Sero-surveillance, risk factors and molecular diagnosis of peste des petits ruminants virus in South Kivu, Democratic Republic of Congo

Abstract

Peste des petits ruminants (PPR) is an acute viral disease of small ruminants caused by PPR virus (PPRV). For many years, the disease was mainly confined to West and Central Africa but has now spread southwards to previously PPR-free countries. The disease was first reported in Democratic Republic of Congo (DRC) in 2012. The disease causes high morbidities of up to 100 % and mortality rates between 50 and 90% in domestic small ruminants (goats and sheep) leading to the socio economic loss impact to the farmers. This study aimed to perform molecular diagnosis and sero-prevalence of PPR associated with transmission risk factors in unvaccinated sheep and goats from South-Kivu in province in DRC using respectively reverse- transcriptase polymerase chain reaction (RT-PCR), competitive enzyme-linked immunosorbent assay (cELISA) and a structured questionnaire. The results showed with cELISA an overall seroprevalence of 28.5% (n=319), out of which 11.3% and 32.7% seropositivity was found in sheep and goats, respectively. Peste des petits ruminants seroprevalence was higher in the territories that recorded high rainfall, 34.5% (n=142) in Shabunda and 29.4% (n=79) in Mwenga. In a total of 11 risk factors investigated four were found to be associated with PPR seroprevalence (p≤0.05). Among them we have animal’s age (OR: 9.34), grazing and farming system (6.28), territory geographic location (OR: 5.1) and the animal’s origin (OR: 0.5). Peste de petits ruminants seroprevalence was higher in small ruminants kept in communal grazing system (30.6%) and free ranging system (31.2%). Sheep and goats of >12 months had a significantly higher PPR seroprevalence (35.1%). As no PPRV RNA was detected in any of the blood collected using reverse transcriptase polymerase chain reaction (RT-PCR), we recommend further studies to be focused on molecular characterization and isolation of PPR virus.