A full year has now passed since the BPEX funded research programme into PMWS started, in which a subsidy to vaccinate against this disease was provided.

Date from NADIS surveillance shows the rapid increase in farms using vaccine in the spring of last year with the percentage of farms vaccinating later levelling off to close to 70 per cent (see graph 1). This is likely to be reflected across the whole of the English pig herd.

NADIS monitoring, however, includes recording whether the disease is actually present on the farm and graph 2 barely reveals any reduction of the disease over the last year. This is not to say that the effects of disease have not decreased – anecdotal reports widely include reduced mortality, reduced sick pigs and more even growth – but does highlight, as expected, that vaccination, at least in the early stages, does not lead to a complete disappearance of disease from farms. It will be interesting to see over the next year whether, as a result of prolonged vaccination, the number of farms still seeing clinical disease declines.

In terms of the application of vaccination there would appear to be very little regional variation with current uptake representing in the region of 70 per cent of affected farms across the country (graph 3) although this is slightly lower in East Anglia .

In terms of vaccine uptake by farm type (graph 4) it is perhaps slightly surprising to see that the breeder/weaner farms have a greater uptake than breeder/feeders (89 & 74 per cent respectively). This may be due to pressure from purchasers of 30kg weaners demanding vaccine to be used either in the sows or at weaning. Conversely, the proportion of breeding only units which vaccinate is much lower (57 per cent). This may well be because purchasers of 7kg weaners prefer to vaccinate themselves on arrival rather than requiring sow vaccination or for the breeder to inject piglets before supply.

There is little variance in presence of PMWS across management systems (graph 5) especially with respect to batch versus continuous flow and indoor versus outdoor derived pigs. However, the percentage of straw-based farms reporting the presence of PMWS continues to exceed those slatted farms with the disease. This may continue to suggest that hygiene and dung recycling remain major components in the development of this condition.

Vaccination has been something of a relief to the industry but many clinicians believe that wholesale use of vaccine over a two year period will be needed before its benefits can be fully evaluated. NADIS surveillance will continue to monitor these benefits.

A report from BPEX of the results of the research programme is expected within the next month.