Detection of canine astrovirus in dogs with diarrhea in Japan

Abstract

Canine astrovirus (CAstV) is the causative agent of gastroenteritis in dogs. We collected rectal swabs from dogs with or without diarrhea symptoms in Japan and examined the feces for the presence of CAstV by RT-PCR with primers based on a conserved region of the ORF1b gene. The ORF1b gene of CAstV was not detected in the 42 dogs without clinical illness but was present in three pups out of the 31 dogs with diarrhea symptoms. Based on the full-length capsid protein, the CAstV KU-D4-12 strain that we detected in this study shared high homology with the novel virulent CAstV VM-2011 strain.

Genome analysis of canine astroviruses reveals genetic heterogeneity and suggests possible inter-species transmission

“…Also, this strain markedly varied from all the other canine AstVs in the highly conserved promoter region for synthesis of subgenomic RNA, located upstream of the ORF2 (Walter and Mitchell, 2003;Mendez et al, 2014). Conversely, all other canine AstVs analysed in this study displayed a conserved genomic architecture, which was shared with all currently canine AstVs for whom the complete or partial (ORF1b and ORF2) genome sequence is available (Martella et al, 2011a(Martella et al, ,b, 2012Takano et al, 2015). In addition, upon sequence comparison and phylogenetic analysis, strain HUN/2012/8 differed markedly from other canine AstVs concerning the partial ORF1b and the full-length ORF2 (Table 3).…”

“…Thus, our prevalence data for AstV must be interpreted with caution, even if the detection rates of AstVs fell in the ranges reported in the literature. For example, canine AstV RNA has been detected in 6-27% of dogs with enteritis and 0-19% of aysmptomatic dogs in studies in Italy ( (Takano et al, 2015), France (Grellet et al, 2012) and UK (Caddy and Goodfellow, 2015). Even if those studies differed in the number, provenience and age of the animals enrolled in the investigations, in most studies the detection rates were found to differ significantly between symptomatic and asymptomatic dogs, suggesting a possible role of AstVs as enteric pathogens of dogs.…”

“…Also, a canine AstV, strain ITA/08/Bari, was successfully adapted to replicate in vitro on MDCK cells, and AstV-specific antibodies were detected in convalescent canine sera (Martella et al, 2011a(Martella et al, ,b, 2012. The prevalence of AstV infection seems higher in dogs with enteric disease than in asymptomatic animals (Martella et al, 2011a,b;Zhu et al, 2011;Caddy and Goodfellow, 2015;Takano et al, 2015). Also, monitoring of natural infection by AstV in dogs has revealed that the acute phase of gastroenteritis overlaps with peaks of viral shedding (Martella et al, 2012).…”

New viruses associated with canine gastroenteritis

“…Human astroviruses are estimated to cause up to 10% of childhood gastroenteritis globally (Moser and Schultz-Cherry, 2005), but the pathology caused by CaAstV infection in dogs is uncertain. A positive association between CaAstV infection and disease has been shown in China, Japan, Italy, the United Kingdom (UK) and Australia (Table 1) (Martella et al, 2011;Zhu et al, 2011;Takano et al, 2015;Moreno et al, 2017). In contrast, a study of French breeding kennels and a study of Hungarian shelter dogs found no significant association with gastroenteritis (Grellet et al, 2012;Mihalov-Kovács et al, 2016).…”

Mamastrovirus 5 detected in a crab-eating fox (Cerdocyon thous): Expanding wildlife host range of astroviruses

“…To date, MAstV5 was reported only in samples derived from the gastrointestinal tract of dogs [24,25,34,[26][27][28][29][30][31][32][33], and the recovery of MAstV5 in the crab-eating fox's CNS is an interesting and unexpected finding. However, the detection of other AstV species in the central nervous system (CNS) of mink [35], cattle [36,37], human [38], pigs [39] and sheep [40] has been the focus of differential diagnosis of nonsuppurative encephalitis.…”