Equine rotaviruses—Current understanding and continuing challenges

Abstract

Equine rotaviruses were first detected in foals over 30 years ago and remain a major cause of infectious diarrhoea in foals. During this time, there has been substantial progress in the development of sensitive methods to detect rotaviruses in foals, enabling surveillance of the genotypes present in various horse populations. However, there has been limited epidemiological investigation into the significance of these circulating genotypes, their correlation with disease and the use of vaccination in these animal populations. Our knowledge of the pathogenesis of rotavirus infection in foals is based on a limited number of studies on a small number of foals and, therefore, most of our understanding in this area has been extrapolated from studies in other species. Questions such as the concentrations of rotavirus particles shed in the faeces of infected foals, both with and without diarrhoea, and factors determining the presence or absence of clinical disease remain to be investigated, as does the relative and absolute efficacy of currently available vaccines. The answer to these questions may help direct research into the development of more effective control measures.

Cloning and nucleotide sequence analyses of 11 genome segments of two American and one British equine rotavirus strains

“…As the development of the gene sequencing technology, a complement rotavirus classification method was developed, which was based on identities between sequences of cognate rotavirus gene segments of VP4, VP6, VP7, and NSP4 (Martella et al, 2006; Martella et al, 2003; Steyer et al, 2007). To date, more than 60 ERV strains have been determined for the complete open reading frames (ORF) sequences of all 11 genome segments and a novel rotavirus nomenclature system was developed based on the nucleotide cutoff value of each segment of 11 full genomic sequence data (Bailey et al, 2013; Ghosh et al, 2013; Matthijnssens et al, 2008b; Matthijnssens et al, 2012; Mino et al, 2013). However, aside from the genes encoding outer capsid proteins (VP7 and VP4) and the intermediate layer protein (VP6), little is known about the whole genomic information of ERV strains because there are few ERV's full-genome sequences have been determined (Matthijnssens et al, 2012).…”

“…The VP7 and VP4 genes, encoding outer capsid, are used to classify rotaviruses into G and P genotypes, respectively (Kapikian, 2001). Group A equine rotavirus (ERV) is the major cause of diarrhea in foals up to 3 months of age and the acute dehydration can incur severe economic burden due to morbidity and mortality in studs (Bailey et al, 2013; Ghosh et al, 2013; Papp et al, 2013). The G3P[12] and G14P[12] are the most prevalent equine rotavirus strains worldwide (Ghosh et al, 2013; Papp et al, 2013).…”

Clinical Approach to Commonly Encountered Problems

“…335,601-565 Lawsonia intracellularis can potentially affect horses of any age, but it is most common in weanling-age foals. 535,539,570,571 Equine coronavirus, also sometimes referred to as equine enteric coronavirus, has been recognized in both foals and adult horses. 566 Escherichia coli is an uncommon cause of diarrhea in foals, unlike in calves and piglets.…”

Application of Transmission Electron Microscopy Techniques in the Veterinary Diagnosis of Viral Gastroenteritis in Livestock Animals

“…Direct electron microscopy readily detects rotavirus particles in feces and intestinal fragments of foals with diarrhea [61][62][63][64].…”