Beware Disease Carriers That Fly.

It almost sounded like a child's nursery school song--the mosquitoes bit the crows, the crows got sick, the mosquitoes bit the sick birds, then bit the humans, who sprayed the pesticide. And the humans got sick, too.

The West Nile encephalitis outbreak in New York late last summer demonstrated that unusual diseases can flourish, and humans can die given the right conditions. The disease, never before seen in the United States, may well have been brought into the country via infected birds.

Carried in the salivary glands of mosquitoes, the illness is transferred to birds when infected bugs bite them. More bugs bite the birds and are infected. Then, they bite people. Generally, West Nile virus causes a mild disease in humans. It was the elderly who were stricken in this epidemic.

In January, the New York Assembly took action to stop transmittal of the virus in its tracks should it emerge again this spring. New York allocated $70,000 for a meeting and further study of the disease and how best to prevent it. The forum drew leading experts from around the country.

A total of 59 probable or confirmed cases (including seven deaths) occurred in New York City and two surrounding counties, according to the National...