A two-year, $150,000 postdoctoral fellowship grant from the U.S. Department of Agriculture will help a researcher in the Virginia-Maryland Regional College of Veterinary Medicine    investigate how porcine circovirus type 2 (PCV2) depletes the lymphatic system and causes inflammation in pigs.

PCV2 has been a global swine disease that has caused significant economic losses since its first discovery in the late 1990s.

Shannon Matzinger, postdoctoral associate in the college’s Department of Biomedical Sciences and Pathobiology, who received the grant, observes: “Although this is arguably one of the most economically important pig viruses, we still do not fully understand the mechanism for how it causes disease. If we can identify the underlying mechanism that causes the disease, we can design better control and prevention strategies against the virus.”

Scientists first identified non-pathogenic porcine circoviruses in contaminated kidney cells in 1974 and the pathogenic strain in pigs with post-weaning multi-systemic wasting disease in 1998. The disease can cause respiratory issues, intestinal disease, and reproductive problems and primarily infects the lymphatic system.

X.J. Meng, University Distinguished Professor of Molecular Virology and Matzinger’s mentor for this fellowship grant, explains that although vaccines against the virus have been on the market since 2006, emerging variant strains of the virus and rare cases of vaccine failures still threaten the swine industry.

Meng and Matzinger hope to identify some of the genetic factors in the host cells and the virus genome that may be wreaking havoc on the immune system of infected pigs.

“One of the questions that remain unanswered is how porcine circovirus type 2 is depleting the immune system,” Matzinger says. “If we can answer this question, we will understand a key component of the viral pathogenesis and disease progression.”

In particular, she will be testing a hypothesis that the virus encodes viral micro-RNAs — molecules that play an important role in the regulation and expression of genes — that obstruct the immune system’s ability to detect the virus either by maintaining low levels of virus replication or preventing specific cells in the immune system from communicating with each other.

The complete story can be found on the Virginia Tech News website: http://www.vtnews.vt.edu/articles/2013/11/110113-vetmed-pcv2grant.html