The disease causes inflammation of the central nervous system, but the clinical symptoms for West Nile fever in the horse and in man often are not diagnostic. They include typical encephalitic symptoms such as disorientation, dementia and coma. In the horse, the disease can present as a weakness or ataxia of the hind limbs. The viremiaand fever that occur following initial infection in the horse often precede the neurological symptoms by several weeks; therefore, the disease can be confusing and difficult to diagnose in the horse. There is no specific treatment for West Nile fever other than lessening the severity of central nervous system disturbance. Currently, there is no vaccine for West Nile fever and routine vaccination against western and eastern equine encephalomyelitis does not confer protection against West Nile fever.

Dr. Bernard Salick discusses the horse owners' concerns regarding West Nile fever.

California Animal Health and Food Safety Laboratory (CAHFS) spokesperson Dr. Sharon Hietala discussed the strategies for dealing with emerging equine viruses in California, including the sentinel chicken program for the early detection of arboviruses (those transmitted by mosquitoes). This disease warning system has been used for many years within California to indicate the presence of dangerous infectious disease agents. Officials maintain flocks of chickens and test them every other week to detect antibodies to various diseases to which the chickens have been naturally exposed. Dr. Hietala also discussed the many diagnostic services available to California horsemen through the CAHFS service.

The public health perspective was represented by Dr. John Edman, Director of the UC Davis Center for Vector Borne Disease, and Dr. Michele Jay, Public Health Veterinarian for the State of California. They discussed the importance of identifying an outbreak of the virus early on so that proper control measures could be adopted. Early detection is accomplished by increasing surveillance through the sentinel chicken flocks and by collecting mosquitoes and testing for a much larger range of viruses to include the flaviviruses. Any sample that tests positive for St. Louis encephalitis needs to be further tested for West Nile virus.

Ms. Amy Mann, the Director of Health and Regulatory Affairs for the American Horse Council, represented the horse industry's point of view. She clearly stated horse owner's concerns regarding regulatory issues such as possible restrictions on the international movement of horses, the need for interaction and coordination between regulatory agencies, and the proper dissemination of accurate information to the public. She also decried the lack of federal funding to the USDA for research and disease control of diseases affecting the equine industry. Ms. Mann clearly made the point that if the West Nile virus did not have the potential to infect humans, there would be no national governmental interest in this disease. She urged all horsemen to lobby their local Congressional representatives on this issue.

Helen Scott-Orr, the Executive Director of Research, Advisory and Education for the New South Wales Department of Agriculture in Australia, explained concerns regarding the international movement of horses to and from areas where West Nile fever was identified. Considering the large number of people and horses that are expected to attend the Olympic Games this summer in Australia, it is reasonable to expect regulators to institute any and all measures necessary to protect public health and safety. Animals from any areas experiencing a contagious disease outbreak will most likely be denied travel to Australia.

Dr. Bernard Salick of Sandstone Farm, represented the show horse owner's point of view. He raises Holsteiners that compete at World Class levels in jumping and dressage. His farm in Thousand Oaks, California has been designated as this year's quarantine area for the US horses competing in the Olympic Games. He discussed the monetary investment owners have in top quality competitive horses and how infectious diseases affect breeding, sales and showing of these animals. He shared his passion for infectious disease research and stated that because there is no worldwide standard for equine disease control, UC Davis and the Bernard and Gloria Salick Equine Viral Disease Laboratory have the power to set a standard, starting with West Nile fever.

Dr. James MacLachlan, Director of the Bernard and Gloria Salick Equine Viral Disease Laboratory, discussed the current status of equine virology research. He stated his goal was not to create hysteria regarding West Nile fever, but instead, to put a group together to address the important issues. He said the equine viral disease laboratory would hold the high ground scientifically and offer a research resource to those investigating the disease. The laboratory will also train the next generation of veterinary scientists to be prepared for emerging equine viral diseases. He concluded by moderating a panel discussion for questions and answers.

Dr. James MacLachlan, Director of the Bernard and Gloria Salick Equine Viral Disease Laboratory.

Dr. Gregory Ferraro, Center for Equine Health Director, hosted the West Nile fever meeting.

Although we won't know if West Nile fever will be a problem again until the summer, it is prudent to plan for a possible outbreak. Now that the virus has been introduced to the United States, it's likely that it is here to stay and sooner or later, it will emerge. Other countries will most likely play it safe and set quarantine regulations which will affect the international movement of horses. The Center for Equine Health and the Bernard and Gloria Salick Equine Viral Disease Laboratory are working together with researchers, regulatory officials and practicing veterinarians to educate and inform the horse-owning public so that if West Nile fever rears its ugly head, we will have a plan of action to fight it.