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Dr. Tanja Opriessnig - Research Topics

Home  Lab Group Announcements Diagnostic Tests PCV2

Porcine circovirus type 2 (PCV2)

PCV2 is a small circular arranged DNA virus that is usually associated with very unique microscopic lesions in lymphoid tissues in affected pigs. These lesions include lymphoid depletion and histiocytic replacement of follicles. PCV2 is associated with several disease manifestations in pigs commonly referred to as porcine circovirus type 2 associated diseases (PCVAD). Our PCV2 research focuses on investigation of host and viral and environmental factors that influence the pathogenesis of PCVAD, understanding and developing and testing prevention and control strategies, and expanding knowledge on transmission of PCV2.

 PCV2 infected pigs Enlarged tracheobronchial node

Pigs experimentally inoculated with PCV2 21 days previously and associated gross lesions.

Enlarged iliac (Left) and tracheobronchial
lymph nodes (Right).
PCV2 antigen
Multinucleated giant cell
PCV2 normal lymph nodes PCV2 lymph node depletion
Normal lymph node. Lymphoid depletion and granulomatous lymphadenitis. 

Erysipelothrix rhusiopathiae

Erysipelothrix rhusiopathiae is the cause of swine erysipelas.  Acute erysipelas outbreaks in pigs may induce substantial morbidity and mortality within days. The chronic form may result in the development of arthritis and endocarditis. Recently, additional diagnostic tools to more accurately and rapidly diagnose erysipelas and further characterize Erysipelothrix sp. from field cases in pigs and other species became available. Our erysipelas research currently focuses on characterization of isolates recovered from unusual manifestations of erysipelas.

Erysipelas infected pig
Pig infected with Erysipelothrix rhusiopathiae:
Classical skin lesions.
Erysipelothrix rhusiopathiae colonies on a
sheep blood agar plate:
Multiple tiny transparent colonies.

Hepatitis E virus (HEV)

Hepatitis E virus (HEV) is a non-enveloped, single-stranded, positive sense RNA virus and a major cause of enterically-transmitted, non-A, non-B hepatitis. The virus is considered to be transmitted via fecal-oral route and is usually associated with water-borne epidemics. The prototype swine HEV was discovered in 1997 in the U.S.  Serologic evidence indicates that HEV is widespread in pigs. HEV infection induces mild hepatitis lesions in growing pigs which exhibit no clinical signs. Pigs are however considered an important reservoir for infection of humans with HEV. Our HEV work is focused on expanding knowledge on HEV transmission and further refining the pig model of HEV to better understand HEV pathogenesis in animals and humans. We work closely with Dr. Xiang-Jin Meng’s group at Virginia Tech on HEV research. 

Porcine reproductive and respiratory syndrome virus (PRRSV)

PRRSV, an RNA virus, continues to be the most economically devastating disease affecting the swine industry worldwide. PRRSV is associated with reproductive failures in breeding animals and respiratory disease in growing pigs. Commercial vaccines for PRRSV are available and widely used but often fail. The marked genetic and antigenic diversity among PRRSV strains is most likely the reason for this. Our PRRSV research focuses on developing and testing intervention strategies and development of experimental co-infection models with other pathogens. 

PRRS associated abortion PRRS infection
Lung from a pig experimentally infected
with PRRSV.
PRRSV-associated abortion.  PRRSV infected alveolar macrophages (brown staining) in a pig experimentally inoculated with PRRSV.