What is West Nile virus?
West Nile virus gets its name from the West Nile District of Uganda where it was first discovered. It was detected in North America in 1999 and has now spread over much of the continent. The virus can cause an infection in the brain and can affect humans and animals.
How do people and animals get West Nile virus?
The virus is mainly transmitted to people and other animals by the bites of mosquitoes that became infected while feeding on the blood of an infected bird. The main reservoirs for West Nile virus are wild birds. Many bird species can carry the virus and not become ill, although some birds do become ill and die.
Very rare methods of transmission have included receiving a blood transfusion, or organ transplant, or from infected mothers to their babies in breast milk and in the womb.
What are the symptoms of West Nile virus in people?
Most people who become infected have no symptoms at all, or experience only mild flu-like symptoms, such as fever, headache, and body aches. Some may also develop a mild rash, or swollen lymph glands. As with many infectious diseases, certain people, including the elderly and those with weak immune systems, are at a greater risk of experiencing serious health effects. These include meningitis (inflammation of the lining of the brain and spinal cord) and encephalitis (inflammation of the brain). In these cases the symptoms could include the rapid onset of severe headache, high fever, stiff neck, vomiting, drowsiness, confusion, muscle weakness, and loss of consciousness. Although there is no specific treatment, many of the symptoms and complications of the disease can be treated.
How does West Nile virus affect animals?
West Nile virus has only rarely caused serious illness in companion animals like dogs or cats; however, horses are susceptible to the virus. Signs of the disease in horses may vary and include any combination of the following: fever, weakness, listlessness, stumbling, lack of coordination, muscle spasms, partial paralysis, or death. The main treatment is supportive therapy to reduce the severity of symptoms. The disease can be prevented in horses through a West Nile virus vaccine, available from licensed veterinarians. For more information contact your veterinarian.
Some bird species (crows, ravens, jays and birds of prey) and other wildlife species also are susceptible to disease. Sick birds may show signs of brain infection: paralysis, depression, tremors, weakness and death. The main treatment is supportive therapy to reduce the severity of symptoms and prevent secondary bacterial infections.
Can you get West Nile virus from an infected animal?
There is no documented evidence of direct animal-to-person transmission of West Nile virus, but infected birds are known to shed a large amount of virus in their droppings and body fluids. Basic precautions should be taken when handling or working around animals to prevent transmission of West Nile virus and other animal diseases. Use good hygiene practices and wash hands thoroughly with soap and warm water or use an alcohol gel cleanser after handling animals, especially before handling food. Wear protective clothing like coveralls, waterproof gloves (rubber, vinyl or latex), boots and glasses. Prevent contact of your skin with animal feces, body fluids (urine and blood), and external parasites.
How can West Nile virus be prevented in people?
West Nile virus is usually spread by the bites of infected mosquitoes. Taking measures to prevent mosquito bites and reducing mosquito breeding sites can reduce the risk of infection in people. Take the following steps to prevent mosquito bites: Make sure door and window screens fit tightly. Minimize time spent outdoors at dawn and dusk. Wear light-coloured clothing, long-sleeved tops, long pants, and socks. Use an insect repellent containing DEET or other Health Canada approved repellents (www.hc-sc.gc.ca).
Reduce mosquito breeding sites. Mosquitoes need water to breed and they can use even a small amount of water that is allowed to stand for a couple of days. Take the following steps to reduce mosquito breeding sites: Eliminate standing water in such things as pool covers, flower pots, children's toys, old tires, etc. Check for clogged roof or rain gutters and clean them out. Turn over plastic wading pools and wheelbarrows when not in use. Change water in birdbaths at least twice weekly.
Report dead birds
Dead birds can be disposed of incineration, burial, or placed in a sanitary landfill. To place a dead bird in a bag, grasp the bird with your hand protected by gloves or several layers of leak-proof plastic bags and then turn the bags inside-out over the bird so it ends up inside the bags, with your hand on the outside. Handle the bird so that its beak or claws do not puncture your bag or gloves.