Update on Testicular Infections With Bovine Viral Diarrhea Virus

Bovine viral diarrhea virus (BVDV) is the prototypical member of the Pestivirus genus of the Flaviviridae family and is a significant cause of disease and economic losses in cattle herds worldwide. Clinical disease is manifested in several body systems including the respiratory, gastrointestinal, nervous and immune systems. However, the effects of infection on reproduction likely have the largest economic impact for the producer. In the female, the consequence of BVDV infection depends largely on the immune status of the dam and the stage of gestation at the time of infection. Conception rates may be negatively impacted if infection occurs near the time of breeding1 and abortion can occur at any time during gestation. Infection of susceptible cattle with a noncytopathic strain of the virus between 18 and 125 days of gestation may result in immunotolerance in the fetus and persistent infection. Persistently infected (PI) animals serve as a viral reservoir and consistently shed high amounts of infectious virus throughout their lifetime. Infection of the pregnant dam may also result in several congenital defects, including cerebellar hypoplasia, hydranencephaly and microphthalmia if the event occurs during critical times of organogenesis.