engleski

Epidemiology of bovine viral diarrhea virus in Croatia

Bovine viral diarrhea virus (BVDV) is one of the most important pathogens of cattle worldwide. Numerous studies confirmed its economic impact on cattle industry, causing reproductive disorders. Serological evidence of BVDV infection has been reported in Croatia since the late 1960s. Also, two cases of BVDV infection have been confirmed in the past fifteen years. However, BVDV has never been studied at the national level. To establish the prevalence of specific antibodies and the prevalence of persistently infected (PI) cattle, 18 non-vaccinated dairy herds from different counties were randomly selected. In selected herds, sera samples from all animals were collected ; a total of 1936 samples. 1851 sera from heifers and cows were analyzed with ELISA and immunoperoxidase (IP) test. 85 sera from calves were analyzed with ELISA and RT-PCR. Specific antibodies were detected in 1486 (76.76%) sera samples and virus was detected in 11 (0.57%) sera samples (Figure 1). 10 positive sera samples from heifers and cows were determined to originate from PI cattle, as demonstrated by repeated testing after four weeks interval. One initially RT-PCR positive calf was determined to be acute infected, as demonstrated by negative RT-PCR result after four weeks. At the herd level, the seroprevalence was 100%, meaning that each herd had at least one seropositive animal. Prevalence of PI herds was 27.7% without any clinical signs of BVDV infection. In all herds with PI, the prevalence of specific antibodies was greater than 90%.

BVDV; seroprevalence; ELISA; IP test; RT-PCR

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