Molecular Detection and Seroprevalence Study of Peste des Petits Ruminants Virus in Small Ruminants in Central Ethiopia.

Abstract

Background: Peste des petits ruminants (PPR) is a severe, highly contagious, and fatal viral disease of small ruminants that causes significant production losses and mortality in Ethiopia. A cross-sectional study was conducted from December 2021 to July 2022 to determine the seroprevalence of the disease in the study area. Samples were collected from the outbreak to conduct viral isolation and molecular detection, focusing specifically on sheep and goats as the study animals in the investigation.

Materials and methods: Clinical specimens were first collected from small ruminants showing signs suggestive of PPR. Paired swab samples and postmortem tissue specimens were obtained for virus isolation and molecular characterization. During necropsy, representative tissue sections were aseptically trimmed and processed. Of 250 clinically suspected animals, 25 were selected for detailed virus isolation and molecular detection of PPR virus (PPRV). PCR-positive samples were further confirmed through virus isolation in cell culture. Subsequently, blood samples (4 mL) were collected from the jugular vein of 384 small ruminants older than 6 months for serological analysis. Serum was separated and analyzed to determine the seroprevalence of the infection.

Results: PPRV was detected in 10 of 25 samples (40%)using reverse transcriptase PCR (RT-PCR), and of these RT-PCR-positive samples, PPRV was isolated from four samples using Vero cells. The overall seroprevalence of PPRV was 20.6% (n = 384). Age, herd composition, and history of the recent introduction of new small ruminants were significantly associated with seropositivity of PPR (p < 0.05).

Conclusion: The study confirmed widespread circulation of PPRV in the study areas, significantly affecting small ruminant productivity. High seroprevalence indicated endemicity, with identified risk factors including introducing new small ruminants and herd composition. Recommendations emphasize integrating small ruminants with other livestock and supporting government efforts. Caution is needed due to regional variations, highlighting the importance of further molecular characterization of circulating PPRV strains.