This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.
Diana S. Vargas-Bermuedez and Jairo Jaime from the Universidad Nacional de Colombia give a summary of a report of PPV8 found this August in Colombia.
Introduction
Porcine parvovirus 1 (PPV1) is a primary reproductive failure virus (PRF) that manifests in the form of SMEDI (Stillbirth, mummification, embryonic death, and infertility) and has been controlled by vaccination programs since the 1970s. Seven new PPVs (PPV2 through PPV8) have been discovered, which we call novel porcine parvoviruses (nPPVs). Details of their pathogenesis, tropism, and disease etiology are still unknown. Research published to date provides some associations between nPPVs and PRF and porcine respiratory disease complex (PRDC) when coinfection with other primary viruses such as PPV1, PCV2, and PRRSV, are present. The most recent nPPV reported was PPV8 in China in 2022. Until this year, PPV8 had not been identified outside China; in July 2024, it was reported in Europe (Hungary and Slovakia) with a surprising finding: the presence of PPV8 on 65% of the farms included in the study. In August 2024, the Center for Research in Veterinary Infectology and Immunology at the National University of Colombia reported PPV8 for the first time in the Americas, specifically in two provinces of Colombia (Cundinamarca and Eje Cafetero) with high swine production. The primary objective was to evaluate viruses involved in PRDC (PCV2, PCV3, and PRRSV).
Methods
A collection of lung samples from pigs with clinical signs of respiratory disease was obtained. A total of 146 lung tissues were collected from nursery pigs (n = 122; aged 3 to 8 weeks) and grow-finisher pigs (n = 24; aged 8 to 23 weeks).
Results
Apart from the results obtained on the three target respiratory viruses, incidentally, PPV8 was detected in 4.1% (6/146) of the total lung samples tested. At the herd level, the virus was detected in 3.1% (3/76) of the herds tested, and by age groups, it was detected in 3.3% (4/122) of nursery pigs and 8.3% (2/24) of grow-finisher pigs.
Discussion
In addition to being the first report for the Americas, this study is the first to provide an estimate of PPV8 prevalence in lungs of pigs with respiratory disease by age groups (nursery and grow-finisher pigs). Additionally, sequences from two Colombian PPV8 strains (GenBank accession numbers PP335559 and PP335560) were obtained, and based on their phylogenetic relationships, PPV8 was confirmed as a member of the Protoparvovirus genus. On the other hand, PPV8 was present in both single infections and coinfections with other viruses. PPV8 mono-infection accounted for 16% (1/6) of the PPV8-positive lung samples. Coinfection PRRSV/PPV8 was found in 2/6 (33.3%), while PCV2/PPV8 was found in 1/6 (16%) PPV8-positive lungs. A triple infection PCV2/PRRSV/PPV8 was detected in 2/6 (33%) PPV8-positive lungs. The presence of PPV8 in pigs with respiratory signs, particularly in coinfection with other viruses (PRRSV and PCV2), suggests the possible participation of PPV8 in PRDC, but this still needs to be investigated experimentally.
The article is available at Arch Virol: https://doi.org/10.1007/s00705-024-06099-z