PMWS - The Danish Experience

By Danish National Committee for Pig Production - This article is extracted from the aforementioned committees Annual Report for 2002 and looks at the Danish experiences with PMWS. Current reports indicate Denmark now has over 50 reported cases of the disease.

18 February 2003

4 minute read

PMWS & PDNS
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PMWS

Post-weaning Multisystemic Wasting Syndrome (PMWS) was first described in 1991 from Canada and now the disease has been diagnosed in most pig-producing countries. PMWS affects pigs postweaning starting 3-4 weeks post-weaning. The symptoms are variable but include unthriftiness, increased mortality and dyspnoea.

Cause

Porcine Circovirus type 2 (PCV2) is causally associated with the development of PMWS. PCV2 is found in most Danish pig herds indicating that other factors are involved in the development of the disease. These factors have not yet been identified, but it seems that factors stressing the pigs could be involved.

PMWS in Denmark

As of July 31, 2002, PMWS has been diagnosed in 39 herds in Denmark cf. the figure below. In affected Danish herds the mortality among the piglets varies between 5% and 30%. PMWS occurs in high health herds as well as in conventional herds. The reason why some herds develop PMWS while others do not is still unknown, and which factor triggers the development of PMWS is under intense research in many countries. There are indications that the sum of stress on the pig is determining to whether PMWS is developed or not. The trigging factor may be a small and apparently insignificant stress on the pig that - combined with other factors - triggers PMWS.

Control measures

Experience shows that establishment of all in-all out production in a herd with PMWS often controls the disease. Table 1 outlines some useful control measures. Partial depopulation of the piglets seems to help controlling the disease and thereby reducing the losses due to PMWS in the herd. It is also important to control other infections in the herd e.g. trough vaccination. The National Committee for Pig Production has given some recommendations on how to control the disease in the herds. This has been forwarded to all vets and can also be found on the website www.lu.dk.

Studies

In ongoing studies, the National Committee for Pig Production is investigating whether PMWS affects pigs of some particular sows. Furthermore, the effect of specific serum against PCV2 will be examined in co-operation with the Danish Veterinary Institute. The National Committee for Pig Production is also working on obtaining permission to test auto serum.

The future

If PMWS is diagnosed in a herd, the management routines should be carefully examined. Routines should be tightened where necessary, e.g. establishing all in–all out, removing sick animals to a hospital pen as soon as possible, and conducting a partial depopulation in the weaning section. In many cases, these measures are likely to reduce the losses caused by PMWS. PMWS – experiences with the disease Farrowing unit All in-all out, good hygiene,