Porcine Parvovirus (PPV) (ssDNA, Paroviridae, Parvovirinae, Protoparvovirus): Molecular diagnosis (PCR)
Porcine parvovirus (PPV) is a virus of the genus Parvovirus, family Parvoviridae. This agent is widely spread in pig production throughout the world, where it causes porcine parvovirus (PVP), a disease whose pathogenic action is exerted only on the embryo or the fetus. Porcine Parvovirus (PVP) is a common cause of reproductive failure in sows, causing embryonic death and fetal mummification, the birth of weak piglets and litters with a reduced number of piglets.
Parvoviruses have a genome of approximately 5,000 nucleotides with single-stranded DNA (ssDNA), so they are included in Group II of the Baltimore Classification. These viruses are constituted by a structurally defined capsid of icosahedral symmetry and lacking a viral envelope. The parvoviruses have a size of 18 to 26 nm in diameter.
Transmission of porcine parvovirus occurs mainly via the fecal-oral route through the ingestion of water or food contaminated by faeces or urine from infected animals, nasally, as well as transplacentally. The virus can also be found on surfaces and objects that have been in contact with infected feces. Developing piglets and contaminated gilts are the main reservoir. Occasionally, infected males can eliminate the virus through semen. Once in the animal's organism, a generalized viremia occurs. The virus replicates mainly in lymphoid tissues and in the lungs resulting in the involvement of various organs. In pregnant sows they cross the placenta, infecting embryos or fetuses.
PVP infection occurs in most cases subclinically, although transient leukopenia may occur. In females during pregnancy, parvovirus infection, especially in the first half of gestation, can cause reproductive failure characterized by infection, death and mummification of the embryo or fetus. In addition, PVP infection can cause infertility and miscarriages.