West Niles Virus and Animals
Posted by Kritter Girl on May 18, 2008
That time of year is here again when we must think about the critters in our life when it comes to those pesty bugs out there.
In 1937 West Niles Virus (WNV) was first isolated in Uganda. It has been most commonly found in the Middle East, West Asia, Europe and Africa. As of 1999 it has been found in the Western Hemisphere. In 2001 the first infected birds were found in Wisconsin. By 2004 WNV has been found in mosquitoes and birds in every state with the exceptions of Hawaii and Alaska. (read more here)
As of 2005 2,949 cases of disease caused by WNV have been reported in the United States which includes 116 deaths as reported by the Center for Disease Control and Protection (CDC) [Also see Mayo Clinic]
So what is West Niles Virus? It is an arthropod virus that causes encephalitis, inflammation of the brain it’s a disease causing virus in the group known as flaviviruses. Other diseases caused by flaviviruses are dengue, yellow fever Saint Louis encephalitis and Japanese encephalitis.
How WNV is Spread
The transmission process starts with a mosquito biting an infected bird or other infected animal. Then it bites another, pretty simple. Scientist have identified more than 43 different species of mosquitoes that can transmit WNV. In the salivary gland of the mosquito is where the virus is maintained and during blood feeding it is injected into the animal/person it is biting. The virus then multiplies and may cause clinical signs.
Although the virus primarily cycles between mosquitoes and birds, infected female mosquitoes also can transmit WNV through their bites to humans and other “incidental hosts” such as horses. With so many susceptible hosts to amplify the virus and so many types of mosquitoes to transmit it, WNV has spread rapidly across the United States.[i]
Who is affected?
Everybody! Birds, horse, cats, dogs, sheep, cattle pigs and people. Anyone who is bitten by a mosquito can become affected by WNV.
Symptoms of WNV
Most cases of infection are mild or unapparent (without clinical signs) and animals can develop antibodies to the virus. Some signs that you pet may show are, fever, uncoordinated, depression, muscle spasms or weakness, paralysis or seizures. If any of these signs are noted see your veterinarian for assessment and appropriate treatment.
People who contract WNV usually experience only mild symptoms-fever, headache, body aches, skin rash, and swollen lymph glands. If WNV enters the brain, however, it can cause life- threatening encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord). Most cases of disease occur in elderly people and those with impaired immune systems. Recent cases have shown that WNV can be transmitted through blood transfusions and organ transplants from WVN-infected donors. Health experts also believe it is possible for WVN to be transmitted from a mother to her unborn child and through breast milk.[ii]
If my pet has WNV can I get it?
This is not likely. Infected mosquitoes transmit WNV through blood feeding. There has been no documented evidence of animal to animal, person to person transmission. But you should take precautions when handling a sick animal by wearing gloves.
What you can do to protect yourself and your pets
Currently there is no treatment for WNV but There are licensed WNV vaccine that can be given to your horse so check with your veterinarian. The following are things you can do to help protected yourself and your pet.
1. Decrease your exposure to adult mosquitoes by staying indoors at dawn and dusk.
2. Apply an insect repellent that contains 20%-35% DEET
3. Were long sleeve shirts and long pants when outdoors.
4. Dispose of any water holding containers such as used tires, they can be a potential breeding area for mosquitoes.
5. Turn over your wheelbarrows and wading pools when no in use.
6. Do not allow water to become stagnate in your birdbaths.
7. Drill some holes in the bottom of containers that are left outside.
8. Clean out clogged roof gutters.
Remember mosquitoes can breed in any puddle of water that last more than 4 days.
If you live in an area that has reported a large number of wild bird deaths and find a dead wild bird you should notify your local health officials.
Other informational sites:
http://www.petfirstaid.org/WestNile.html
http://www.health.alberta.ca/public/wnv_fsanimals.html
http://westnilemaps.usgs.gov/2002/
[i] http://www.niaid.nih.gov/factsheets/westnile.htm
