PRRS virus infection can be considered common in areas of high pig density and, in such cases, the idea that biosecurity and can do little is widespread. However, proper biosecurity measures must be implemented in order to prevent the introduction of new strains.

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.

Since a vast majority of commercial farms are endemically infected with M. hyopneumoniae, the control measures applied against PRRS should include measures against M. hyopneumoniae.

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.

In areas with a high density of pigs, a large proportion of farms are endemically infected. In these situations, the group at the highest risk is the gilts.

The high seroprevalences found supports the feeling you get in the field that PCV2, PRRSV, and SIV are very widespread viruses in our farms.

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?

It is a test that allows the verification of the carrying out and/or the quality of the vaccination in cases such as the entrance of piglets for their fattening.

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.

During 2012 PCV2 variants or mutants (mPCV2) appeared in the USA and were frequently associated with PCV-associated diseases. The possibility of lack of cross-protection of commercial vaccines against mPCV2 is now of major concern.

Reducing piglets mingling in farrowing and nursery facilities was found to delay the infectious process leading to a lower number of early infections. Clustering piglets by litter in small units after weaning also decreased significantly the probability of early infection.

What further increases profitability in pig production is not minimizing costs, but maximizing revenue.

Despite the evident usefulness of laboratory diagnosis, we must not forget that a field necropsy allows us to us recover part of the loss caused by the death of the animal.

PCV2 vaccination of the gilts prior to insemination with PCV2 spiked-semen showed a clear decrease of viral load in the gilts as well as a much lower viral excretion that were compatible with foetus protection.

The virus is highly resistant in the environment, showing also high resistance to chemical and thermal treatments.

Might be there is a little doubt nowadays on the beneficial clinical and economic effects of PCV2 vaccination in subclinical infections in piglets, but… which is the role that sows play in the whole picture?

This economic model was create to provide a decision support tool for farmers and veterinarians, who can enter their own data to calculate the severity of PMWS on their farm, the cost of disease and what could be the most cost-effective control measure.

PCV2 may reach embryos/foetuses upon transplacental spread during viremia or upon insemination with contaminated semen.

It has been shown that the efficacy of PCV2 vaccines was dramatically decreased in the context of husbandry deviations such as excess of cross-fostering, mingling at weaning or very large groups in nursery.

The efficacy of PCV2 vaccines to control PCV2 associated diseases has been clearly demonstrated not only in piglets but also in sows. Moreover, it is also feasible to vaccinate sows and their offspring without hampering its growth during the rearing period.

Experimental Mhyo and PCV2 co-inoculations have resulted in somewhat divergent results.

PCV2 can be shed into semen by infected boars and research suggests that the virus can then be transmitted to gilts and sows by AI causing reproductive failure but there is no evidence that PCV2 in semen has effects on various characteristics of sperm cells.

Genomic changes can be associated with increased virulence or decreased immunogenicity.

The PCV2 has been associated, in an ongoing way and throughout time, with more pathologies called, collectively, diseases associated with the PCV2 (PCVDs): PCV2 systemic disease, PCV2 lung disease, PCV2 enteric disease, PCV2 reproductive disease,PCV2 subclinical infection and porcine dermatitis and nephropaty syndrome.

Novelties about the excretion routes, the transmission routes, the risk factors, etc., and explanation about how the PCV2 becomes a pathogenic virus.

The most effective way of avoiding the production losses associated with the PCV2 consists in avoiding the appearance of the viraemia by inducing a passive or an active immunity that minimizes the circulation of the virus in the farm.

A summary of current knowledge to address frequently asked questions from producers and practitioners on PCV2-associated reproductive disease.

Given the high prevalence of the infection due to the PCV2 and its presence in healthy and sick animals, the serological tests against this pathogen have been questioned as a diagnostic test.