Epidemiology and control of peste des petits ruminants in East and West Africa

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    Willingness to vaccinate and willingness to pay for vaccination against peste des petits ruminants in northern Senegal
    (Journal Article, 2024-06-26) Ilboudo, Guy S.; Wanyoike, Francis N.; Bahta, Sirak T.; Sy, S.; Djigo, C.A.T.; Sall, P.A.; Lô, M.M.; Dione, Michel M.
    Background: This study was carried out in Linguere department, Louga region of Senegal. Its objective was to explore the socio-economic factors that influence small ruminant producers’ decisions on vaccination against peste des petits ruminants. Methods: We carried out a willingness to vaccinate and willingness to pay for vaccination using a choice experiment approach with 200 small ruminant producers. Results: Results showed that the key factors that influence willingness to vaccinate, include perceived benefits of vaccination (98, 95%CI: 96–100%), the type of vaccinator (91, 95%CI: 87–95%), the access to information (86, 95%CI: 81–91%), the vaccine availability (80, 95%CI: 74–86%), and the possession of a vaccination certificate by the producer (76, 95%CI: 70–82%). Preferences of producers leaned toward home vaccination (preference weight = 0.74, p = 1%), individual herd vaccination (preference weight = 0.45, p = 1%), elective participation to vaccination (preference weight = 0.33, p = 0.01), and low-cost services (preference weight = −0.004, p = 0.1). Producers expressed a willingness to pay for vaccination per animal of XOF 184 (USD 0.3), XOF 113 (USD 0.18), and XOF 82 (USD 0.13) for home, individual herd, and elective vaccination, respectively. Conclusion: The findings underscore the importance of targeted awareness campaigns and bringing vaccination services closer to the producers.
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    Economic impact of peste des petits ruminants on small ruminant production in Senegal: Gender considerations within a system dynamics modelling approach
    (Journal Article, 2024-05) Aboah, Joshua; Campbell, Zoë A.; Dione, Michel M.; Kotchofa, Pacem; Ilboudo, Guy S.; Wieland, Barbara; Lo, M.M.; Rich, Karl M.
    CONTEXT Peste des petits ruminants (PPR) remains a persistent challenge for small ruminant production in Senegal, leading to economic losses for livestock keepers. Gender dynamics and socio-cultural factors influence production decisions at the household level. Despite its relevance, economic impact models of PPR have not incorporated gender dynamics. OBJECTIVE This paper seeks to redress this gap by disaggregating the farm-level impacts of PPR based on the gender of the household head and implementers of routine and management activities in small ruminant production at the household level. METHODS To quantify the gendered economic impacts of PPR, a system dynamics model was developed with four modules: integrated production-epidemiology, economics and profitability, disease control, and marketing. The model was parameterised based on survey data from 747 households in 49 agro-pastoral and pastoral villages in Senegal and augmented by secondary data. The model was validated (structurally and behaviourally) and simulated for 30 years with a weekly timestep. A set of disease scenarios were run for ten different farm household typologies based on the gender of the household head and household members who perform production management activities (like purchasing, selling, gifting, and vaccinating animals) and routine activities (like feeding, cleaning pens, and caring for sick animals). RESULTS AND CONCLUSIONS Model results estimated annual reductions in farm profitability of 51% to 61% with a hypothetical 25% incidence rate of PPR, corresponding to an average of $1051 to $1246 USD lost per household per year. In the two most impacted household typologies, management activities were performed by either men only or women only, and in the three least impacted household typologies, management activities were shared by men and women. The least impacted household typology with the highest gross margins without PPR ($2429 USD per year) and the lowest percentage of loss (51%) was female-headed households with men and women doing management tasks and primarily women or girls doing routine activities. SIGNIFICANCE Households with both women and men engaged in management activities were less impacted by PPR, highlighting the crucial role of women's agency in management decisions taken in small ruminant production at the farm level. The findings further provide the empirical grounding for considering gender dynamics in interventions to control PPR and other livestock diseases in small ruminant production systems.
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    First report of the emergence of peste des petits ruminants lineage IV virus in Senegal
    (Journal Article, 2024-02-17) Ba, A.; Diop, G.L.; Ndiaye, M.; Dione, Michel M.; Lo, M.M.
    Peste des petits ruminants (PPR) is a highly contagious viral disease and one of the deadliest affecting wild goats, sheep, and small ruminants; however, goats are generally more sensitive. The causative agent is the Peste des Petits Ruminants virus (PPRV), which is a single-stranded RNA virus of negative polarity belonging to the Paramyxoviridae family. In February 2020, an active outbreak of PPR was reported in a herd of a transhumant farmer in the village of Gainth Pathé (department of Kounguel, Kaffrine region, Senegal). Of the ten swabs collected from the goats, eight returned a positive result through a quantitative real-time PCR. The sample that yielded the strongest signal from the quantitative real-time PCR was further analyzed with a conventional PCR amplification and direct amplicon sequencing. A phylogenetic analysis showed that the sequence of the PPR virus obtained belonged to lineage IV. These results confirm those found in the countries bordering Senegal and reinforce the hypothesis of the importance of animal mobility between these neighboring countries in the control of PPRV. In perspective, following the discovery of this lineage IV in Senegal, a study on its dispersion is underway throughout the national territory. The results that will emerge from this study, associated with detailed data on animal movements and epidemiological data, will provide appropriate and effective information to improve PPR surveillance and control strategies with a view to its eradication.
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    Molecular epidemiology of peste des petits ruminants virus in West Africa: Is lineage IV replacing lineage II in Burkina Faso?
    (Journal Article, 2024-02-03) Biguezoton, A.S.; Ilboudo, Guy S.; Wieland, Barbara; Sawadogo, R.W.-Y.; Dah, F.F.; Sidibe, C.A.K.; Zoungrana, A.; Okoth, Edward A.; Dione, Michel M.
    This study aimed at investigating the genetic lineages of peste des petits ruminants virus (PPRV) currently circulating in Burkina Faso. As part of PPR surveillance in 2021 and 2022, suspected outbreaks in different regions were investigated. A risk map was produced to determine high-risk areas for PPR transmission. Based on alerts, samples were obtained from three regions and all sampled localities were confirmed to fall within PPR high risk areas. We collected swab samples from the eyes, mouth, and nose of sick goats. Some tissue samples were also collected from dead animals suspected to be infected by PPRV. In total, samples from 28 goats were analysed. Virus confirmation was performed with RT-PCR amplification targeting the nucleocapsid (N) gene. Partial N gene sequencing (350 bp) was carried out using the RT-PCR products of positives samples to characterise the circulating lineages. Eleven sequences, including ten new sequences, have been obtained. Our study identified the presence of the PPRV lineage IV in the three studied regions in Burkina Faso with a genetic heterogeneity recorded for the sequences analysed. Previously published data and results of this study suggest that PPRV lineage IV seems to be replacing lineage II in Burkina Faso.
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    Small ruminant keepers’ knowledge, attitudes and practices towards peste des petits ruminants and its control in West Africa: Case studies from Burkina Faso, Mali and Senegal
    (Presentation, 2023-11-30) Ilboudo, Guy S.; Biguezoton, A.S.; Sidibé, C.A.K.; Lo, M.M.; Campbell, Zoë A.; Dione, Michel M.
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    Small ruminant keepers’ knowledge, attitudes and practices towards peste des petits ruminants and its control in West Africa: Case studies from Burkina Faso, Mali and Senegal
    (Poster, 2023-11-29) Ilboudo, Guy S.; Biguezoton, A.S.; Sidibé, C.A.K.; Lo, M.M.; Campbell, Zoë A.; Dione, Michel M.
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    Ex-ante impact of peste des petits ruminants control on micro and macro socioeconomic indicators in Senegal: A system dynamics modelling approach
    (Journal Article, 2023-07-05) Aboah, Joshua; Apolloni, A.; Duboz, R.; Wieland, Barbara; Kotchofa, Pacem; Okoth, Edward A.; Dione, Michel M.
    Vaccination is considered as the main tool for the Global Control and Eradication Strategy for peste des petits ruminants (PPR), and the efficacity of the PPR-vaccine in conferring long-life immunity has been established. Despite this, previous studies asserted that vaccination can be expensive and consequently, the effectiveness of disease control may not necessarily translate to overall profit for farmers. Also, the consequences of PPR control on socioeconomic indicators like food and nutrition security at a macro-national level have not been explored thoroughly. Therefore, this study seeks to assess ex-ante the impact of PPR control strategies on farm-level profitability and the socioeconomic consequences concerning food and nutrition security at a national level in Senegal. A bi-level system dynamics model, compartmentalised into five modules consisting of integrated production-epidemiological, economics, disease control, marketing, and policy modules, was developed with the STELLA Architect software, validated, and simulated for 30 years at a weekly timestep. The model was parameterised with data from household surveys from pastoral areas in Northern Senegal and relevant existing data. Nine vaccination scenarios were examined considering different vaccination parameters (vaccination coverage, vaccine wastage, and the provision of government subsidies). The findings indicate that compared to a no-vaccination scenario, all the vaccination scenarios for both 26.5% (actual vaccination coverage) and 70% (expected vaccination coverage) resulted in statistically significant differences in the gross margin earnings and the potential per capita consumption for the supply of mutton and goat meat. At the prevailing vaccination coverage (with or without the provision of government subsidies), farm households will earn an average gross margin of $69.43 (annually) more than without vaccination, and the average per capita consumption for mutton and goat meat will increase by 1.13kg/person/year. When the vaccination coverage is increased to the prescribed threshold for PPR eradication (i.e., 70%), with or without the provision of government subsidies, the average gross margin earnings would be $72.23 annually and the per capita consumption will increase by 1.23kg/person/year compared to the baseline (without vaccination). This study’s findings offer an empirical justification for a sustainable approach to PPR eradication. The information on the socioeconomic benefits of vaccination can be promoted via sensitization campaigns to stimulate farmers’ uptake of the practice. This study can inform investment in PPR control.
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    Epidemiology of peste des petits ruminants virus in West Africa: Is lineage IV replacing lineage II in Burkina Faso?
    (Presentation, 2022-12-07) Biguezoton, A.S.; Ilboudo, Guy S.; Wieland, Barbara; Sawadogo, R.; Dah, F.; Zoungrana, A.; Dione, Michel M.
    Objective This study aimed at investigating the lineages of peste des petits ruminants virus (PPRv) currently circulating in Burkina Faso. Methods As part of the PPR surveillance from 2021 to 2022 in Cascades, Centre Ouest and Plateau central regions of Burkina Faso, outbreak investigations were carried out. We collected swab samples from eyes, mouth and nose from suspicious goats and sheep after confirmation of PPR through a rapid diagnostic test. Tissue samples (spleen, lung, lymph nodes) of suspicious dead animals were also collected. Virus confirmation was performed with RT-PCR amplification targeting nucleocapsid (N) gene. The RT-PCR products of positives extracts were sequenced in both forward and reverse sense. Sequence analysis, including pairwise alignment and BLAST algorithm application on GenBank were used to determine the lineages within our samples. Results In total, nine outbreaks were recorded in the three studied regions during the investigation. The outbreak investigation found 21 small ruminants positive to PPRv out of the 39 (53.84%) analysed. The sequences of samples from the three regions have at least 95% (333/350 bp) of similarity with lineages IV samples from Nigeria (MN725768) and Cameroon (MH447978). The same percentage of similarity was also obtained with the lineage IV sequence from Niger but on lower sequence size: i.e. 222/234 bp. Pairwise alignment with lineages I and II from Burkina Faso published in previous work showed no significant similarity or no more than 87% of similarity on smaller sequences (i.e. 188/218 bp). To our knowledge, this is the first time that lineage IV of PPRv is identified in Burkina Faso. Even though the results of this study are based on sequences of around 300 bp only, they suggest that the expansion of PPRv lineage IV in West Africa which started in Nigeria and has now spread to Burkina Faso after occurring also in Niger and Mali. Hence, further investigations are needed to better understand how the lineage IV has spread toto non-neighbouring regions in Burkina Faso and seems to have replaced lineage II of PPRv. Conclusion This study confirms the presence of the PPRv lineage IV in Burkina Faso. Based on outbreaks investigated, this lineage seems to have replaced lineage II. Further investigations are thus needed to better understand how PPRv lineage spread in the region and if lineage II is still present and what the implications for PPR control are.
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    Willingness to vaccinate and willingness to pay for vaccination against peste des petits ruminants in Linguère, Senegal
    (Presentation, 2022-12-07) Ilboudo, Guy S.; Wanyoike, Francis N.; Moore, V.B.; Rich, Karl M.; Djigo, C.A.T.; Dione, Michel M.
    Objective As part of the national strategy for controlling and eradicating peste des petits ruminants (PPR), Senegal organizes an annual mass vaccination campaign. The government subsidizes the vaccine by XOF 69 ($0.1), while the farmers pay only XOF 50 ($0.08), making a total cost of vaccine of XOF 119 ($0.18). This study aims to identify the factors that influence the decision of farmers to vaccinate their animals against PPR and their willingness to pay for improved vaccination service. Methods Using a choice experiment with 200 farmers in four communes of the department of Linguère, we considered a combination of attributes that improved the vaccine quality and delivery. These include, location of vaccination activities (home vs parc), vaccination strategy (individual vs group), type of vaccine (thermotolerant vs thermolabile), combination of vaccine with other services (other small ruminant vaccines vs deworming), nature of vaccination (elective vs compulsory), different costs of the vaccine. Results Preliminary descriptive results are reported here. Most of the respondents are male (84%) and have no formal education level (62%). Livestock is the main source of income for 85% of the respondent’s households. Most of the farmers keep more sheep than goat (77%) and the flock size is ranged from 3 to 700 animals with a median value of 70 animals. The median reported morbidity and mortality rates are respectively 20% and 10%. Nearly 40% of farmers said they have never vaccinated their animals against PPR. The reasons for non-vaccination were that they have never heard of PPR vaccination (51%), the non-availability of the vaccine (29%) and cultural barriers (10%). Most farmers preferred an annual vaccination (64%) and home vaccination (91%) to save travel time. Farmers state that they would vaccinate more if vaccination is combined with other services such as deworming (99%) or with another small ruminant vaccine (97%). The main expectations of the farmers in term of improved vaccine are the reduction in mortality (98%), increase in productivity (99%) and the increase in the market price (83%). The main factors influencing the decision of farmers to vaccinate are respectively the benefit of the vaccine (98%), the type of vaccinator (91%), the access to the information (86%), the vaccine availability (80%), the vaccination certificate (76%) and other reasons such as vaccination period (41%), immunity duration of the vaccine (31%), vaccination cost (30%), vaccination strategy (27%) and type of identification of vaccinated animals (26%). Conclusion Choice experiment analysis are ongoing. Results from this study will be useful in informing the implementation of vaccination campaigns against PPR in Senegal, and in the Sahel in general given that the production systems are similar.
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    Evaluation of a candidate thermotolerant vaccine against peste des petits ruminants in Mali
    (Presentation, 2022-12-07) Sidibé, C.A.K.; Séry, A.; Kantao, O.; Fall, Abdou; Niang, M.; Dione, Michel M.
    Objective The objective of this study was to evaluate the thermotolerance profile of a PPR vaccine protocol developed by ILRI and transferred to the LCV (lot ILRI 005ND) under laboratory and field conditions. Methods The attenuated PPRV 75/1 LK6 BK2 Vero70 strain was used as a production antigen with Lactalbumin hydrolysate-sucrose (LS) as stabilizers and vero cells used as host cells in the multiplication of the viral strain. The formed vaccine fluid was divided into a 2 ml per vial/100 doses. The freeze-drying was carried out according to the ILRI protocol during 62h50mn following 20 steps. The final titre of the vaccine was 105.66 TCID50. The quality of the vaccine lot ILRI 005ND, as well as its thermostability profiles have been tested by the PANVAC under the QCR1731, reference N°P188/709/58/20 of 08 January 2021. In the laboratory, the thermotolerance of the vaccine was evaluated at the LCV under three scenarios for 14 days: Scenario A: under ice (+4°C to +8°C) Scenario B: room temperature (32.5°C to 38.5°C) Scenario C: under incubation at 40°C and 45°C. In the field, 626 serum samples were collected from sheep and goats in three villages in Koutiala region. These sera were subject to two successive PPR serological tests to ensure they were negative. The vaccine was then reconstituted with 500 ml of sodium chloride solute 0.9% before use on animals. Scenario 1: 284 animals were vaccinated after 3 to 5 days of vaccine stored at ambient temperature during transport from the laboratory in Bamako to the field (395 Km) (+21.5°C to +34.8°C), storage on site (± 25 °C) and field for vaccination (maximum exposure + 51°C). Scenario 2: 162 animals were vaccinated after 6 to 7 days of vaccine having undergone thermal shocks with freezing storage temperature (-20 °C), storage on site (±33°C) and maximum field exposure (+47 °C). Scenario 3: 180 animals were vaccinated after 8 to 9 days of vaccine stored permanently under cold chain from the laboratory to the feet of the animal (-18°C to +19°C). Results In the laboratory after 14 days, with an initial vaccine titre of 105.66 TCID50 Scenario A: titre was 105.45 TCID50 Scenario B: titre was 103.80 TCID50 Scenario C: titres were 104.30 TCID50 at 40°C but less than 102.5 (minimum required) at 45° C In the field at one month post vaccination Scenario 1: 97.88% seroconversion Scenario 2: 98.76% seroconversion Scenario 3: 99.44% seroconversion No significant difference was observed in seroconversion between the tree lots (X-squared=1.9488; p-value =0.3774) Conclusion The vaccine maintained a satisfactory titre under different thermostability profiles in the laboratory. Sero-conversion rates in the field after vaccination was also good . The next step is to carry out sero-neutralization assays on the collected serums to measure protection rates of animals.
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    Ex ante impact of peste des petits ruminants control on micro and macro socioeconomic indicators in Senegal
    (Poster, 2022-12-15) Aboah, Joshua; Apolloni, A.; Duboz, R.; Okoth, Edward A.; Dione, Michel M.
    Vaccination is espoused as the effective control mechanism outlined in the Global Control and Eradication Strategy for peste des petits ruminants (PPR). However, extant studies assert that vaccination can be expensive; hence, the effectiveness of disease control may not necessarily translate to overall profit. Also, the consequences of PPR control on socioeconomic indicators like food and nutrition security at a macro national level is an important lacuna in the literature. This study seeks to examine the ex ante impact of PPR control strategies on farm-level profitability and the socioeconomic consequences in relation to food and nutrition security at a national level in Senegal. A bi-level system dynamics model, compartmentalised into five modules consisting of integrated production-epidemiological, economics, disease control, marketing, and policy modules, was developed with the STELLA Architect® software, validated, and simulated for 30 years at a weekly timestep. The model was parameterised with data from household surveys from pastoral areas in Northern Senegal and relevant archival data. Nine vaccination scenarios were examined from three vaccination dimensions (vaccination coverage, vaccine wastage, and the provision of government subsidies). This study’s findings indicate that, compared with a no-vaccination scenario, all the vaccination scenarios for both 26.5% (actual vaccination coverage) and 70% (expected vaccination coverage) resulted in a significant difference in the gross margin earnings and the potential per capita consumption for the supply of mutton and goat meat. At the prevailing vaccination coverage (with or without the provision of government subsidies), farm households will earn on average $69.43 (annually) more than the no-vaccination scenario, and the average per capita consumption for mutton and goat meat will increase by 1.13kg/person/year. When the vaccination coverage is increased to the prescribed threshold for PPR eradication (i.e., 70%), with or without the provision of government subsidies, the average gross margin earnings will be $72.23 annually and the per capita consumption will increase by 0.1kg/person/year. To examine the impact of vaccine wastage, a within group comparison of the actual and expected vaccination coverage was conducted. The findings indicate that 10% of multiple vaccinations of the same animals will result in a decline in the; (i) average gross margin earnings (annually) by $11.37 and $12.98 for vaccination coverage of 26.5% and 70%, respectively; and (ii) per capita consumption by 0.3kg/person/year and 0.34kg/person/year for the vaccination coverage of 26.5% and 70%, respectively. Considering that there was no statistically significant difference in the gross margin earnings and the potential per capita consumption when vaccination is performed with or without government subsidies, a sustainable strategy for PPR eradication will include the promotion of the benefits of vaccination via sensitization campaigns to stimulate farmers’ uptake of the practice.
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    Peste des petits ruminants (PPR) vaccination cost estimates in Burkina Faso
    (Journal Article, 2022-08-22) Ilboudo, Guy S.; Kane, P.A.; Kotchofa, Pacem; Okoth, Edward A.; Maiga, Assoumane; Dione, Michel M.
    Every year the government organizes country-wide vaccination campaigns targeting peste des petits ruminants (PPR) for small ruminants (sheep and goats). Despite the heavy investment in vaccination, no study has either rigorously estimated or described the cost of vaccine delivery. This study aimed to fill this gap by assessing and describing the cost of delivery of vaccines against PPR using the 2020 vaccination campaign data. The microcosting approach based on the World Health Organization (WHO) guidelines to construct comprehensive multiyear plans (cMYP) for human immunization programs was used. The cost data is presented for the public and private vaccine delivery channels separately and analyzed using three approaches considering activity lines, inputs, and nature of cost (fixed versus variable). Results show that the unit cost of vaccinating a sheep or goat is estimated at XOF 169 (USD 0.3) and XOF 103 (USD 0.18) through the public and private channels, respectively. Using the activity line framework, we found that the field activities including charges for vaccinator, cost of vaccination materials, and field transportation account for more than 50% of the vaccination cost. In terms of inputs, the personnel cost is the most significant contributor with 65%. Fixed costs are higher in the public sector with up to 46% compared to the private sector which is estimated to take 26% of the cost. This study informs veterinary services’ investment decision options for a better allocation of resources in implementing PPR and other small ruminant disease control efforts in Burkina Faso and the Sahel.
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    Livestock Health―ECo-PPR Project: Tools to support peste des petits ruminants (PPR) control and eradication
    (Brief, 2021-12-01) Kotchofa, Pacem; Dione, Michel M.; Campbell, Zoë A.; Okoth, Edward A.; Ilboudo, Guy S.; Wieland, Barbara
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    Macroeconomic impact assessment of peste des petits ruminants (PPR) in Ethiopia and Burkina Faso
    (Brief, 2021-09-15) Kotchofa, Pacem; Rich, Karl M.; Baltenweck, Isabelle; Dione, Michel M.
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    Epidemiology and Control of Peste des Petits Ruminants in East and West Africa (ECo-PPR)―Building capacity of African researchers on epidemiology and socio-economic impacts of PPR: ECo-PPR toolbox training report
    (Report, 2021-02-15) IIboudo, G.; Kotchofa, Pacem; Dione, Michel M.; Ochieng, Laurence; Machuka, Eunice M.; Tune, Fiona; Rutto, Erick; Campbell, Zoë A.; Okoth, Edward A.; Jones, B.; Wieland, Barbara