West Nile Facts

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WEST NILE VIRUS

Facts you should know:
The West Nile Virus (WNV) is a viral disease previously seen only in Africa, Asia and Eastern Europe. In 1999, an unexpected outbreak of WNV occurred in New York City. In 2000, the virus spread east and south, causing 21 human cases of WNV encephalitis in the United States including two deaths. The WNV was detected in Erie, Pennsylvania in summer 2000, and the virus was found in northeastern Ohio in 2001. The virus can cause encephalitis, an infection of the brain and spinal cord. The WNV is spread by infected mosquitoes.

The Center for Disease Control reports that even in areas where mosquitoes have been tested and are found to carry the virus, very few mosquitoes - less than 1% - are infected. If a mosquito is infected, less than 1% of the people who are bitten and become infected will get severely ill. The chances of becoming severely ill from any mosquito bite are extremely small.

Healthy wetlands do not provide the best breeding sites for the type of mosquito that carries the West Nile Virus - Culex pipiens. Natural populations of predators (fish & amphibians) and parasites control larval mosquito populations. Flowing or standing water with "wave or ripple action" serves as a poor breeding site for Culex mosquitoes.

Sites that hold standing water like tire ruts and receptacles including retention basins, discarded tires, and outdoor pots, will attract and serve as prime breeding areas for Culex pipiens because those catchments hold few natural predators.

The "Fact Sheets" below should answer most questions you may have. Please contact them at (216) 443-7520 for more information.

West Nile Virus Fact Sheet (Cuyahoga County Board of Health)
Before August 1999, West Nile virus had never been reported in the United States. In 1999, 62 cases of severe disease and 7 deaths occurred in New York.
The number of human cases recorded during the year 2000 West Nile virus outbreak in the USA was 20 with 2 deaths.
Mosquitoes become infected when they feed on infected birds, which may circulate the virus in their blood for a few days. After an incubation period of 5 to 15 days, infected mosquitoes can then transmit West Nile virus to humans and animals while biting to take blood. The virus is located in the mosquito's salivary glands.
During blood feeding, the virus is then injected into the animal or human, where it multiplies and may cause illness.
West Nile encephalitis is NOT transmitted from person-to-person.
There is no documented evidence that a woman's pregnancy is at risk due to West Nile virus.
There is no evidence that a person can get the virus from handling live or dead infected birds. however, avoid bare-handed contact when handling dead animals, including dead birds. Use gloves or double plastic bags to place the carcass in a garbage can.
There is no specific therapy for West Nile encephalitis.
There is no vaccine against West Nile encephalitis.
The incubation period in humans (i.e. time from infection to onset of disease symptoms) for West Nile encephalitis is usually 5 to 15 days.
The West Nile virus case fatality rates range from 3% to 15% and is highest in the elderly.
Following transmission by an infected mosquito, West Nile virus multiplies in the person's blood system and, in severe cases, crosses the blood-brain barrier to reach the brain. The virus interferes with normal central nervous system functioning and causes inflammation of brain tissue.
West Nile encephalitis cases occur primarily in the late summer or early fall.
Less than 1% of the mosquitoes have West Nile virus in areas where West Nile virus is present.

West Nile Virus - Personal Precautions Against Mosquitoes
Q: What can I do to reduce my risk of becoming infected with West Nile virus?
A: From April to October, when mosquitoes are most active, take the following precautions:
• If outside during the evening, nighttime and dawn hours when mosquitoes are most active and likely to bite, children and adults should wear protective clothing such as long pants, long sleeves-shirts, and socks.
• If outside during the evening, nighttime and dawn hours, consider the use of an insect repellent containing 10% or less DEET (N,N-diethyl-methyl-meta-toluamide) for children and no more than 30% DEET for adults.
• Use DEET according to manufacturer's directions:
o Do not use DEET on infants or pregnant women
o Do not allow young children to apply DEET themselves
o Do not apply DEET directly to children. Apply to your own hands and then put it on the child.
o DEET is effective for approximately four hours. Avoid prolonged or excessive use of DEET. Use sparingly to cover exposed skin and clothing.
o Wash all treated skin and clothing after returning indoors.
o Store DEET out of reach of children.
Please note: Vitamin B, ultrasonic devices, incense and bug zappers have not been shown to be effective in preventing mosquito bites.

Q: What can I do around my home to prevent exposure to mosquitoes?
A: Mosquitoes lay their eggs in standing water around the home. Weeds, tall grass, and bushes provide an outdoor home for the adult Culex pipiens mosquito (the common house mosquito) which is most commonly associated with West Nile virus. Mosquitoes can enter the home through unscreened windows or doors, or broken screens.
• Make sure that doors and windows have tight-fitting screens. repair or replace all screens in your home that have tears or holes.
• Remove all discarded tires from your property.
• Dispose of tin cans, plastic containers, ceramic pots, or similiar 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 water in bird baths at least once a week.
• Turn over plastic wading pools and wheelbarrows when not in use.
• Eliminate any standing water that collects on your property.
• Remind or help neighbors to eliminate breeding sites on their properties.

West Nile Virus - Birds
Q: How are birds involved in the transmission of the West Nile virus?
A: Birds become involved through the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds that serve as a reservoir for the virus. Infected mosquitoes can transmit West Nile virus to humans.

Q: What is the significance of dead birds?
A: In 1999, it was determined that West Nile virus was responsible for a significant number of bird deaths in New York City and in surrounding areas. However, since birds can die of many different causes, finding a dead bird does not necessarily mean that the virus is present.

Q: Can I get West Nile virus from an infected bird?
A: No, West Nile virus is not spread directly from birds to persons.

Q: If I see a dead bird, what should I do?
A: The Cuyahoga County Board of Health is taking reports on dead bird sightings within Cuyahoga County, especially crows and blue jays. While the Cuyahoga County Board of Health is interested in collecting information about dead birds as part of its efforts to understand West Nile virus, we will not be picking up every dead bird reported. The Board of Health will only collect a small sample of the bird population. However, we encourage Cuyahoga County residents to report all dead bird sightings to assist the department's monitoring efforts.

Q: If the Cuyahoga County Board of Health is going to pick up dead birds, then what do I do?
A: Wear plastic gloves if available and place the bird in a plastic bag and tie the bag and place it in another plastic bag and tie it closed. If gloves are not available, then place a plastic bag over your hand and pick up the bird with the bagged hand and pull the bag over your hand holding the bird now in the bag. Tie up the bag and place it in another bag and tie it closed. If possible, place the bird in your freezer or place in a cool area out of direct sunlight. If you are not able to place the bird in a bag, then please place a bucket or bag over the bird to protect it from insects or animals.

Q: How do I dispose of a dead bird?
A: If you do not receive a phone call from the Cuyahoga County Board of Health to arrange pick up of the dead bird within 24 hours after you report it or by the next business day, please dispose of the dead bird. West Nile virus cannot spread directly from birds to people. However, dead birds should not be handled with bare hands. Use gloves to carefully place dead birds in a double plastic bag and then place the dead birds in the outdoor trash or bury on your property.

Q: Are we testing birds for presence of the West Nile virus?
A: Since certain species of of mosquitoes feed abundantly on birds, testing birds for West Nile virus is particulary important for surveillance and control of mosquito-borne diseases. The Cuyahoga County Board of Health will submit dead birds, as well as blood samples from live birds, for testing as part of the West Nile Surveillance and Control Plan.

West Nile Virus - Dogs and Cats
Q: Can West Nile virus cause illness in dogs or cats?
A: West Nile virus was isolated from a dead cat during the New York area outbreak in 1999. Most dogs or cats infected with the West Nile virus recover from the infection. A sero-survey of healthy dogs in New York City and Nassau County indicated a 5-11% infection rate. there is no specific therapy, but in more severe cases, supportive treatment may be indicated.

Q: Can infected dogs or cats be carriers and transmitters of West Nile 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 other viral infection.

Q: How do dogs or cats become infected with West Nile virus?
A: Dogs and cats become infected the same way humans become infected; by the bite of an infected mosquito.

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: Should a dog or cat infected with West Nile virus be euthanized? What is the treatment for an animal infected with West Nile virus?
A: No. there is no reason to euthanize an animal infected with West Nile virus. Refer to your veterinarian for proper care of your sick pet. Full recovery from the infection is likely. Treatment would be supportive and consistent with standard veterinary practices for animals infected with a viral agent.

West Nile Virus Web Sites
Centers for Disease Control and Prevention (CDC)
http://www.cdc.gov/ncidod/dvbid/westnile/index.html
New York state Health Department
http://www.health.state.ny.us/nysdoh/westnile/index.html
U.S. Geological Survey, Animal Disease Laboratory
http://www.nationalatlas.gov/virusmd.html
New York City
http://www.ci.nyc.ny.us/html/doh/html/wnv/wnvhome.html
Ohio State University
http://www.prevmed.vet.ohio-state.edu/extension/savilleEXTProgram.html

To obtain more information about west Nile virus, call the Cuyahoga County Board of Health at (216) 443-7520 or visit our website at www.ccbh.net

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