West Nile virus is transmitted by the bite of an infected mosquito. It is widespread in Africa, southern Europe, and western Asia. It first appeared in the United States in 1999. It has caused illness and mortality in humans, wildlife and domestic animals, especially birds and horses. In humans, it causes an influenza-like illness that may lead to aseptic meningitis, encephalitis, and death, especially in persons over 50 years of age. West Nile virus is important because it affects not only people, but also wildlife (including many game animals) and some domestic animals. 

Q. Can West Nile virus cause illness in dogs or cats?
A. West Nile virus does not appear to cause serious illness in dogs or cats. A study conducted in New York City in 1999 indicated that dogs do become infected with the virus, however disease from WN virus infection in dogs has yet to be documented. 

Q. Can infected dogs or cats be carriers (i.e., reservoirs) for West Nile virus and transmit the virus to humans?
A. West Nile virus is transmitted by infectious mosquitoes. There is no documented evidence of person-to-person, animal-to-animal, or animal-to-person transmission of West Nile virus. Veterinarians should take normal infection control precautions when caring for an animal suspected to have this or any viral infection. 

Q. How do dogs or cats become infected with West Nile virus?
A. The same way humans become infected—by the bite of infectious mosquitoes. The virus is located in the mosquito's salivary glands. During blood feeding, the virus is injected into the animal. The virus then multiplies and may cause illness. Mosquitoes become infected when they feed on infected birds, which may circulate the virus in their blood for a few days. It is possible that dogs and cats could become infected by eating dead infected animals such as birds, but this is unproven. 

Q. Can a dog or cat infected with West Nile virus infect other dogs or cats?
A. No. There is no documented evidence that West Nile virus is transmitted from animal to animal.

Q. How long can a dog or cat be infected with West Nile virus?
A. The answer is not known at this time. 

Q. Should a dog or cat infected with West Nile virus be destroyed? What is the treatment for an animal infected with West Nile virus?
A. No. There is no reason to destroy an animal just because it has been infected with West Nile virus. Full recovery from the infection is likely. Treatment would be supportive and consistent with standard veterinary practices for animals infected with a viral agent. 

Q. Is there a vaccine for cats and dogs?
A. Currently, there is no vaccine to protect cats and dogs. 

Q. Can I put DEET on my pets to protect them from mosquito bites?
A. NO! It is recommended that you do not apply repellents with DEET to animals, because they may lick themselves and therefore "eat" the product.  

Q. Can my pet birds contract WNV?
A. Although various species of pet birds might be highly vulnerable to WNV, their chances of getting infected are minimal because they are (typically) confined indoors.  If you take your bird outdoors, try to avoid the hours when mosquitoes are most active. 

Q. Can WN virus cause illness in horses?
A. Yes. Clinical signs of illness due to WN virus could include any combination of the following: fever, weakness, listlessness, stumbling and lack of coordination, muscle spasms, partial paralysis, or death. There have been no documented cases of horse-to-horse transmission or of horse-to-person transmission

Q. Is there any treatment for horses that become infected with WN virus?
A. The main treatment is supportive therapy to reduce the severity of symptoms. If your horse shows any symptoms that may be associated with WN virus infection, contact your veterinarian.

 Q. Is there a vaccine for horses?
A. Yes. A WN virus vaccine for horses has been given a provisional licence and is now available in Canada. The vaccine is only available from licenced veterinarians. For further information, contact your veterinarian. Vaccine status must be taken into account before blood samples are tested for WN virus.

Q. Is there a human vaccine?
A. There is no licensed human vaccine for WN virus at this time.

 Q. What can I do to protect myself and my animals?
A.Mosquitoes lay their eggs in standing water, which includes puddles, stagnant ditches, and containers such as old tires, buckets, cans, neglected swimming pools, etc. Storm sewers, culverts, and catch-basins, etc. provide an outdoor resting place for adult Culex pipiens mosquito (the common house mosquito) which is most commonly associated with West Nile virus. This mosquito often enters homes through unscreened windows or doors, or broken screens.

• Make sure that doors and windows have tight-fitting screens. Repair or replace all torn screens in your home.
• Remove all discarded tires from your property.
• Dispose of tin cans, plastic containers, ceramic pots, or similar water-holding containers.
• Make sure roof gutters drain properly. Clean clogged gutters in the spring and fall.
• Clean and chlorinate swimming pools, outdoor saunas and hot tubs. If not in use, keep empty and covered.
• Drain water from pool covers.
• Change the water in bird baths at least once a week.
• Turn over plastic wading pools, and wheelbarrows, etc. when not in use.
• Clean ditches of obstructions so they drain properly.
• Eliminate any standing water that collects on your property.
• Check trees for cavities that hold water and fill them with soil, gravel, or sand.
• Remind or help neighbors to eliminate breeding sites on their properties.

Repellents

If you will be outside during evening, nighttime and dawn hours, consider the use of an insect repellant containing 10% or less DEET (N, N-diethyl-methyl-meta-toluamide) for children and no more than 30% DEET for adults. DEET is effective for approximately four hours. Avoid prolonged or excessive use of DEET and use it sparingly to cover exposed skin and clothing. Always use DEET according to the manufacturer’s instructions.

DO NOT use DEET on:

• Infants
• Pregnant women
• pets