Molecular Detection of Porcine Parvovirus in Swine with Reproductive Failure

Abstract

Background: Porcine parvovirus (PPV) is considered to be one of the most important causes of reproductive failure in swine. Fetal death, mummification, stillbirths and delayed return to estrus are predominant clinical signs commonly associated with PPV infection in a herd. Methods: In this field laboratory investigation during 2020-2022, the aim was to study the prevalence of PPV in swine reproductive failure in an organized farm in Chennai, Tamil Nadu. A detailed necropsy examination was conducted on 3 mummified fetuses and 17 still born fetuses and salient gross finding were accumulation of serosanguinous fluid in the cavities. Representative tissues samples from brain, lungs, heart, spleen, intestine, kidneys, mesenteric, inguinal lymph nodes and liver were collected on ice and in 10% neutral buffered formalin for histopathological, immunohistochemical and molecular studies. Result: Out of the 20 fetal tissues analyzed by PCR for PPV genome, 19 samples were found to be positive for the NS1 gene. The identification of the amplified products was confirmed by direct sequencing of purified PCR products. Histopathological examination of the liver showed intranuclear inclusion bodies and necrotic myocarditis. Immunohistochemical studies showed PPV antigen distributed in the striated muscle cells of the heart, alveolar epithelial cells of lungs, hepatocytes of the liver and tubular epithelial cells of kidneys. The present study confirms the prevalence of PPV in fetal tissues in an organized pig farm in Tamil Nadu which warrants further surveillance.