Kansas Department of Health and Environment West Nile Virus Infection and Animals Fact Sheet
It is an infection caused by West Nile Virus (WNV), which is spread by the bite of a mosquito infected with the virus. The disease can cause encephalitis (swelling of the brain), meningitis (swelling of the lining of the brain), or even death. The virus is named after the West Nile region of Uganda where the virus was first identified.
The virus was first identified in 1937 in Uganda, Africa. Prior to 1999, the virus had only been identified in Africa, Europe, the Middle East, and Asia. WNV was first detected in the United States in 1999.
Infected mosquitoes are the primary source of the virus and caused the recent outbreaks in the United States. Mosquitoes draw the virus from infected birds and then transmit to animals and humans through bites. WNV is not transmitted directly from person to person, from person to animal, from animal to person, or from animal to animal. There is no evidence that other insects or ticks transmit WNV in the United States.
Yes. Most horses infected with West Nile Virus recover, but WNV has caused deaths in horses in Kansas and in other parts of the United States.
Following transmission by an infected mosquito, West Nile Virus multiplies in the horse's blood system, crosses the blood brain barrier, and infects the brain. The virus interferes with normal central nervous system functioning and causes inflammation of the brain.
No. There is no documented evidence that West Nile Virus is transmitted between horses. However, horses with suspected West Nile Virus should be isolated to prevent them from being bitten by mosquitos, if at all possible.
My horse is vaccinated against eastern equine encephalitis (EEE), western equine encephalitis (WEE), and Venezuelan equine encephalitis (VEE). Will these vaccines protect my horse against West Nile Virus infection? No. EEE, WEE, and VEE belong to another family of viruses for which there is no cross-protection.
Yes. WNV vaccine for horses is approved and available in Kansas, but its effectiveness is unknown. Consult your local veterinarian.
Should it be destroyed? There is no reason to destroy a horse just because it has been infected with West Nile Virus. Most horses recover from the infection. Horses with severe signs may need intensive veterinary treatment.
There have not been clinical signs associated with WNV in dogs or cats. Although they may be infected, they may not develop signs of disease. There is a published report of West Nile Virus isolated from a dog in southern Africa (Botswana) in 1982 and WNV has been isolated from several cats in 1999 and 2000. A study of dogs and cats in the New York City area showed a low infection rate.
No. West Nile Virus is transmitted by infectious mosquitoes. There is no evidence of transmission of WNV directly through dogs, cats or other animals.
No. There is no documented evidence that West Nile Virus is spread from animal to animal.
In the 1999 New York area epidemic, there was a large die-off of American crows. West Nile Virus has been identified in more than 110 species of birds found dead in the United States. Most of these birds were identified through reporting of dead birds by the public.
There is currently no evidence that West Nile Virus can be spread directly from an infected bird to people. However, dead birds can carry other diseases and should not be handled with bare hands. Use gloves to place dead birds into plastic bags and then placed into outdoor trash.
Kansas has a toll free hotline for reporting dead birds: 1-877-228-2287.
Can domestic animals get West Nile Virus? All birds can get infected with West Nile Virus. Chickens may be more resistant than some other birds to dying from West Nile Virus.
There is no evidence that West Nile Virus is spread by eating eggs or meat from infected birds. However, any animal that appears sick should not be slaughtered for human consumption.
Because of their outdoor exposure, game hunters may be at risk if they become bitten by mosquitoes in areas with West Nile Virus activity. The extent to which West Nile Virus may be present in wild game is unknown. Surveillance studies are currently underway to answer this question.
Hunters should follow the usual precautions when handling wild animals. If they anticipate being exposed to mosquitoes, they should apply insect repellents to clothing and skin, according to label instructions, to prevent mosquito bites.
Who should wild game hunters contact for information about the risk for West Nile Virus infection in specific areas in Kansas? Hunters should check with the Kansas Department of Wildlife and Parks in the area for information on local risks.
There is no evidence that West Nile Virus can be transmitted from eating cooked meat. Animals that are obviously sick or are found dead should not be eaten.
Preventing mosquito bites will prevent West Nile Virus infection. Personal protection and reducing mosquito populations will minimize the chance of developing WNV infection when it is present in an area.
Personal protective measures to reduce or prevent mosquito bites include limiting time spent outdoors at dusk and dawn and using insect repellents containing DEET (N,N-diethyl-methyl-meta-toluamide) when outdoors. Follow the manufacturer’s directions carefully.
Reducing mosquito populations will also reduce mosquito bites. You can eliminate standing, stagnant water where mosquitoes breed on your own property or yard.