Identification of a Ruminant Origin Group B Rotavirus Associated with Diarrhea Outbreaks in Foals.

Tirth Uprety,Jocelynn Morgan,David Horohov,Chithra C Sreenivasan,Ganwu Li,Erdal Erol,Solomon O Odemuyiwa,Peter Timoney,Ben M Hause,Feng Li,Stephan Locke,Li Zeng,Dan Wang,William F Gilsenan,Craig N Carter,Emma Adam,Laurie Metcalfe,Nathan Slovis

doi:10.3390/v13071330

Abstract

Equine rotavirus group A (ERVA) is one of the most common causes of foal diarrhea. Starting in February 2021, there was an increase in the frequency of severe watery to hemorrhagic diarrhea cases in neonatal foals in Central Kentucky. Diagnostic investigation of fecal samples failed to detect evidence of diarrhea-causing pathogens including ERVA. Based on Illumina-based metagenomic sequencing, we identified a novel equine rotavirus group B (ERVB) in fecal specimens from the affected foals in the absence of any other known enteric pathogens. Interestingly, the protein sequence of all 11 segments had greater than 96% identity with group B rotaviruses previously found in ruminants. Furthermore, phylogenetic analysis demonstrated clustering of the ERVB with group B rotaviruses of caprine and bovine strains from the USA. Subsequent analysis of 33 foal diarrheic samples by RT-qPCR identified 23 rotavirus B-positive cases (69.69%). These observations suggest that the ERVB originated from ruminants and was associated with outbreaks of neonatal foal diarrhea in the 2021 foaling season in Kentucky. Emergence of the ruminant-like group B rotavirus in foals clearly warrants further investigation due to the significant impact of the disease in neonatal foals and its economic impact on the equine industry.

Highlights

Rotavirus (RV) is a common enteric pathogen associated with diarrhea in newborn children, animals, and birds [1,2]
The horse is a unique species in which only group A rotaviruses are frequently found in diarrhea outbreaks worldwide, especially in foals aged 60–90 days [32,42,55]
G3P(12) and G14P(12) strains have been isolated from samples of affected foals, with some foals co-infected with both strains [30,37,38]

Summary

Introduction

Rotavirus (RV) is a common enteric pathogen associated with diarrhea in newborn children, animals, and birds [1,2]. Rotavirus is the leading cause of diarrhea in children less than 5 years old [3]. The RV genome comprises 11 dsRNA segments, with each segment dedicated to coding for one protein (segment 11 is an exception; it codes for two non-structural proteins: NSP5 and NSP6). Segments 1, 2, 3, 4, 6, and 9 code for VP1, VP2, VP3, VP4, VP6, and VP7, respectively, while segments 5, 8, 7, 10, and 11 code for non-structural proteins NSP1–NSP6, respectively [5]. The numbering of genome segments is based on the migration pattern of RNA segments in analytical gels that can vary between strains [6]

Methods

Results

Conclusion