Prevalence of Bovine Viral Diarrhea Virus Persistency in 12 Holstein Cattle Dairy Herds of Charlottetown, Canada

The prevalence of bovine viral diarrhea virus (BVDV) persistency was examined in 12 Holstein dairy herds in Charlottetown, Canada, from Feb. 2009 to Oct. 2009. A total of 469 serum and ear notch biopsy pairs were collected. Depending upon the age and vaccination status, the sampled animals were divided into three groups. A, B1 and B2. Group A consisted of 146 animals originating from 4 herds (<= 6 month of age, FN1, FN2, 1:FN3, FN4), group B1 comprised 267 animals representing 5 vaccinated herds against BVDV (>= 6 months of age, FV1, FV2, FV3, FV4, FV5), whereas, 56 samples were taken from 3 BVDV non-vaccinated herds of group 82 (>= 6 months of age, FN5, FN6, FN7). All the animals were pre-screened through scrum neutralization test (SNT), whereas, all ear notch biopsies of group A (n = 146) and only of those animals of group B1 (n = 15) and B2 (n = 37) which had SN titer <= 1:64 were processed to confirm the BVDV persistent infection. Only five animals were found positive originating from group A (n = 3) and B1 (n = 2) during first sampling. Upon follow pp testing, two animals from each of group A and B I remained positive confirming persistent infection (PI). A prevalence of 0.85% and 2.03% was observed in all the collected and pre screened animals, respectively. The results obtained in this study, demonstrates that the prevalence of PI animals in dairy herds of Prince Edward Island is similar to that, reported from other surveys carried out in other countries. This prevalence PI animals with BVDV in Holstein dairy herds of Charlottetown. Canada, reveal the necessity of further studying BVDV infection in the area.