Background and Aims: Bovine viral diarrhea virus (BVDV) is considered as worldwide and economically significant infection. The aim of this study was to estimate prevalence of persistent bovine viral diarrhea infection (PI) in industrial dairies of Tehran and Alborz province, Iran. Materials and Methods: In this cross-sectional study, 102371 blood samples were collected from bovine of industrial dairies of Tehran and Alborz province during 2018. Indirect enzyme-linked immunosorbent assay (ELISA) and Reverse transcription-polymerase chain reaction (RT-PCR) were performed for determination of viral genotypes, including BVDV1, BVDV2, and HOBi like among PI samples. Results: A total of 102371 samples were collected from 76 industrial dairies in Tehran and Alborz province, that 512 cases were PI. All samples were positive for BVDV1 (100%). Other genotypes were not found among PI samples. Conclusion: Prevalence of persistent bovine viral diarrhea infection in industrial dairies in Tehran and Alborz was not high. However, it will be further decreased by implementing control and eradication programs.

In a prototypical response to an acute viral infection it would be expected that the adaptive immune response would eliminate all virally infected cells within a few weeks of infection. However many (non-retrovirus) RNA viruses can establish ‘, within host’,persistent infections that occasionally lead to chronic or reactivated disease. Despite the importance of ‘, within host’,persistent RNA virus infections, much has still to be learnt about the molecular mechanisms by which RNA viruses establish persistent infections, why innate and adaptive immune responses fail to rapidly clear these infections, and the epidemiological and potential disease consequences of such infections.