Monitoring bovine viral diarrhea virus (BVDV) infection status in dairy herds

Abstract

588Pesq. Vet. Bras. 28(12):588-592, dezembro 2008 RESUMO.-[Monitoramento do estado de infecção pelo vírus da diarrhéia viral bovina (BVDV) em rebanhos bovinos leiteiros.] Os objetivos do presente estudo foram avaliar a relação entre os níveis de anticorpos frente ao vírus da diarréia viral bovina (BVDV) no tanque de leite e a prevalência de animais seropositivos em cada rebanho; e também avaliar a eficiência da medição dos ní-veis de anticorpos no tanque de leite como método de monitoramento do status de infecção frente ao BVDV. Nos rebanhos estudados, obtiveram-se amostras de soro de todos os animais com idade superior a um ano, assim como uma amostra de tanque coletivo de leite. As amostras de soro e leite foram analisados por um teste ELISA de bloqueio baseado na detecção de anticorpos anti-p80. Posteriormente coletaram-se mais duas amostras do tanque de leite em cada exploração com intervalos de nove meses entre as coletas. This study was designed to assess the relationship between antibodies against bovine viral diarrhea virus (BVDV) determined in the bulk tank milk (BTM) and the within-herd seroprevalence. We also assessed the efficiency of measuring antibody levels in BTM samples to monitor BVDV infection status in a herd. In the 81 farms included in the study, BTM samples were obtained and blood samples withdrawn from all cattle older than one year. The infection status was then determined in serum and milk using a commercial blocking ELISA based on the detection of anti-p80 antibodies. Apart from these baseline serum and milk samples, another BTM sample was collected from each herd 9 months later, and a third BTM sample obtained 9 months after this. In these second and third milk samples, anti-BVDV antibodies were determined using the same ELISA kit. Statistical tests revealed good agreement between herd seroprevalences (% seropositive animals in the herd) and the antibody levels detected in the BTM samples. During the 18 months of follow-up, the farms with persistently infected cattle at the study outset (14.8% of the herds) showed a significant decrease in BTM antibody titers after virus clearance. Conversely, a significant increase in BTM antibody levels was observed in the herds infected with BVDV during the follow-up period. Our findings indicate that monitoring antibody levels in the BTM is a useful method of identifying changes in the BVDV infection status of a herd.

Comparative study in the control of bovine viral diarrhea

“…The first region of Spain to implement a voluntary program of BVD control was Galicia, which started in 2004 (Diéguez et al ., 2008). In the first stage, the initial BVD status of each herd is evaluated in order to differentiate herds with BVDV from those which are BVDV-free.…”

Short communication: Correlation between within-herd antibody-prevalence and bulk tank milk antibody levels to Mycobacterium avium ssp. paratuberculosis using 2 commercial immunoassays

“…Bulk tank milk testing is a frequently used tool for the surveillance and monitoring of several infectious diseases in dairy cattle, such as infectious bovine rhinotracheitis (IBR), enzootic bovine leucosis, bovine virus diarrhea (BVD), and salmonellosis. Bulk tank milk for BVD, IBR, and salmonellosis has been widely used to estimate the within-herd prevalence of antibody-positive cows and to monitor dairy herds (Nylen et al, 1999;Warnick et al, 2006;Diéguez et al, 2008;Eiras et al, 2012).…”

Bovine viral diarrhea virus

“…Consequently, an initial herd classification could be determined and then monitored with additional samples to help control and observe bovine viral diarrhea infection over time. 5 help in collecting the serum samples, as well as their colleagues from Seroloxía, ADSG, and Campañas de Saneamento Gandeiro for their help in processing and analyzing the samples.…”

“…13 Along this line, several European countries have monitored dairy herds for several years using BTM antibody ELISAs. 2,5,9,14 Previous studies have shown that the sensitivity of tests using antibody levels in bulk milk to predict the presence of persistently infected animals is close to 1, whereas the specificity is lower. 2,9,14 The objective of the current study was to examine the relationship between within-herd seroprevalence and BTM antibody levels against BVDV using 4 commercial ELISAs.…”

“…Consequently, an initial herd classification could be determined and then monitored with additional samples to help control and observe bovine viral diarrhea infection over time. 5…”