Molecular Epidemiology of Peste des Petits Ruminants Virus Circulating in Fat-Tailed Sheep in Bangladesh

Peste des petits ruminants (PPR) is a highly contagious viral disease of sheep and goats that causes substantial economic losses through high morbidity, mortality and rapid transmission among small ruminants. Molecular epidemiological data on circulating PPR virus (PPRV) strains in Bangladesh remain limited.

To investigate the molecular epidemiology and phylogenetic characteristics of PPRV among fat-tailed sheep and goats traded in livestock markets in Bangladesh.

A cross-sectional survey was conducted in livestock markets in Dhaka city, Bangladesh, during the Eid-ul-Adha festival between August and October from 2015 to 2018. Oral, nasal and rectal swabs were collected from 161 animals comprising 141 sheep (including 111 fat-tailed sheep) and 20 goats. Samples were screened for PPRV using conventional hemi-nested polymerase chain reaction (PCR) targeting the nucleocapsid gene. Positive amplicons were sequenced, analysed phylogenetically and subjected to three-dimensional (3D) structural prediction of the RNA-dependent RNA polymerase protein.

The overall prevalence of PPRV in small ruminants was 2.5% (95% confidence interval [CI]: 0.7-6.2). In fat-tailed sheep, the prevalence was 3.6% (95% CI: 1.0-8.9), whereas no positive cases were detected among goats. A significantly higher (p < 0.05) prevalence was observed in animals sampled from the Gabtoli livestock market. Phylogenetic analysis revealed that two of the four positive samples clustered closely with PPRV strains from India and the United Arab Emirates, whereas the other two clustered with strains from China and Tibet.

These findings demonstrate the transboundary circulation of genetically diverse PPRV strains among small ruminants traded in livestock markets in Bangladesh. Strengthened molecular surveillance in livestock markets and coordinated regional control strategies are needed to support PPR prevention and eradication.