Molecular detection of bovine coronavirus in a diarrhea outbreak in pasture-feeding Nellore steers in southern Brazil

Abstract

Worldwide diarrhea outbreaks in cattle herds are more frequently detected in calves being that diarrhea outbreaks in adult cattle are not common. Winter dysentery (WD) is a bovine coronavirus (BCoV) enteric infection that is more reported in Northern hemisphere. Seasonal outbreaks of WD in adult cattle occur mainly in dairy cows. WD has not been described in beef cattle herds of tropical countries. This study describes the molecular detection of BCoV in a diarrhea outbreak in beef cattle steers (Nellore) raised on pasture in Parana, southern Brazil. During the outbreak, the farm had about 600 fattening steers. Watery and bloody diarrhea unresponsive to systemic broad-spectrum antibiotic therapy reveals a morbidity rate of approximately 15 %. The BCoV N gene was identified in 42.9 % (6/14) of the diarrheic fecal samples evaluated by semi-nested polymerase chain reaction (SN-PCR) technique. Other enteric microorganisms occasionally identified in adult cattle and evaluated in this study such as bovine groups A, B, and C rotavirus, bovine viral diarrhea virus, bovine torovirus, aichivirus B, and Eimeria sp. were not identified in the fecal samples. To the best knowledge of the authors, this is the first description of the BCoV diagnosis in fecal samples collected in a diarrhea outbreak in adult beef cattle grazing in the grass in a tropical country.

Molecular epidemiology of coronavirus in faeces of Brazilian calves and Peruvian camelid herds

“…Nearly half of the cattle in our study (46.5%) were infected with BCoV. Previous studies conducted at Brazilian dairy and beef farms have reported BCoV infection frequencies ranging from 15.6-68.6% [4,12,[15][16][17][18][19][20]. These studies predominantly focused on medium and large farms with good nutritional and health management that were located in states considered as large producers of bovine meat and milk for export.…”

Coronaviruses in cattle

“…BCoVs are widespread all over the world (Boileau and Kapil 2010 ; Toftaker et al 2017 ). Winter dysentery was typically reported in colder regions but new reports have documented episodes in warmer seasons (summer in Korea) or in tropical countries like Thailand, Brazil and Cuba (Barrera Valle et al 2006 ; Park et al 2006 ; Takiuchi et al 2009 ; Ribeiro et al 2016 ; Singasa et al 2017 ). They can be divided into two groups based on clinical signs.…”

Brazilian strain of bovine respiratory coronavirus is derived from dual enteric and respiratory tropism

“…Since the first description of a Brazilian BCoV associated with calf diarrhea, most Brazilian strains of enteric origin have now been described and characterized by molecular methods (Jerez et al, 2005;Takiuchi et al, 2008;Stipp et al, 2009;Ribeiro et al, 2016); in addition, assessment of major public databases did not reveal any description of BRCoV in other South American countries. This study investigates the recent molecular evolution of BCoV by addressing the phylogenetic relationship between the enteric and winter dysentery strains based on a polymorphic region of the Brazilian BRCoV.…”