NADIS Veterinary Report & Forecast - March 2009

by 5m Editor
6 April 2009, at 9:38am

UK - This is a monthly report from the National Animal Disease Information Service (NADIS), looking at the data collected from their UK farm inspections.

Erysipelas continues to be one of the most frequently diagnosed specific diseases of pigs by veterinary surgeons reporting under the NADIS surveillance scheme. The data suggests that over 90 per cent of farms reporting Erysipelas to be present – whether as a clinical entity at the time or based on recent history and familiarity with the farm – actually apply some form of protective vaccination, (Graph 1).

The vast majority of this vaccination will be applied in breeding animals. 90 per cent of all farms containing sows, whether they are breeder only farms or those retaining some or all of their progeny, report Erysipelas to be present . This is a picture far less likely to be encountered, for instance, in Southern Europe , despite the historical perception that Erysipelas is a warm weather disease.

Whilst over the last year there have been changes to the availability of vaccines in the UK , there is no objective evidence to date to suggest wholesale failure of commercial vaccine. Claims have been made that novel strains of the organism, to which vaccines afford no or restricted protection, have emerged, but no isolates of such strains have been made. Anecdotal comments received from reporters in the main suggest that most clinical disease is seen in unvaccinated animals, particularly in growing pigs in which maternally derived (colostral) immunity has waned, or in situations where there have been identifiable faults with vaccine handling or application on farm. This is a subject requiring regular on farm review.

Graph 1 also shows Erysipelas to be present in a much higher proportion of East Anglian herds with compared to the NE of England. When taken in conjunction with Graphs 2 and 3, showing higher percentages of farms with Erysipelas where sows are kept on straw or outdoors, this may explain the regional variation, as these types of systems regularly highlighted as more prevalent in East Anglia .

However, confounding this observation is the report that Erysipelas is believed to be present in almost twice the percentage of herds in which growing pigs are kept on slats compared with those kept on straw (Graph 4).

There is a need for further differentiation of the data at the point of collection into herds in which the causative organism is believed to be present and those in which actual clinical disease is appearing. Further information on the vaccination protocols of the herds from which pigs are sourced would also be useful. Anecdotal remarks received through the year suggest that clinical cases of Erysipelas in growers are more common in straw based yard systems, particularly those exposed to bird ingress. However the role of rodents, which are common in all pig keeping systems, should be considered when investigating the disease.

Erysipelas is reported to be more commonly present on continuous flow farms compared to those utilising batch systems (whether for breeding or growing herds) (Graph 5), suggesting that in this instance, the potential hygiene benefits of batching are providing advantages for disease control.

5m Editor