Detection of rotavirus genotypes and coronavirus among diarrheic and healthy beef and dairy calves from Buenos Aires Province, Argentina

LOUGE URIATE E; PARREÑO V; BADARACCO A; GARAICOECHEA L; SPÄTH E; VERNA AE; LEUNDA MR; FERNANDEZ F; SAIF LJ; ODEÓN A

Conferencia; Conference of Research Workers in Animal Diseases (CRWAD); 2011

Bovine rotavirus (BRV) and coronavirus (BCoV) are enteric pathogens associated with neonatal calf diarrhea (NCD). BRV is classified into G and P genotypes based on genetic variation in the outer capsid proteins VP7 and VP4, respectively. The aim of this study was to assess BRV and BCoV as etiologies associated with NCD in beef and dairy farms and to compare the genetic diversity of BRV strains circulating in the farms under study. The survey was conducted in beef (n: 14) and dairy (n: 18) farms from Buenos Aires province, Argentina (2007-2011). Feces (beef n: 182; dairy n: 240) were collected from 2 to 60 day-old diarrheic (beef n: 102; dairy n: 137) and non-diarrheic (beef n: 80; dairy n: 103) calves. BRV and BCoV were detected by ELISAs. BRV positive samples were analyzed by heminested multiplex RT-PCR to determine the G (including G6 lineages III or IV, G8 and G10) and P genotypes (P[1], P[5] and P[11]). BRV was detected in 12 beef (86%) and in 15 dairy (83%) farms, while BCoV was detected in only 3 dairy farms (17%). BRV single infection rates were significantly higher (p= 0.009) in beef than in dairy calves (22.5% vs. 12.9%) and also in diarrheic (beef: 33 [32.3 %], dairy: 26 [19%]) than in non-diarrheic (beef: 8 [10%], dairy: 5 [4.8%]) (p< 0.001) calves. BCoV single infection rate in diarrheic dairy calves (2; 1.4%) was lower than that for BRV (26; 19%). Co-infections with both viruses were detected in 3 (2.2 %) calves. The 33 BRV strains from beef calves were genotyped as: G6IVP[5] (91%), (G6IV+G10)P[11] (3%), and G?(nontypeable)P[5] (6%). The 33 BRV strains from dairy calves were: G6IIIP[11] (42.4%), G6IVP[5] (9.1%), G10P[11] (9.1%), (G6III+G10)P[11] (6.1%), (G6IV + G10)P[11] (6.1%), (G6IV+G10)P[5+11] (6.1%), (G6IV+G10)P[5] (3%), G6IVP[5+11] (3 %), G8P[11] (3%), G?P[5] and G?P[11](12%). BRV was associated with NCD, either in beef or dairy farms, although the infection rate was higher in beef calves. The distribution of G and P genotypes differed according to the husbandry system with greater diversity in dairy calves as previously described in Argentina. In addition this work reports the first detection of a single infection by G8P[11] in dairy calves in Argentina.