Isolation and molecular detection of Peste des petits ruminants virus in an outbreak investigation in Benishangul Gumuz, Ethiopia

Abstract

Peste des petits ruminants (PPR) is a severe and highly communicable disease. It is viral disease that particularly affects shoats. Its domino effects are economic losses through loss of production, deaths, abortions, and the cost of disease control. An outbreak investigation was conducted from May to November 2022 in Bambase district of Benishangul Gumuz regional state to determine the presence of PPR virus, and morbidity, mortality and case fatality rates. Altogether, 180 clinically diagnosed and 32 shoats with typical clinical sign of PPR were identified for laboratory confirmation Nasal and rectal swabs from 32 sheep and goats were collected and cultured on Verodog SLAM (VDS) cell line and tested using then tested using a quantitative real-time polymerase chain reaction (RT_PCR) assay and conventional PCR with 1.5% gel electrophoresis for detection of the N gene. The overall morbidity, mortality and case fatality rate was 17.77%, 2.77% and 15.62% respectively. Meanwhile, goats had a higher morbidity (26.5%), mortality (4.81%) and case fatality rate (18.18%) than sheep (10.3%, 1.03% and 10% respectively). Half (50%; 16/32) of samples were successfully cultivated on Vero dog SLAM cell line, showing cytopathic effects of PPR virus such as rounding cells, foamy vacuolation, aggregation and syncia formation. Out of 32 animals tested, 17 (53.13%) showed positive results for PPR virus by real-time PCR. Further analysis with conventional PCR revealed the presence of the N gene in all 17 positive samples with a 351bp fragment size. The results showed a higher morbidity rate in caprines than in ovines. Based on these findings, it is recommended to carry out a further phylogenetic study to identify the strain of virus circulating in the study area.

Keywords

• cytopathic effect
• gel electrophoresis
• goats
• n gene
• sheep