Porcine Circovirus was first described in Canada as a cause of disease in the late 1990s and since then it showed up causing disease sporadically until 2004 when the pathogen began causing epidemic losses in Canada and spread world wide.

Dr Francisco De Grau, the global technical director with Merck Animal Health, says new vaccines have been very effective in reducing mortality but the virus may still be impacting productivity.

Dr Francisco De Grau-Merck Animal Health

Mainly the principle problems that we have right now is that it's a sub-clinical disease and pigs may be fighting this virus trying to get rid of it which decreases growth and it's really not causing a lot of clinical signs now a days so we need to find out if it's a sub-clinical problem.

Circovirus is a very resistant virus, it's out there, it always will be there and that's a problem.

It could manifest in sows by having mortalities or sows are not getting pregnant.

It could be a disease of the grow finisher pig having not the right performance, poor growth, slow growth, high variation so it can manifest itself in different ways and the more common problem is that this disease, being a disease of the immune system, pigs could get infected by other diseases, bacteria's and viruses creating a weak immune system.

Dr De Grau notes, if we stop vaccinating, we start seeing clinical cases with high mortality and a lot of problems so the vaccines have been highly effective.

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