swine fever ( ) ( ) ( )
20. Where did you get the Information?
a) Health Institutions
b) Orally/Village
c) Radio/Mass media
d) Church
e) Public meetings
f) School/training
21. Do you know the factors cause African swine fever? ( ) ( ) ( )
22. If yes mention them
a) ______
b) ______
c) ______
d) ______
23. Do you know how African swine fever is transmitted? ( ) ( ) ( )
46
24. If yes what are the Ways of African swine fever Transmission
a) ______
b) ______
c) ______
d) ______
e) ______
25. You and other members of your household eat pork? ( ) ( ) ( )
26. If yes how often do you eat pork meat?
a) Daily, more than 3 kg
b) Daily, less than 3 kg
c) Weekly, less than 3kg
d) Rarely/Occasionally
f) Never
27. If yes, in what form?
a) Boiled
b) Fried
c) Roasted
d) Other (specify) ______
28. Where is the Source of pork?
a) Home slaughter
b) Butchery
c) Funerals
d) Other (specify) ______
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29. If the pigs are slaughtered at home, is the meat inspected? ( ) ( ) ( )
30. If inspected, by who?
______
31. Do you know of any infectious disease in pigs? ( ) ( ) ( )
32. Has any pig in your farm had fever or any clinical sign in the last one year? ( ) ( ) ( )
33. How do pigs acquire the disease/fever?
a) Eating raw or inadequately cooked blood/offal’s from abattoir
b) Eating House hold left over (waste)
c) Scavenges around
d) Other (specify) ______
34. How can you tell when a pig has fever/disease?
a) Skin with small red inflammation
b) Have no appetite
c) Blood in the feces
d) Weight loss
e) Other (specify) ______
35. Who would you consult if your pigs had fever?
a) Witch doctor
b) Veterinary doctor
c) Slaughter it for food/sell?
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d) Other (specify) ______
36. Have any of your neighbor pigs had African swine fever? ( ) ( ) ( )
37. If yes, when? ______(Year)
38. Do you know ways of preventing African swine fever
(Can African swine fever be prevented?) ( ) ( ) ( )
39. If yes mention the ways you know
a) ______
b) ______
c) ______
d) ______
40. Do you know type of disease reported to be caused
by African swine fever in pigs ( ) ( ) ( )
41. If yes mention the illness
a) ______
b) ______
c) ______
d) ______
42. Does your pigs indoor ( ) ( ) ( )
43. Is the free range management common in this village? ( ) ( ) ( )
44. If yes do the free roaming pigs eat the raw feed left over? ( ) ( ) ( )
45. Do you know any pig farm with African swine fever or before ( ) ( ) ( )
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46. If yes how is the family affected after the pigs started dying?
a) ______
b) ______
c) ______
d) ______
THANK YOU FOR YOUR HELP!
SECTION D: QUESTION TO PIG MEAT INSPECTOR EXPERIENCE OF DISEASE
YES NO DON’T KNOW
1. Do you have knowledge about African swine fever? ( ) ( ) ( )
2. If yes what is the guidelines of African swine fever meat in the country?
a) ______
b) ______
c) ______
3. Have you observed a pig with African swine fever
during meat inspection? ( ) ( ) ( )
4. If yes when you see measles in the meat what do you do with the meat?
5. How frequently do you see pigs with African swine fever during meat inspection?
a) Everyday
b) Once per week
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c) Three time per week
d) Once per month
e) Once per year
f) Not at all
THANK YOU FOR YOUR HELP!
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Leaflet given to the farmers
52
REFERENCES
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Africa. Virus research 2013, 173(1):228-246.
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#18 African Swine fever in Eastern Europe. 2018.
3. Brown VR, Bevins SN: A Review of African Swine Fever and the Potential for
Introduction into the United States and the Possibility of Subsequent Establishment
in Feral Swine and Native Ticks. Frontiers in veterinary science 2018, 5:11-11.
4. Laurence Vial BW, Ferran Jori,Eric Etter, Linda Dixon,and François Roger: African
Swine,Fever Virus DNA in Soft Ticks, Senegal 2007.
5. Spickler AR: African swine fever. 2015.
6. Rweyemamu MM: RECOGNIZING AFRICAN SWINE FEVER A Field manual.
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS 2000.
7. Penrith ML, Vosloo W, Jori F, Bastos AD: African swine fever virus eradication in
Africa. Virus research 2013, 173(1):228-246.
8. Van Effelterre T, Soriano-Gabarro M, Debrus S, Claire Newbern E, Gray J: A
mathematical model of the indirect effects of rotavirus vaccination. Epidemiol Infect
2010, 138(6):884-897.
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