Molecular Survey on Porcine Parvoviruses (PPV1-7) and Their Association with Major Pathogens in Reproductive Failure Outbreaks in Northern Italy

Abstract

Successful reproductive performance is key to farm competitiveness in the global marketplace. Porcine parvovirus 1 (PPV1) has been identified as a major cause of reproductive failure, and since 2001 new species of porcine parvoviruses, namely PPV2–7, have been identified, although their role is not yet fully understood yet. The present study aimed to investigate PPVs’ presence in reproductive failure outbreaks occurring in 124 farms of northern Italy. Fetuses were collected from 338 sows between 2019 and 2021 and tested for PPVs by real-time PCR-based assays and for other viruses responsible for reproductive disease. At least one PPV species was detected in 59.7% (74/124) of the tested farms. In order, PPV1, PPV5, PPV6, PPV7 and PPV4 were the most frequently detected species, whereas fewer detections were registered for PPV2 and PPV3. Overall, the new PPV2–7 species were detected in 26.6% (90/338) of the cases, both alone or in co-infections: PCV-2 (7.1%, 24/338), PCV-3 (8.2%, 28/338), and PRRSV-1 (6.2%, 21/338) were frequently identified in association with PPVs. Single PPVs detections or co-infections with other agents commonly responsible for reproductive failure should encourage future studies investigating their biological, clinical, and epidemiological role, for a better preparedness for potential emerging challenges in intensive pig production.

First Molecular Characterisation of Porcine Parvovirus 7 (PPV7) in Italy

“…Possibly, the biosecurity measures adopted in domestic pig farms might have played a relevant role in reducing the introduction and spreading of infectious agents, including PPV7. The proportion of PPV7 infection found in this study was similar to that previously reported in Italy (5.9%) [34], but appeared to be lower than in Poland (19.6%) [32], Southern China (25.73%) [28], Mongolia (28.72%) [10], and the Republic of Korea (14.2%) [48]. Few reports on PPV7 infection in wild boars have been published so far; the positivity percentages found in wild boars in the present work are higher than what was observed by other authors in the Republic of Korea (less than 0.5%) [29].…”

“…A study conducted by Miłek et al in Poland [ 32 ], provided the first evidence of detection of PPV7 in domestic pigs in Europe, followed by the report by Blomström et al [ 33 ] in Sweden. More recently, Faustini et al [ 34 ] reported the circulation of PPV7 in domestic pig farms, with reproductive problems in northern Italy in association with other pathogens.…”

“…In Europe, PPV7 was firstly detected in Poland [ 32 ] and subsequently in Sweden [ 33 ]. More recently, the presence of the newly emerging PPV7, together with other PPV species, was revealed in Northern Italy in pig farms experiencing reproductive failure [ 34 ], but no information about the molecular characteristics of the strains was reported. Hence, this study was performed on blood and tissue samples collected from Sardinian domestic and wild pigs to investigate the presence of PPV7, to molecularly characterise the Sardinian strains and perform a time-scaled phylogenetic analysis.…”