Reproductive Syndrome Virus Infection Research Articles

Porcine circovirus 2d associated with stillborn mummified foetus of pig

Recurrent occurrence of stillborn piglets was noticed along with live births during farrowing in pigs in an organized pig farm of Uttar Pradesh. On detailed post mortem examination, externally, the foetus was found to be partially dehydrated and dark brown in colour with shrunken eyes. Internally, visceral organs including lungs, heart, kidneys, liver, spleen and intestine were partially dehydrated and dark brown in colour. Upon molecular investigation, the pooled tissue samples were found positive for porcine circovirus 2 (PCV2) infection using PCR technique and further confirmed the PCV2d genotype by DNA sequencing. Other most possible infections including porcine parvoviral infection (PPV), PCV3 and porcine respiratory and reproductive syndrome virus infection (PRRS) were found negative using PCR and RT-PCR techniques, respectively. This result is suggestive of role of PCV2d as a possible etiological agent to cause stillbirth and mummification of porcine foetuses.

Porcine serum amyloid A3 is expressed in extrahepatic tissues and facilitates viral replication during porcine respiratory and reproductive syndrome virus infection

Serum amyloid A (SAA) is an acute phase protein that is expressed rapidly in response to infection and inflammation in vertebrates. Here, we detected the expression of porcine SAA3, an isoform of porcine SAA, during porcine respiratory and reproductive syndrome virus (PRRSV) infection, which is a major threat to the pig industry. In response to PRRSV infection, porcine SAA3 expression was upregulated significantly in porcine pulmonary alveolar macrophages and in extrahepatic tissues, including the lungs and inguinal, mandibular, and hilar lymph nodes, which were affected mainly by PRRSV infection, demonstrating that porcine SAA3 is a tissue-derived isoform that is induced in extrahepatic tissues during the acute phase response. Overexpression of porcine SAA3 increased PRRSV titers in cultured cells, and the exogenous administration of porcine SAA3 facilitated PRRSV adsorption to cells, suggesting that porcine SAA3 assists PRRSV replication. Our data provide insights into the role of porcine SAA3 during PRRSV infection.

Identification of SNPs in porcine genes expressed during porcine respiratory and reproductive syndrome virus infection

Identification of SNPs in porcine genes expressed during porcine respiratory and reproductive syndrome virus infection

Enzyme-linked immunosorbent assay employing a recombinant antigen for detection of protective antibody against swine erysipelas.

The specificities and sensitivities of five recombinant proteins of the surface protective antigen (SpaA) of Erysipelothrix rhusiopathiae were examined by indirect enzyme-linked immunosorbent assay (ELISA) with the aim of developing a reliable serological test for the detection of protective antibody against E. rhusiopathiae. Fully mature protein and the N-terminal 416 amino acids (SpaA416) showed sufficient antigenicities, and further examination was done with SpaA416 because of its higher yield. The antibody titers of pigs experimentally immunized with commercial live vaccine and two types of inactivated vaccines clearly increased after immunization, and all pigs were completely protected against challenge with virulent strains. On the other hand, the antibody titers of nonimmunized control pigs remained very low until they were challenged, and all showed severe symptoms or subsequently died. Interference with the production of antibody against live vaccine by maternal antibody or porcine respiratory and reproductive syndrome virus infection 1 week after vaccination was also clearly detected. Because the ELISA titer correlated well with the protection results, the specificity and sensitivity of the ELISA were further evaluated with sera collected from pigs reared on 1 farm on which animals had acute septicemia, 2 farms on which the animals were infected or free from infection, and 10 farms on which the animals were vaccinated with live vaccine, among others. The ELISA titers clearly revealed the conditions of the herds. These results indicate that the SpaA416 ELISA is an effective method not only for evaluating pigs for the presence of protective antibody levels resulting from vaccination or maternal antibody but also for detecting antibody produced by natural infection. This test has important potential for the effective control of swine erysipelas.