Health Alerts
September. 6, 2001

It's the mosquito to worry about, not the bird

Even though both mosquitoes and birds have been found in DuPage County with the West Nile virus, the chances of becoming severely ill from one mosquito bite are extremely small. Less than 1 percent of mosquitoes--even in areas where they carry West Nile virus--are infected.

West Nile encephalitis is not transmitted from person-to-person or by birds. Mosquitoes become infected when they feed on infected birds and mosquitoes transfer this virus to humans.

Only crows, blue jays and raptors (e.g. hawks, falcons and owls) carry West Nile in this area and will be accepted for testing. Since these types of birds die readily from the virus, they tell us about the prevalence and distribution of the virus in our county. The DuPage County Health Department is collecting these types of dead birds, but not over the weekend. Collection will begin again on Monday, Sept. 10. Birds found over the weekend should be disposed of properly because they will have been dead for too long for test purposes.

Useful information for distinguishing crows from other birds with black feathers include:

1. Crows can be confused with other birds with black feathers such as grackles and starlings. Crows are all black including feathers, beak, legs and feet. They are large birds approximately as long as an adult's forearm. The crow's nostrils are covered with bristles.

2. Grackles are also all black, smaller than crows, but are larger than a robin
(11 inches to 13 inches). They can be distinguished from crows because
their tail feathers are nearly as long as the bird's body.

3. Starlings are robin-sized birds with black spotted feathers, yellow beaks and yellow feet.

Birds submitted for testing should be eligible birds that have no obvious cause of death, such as being found in a roadway and most likely killed by a motor vehicle, or birds killed by a gunshot.

Birds submitted for testing must be submitted through the local health department.

The DuPage County Health Department will transport the birds to the Illinois Department of Public Health for testing. Birds should be dead no longer than 48 hours for testing. Birds can be picked up with a gloved hand, double bagged in a garbage bag with ice and brought to any of the DuPage County Health Department's Public Health Centers.

What is West Nile virus encephalitis?
West Nile virus encephalitis is an infection of the brain caused by the West Nile virus.

How is the West Nile virus transmitted? Mosquitoes
People get West Nile virus encephalitis from the bite of a mosquito that is infected with the West Nile virus. The West Nile Virus is not transmitted person to person.

Where did West Nile virus come from?
The virus is commonly found in Africa.
It is not known how West Nile virus was introduced to the United States.

Why is the United States concerned about West Nile virus?
In 1999 and 2000, an outbreak of human encephalitis was found in and around New York City. No specific therapy for West Nile encephalitis.
Intensive supportive therapy. 1999 Outbreak - 11 Deaths in New York

How is West Nile virus carried from state to state?
Birds also become infected and act as a Reservoir Host.
West Nile virus reported now in 70 species of birds since 1999.
Birds are migratory.
1999 - West Nile virus reported in 4 States
2000 - West Nile virus reported in 12 States 4100 West Nile virus infected
dead birds in these 12 states. 7 of the 12 states reported WNV infections
in humans, horses and other mammals.

What is being done in Illinois?
 Mosquito Control Measures - kill mosquitoes in the larvicide stage.
Surveillance of Birds Crows very susceptible and die; therefore a good indicator.

What can you do to lessen the risk for West Nile Virus?
Eliminate standing water and collection basins for mosquito
breeding - clogged gutters, buckets, flower pots, pet bowl water
dishes, tires, swimming pool covers.

Wear long sleeves and pants when outdoors in mosquito areas.
Use mosquito repellent containing 30 percent to 35 percent DEET
when it is necessary to be outdoors, applied sparingly to exposed
skin or clothing, as indicated on the repellent label. Consult a
physician before using repellents on young children. 

Protect the indoors - Maintain screens on doors and windows.

Sources: Centers for Disease Control and IDPH
For more information contact your local Public Health Center.

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