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

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

Kobuviruses are known to infect the gastrointestinal tract of different animal species. Since its discovery in 2003, bovine kobuvirus (BKV) has been identified in faecal samples from diarrhoeic cattle in many countries, but only recently in North America. Although its possible role as an agent of calf diarrhoea remains to be determined, evidence is mounting. Our study reports for the first time the detection of BKV in faecal samples from diarrhoeic calves raised in Quebec, Canada. BKV was more commonly identified than eight known and common enteric calf pathogens. Further sequence analysis revealed that Canada BKV strain 1,043,507 was more closely correlated with the US BKV IL35164 strain than other BKV strains with complete genome. Continued surveillance and genomic characterization are needed to monitor BKV in the cattle around the world.

Viral Enteritis in Cattle: To Well Known Viruses and Beyond

Livestock products supply about 13 percent of energy and 28 percent of protein in diets consumed worldwide. Diarrhea is a leading cause of sickness and death of beef and dairy calves in their first month of life and also affecting adult cattle, resulting in large economic losses and a negative impact on animal welfare. Despite the usual multifactorial origin, viruses are generally involved, being among the most important causes of diarrhea. There are several viruses that have been confirmed as etiological agents (i.e., rotavirus and coronavirus), and some viruses that are not yet confirmed as etiological agents. This review summarizes the viruses that have been detected in the enteric tract of cattle and tries to deepen and gather knowledge about them.

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

This study describes the etiological diversity observed in a severe neonatal diarrhea outbreak with morbidity and mortality rates of 80 and 20%, respectively, with detection of mixed infections with viral, bacterial, and protozoan disease agents in a dairy calf rearing unit. Diarrheic fecal samples were collected from eight 5 to 18 days of age calves and were submitted to the investigation of the presence of rotavirus A (RVA), bovine coronavirus (BCoV), bovine kobuvirus (BKV), bovine viral diarrhea virus 1 and 2 (BVDV-1 and BVDV-2), enteropathogenic Escherichia coli (ETEC), Salmonella sp., and Cryptosporidium spp. Fragments of the small intestine of one calf with diarrhea that spontaneously died were submitted for histopathological analyses. The most frequent infectious agent detected in diarrheic fecal samples was BKV (8/8—100%), followed by RVA (5/8—62.5%), BVDV (5/8—62.5%), Cryptosporidium parvum (5/8—62.5%), ETEC (4/8—50%), and Cryptosporidium ryanae (1/8—12.5%). These etiological agents were found in mixed infections with two or more pathogens per diarrheic fecal sample. The association of viral and protozoan pathogens was the most frequently identified (37.5%) in these samples, followed by viral and bacterial (25%); viral, bacterial, and protozoan (25%); and only viral agents (12.5%). BCoV and Salmonella sp. were not identified in the diarrheic fecal samples analyzed. Additionally, histopathology of the small intestine diagnosed chronic lymphocytic enteritis. In conclusion, in calf rearing units, the adoption and strict monitoring of health management practices are critical to the success of this calf creation system.

Kobuvirus shedding dynamics in a swine production system and their association with diarrhea

Porcine kobuviruses are widely distributed in swine, but the clinical significance of these viruses remains unclear, since they have been associated with both diarrheic and healthy pigs. In addition, there is a paucity of data on Kobuvirus prevalence in Canadian pig herds. In this study, a total of 181 diarrheic and healthy piglets were monitored and sampled on four occasions, intended to represent the different stages of production. The piglets were sampled at the nursing farms (birth to weaning stage), at the nursery farms (post-weaning stage), and at finishing farms (at the beginning and the end of the fattening stage). Fecal and environmental samples were collected during each life stage. Following viral extraction, Kobuvirus detection by RT-PCR was conducted, and positive samples were sequenced. During the late-nursing stage (6-21 days old), piglets with diarrhea shed more Kobuvirus than healthy individuals. Piglets shed more Kobuvirus during the post-weaning stage (nursery farms) than during any of the other life stages. This was evidenced in individual samples as well as in environmental samples. Over 97% of the sampled piglets shed Kobuvirus at least once in their lifetime. All piglets shedding a Kobuvirus strain or mix of strains at the nursing stage did not appear to shed another porcine kobuvirus strain at a later life stage. Overall, our findings throw light on Kobuvirus shedding dynamics and their potential role in neonatal diarrhea at the nursing stage, which appears to be the point of entry for kobuviruses into swine production systems.

Proposed New Strain of Canine Kobuvirus from Fecal Samples of Brazilian Domestic Dogs

A proposed new strain of canine Kobuvirus was identified in fecal samples of domestic dogs from a rural community located in the municipality of Peixe-Boi, Pará, Brazil. The nucleotide identity was 92.3% similar to other representatives of the family Picornaviridae, genus Kobuvirus, and species Aichivirus A, which suggests that this is possibly a new strain within this species.

A proposed new strain of canine Kobuvirus was identified in fecal samples of domestic dogs from a rural community located in the municipality of Peixe-Boi, Pará, Brazil. The nucleotide identity was 92.3% similar to other representatives of the family Picornaviridae, genus Kobuvirus, and species Aichivirus A, which suggests that this is possibly a new strain within this species.