Serological and molecular diagnosis of bovine viral diarrhoea virus and evidence of other viral infections in dairy calves with respiratory disease in Venezuela.
An investigation based on 2 studies was carried out to assess the involvement of bovine virus diarrhoea virus (BVDV), bovine herpesvirus type 1 (BHV-1), and bovine respiratory syncytial virus (BRSV) in calf respiratory disease in dairy farms in Venezuela. In the first study, 8 farms were selected and paired serum samples from 42 calves with respiratory disease were tested by ELISA for antibodies to the 3 viruses. Seroconversion to BVDV, BHV-1, and BRSV was found to 5, 2, and 6 farms out of the 8, respectively. The proportion of calves that showed seroconversion to BVDV, BHV-1, and BRSV were 19%, 14%, and 26%, respectively. In the second study, another farm having previous serological evidence of BVDV infection was selected. The decline of maternal antibodies against BVDV was monitored in 20 calves and the half-life of maternal antibodies was 34 +/- 12 days presumably indicating an early natural infection with BVDV. Furthermore, sera free of BVDV antibodies that were collected in studies 1 and 2 and were assayed for the presence of BVDV by nested RT-PCR. Two BVDV strains were detected and compared to those of ruminant and porcine pestiviruses. Both strains were assigned to subgroup Ib of type I BVDV. This investigation provides information on BVDV genotypes circulating in Venezuela and may contribute to the establishment of official control programmes against the viruses studied.
Obando
C
C
Department of Veterinary Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Baule
C
C
Pedrique
C
C
Veracierta
C
C
Belák
S
S
Merza
M
M
Moreno-Lopez
J
J
D000818:Animals; D000914:Antibodies, Viral / Q000302:isolation & purification; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000097:blood / Q000453:epidemiology* / Q000276:immunology; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood / Q000453:epidemiology* / Q000821:virology; D003612:Dairying; D004797:Enzyme-Linked Immunosorbent Assay; D005838:Genotype; D007242:Herpesvirus 1, Bovine / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D007112:Immunity, Maternally-Acquired; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000302:isolation & purification; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology / Q000276:immunology / Q000662:veterinary*; D018112:Respiratory Syncytial Virus, Bovine / Q000276:immunology / Q000302:isolation & purification*; D016036:Seroepidemiologic Studies; D016092:Spumavirus / Q000276:immunology / Q000302:isolation & purification*; D014687:Venezuela / Q000453:epidemiology
D000914:Antibodies, Viral; D012367:RNA, Viral