Serological and genotypic characterization of group A rotavirus reassortants from diarrheic calves born to dams vaccinated against rotavirus.
Two strains of bovine rotavirus (BRV), designated strain Nebraska Scottsbluff-1 (NS-1) and NS-2, were isolated from 2 neighboring cow-calf beef cattle ranches where dams had been vaccinated with a commercial vaccine containing group A BRV strain Neonatal Calf Diarrhea Virus (NCDV)-Lincoln (P1:G6). Northern blot hybridizations using whole genomic RNA probes indicated that strains NS-1 and NS-2 had identical group A RNA electrophoretic patterns and were homologous at all gene segments. Strain NS-1 was compared with reference group A BRV strains using serological and genotypic methods. In vitro virus neutralization assays indicated that strain NS-1 was neutralized by a G6-specific neutralizing monoclonal antibody (mAb) and guinea pig hyperimmune serum (GPHS) raised against BRV strain B641 (P5:G6), but not by G10-specific neutralizing mAb or GPHS raised against BRV strain B223 (P11:G10). Nucleic acid hybridization experiments using whole-genomic RNA probes revealed that gene segment 4 of strain NS-1 differed from BRV strains NCDV-Lincoln and B223, but hybridized with strain B641. Conversely, gene segment 5 of strain NS-1 hybridized with BRV strain B223, but not with BRV strains NCDV-Lincoln and B641. A G-specific cDNA probe produced by reverse transcription polymerase chain reaction (RT-PCR) amplification of strain NS-1 hybridized specifically only with G6 strains NCDV-Lincoln and B641, but not with G10 strain B223. Co-electrophoresis experiments using strains NS-1, B641, and B223 further confirmed these results, suggesting that strain NS-1 was a naturally-occurring reassortant BRV between strains B641 and B223. Taken together these results indicated that a naturally-occurring group A BRV reassortant with a P gene different from the vaccine virus was responsible for the diarrheal syndrome observed on both ranches. Results from this study also indicate the existence of at least 2 different gene segments 5 among group A BRV infecting cattle.
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Department of Veterinary and Biomedical Sciences, University of Nebraska-Lincoln 68583-0905.
Duhamel
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GE
Benfield
D A
DA
Grotelueschen
D M
DM
D000818:Animals; D000831:Animals, Newborn; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D003967:Diarrhea / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D005260:Female; D005838:Genotype; D007112:Immunity, Maternally-Acquired; D009329:Nebraska; D011247:Pregnancy; D012401:Rotavirus / Q000145:classification / Q000235:genetics* / Q000276:immunology*; D012400:Rotavirus Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D012703:Serotyping; D014611:Vaccination / Q000662:veterinary