Veterinary session

The members of the Parvoviridae family are versatile, small viruses occurring in a broad range of hosts worldwide. Since its discovery in 1965, porcine parvovirus 1 (PPV1) is well known for its ability to cause reproductive failure in sows. Fortunately, the proper vaccination protocol greatly reduce the economic losses.

Thanks to the rapidly evolving molecular biological methods several new viruses were discovered in recent decade, such porcine parvovirus 2 (PPV2) described in 2001. Recent studies reported the presence of PPV2 in different geographical regions, however concerning the pathogenic role of the virus, no available information can be found. PPV2 is often detected from pigs affected by respiratory diseases suggesting a role of this virus in clinical and pathologic signs. Since PPV2 itself cannot be propagated in vivo at present time, therefore its potential of inducing sickness can only be investigated by a different approach. In this case, only indirect methods can be used to deduce the importance of the virus.

In our studies, an ELISA method was developed for detection of PPV2 specific antibodies, enabling us to determine the serological profile of the infected swine herd. In order to depict the immunological status of these animals, 185 serum samples were collected from pigs belonging to different age groups (sows, piglets and growing pigs) and tested using newly elaborated ELISA. The results of analysis showed decreasing levels of maternal antibodies during the first two weeks of ages. Later, PPV2 specific antibody quantity started to increase between 36 to 43 days, in relation with the onset of respiratory signs. The animals no longer exhibited such symptoms by the age of 57 days, which can be attributed to the significant elevation of PPV2 specific antibody titers, reaching their peak at this age group. Viremic status of infected swine herd was also investigated by qPCR method using the acquired serum samples. Low levels of viremia were present in all analyzed age groups, however pigs of 57 days of age carried the highest amount of PPV2 copies, which decreased with progression of time.

Changes concerning the levels of virus loads and antibodies, as well as the clinical signs suggest that PPV2 may possess an important role in the development of respiratory diseases. In order to determine the pathological importance of PPV2 further studies are needed.