TDK conference 2009

Bovine Viral Diarrhoea (BVD) is a viral disease appearing in various forms and caused by a virus (Bovine Viral Diarrhoea Virus, BVDV) belonging to the Pestivirus genus Flaviviridae family. It is very important, because it causes the highest economic losses in the cattle stock of Hungary following the Infectious Bovine Rhinotracheitis (IBR).

The aim of the study described in the present work was to determine the prevalence of the virus in Hungary by the help of a monitoring survey carried out on samples from several samples collected at cattle keeping units throughout the country. Since no such survey has been carried out in Hungary in the last thirty years, our study may serve as a basis for later monitoring examinations aimed to follow the expected eradication of BVD.

The examinations were carried out using the ELISA (Enzyme Linked Immunosorbent Assay) method, on 1176 blood samples sent from 59 cattle stocks localised in 16 counties of the country. The number of the samples reflected the number of the animals kept in the cattle farm, according to the rules of the statistical sampling, therefore our study can be regarded as representative. (The sample number varied between 5 and 70.) From a total of 1176 samples 500 proved to be positive (42.5%), 34 gave doubtful result (2.9%), while 642 was negative (54.6%). Regarding the cattle keeping units, from the 59 units sending samples for investigation there were 40 stocks in which at least one positive was found (67.8%), while among the blood samples of 19 stocks no positive was demonstrated (32.2%). Among these latter stocks there were several ones, where the samples were collected from old cows serving already through several lactation periods, therefore the seronegativity clearly indicates the BVDV free status of the given stock. Even among the positive cattle keeping units we found a few, where the seropositivity rate was rather low (x<5%).

According to the result of the investigation, a rather high portion (about one third) of the cattle keeping units of Hungary can be regarded as BVDV free, which ratio is much better then it has been anticipated, based upon surveys carried out on lower number of samples and in smaller regions of the country. Hence the chances of an eradication campaign launched in the near future, or carried out parallel with the IBR eradication are better then expected. Based on the results of the survey, before starting vaccination in a certain unit due to reproductive disorders or enteric problems, it is advisable to clarify the status of the stock by serological investigations.