A Comparative study of the Sero-prevalence of Peste Des Petits Ruminants Virus among Districts of Different Agro-Ecological Zones in Tanzania

Abstract

Peste des petits Ruminants (PPR), a disease affecting sheep and goats, was confirmed in Tanzania in the year 2018. Since then the disease has continued to spread into different districts, causing significant socio-economic losses to livestock keepers. This study aimed at determining the sero-prevalence of PPR in 32 districts from the coastal, semi-arid and plateau ecological zones, respectively. Sera samples were collected from sheep and goats, and analysed by competitive Enzyme Linked Immunosorbent Assay (c-ELISA). Findings indicated that six (18.8%) districts had very high PPR sero-prevalence of which four (66.7%; Chamwino, Kondoa, Mvomero and Kilosa) belong to the semi-arid ecological zone and two (33.3%; Bagamoyo and Mkuranga) to the coastal ecological zone. Three districts (9.4%) had high PPR sero-prevalence, all from the semi-arid ecological zone. Twelve districts had low PPR sero-prevalence of which two (16.7%) were from semi-arid, one (8.3%) from coastal and nine (75.0%) from plateau ecological zones. A zero PPR sero-prevalence was recorded in three districts and eight districts from semi-arid and plateau ecological zones, respectively. There was a statistically significant difference in sero-positivity between the different ecological zones, χ2 (2) = 9.121, p = 0.010, with a mean rank sero-positivity of 24.7% for coastal zone, 12.0% for plateau and 20.8% for semi-arid zone. Post hoc pairwise comparison with Bonferroni correction for multiple tests showed a statistically significant difference between plateau and semi-arid zones (p = 0.032). Although the coastal zone had a higher mean rank positivity than the plateau zone, the difference was not statistically significant (p = 0.083). The study suggests a zonal predisposition of PPR sero-prevalence with districts in the semi-arid and coastal zones having significantly higher values compared to those in the plateau ecological zones. Efforts for control of the disease need to concentrate in those two high risk ecological zones.