BVD Type 1 and Type 2
Volker Moennig
In 1989, a new clinical condition caused by BVD was described. Up to this point, an acute infection leading to death was unknown for BVD. The clinical picture was very similar to the fatal mucosal disease accompanied by petechial bleedings and large-scale bleedings of the internal organs. Young animals died in almost all cases of infections.
Once the virus from all cases of BVD induced diseases was isolated, people moved on to characterise the virus by sequencing it. What they found was quite surprising: this BVD virus was very different from what was known about BVD at that point. Hence, it was decided to call the new pathogenic variant BVD type 2 and the ‘old’ variant became BVD type 1. After further investigations it turned out that in the United States of America 50 % of all BVD isolates were BVD type 2.
In Europe the development of BVD is a less dramatic one. BVD type 2 can be scientifically proven in very few cases. Proven infections with BVD type 2 range well below 10 %, in the 1 to 3 % area. Contrary to initial presumptions, not all BVD type 2 rates are highly pathogenic. BVD type 2 is quite similar to BVD type 1 regarding its adaptability to cattle. Furthermore, it does not cause a dramatic disease each time it is contracted. The last outbreak of virulent BVD type 2 was situated in North-West Germany and caused considerable damage.
