BVDV and BHV-1 Infections in Dairy Herds in Northern and Northeastern Thailand

J Kampa,K Ståhl,A Chanlun,S Alenius,J Moreno-López,S Aiumlamai

doi:10.1186/1751-0147-45-181

J Kampa, K Ståhl + Show 4 more

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https://doi.org/10.1186/1751-0147-45-181

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Abstract

Bulk milk samples from 220 dairy herds were collected at 9 public milk collection centres in the northeastern and northern Thailand, and a subset of 11 herds was selected for individual testing. The samples were tested for presence of antibodies to BVDV and BHV-1 using an indirect ELISA. The results from the bulk milk testing demonstrated a moderate level of exposure to BVDV and BHV-1 (73% and 67%, respectively). However, the low proportion of herds with high BVDV antibody-levels (13%) and the low within-herd seroprevalence of BVDV and BHV-1 in the 11 herds (24% and 5%, respectively), particularly among the young stock (15% and 0%, respectively), demonstrated a low prevalence of active BVDV infection and a low rate of reactivation of latent BHV-1. The presence of a self-clearance process was also indicated by the results from the individual testing. Moreover, a surprisingly low prevalence of BVDV and BHV-1 antibody-positive herds at one of the milk centres was found. This centre was established 5–10 years before the others. Our impression is that this reflects the self-clearance process, where consecutive replacement of imported infected animals without further spread has resulted in a nearly total elimination of the infections.Based on our experiences and on these results we are convinced that this process can continue if there is awareness of herd biosecurity. This is especially important in the context of a future intensification of the dairy production.

Highlights

Bovine viral diarrhoea virus (BVDV) and bovine herpesvirus type 1 (BHV-1) are wellknown, important pathogens of cattle that give rise to substantial economic losses due to reproductive failures and increased calf mortality, as well as enteric and respiratory disease
Bulk milk testing The distributions of bulk milk corrected optical density (COD) levels from BVDV and BHV-1 antibody assays are shown in fig
Milk centre 9 differed from all the other milk centres, with a very low prevalence of BVDV and BHV-1 antibody-positive herds, and significantly lower mean CODs

Summary

Introduction

Bovine viral diarrhoea virus (BVDV) and bovine herpesvirus type 1 (BHV-1) are wellknown, important pathogens of cattle that give rise to substantial economic losses due to reproductive failures and increased calf mortality, as well as enteric and respiratory disease These pathogens have a worldwide distribution and tend to be endemic in most populations, national and regional variations occur (for BVDV review see Nettleton & Entrican 1995, Houe 1999, Lindberg 2003; for BHV-1 review see Gibbs & Rweywmamu 1977, Kahrs 2001, Straub 2001). During the last decades eradication programmes against BVDV and BHV-1, without the use of vaccines, have been implemented in some European countries These have been based on identification and elimination of carrier animals, together with increased herd biosecurity. The purpose was to estimate the prevalence of active or recent infection of BVDV and BHV-1, with the aim to make recommendations for disease control

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