Outbreaks of bluetongue disease in East Anglia are an indication that its close relative African Horse Sickness is poised to strike the UK horse industry, warns Paul Jepson, chief executive and resident veterinary surgeon at The Horse Trust.

Speaking at The Thoroughbred Racing and Breeding Seminar at Cheltenham racecourse last week, Mr Jepson said: "The midge-borne African Horse Sickness (AHS) virus, closely related to Bluetongue virus, may strike the UK's equine population in the future, in which case high mortality might be expected."

The severity of the effects of African Horse sickness and its social and economic impact, mean it is listed as notifiable by the World Organisation for Animal Health (OIE) in Paris, by the European Commission in Brussels under Directive 92/25/EC and therefore also in UK legislation under the Infectious Diseases of Horses Order 1987. This means that, in practice, if there is any suspicion of AHS, Defra must be notified immediately and stringent measures taken to control the disease.

"The incubation period for AHS is usually 7 to 14 days, but may be as short as two days," Mr Jepson warned. "The illness is profound and typically features fever, breathing difficulties and death usually within a week of the onset of symptoms."

The disease is spread by the same Culicoides midges as those which transmit Bluetongue virus. In horses the mortality rate can be as high as 90%. In donkeys the mortality rate is much lower (about 10%) and there are concerns that donkeys and certain other exotic species may act as carriers for some time following infection. Infected midges can be blown by the wind for more than 100 km and transported long distances in farm vehicles.

"The Horse Trust has recently launched a disease awareness campaign for AHS," Mr Jepson told the conference. "A working group has been set up involving Defra and others from the horse industry to look at how best Government and industry can work together to prepare for and manage any such outbreak.

"In particular this group is considering the difficulties that might be encountered and working to provide options to prevent and resolve problems."