Investigating porcine parvoviruses genogroup 2 infection using in situ polymerase chain reaction

Abstract Background Porcine parvovirus 2 (PPV2) was detected in swine serum without showing any relationship with disease. The emergence of the virus seemed to be a unique event until other genetically highly similar parvoviruses were identified in China and, later in 2012, the presence of the virus was also described in Europe. PPV2 is widely distributed in pig populations where it is suspected to be involved in respiratory conditions, based on its frequent detection in lung samples. In order to investigate the potential pathogenic involvement of PPV2, 60 dead pigs were examined from two farms. They were necropsied and tested for PPV2 and PCV2 (Porcine circovirus type 2) by PCR; by Brown and Brenn (B&B) staining for bacteria; by immunohistochemistry (IHC) to detect CD3, Swine leukocyte antigen class II DQ (SLAIIDQ), lysozyme, porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza (SIV), Mycoplasma hyopneumoniae (Mhyo); and by in situ hybridization (ISH) to detect ssDNA and dsDNA of PCV2. PPV2 positive samples were subjected to in situ polymerase chain reaction (IS-PCR) including double staining method to detect PPV2 and host cell markers. To calculate statistical difference we used GENMOD or LOGISTIC procedures in Statistical Analysis System (SAS®). Results We found that the PPV2 was localized mostly in lymphocytes in lungs, lymph nodes and liver. Neither CD3 antigen nor lysozyme was expressed by these infected cells. In contrast, low levels of SLAIIDQ were expressed by infected cells, suggesting that PPV2 may have a specific tropism for immature B lymphocytes and/or NK lymphocytes though possibly not T lymphocytes. Conclusion The overall conclusion of this study indicates that PPV2 may contribute to the pathogenesis of pneumonia

Evidence of CPV2c introgression into Croatia and novel insights into phylogeny and cell tropism

International audienceCanine parvovirus type 2 (CPV2) emerged for the first time in 1978 and evolved into two antigenic variants CPV2a and CPV2b and the third new antigenic variant CPV2c reported in 2000 in Italy. During 2014 unexplained outbreaks of gastroenteritis were observed in kennels where an extensive vaccination program was ongoing and where vaccinated animals showed pathologic lesions consistent with typical parvovirosis. The aim of this study was to investigate whether CPV2 could have played a role in the emergence of these cases and to evaluate genetic or pathological specificities of the virus and the disease. Using PCR and phylogenetic analysis we showed that the CPV2c variant is circulating in Croatia and is in close relationships with isolates from North and South America. Histopathological lesions and cell tropism that are known for CPV2 we are reporting the identification of the virus in glial cells and ovaries. It seems that evolution of CPV and CPV2a-c and adaptation to dogs are two independent events. Croatian isolates had specific and some unique amino acid mutations under positive selection. The effect of the alterations on the immunoglobulin binding cannot be excluded

Additional file 2: of Investigating porcine parvoviruses genogroup 2 infection using in situ polymerase chain reaction

ODS results Farm E– PPV2 vs viruses. (DOCX 14 kb

Additional file 1: of Investigating porcine parvoviruses genogroup 2 infection using in situ polymerase chain reaction

Table presents results of PCR test for presence of following viruses: TTSuV, PPV1–4, PoBoV1–4, PoBolV, 6 V/7 V, PCMV, PRRSV, SIV and ADV in farm E. (XLS 30 kb

Legislative Documents

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Additional file 10: of Investigating porcine parvoviruses genogroup 2 infection using in situ polymerase chain reaction

Presence of PPV2 by in situ PCR and other pathogens in farm T. (XLSX 9 kb

Additional file 4: of Investigating porcine parvoviruses genogroup 2 infection using in situ polymerase chain reaction

Table presents results of presence of PCV2 in lungs tested by ISH in farm E. (XLS 33 kb

Additional file 3: of Investigating porcine parvoviruses genogroup 2 infection using in situ polymerase chain reaction

Table presents results of histopathological examination of lungs in farm E. (XLS 27 kb

Additional file 7: of Investigating porcine parvoviruses genogroup 2 infection using in situ polymerase chain reaction

Wald Chi2-square Farm E: IHC immune cells. (DOCX 16 kb