From November 2020 to July 2022, a mixed approach, combining a serological survey and focus group discussions with smallholders, was conducted in Plateau State (Nigeria) to characterize the distribution and the prevalence of Peste des petits ruminants (PPR) in goats and sheep, as well as the potential risk factors for this disease.
A sample of 200 villages were investigated across the 17 Local government areas (LGA) of Plateau. In each village, serum samples were collected from 10 animals in two different herds. The presence of antibodies was evaluated using the ELISA test. We considered a village positive if at least one animal was positive. We applied a mixed model with nested random effects of LGA, villages, and herds to account for the aggregation structure of the sampled animals. Among the 200 villages visited for the serological survey, 20 villages were selected to conduct focus group discussions with male and female farmers separately. Using interactive and participatory tools, farmers were questioned about the epidemiology of the most devastating diseases for their herds. When PPR was identified among those diseases, they were asked to estimate the morbidity, mortality, and case fatality rate of the disease.
In total, we sampled 2000 animals, 766 sheep and 1234 goats. The prevalence of positive villages was 84% with no significant difference across the LGA. Seroprevalence was higher in sheep (38.2%) than in goats (29.7%), and in adults (36.7%) than in young animals (29.3%). However, there was no significant difference between males and females. Focus group discussion identified that PPR outbreaks occurred in all the visited villages in the last 12 months, even in those for which antibodies against the PPR virus were not detected with the serological survey. Zawo is the name most often used by farmers to describe a clinical picture suggestive of PPR. Farmers considered Zawo to be the most devastating disease for their herds. The mortality rate was estimated to be 36% in goats and 35% in sheep while the morbidity rate was significantly higher in goats (75%) than in sheep (65%).
The findings of this extensive survey imply that there is a widespread occurrence of PPR among small ruminants in Plateau. They also suggest that PPR is one of the major disease militating against sheep and goat production and is usually referred as Zawo by farmers in Plateau state. The use of mixed approaches, combining participatory surveys and conventional epidemiological methods, offers significant added value. These approaches make it possible to reduce the uncertainty associated with the results by comparing information obtained from different data sources. By integrating farmers’ knowledge with epidemiological data, we obtained a more global and complete understanding of the epidemiological situation. Incorporating these approaches into animal disease prevention and control programmes will enable more effective strategies to be developed, and tailored to the specific needs of farmers.