PCVAD - Focus on Porcine circovirus associated disease

We are finding more evidence of the possible role PCV-3 plays in certain reproductive problems.

Serious problems occurred much less frequently with genotype a than with genotype b. Why did the frequency of these genotypes change?

The world of viruses is dynamic. Their epidemiology varies according to our actions. New strains and new serotypes appear. Are we prepared?

In the years since the PCV-2 vaccine was introduced to solve the enormous problem caused by circovirus, what do you think has changed and how does it affect farms?

The average piglet birth weight from the 3 groups of vaccinated sows was statistically higher than that from the unvaccinated sows.

The current diagnostic tests are very powerful, allowing us to detect even small changes in the genome of a virus, but what do they tell us?

The decrease in PCV2a and PCV2b genotypes over time and the increase in PCV2d in 2012 may be due more to other, unknown, factors than to immunological selection resulting from PCV2a-based vaccination.

PCV2 vaccination is nearly universal. Has viral presence decreased after 6 years of vaccination? Could vaccination policies be changed?

All available vaccines in the European and North-American market are based on PCV2a genotype, while the most prevalent ones are PCV2b and PCV2d ones. Although significant level of cross-protection among these three genotypes has been demonstrated, it would be interesting to assess if vaccine efficiency would be equivalent in front of all these different genotypes.

The immune status of farms is quite possibly different from the one they had before piglets mass vaccinations.

Despite not having a consistent post-vaccination serological reaction, vaccinated animals behave differently from unvaccinated animals under field conditions.The article explains why vaccines offer protection.

This article deals with the factors to be considered for deciding the optimal time of vaccination against PCV2  and shows the results of a study that evaluates the efficacy of different vaccination programs in PCV2 subclinically infected piglets.

Recently, PCV2 has been suggested as a pathogen able to induce diarrhoea in pigs, and PCV2-enteric disease (PCV2-ED) as a separate entity within porcine circovirus diseases (PCVDs) has been proposed.

The loss associated with decreased ADWG was of 13.1 € and 7.5 €/pig at 21 weeks of age for pigs with high and medium serum PCV2 load under the scenario studied.

This article proves that, at least "in vitro" order matters. In PRRSV/PCV2 mixed infections, the consequences are worse when PRRSV infection occurs before or concurrently to PCV2 infection, than when the sequence is reversed.

Distinct PCV2 variants are circulating in commercial pig farms. How the vaccine induced immunity may affect PCV2 evolution?

The benefit on antibiotic use is particularly clear when herds are multicontaminated by pathogenic virus and bacteria, allowing also to maintain animal welfare and operational productivity, but a good immunity against PCV2 is effective also in high health status herds.

Finding an occasional pig with PCVAD within a large population is not unexpected since vaccination compliance is rarely 100%. How does one assess impact of PCVAD in a vaccinated population?

The first cause of PCV vaccine failure is the purchase and use of generic vaccine of low quality and titre, but the exact cause of the failures can occur in various forms.

The aim of this article is to discuss those differentiating topics which are relevant from a practical point of view and which in some way elude the disease's definition.

Serious problems occurred much less frequently with genotype a than with genotype b. Why did the frequency of these genotypes change?

The relatively high prevalence in wild boar and the low prevalence in Iberian pigs suggest wild boar as a potential viral reservoir.

PCV-2 and PCV-3 associated disease outcomes are distinguishable at a histopathological level. Final thesis at the College of Veterinary Medicine, UAB, Spain, advised by Joaquím Segalés.

This is the first report of the detection and genetic characterisation of the PCV-2e genotype in Europe, from sows on a farm in Italy.

This study investigated the association between the presence of PCV3 mRNA detected by in situ hybridization within histological lesions and PCV3 DNA detected by real-time PCR in naturally infected pigs.

Circovirus 4 was identified in several pigs with severe clinical disease in Hunan Province, China.

The suggested classification can establish a "common language" for future studies, further efforts should be paid to achieve a more homogeneous and informative representation of the PCV-2 global scenario.

Wild boar is susceptible to PCV‐3 infection, showing high frequency of detection in this animal species.

This study set out to describe detection patterns of porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), swine influenza virus type A (SIV) and Mycoplasma hyopneumoniae (M. hyo) among farms showing differing severity of PRDC.

The purpose of the study was to evaluate the effect of vaccination against PCV2 in a sub-clinically infected, high-health finishing herd in terms of viral load in serum, feed conversion ratio and antimicrobial treatments.

The need for developing PCV2-specific ELISA methods is urgent to evaluate PCV2 antibody level in exclusion of PCV1 antibody interference after PCV2 vaccination.

In all three cases we characterized the genome of a new circovirus we called PCV3.

Here, a novel porcine circovirus (PCV3) that is distantly related to known circoviruses was identified in sows with porcine dermatitis and nephropathy syndrome (PDNS) and reproductive failure.