Bovine viral diarrhea is one of the most common viral diseases in the world livestock (60-80% prevalence). The circulation of livestock within Europe fuels a perpetual cycle of infection. Most of the time, it remains subclinical and is not perceived as a threat by farmers. However, this changes as soon as the virus manifests itself. Its effects on naive herds are often devastating as it impairs the immune system, the reproductive system, the respiratory system and the gastroenteric system. There are two genotypes of the virus: type 1 and type 2.
Type 1 is more common in the European Union with a prevalence of over 90 % while type 2 is strongly advancing. The last outbreak in Germany showed a mortality rate as high as 80 %. Due to the wide range of symptoms, BVD is difficult to detect and can therefore remain invisible for years. Despite the lack of symptoms, the disease is present nonetheless and can cause extreme economic losses to livestock. Some of the gravest damage inflicted by BVD affects the immune system, the respiratory system and the gastroenteric system. Furthermore, it can cause abortions, malformations and neonatal deaths. These factors pose considerate threats to the farmers’ status.
The primary source of transmission are persistently infected animals. These specimen can be asymptomatic, are likely to go unnoticed and are hence responsible for its viral persistence. Another significant source for infection are animals with chronic infection as well as those with transient infection. In order to put a stop to the vicious cycle of infection and reinfection, some measures need to be taken. These include biosecurity, the identification of PI animals, the elimination of PI animals, vaccination and constant monitoring. Vaccinating livestock is a fundamental measure of attaining a biosecurity system.