Molecular characterization and genetic diversity of bovine Kobuvirus, Brazil

Abstract

It is suggested that Bovine kobuvirus (BKV) is involved in the etiology of gastroenteric diseases especially among calves; however, this association remains unknown. This study evaluated 216 fecal samples from cattle with and without diarrhea symptoms obtained from different regions of Brazil. A 216 bp fragment of the BKV 3D gene was amplified by RT-PCR in 14.4 % (31/216) of the studied samples, and 17 samples were subjected to nucleotide sequencing. All positive samples were obtained from animals aged less than 5 months, and most of animals presented diarrhea (p < 0.05). Phylogenetic analyses showed that the obtained sequences were grouped within the genogroup 2 of BKV forming subclades specific for each Brazilian municipality sampled. In addition, the alignment of the sequences revealed differences of nucleotides between sequences from different locations. Our results indicate for the first time that there is a regional genotypic differentiation of BKV in Brazil.

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

“…In other studies, high positivity rates have been reported for this enteric virus, reaching 34.9% (58/166) in China [8] and 77.8% (7/9) in the Netherlands [5]. Furthermore, retrospective transversal studies conducted in Brazil revealed the presence of this enteric viral agent in 18.2% (40/222) [23] and 14.4% (31/216) [7] of the fecal samples analyzed, with a larger number of positive animals on dairy cattle farms.…”

“…In Brazil, aichivirus B was identified in young and adult cattle in all geographical regions of Brazil in both dairy and beef herds [7,23]. However, most reports of the occurrence of aichivirus B worldwide have been based on retrospective and transversal epidemiological surveys [7,19,23].…”

Detection and genetic characterization of bovine kobuvirus from calves in Egypt

“…For example, kobuvirus was detected in 16.7% of healthy cattle in Japan [10], 8.3% of diarrheic cattle in Thailand [17], and 18.2% of diarrheic cattle in Brazil [18,19]. In other countries, the prevalence has been described as follows: 6.25% in Hungary [12], 1% in Belgium [20], 25.8 -34.6% in Korea [21,22], 77.8% in the Netherlands [23], 4.9% in Italy [11], and 34.9% in China [6]. The highest rates of BKoV have been observed in Egypt (66.7% in this study) and the Netherlands (77.8) possibly due to the smaller sample size tested in these two studies (n = 36 and n = 9, respectively).…”

“…Similarly, Chang et al [6] and Candido et al [19] stated that BKoV-3D sequences from the same epizootic areas grouped together and shared higher identities. Earlier studies have concentrated mostly on detection and sequencing of a smaller part of the BKoV-3D (RdRp) gene [21,18,19,23]. The 3D genes are usually conserved.…”

Molecular detection and genomic characteristics of bovine kobuvirus from dairy calves in China

“…Since BKoV was first identified in Japan in 2003 (Yamashita et al, 2003), this virus has been detected in bovine with and without diarrhea symptomatology in 9 countries (Liu et al, 2013). It had been suggested that BKoV may be associated with diarrhea in calves (Candido et al, 2017), but the pathogenicity of BKoV still needs to be determined. Recently, BKoV was also detected in the spinal fluid from the brain of an 11 day-old calf where the animal had a history of diarrhea and neurological disease (Moreira et al, 2017), which indicates that this virus can cause systemic infections.…”