Phylogenetic analysis of VP1 and RdRP genes of Brazilian aichivirus B strains involved in a diarrhea outbreak in dairy calves

Abstract

Aichivirus B has been reported worldwide in calves and adult cattle with and without diarrhea. The aim of this study was to describe the molecular characteristics of the RdRP and VP1 genes of aichivirus B strains identified as the most frequent etiologic agent in a neonatal diarrhea outbreak in a high-production Brazilian dairy cattle herd. Preliminary laboratory analysis ruled out important enteropathogens (Cryptosporidium spp; Eimeria spp., E. coli F5, and bovine coronavirus). Fecal samples from diarrheic (n = 24) and asymptomatic (n = 5) calves up to 30 days old were collected for virological analysis. RT-PCR assays were performed for the detection of aichivirus B RdRP and VP1 genes and for rotavirus A VP7 and VP4 genes in fecal samples. Asymptomatic calves (control group) were negative for both viruses. Aichivirus B and rotavirus A G10P[11] genotypes were found in 54.2% (13/24) and 25% (6/24) of the diarrheic fecal samples, respectively. Aichivirus B was only identified (83.3%, 10/12) in calves up to two weeks old. Phylogenetic analysis based on the RdRP gene grouped the Brazilian strains in a new branch within the aichivirus B group. Comparative analysis of the nucleotide sequence of the VP1 gene of Brazilian and Chinese aichivirus B strains allowed the strains identified in this study to be classified in the putative lineage 1. This is the first description of a high rate of aichivirus B detection in a diarrhea outbreak in dairy calves, and the first phylogenetic study of the VP1 gene of aichivirus B wild-type strains performed in South America.

Severe outbreak of bovine neonatal diarrhea in a dairy calf rearing unit with multifactorial etiology

“…The exact role of BKV in the pathogenesis of diarrhea is not fully elucidated; however, the detection rate of BKV in fecal samples from calves with clinical signs is higher when compared with animals without clinic signs, reinforcing the participation of BKV in the pathogenesis of diarrhea [35]. In this study, BKV was identified in mixed infections, and similar findings were previously described [21,36], suggesting that the occurrence of this virus may be associated with the concomitant presence of other diarrheic pathogens of cattle.…”

“…Aliquots of sterile ultrapure diethylpyrocarbonate-treated water were included as negative controls in all procedures. Samples previously known as positive for each of the virus investigated in this study were included as positive controls: prototype NADL and Mebus strains cell culture (Madin-Darby bovine kidney) adapted for BVDV and BCoV, respectively, and fecal samples known to be positive for RVA [9] and BKV [21].…”

Exploring the Potential Parasitic Pathogens Causing Diarrheal Death to Yak Calves With Bloody Excrement Through High-Throughput Sequencing

“…The globally distributed bovine diarrhea disease seriously harms the health of animals, causing tremendous economic losses to the cattle industry (Brar et al 2017, Han et al 2017, Ribeiro et al 2017, Li et al 2018a. A lot of measures including vaccinations, medications and herd management have been taken with the go of decreasing the economic losses caused by diarrhea, however, the overall effect has been limited (Cho andYoon 2014, Li et al 2018a).…”

Detection and genome characterization of bovine kobuvirus (BKV) in faecal samples from diarrhoeic calves in Quebec, Canada

“…Since its serendipitous discovery as a cell culture contaminant, the presence of BKV in bovine faecal samples has been reported in Japan, Thailand (Yamashita et al., 2003), South Korea (Jeoung et al., 2011; Park et al., 2011), China (Chang et al., 2014; Li et al., 2019), Hungary (Reuter & Egyed, 2009), Belgium (Mauroy et al., 2009), the Netherlands (Barry et al., 2011), Italy (Di Martino et al., 2012), the United Kingdom, Turkey (Isidan et al., 2019), Egypt (Mohamed et al., 2018), Brazil (Candido et al., 2017; Ribeiro et al, 2014; Ribeiro et al., 2017) and the USA (Wang et al., 2020). Although identified in deep nasal swabs from Western Canada feedlot cattle, the presence of BKV in faecal samples from diarrhoeic calves has not been reported in Canada prior to this study (Zhang et al., 2020).…”