Chapters 10.9

10.9 - Use of Peste des Petits Ruminants Virus (PPRV) Vaccines for Protecting Livestock of Smallholder Farmers in Africa

Henrique Sonsin, University of Guelph, Canada

Suggested citation for this chapter.

Sonsin,H. (2022) Use of Peste des Petits Ruminants Virus (PPRV) Vaccines for Protecting Livestock of Smallholder Farmers in Africa, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org

Introduction to PPRV and its Effects on Livestock

Peste des petits ruminants virus (PPRV) is a highly dangerous virus that is actively spreading in Africa, Asia, and Europe (Zhao et al., 2021). PPRV primarily affects sheep and goats, but it also infects cattle, camels, water buffalo, and various other wildlife species as well (Zhao et al., 2021). PPRV is one of the fastest expanding viruses that impacts sheep and goats (Baron et al., 2016), as sheep and goats can transmit the disease to other animals (Zhao et al., 2021). Typically, transmission occurs when healthy animals come into direct contact with animals that are infected with the virus (Baron et al., 2016). Once an animal is infected with PPRV, it is quite deadly as mortality rates from PPRV can be as high as 50-80% (Baron et al., 2016). This is especially harmful to smallholder farmers in poor nations as goats and sheep often serve as the main livestock for these farmers as they can more easily adapt to the harsh environments that come from poverty-stricken areas (Food and Agriculture Organization [FAO] & World Organization for Animal Health [OIE], 2016). As well, outbreaks of PPRV are common in Africa as a study found that there was a total of 4,961 outbreaks of the virus from 2015 to 2019 in the entire continent of Africa (Zhao et al., 2021). For these reasons, PPRV is a major concern for many smallholder farmers in Africa.

Introduction to PPRV Vaccines and their Benefits

The solution to PPRV can be found in the use of vaccines that work to prevent livestock from contracting the virus. The first vaccine developed specifically to prevent animals from being infected with PPRV was introduced in 1989 in the form of a live-attenuated vaccine named Nigeria 75/1 (Zhao et al., 2021). Live-attenuated forms of the vaccine are often used as they can provide lifelong immunity to the animals that receive it (Zhao et al., 2021). The current belief is that a sustained herd immunity rate, which refers to the number of animals protected against the disease, of 80% will be enough to completely eradicate the virus (Britton et al., 2019). It is for this reason that some non-governmental organizations, including the Food and Agriculture Organization of the United Nations (FAO) and the World Organization for Animal Health (OIE), are endorsing the PPR Global Control and Eradication Strategy, a project that has a stated goal to eradicate PPRV by 2030 (Zhao et al., 2021). These projects will involve mass vaccination of livestock to reach these high goals (Lyons et al., 2019). Eradicating this virus would be quite a substantial endeavour, as only one livestock virus in history, rinderpest, has ever been completely eradicated (Acosta et al., 2019). In terms of the efficacy of PPRV vaccines, which refers to the effectiveness of vaccines, a study found that in five trials with five animals testing two different vaccines, with additional data from previous studies on other vaccines, that each of the vaccines were effective in that none of the vaccinated animals had detectable levels of PPRV RNA in their blood (Hodgson et al., 2018). This study even showed that vaccines designed for specific strains of the virus were effective against all PPRV strains. This result shows that these vaccines are quite effective at preventing livestock from contracting PPRV (Hodgson et al., 2018).

Challenges and Solutions for PPRV Vaccines

Vaccine Storage

The first challenge that heavily restricts PPRV vaccine access to smallholder farmers is the storage requirement of vaccines during shipment from laboratories to farms. Appropriate storage of the vaccine is difficult to achieve as it requires cold chain facilities, which are locations that can maintain a consistently low temperature, as exposure to high temperatures may cause the vaccine to lose its potency (Acosta et al., 2019). This requires infrastructure that often does not exist in impoverished areas, such as reliable power grids and access to refrigeration. Because of this, access to vaccines is restricted from remote locations (Acosta et al., 2019). However, there is work being done to create a thermostable vaccine to help combat this (Mariner et al., 2017). This is being done using xerovac and lyophilization, two methods that involve freezing and dehydrating vaccine vials. Use of these methods can allow for vaccines to be outside of a cold chain for up to one month without losing their potency (Mariner et al., 2017). This will be very useful for getting vaccines to smallholder farmers in remote areas.

Farmer Awareness

The second challenge is the awareness that farmers have of the PPRV vaccine. Ensuring that farmers are aware of the vaccine is crucial to getting more livestock vaccinated. Based on a study from Nigeria, a majority of farmers stated they treat PPRV with herbal medicine (52%), with a minority of the farmers either using orthodox medicine (38%) or a combination of herbal medicine and orthodox medicine (10%) (Chukwudi et al., 2020). None of the respondents in the study used the vaccine to prevent livestock from being infected. This study also found that one of the primary complaints of veterinarians in Nigeria was that stored vaccines had expired (Chukwudi et al., 2020). What this shows is that when vaccines are available from veterinarians, there is still a lack of demand on the part of farmers to obtain them. In addition, farmer awareness of the vaccine also requires proper knowledge of not only what to do, but who to consult to vaccinate their livestock. Based on this study, a majority of the farmers who did use orthodox medicine (62%) did not consult with a veterinarian when deciding which treatments were best for their livestock (Chukwudi et al., 2020). Part of the solution to this is employing the use of mass vaccination campaigns through non-governmental organizations. This helps to get vaccines out to farmers and allows for farmers to become educated on the topic of livestock vaccines. A PPRV vaccination campaign in Mali was quite successful, as 89% of the farmers interviewed stated that they vaccinated their livestock during the campaign. This is partly due to the vaccination campaign’s ability to inform farmers of the benefits of the vaccines as well as provide them access to the vaccines (Zhao et al., 2021).

Need for Trained Veterinarians

It is important that vaccines are administered by trained veterinarians. This is because administering vaccines requires proper technique and know-how that can only come with adequate training. This can be seen in how, on average, 12.2% of attempted vaccinations fail due to improper administration of the vaccine (Lyons et al., 2019). This is typically caused by needles not being properly injected into the animal and instead being applied to the animal’s coat (Lyons et al., 2019). This failure ultimately leads to the potential for PPRV to spread and for money spent on vaccines to be lost. For this reason, it is vital that smallholder farmers consult with trained veterinarians when considering vaccinating their livestock.

Cost-Benefit Analysis

When it comes to smallholder farmers vaccinating their livestock, it is important to weigh the benefits of vaccination to the total cost of vaccination. In Ethiopia, it is estimated that the cost of vaccination per animal ranges from 3 ETB (Ethiopian Birr) to 6 ETB per animal, which is equivalent to $0.10 to $0.20 USD, depending on if the farmer is using a mixed-crop livestock system or a pastoral system (Lyon et al., 2019). This amount comes from factoring in the vaccine cost, transportation, storage, delivery, time, coordination, and publicity. From this study, it was found that delivery costs were the greatest component of the total cost in the pastoral system, while in the crop-livestock system, farmer’s time was the greatest expense (Lyons et al., 2019). This data shows that PPRV vaccines are a relatively inexpensive solution to this serious problem and that the potential benefits are huge in that around 70% of the rural poor in Sub-Saharan Africa are somewhat reliant on livestock as a source of income (Otte & Knips, 2005). As well, livestock help to provide income stability and labour as animals can assist in crop production (Otte & Knips, 2005). It is also important to consider that smallholder farmers in Sub-Saharan Africa on average have less than five Tropical Livestock Units (Rapsomanikis, 2015), in which one unit is defined as 250 kg of livestock weight (Rothman-Ostrow, 2020). This means that ensuring the health of livestock is critical to these farmers as the number of livestock they have is quite limited. All of this shows that PPRV vaccines are not only greatly beneficial to smallholder farmers but are also a relatively inexpensive solution to a major problem.

Additional Resources

https://www.ilri.org/publications/manuel-de-vaccination-contre-la-peste-des-petits-ruminants-pour-les-pays-sah%C3%A9liens-d A manual from the ILRI on PPRV and vaccines, including background on the virus, tips for obtaining vaccines, and what to do post-vaccination. The manual is in French.

https://www.youtube.com/watch?v=4XdDRTuGUgY A video on the effects of PPRV in Côte d'Ivoire with an examination into the benefits of the FAO’s projects to eradicate the virus. The video is in French, but subtitles in most languages are provided.

https://www.youtube.com/watch?v=RPd7nzQAf6I A video on PPRV vaccine production and vaccine administering in Cameroon. The video is in French, but subtitles in most languages are provided.

https://www.fao.org/3/x1703e/x1703e00.htm A manual by the FAO that explains the symptoms and diagnosis of PPRV

https://www.youtube.com/watch?v=ecAzIqkfBew A video on the effects of PPRV on smallholder farmers with instructions for what to do when it comes to treating animals infected with PPRV.

https://www.fao.org/3/i6316e/i6316e.pdf https://www.fao.org/3/I4477E/i4477e.pdf Two articles by the FAO that go into detail on their strategy to eradicate PPRV

References

1.Acosta, D., Hendrickx, S., & Mckune, S. (2019). The livestock vaccine supply chain: Why it matters and how it can help eradicate peste des petits ruminants, based on findings in Karamoja, Uganda. Vaccine, 37(43), 6285-6290. https://doi.org/10.1016/j.vaccine.2019.09.011

2.Baron, M.d., Diallo, A., Lancelot, R., & Libeau, G. (2016). Peste des petits ruminants virus. Advances in Virus Research, 95, 1-42. http://dx.doi.org/10.1016/bs.aivir.2016.02.001

3.Britton, A., Caron, A., & Bedane, B. (2019). Progress to control and eradication of peste des petits ruminants in the southern African development community region. Frontiers in Veterinary Science, 6, 343. https://doi.org/10.3389/fvets.2019.00343

4.Chukwudi, I. C., Ogbu, K. I., Nwabueze, A. L., Olaolu, O. S., Ugochukwu, E. I., & Chah, K. F. (2020). Update on peste des petits ruminants status in south east Nigeria: Serological and farmers' awareness investigation, and potential risk factors. Tropical Animal Health and Production, 52(6), 3285-3291. https://doi.org/10.1007/s11250-020-02359-7

5.Food and Agriculture Organization, & World Organization for Animal Health. (2016). Peste des Petits Ruminants Global Eradication Programme - Contributing to food security, poverty alleviation, and resilience. FAO and OIE. https://www.fao.org/3/i6316e/i6316e.pdf

6. Hodgson, S., Moffat, K., Hill, H., Flannery, J. T., Graham, S. P., Baron, M. D., & Darpel, K. E. (2018). Comparison of the immunogenicities and cross-lineage efficacies of live attenuated peste des petits ruminants virus vaccines PPRV/Nigeria/75/1 and PPRV/Sungri/96. Journal of Virology, 92(24), e01471-18. https://doi.org/10.1128/JVI.01471-18

7. Lyons, N. A., Jemberu, W. T., Chaka, H., Salt, J. S., & Rushton, J. (2019). Field-derived estimates of costs for peste des petits ruminants vaccination in Ethiopia. Preventive Veterinary Medicine, 163, 37-43. https://doi.org/10.1016/j.prevetmed.2018.12.007

8. Mariner, J. C., Gachanja, J., Tindih, S. H., & Toye, P. (2017). A thermostable presentation of the live, attenuated peste des petits ruminants vaccine in use in Africa and Asia. Vaccine, 35(30), 3773-3779. https://doi.org/10.1016/j.vaccine.2017.05.040

9. Otte, J., & Knips, V. (2005, November). Livestock Development for Sub-Saharan Africa (Research Report No. 05-09). Food and Agriculture Organization, Rome. https://www.fao.org/3/bp306e/bp306e.pdf

10. Rapsomanikis, G. (2015). The economic lives of smallholder farmers - An analysis based on household data from nine countries. Food and Agriculture Organization, Rome. https://www.fao.org/3/i5251e/i5251e.pdf

11. Rothman-Ostrow, P., Gilbert, W., & Rushton, J. (2020). Tropical livestock units: Re-evaluating a methodology. Frontiers in Veterinary Science, 7, 556788. https://doi.org/10.3389/fvets.2020.556788

12. Zhao, H., Njeumi, F., Parida, S., & Benfield, C. T. O. (2021). Progress towards eradication of peste des petits ruminants through vaccination. Viruses, (59). https://doi.org/10.3390/v13010059