A collaboration between the  of the Pathology and Welfare Laboratory of the porcine species of the Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe) and the Department of Animal Medicine, Productions and Health

of the University of Padua led to the first report of type 2e porcine Circovirus (PCV-2e) in Europe. This variant of the virus, identified in samples taken from a Venetian herd, had so far been detected only in Asia and North America. The discovery was then published in the international scientific journal The Veterinary Journal .

 

 

 

Porcine Circumvirus Type 2 (PCV-2) is a worldwide spread pathogen that can cause different clinical conditions in pigs that fall under the Porcine Circovirus Disease (PCVD) framework, causing serious economic losses for livestock farmers in the sector. To date, the circulation of PCV-2 in herd mainly results in subclinical forms, which should not be overlooked as they are associated with a decrease in animal productivity.

 

 

 

PCV-2 is a single strand circular DNA virus, with a genome of about 1.7 kb. Eight genotypes (PCV-2a-h) are currently recognized, of which only three (PCV-2a, -2b, -2d) have been shown to have a worldwide distribution, while the others have been reported occasionally. The high variability of the virus has led to questioning the effectiveness of vaccines in use against the latest variants, and increased the interest of veterinarians and breeders in identifying the viral genotype circulating on the farm.

 

 

 

The detection of PCV-2e by researchers from the Pordenone section of IZSVe and the University of Padua stems precisely from the request for genotyping some viruses isolated from samples taken from a pig farm in Veneto. The controlled pigs did not show any indicative symptoms of PCVD and the finding was accidental, but this does not mean that the virus is harmless to the animals. It should be borne in mind that PCV-2e is the most different among PCV-2 genotypes and has a distinct phenotype, to the point that doubts have already been expressed about the efficacy of vaccines available against this variant in the past.

 

 

 

To this is added the identification of viral strains belonging to the most common genotype PCV-2d in samples taken from the same herd, following further diagnostic insights. This confirmed the simultaneous spread in breeding of two genotypes: a factor that can not only aggravate symptoms in animals, but also make possible recombination in case of co-infection, further encouraging the increase in variability of PCV-2.

 

 

 

As a result, although the absence of clinical symptoms is a favorable aspect, it is not necessary to lower the guard as PCVD is characterized by a multifactor pathogenesis. For this reason, researchers recommend raising the attention threshold in monitoring the possible circulation of PCV-2e genotype in Italy and Europe, as it cannot exclude its wider spread.

 

 

 

 

Article on The Veterinary Journal 

 

 

 

 

 

 

 

Source: IZSVe