Published on October 21, 2007
Slide1: West Nile Virus (WNV) Slide2: West Nile virus was first isolated in the West Nile District of Uganda in 1937. Equine disease was first noted in Egypt and France in the early 1960s. The appearance of WN virus in North America in 1999, with encephalitis reported in humans and horses, may be an important milestone in the evolving history of this virus. Slide3: West Nile virus (WNV) has emerged in recent years in temperate regions of Europe and North America, presenting a threat to public, equine, and animal health. The most serious manifestation of WNV infection is fatal encephalitis (inflammation of the brain) in humans and horses, as well as mortality in certain domestic and wild birds. Slide4: Finding a dead crow could be the first sign of WNV Three State Agencies Involved in WNV Activities in Illinois: Three State Agencies Involved in WNV Activities in Illinois Illinois Department of Agriculture Equine surveillance Dead bird necropsy and testing Illinois Department of Natural Resources Field biologists Research Illinois Department of Public Health Management of surveillance data Slide13: The Culex mosquito Slide14: Although the vast majority of infections have been identified in birds, WN virus has been shown to infect horses, cats, bats, chipmunks, skunks, squirrels, dogs and domestic rabbits. Slide15: Symptoms of WNV in Horses Ataxia (failure of muscle coordination) Weakness of limbs Recumbency (lying down) Muscle fasciculation Death Fever has been detected in less than one-quarter of the confirmed cases Incubation period for WNV is usually 5 to 15 days Slide16: There is not specific treatment for WNV in horses. Supportive veterinary care is recommended. Many horses infected with WNV never develop the illness. Of those that did during the 1999-2000 outbreak, 38% died or were euthanized. Slide17: WNV in horses is often confused with Equine herpesvirus-1 Equine protozoal myeloencephalitis (EPM) Eastern, western or Venezuelan equine encephalomyelitis (EEE, WEE, VEE) Rabies Slide18: How Can I Help Protect My Horses From WNV? Keep horses indoors during peak periods of mosquito activity (dusk and dawn) Avoid turning on lights inside the stable after dark, as mosquitoes are attracted to lights. Keep birds away from the stable area. Eliminate areas of standing water including plastic containers, old tires, bird baths, wheelbarrows and gutters. Use fans on the horses while in the stable to help deter mosquitoes. Drain puddles as mosquitoes can breed in any puddle that lasts for more than four days Slide20: Protection against the virus is best achieved if both doses of vaccine are received by the horse 4 - 6 weeks prior to the onset of mosquito season. Slide21: Human Symptoms of West Nile Virus Most infections are mild, and symptoms include fever, headache, and body aches, occasionally with skin rash and swollen lymph glands. More severe infection may be marked by headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, paralysis, and, rarely, death. The incubation period in humans is usually 3 to 15 days.