MOLECULAR DIAGNOSIS AND PATHOLOGY OF PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS AND PORCINE PARVO VIRUS INFECTIONS
Loading...
Date
2019
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
College of Veterinary and animal Science,Mannuthy
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine parvo virus
(PPV) are important emerging viral diseases having significant impact on global swine
industries. Hence, the present research work was designed with the objective of detecting
PRRSV and PPV from naturally occurring cases in swine population. Gross and
histopathological lesions due to PRRSV and PPV infections were studied and these infections
were further confirmed with immuno-histochemistry (IHC). 56 samples from pig carcasses
suspected for PRRSV and PPV infections were collected during the study period from June
2018 to June 2019 from different swine farms across Kerala. Reverse transcriptase polymerase
chain reaction (RT-PCR) and polymerase chain reaction (PCR) identified eight cases positive
for PRRSV and one case positive for PPV, respectively. Common gross lesions of PRRSV
positive cases were non-collapsed voluminous lungs, enlarged and congested lymph nodes,
splenomegaly, hemopericardium with multifocal whitish areas of necrotic spots in the liver.
Gross lesions in PPV positive cases were non-collapsed voluminous lungs, fibrinous
pericarditis, splenomegaly and multifocal whitish necrotic foci in kidneys. Histopathologically,
PRRSV cases revealed interstitial pneumonia and severe lymphoid depletion in the tonsils of
the soft palate, spleen and lymph nodes. PPV positive case displayed interstitial pneumonia,
moderate lymphoid depletion in various lymphoid organs and interstitial nephritis. With IHC,
viral antigens in positive cases of PRRSV and PPV were demonstrated in lungs and lymphoid
organs. In addition, phylogenetic analysis of PRRSV isolate in this study was genetically
related to other Indian isolates but forms a separate clade whereas PPV showed close
relationship with Korean and Pookode strains. Therefore, this study establishes the presence of
PRRSV and PPV in the swine population of Kerala. Routine screening of these viruses in swine
farms needs to be practised as an effective measure to control these diseases. So, this study will
serve as an evidence for the importance of vaccination against PRRSV and PPV infections of
swine populations in near future.