Worry over threat of fatal horse diseases in Britain

December 23, 2007

The growing threat of possible outbreaks of African Horse Sickness (AHS) and equine encephalitis in Britain continues to worry authorities.

The latest issue of Equine Disease Quarterly discusses planning for any outbreak, which would potentially have devastating consequences for British horses.

An outbreak of a related disease, bluetongue, in cattle in September, which is spread by the same midges that can carry AHS, has highlighted the growing risk.

A fresh outbreak of bluetongue in the last week in imported cattle has seen British authorities place a major order for vaccine.

Bluetongue causes fever and mouth ulcers and is so-named because it can turn an animal's tongue blue. It does not affect people but can affect both sheep and cows.

Equine Disease Quarterley named equine encephalitis - an often fatal viral disease transmitted by infected mosquitoes which affects the central nervous - and African horse sickness as the two notifiable diseases of greatest concern.

Neither has been reported in Britain to date, but climate change has seen the threat growing.

"AHS is of concern due to the devastating effect of this disease on the equine population with high mortality recorded when a disease outbreak occurs in a naïve population.

"The encephalitis viruses also have the potential to be of serious concern due to their potential to cause human disease as well as equine disease.

"Because of the serious public health implications, control of any encephalitides outbreak would probably have to be led by the Department of Health acting in partnership with DEFRA (the Department of Environment, Food and Rural Affairs)."

It said current legislation provided DEFRA with the power to issue essential orders to try to control any disease outbreak and limit disease spread.

However, a new updated version of the Infectious Diseases of Horses Order 1987 (IDHO) is needed to reflect new information and lessons learnt from the control of bluetongue.

"This vector borne disease is seen as a model of how other insect borne-diseases might spread in the European Union. Updated measures would allow more efficient controls to be enacted should an outbreak of exotic disease occur in the UK equine population.

"A revised draft of the Infectious Diseases of Horses Order was extensively discussed within DEFRA in the early part of 2007 but the three outbreaks of notifiable disease in England this year (foot and mouth disease, bluetongue virus and avian influenza) have temporarily diverted resources away from this area.

"With the end of the current outbreaks now in sight, it is hoped that work on completing the update of the equine legislation can resume as soon as is practicable."

In August 2005, DEFRA published the STEED contingency plan, a comprehensive emergency response plan for equine diseases. The plan has now been overtaken by DEFRA's contingency planning for all exotic animal diseases. These contingency plans are updated annually.

The most recent plan was put out to public consultation in July and covers some equine diseases, such as equine encephalitis.

Policy aspects of control of notifiable diseases are not included in this plan to allow DEFRA to be more flexible and respond more rapidly to changing disease situations and changing EU legislation.

Horse organisations in Britain have been lobbying government in Britain to ensure plans are in place should African horse sickness arrive.

AHS can kill 90 per cent of the horses it infects.