Pathogen test
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The ELISA test detects antibodies to the West Nile Virus (WNV).
Sample
- 5 mL - blood - serum tube
Turnaround time
- 2 to 5 working days
What is West Nile Virus?
- West Nile virus (WNV) is a zoonotic mosquito-transmitted viral disease that cause can cause encephalitis or meningitis, infection of the brain and the spinal cord or their protective covering.
- Most horses bitten by carrier mosquitoes do not develop disease. Of those that do, approximately one-third develop severe disease and die or are so affected that euthanasia is required. The time between the bite of an infected mosquito and when clinical signs appear, ranges from three to 14 days.
Clinical signs
- In horses that do become clinically ill, the virus infects the central nervous system and causes symptoms of encephalitis.
- Clinical signs of encephalitis in horses include loss of appetite and depression, in addition to any combination of the following signs: fever, weakness or paralysis of hind limbs, muscle fasciculations or muzzle twitching, impaired vision, ataxia (incoordination), head pressing, aimless wandering, convulsions, inability to swallow, circling, hyper-excitability, or coma.
- It is important to note that not all horses with clinical signs of encephalitis have West Nile encephalitis. Other diseases, including rabies, botulism, equine protozoal myeloencephalitis (EPM), and other mosquito-borne viral encephalitic diseases of horses caused by Eastern,Western, and Venezuelan encephalitis viruses, can cause a horse to have symptoms similar to WNV.
- Only laboratory tests can confirm the diagnosis of West Nile encephalitis.
Transmission
- WNV is spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds.
- Horses cannot spread the disease to humans, but humans are susceptible to the disease if bitten by a carrier mosquito.
- There is no evidence that horses can transmit WNV to other horses, birds, or people.
- WNV may cross the placenta from mother to gestating foal.
- No transfusion related horse illnesses have been reported. However, human to human transmission via blood transfusions have been confirmed, so this method of transmission is possible in horses.
Prevention
- There is no specific treatment for West Nile encephalitis in horses, supportive veterinary care is recommended.
- Currently, there are some vaccines available against West Nile Virus. It is imperative that horses are vaccinated according to the label on the vaccine. Horses vaccinated against Eastern, Western, and Venezuelan equine encephalitis are not protected against West Nile Virus.
- There are some easy steps you can take to prevent mosquitoes from affecting your horses:
- House horses indoors during peak periods of mosquito activity (dusk and dawn).
- Avoid turning on lights inside the stable during the evening and overnight (mosquitoes are attracted to lights).
- Place incandescent bulbs around the perimeter of the stable to attract mosquitoes away from the horses.
- Remove all birds, including chickens, that are in or close to the stable.
- Look around the property periodically for dead birds, such as crows. Any dead birds should be reported to the local health department. Use rubber gloves to handle dead birds or use an implement, such as a shovel.
- Eliminate areas of standing water on your property. Shallow standing water, used tires, manure storage pits, and drainage areas with stagnant water are ideal mosquito breeding places.
- Topical preparations containing mosquito repellents are available for horses. Read the product label before using and follow all instructions.
- Use fans on the horses while in the stable to help deter mosquitoes.
- Fog stable premises with a pesticide in the evening to reduce mosquitoes. Read directions carefully before using.