States On Guard For West Nile Virus

By: - April 19, 2000 12:00 am

This week, New York City renews its war on the West Nile virus — the mosquito-borne disease that killed 7 New Yorkers and sickened 55 others without warning last summer. As the city gears up to ward off another outbreak, states on the Eastern Seaboard and in the southeast are putting plans into place to guard against the virus as well.

Last August, the West Nile virus, which had never been seen before in the Western Hemisphere, caught New York City off guard.

No one is quite sure how the virus, which causes encephalitis (a swelling of the brain), reached this continent. Experts theorize that it might have been brought in by a wayward bird migrating across the Atlantic from Africa, by an infected foreigner visiting the United States or by exotic birds smuggled into this country.

The West Nile virus is carried by birds and transmitted by common house mosquitoes (Culex pipiens) that have bitten an infected bird. People catch the virus only from a mosquito, not from a bird or another person.

West Nile virus is typically not life-threatening for humans — it is possible for a person to become infected with the virus and never experience any of the flu-like symptoms that accompany it.

However, it is dangerous for people with weakened immune systems, particularly the elderly and the very young, because there is no vaccine for it and no cure.

So when the federal Centers for Disease Control and Prevention (CDC) said last month that strains of the virus had survived the winter in some mosquitoes in Queens, New York, states began arming for the mosquito season with preventive plans. Queens was the site of the majority of last year’s cases.

Most plans have several elements in common:

  • Encouraging people to clear away areas that mosquitoes breed in, such as standing water in bird baths or old tires;
  • Stepping up mosquito, bird, and human monitoring for signs of the virus;
  • Enhancing laboratories and training scientists to test for the virus;
  • And as a last resort, spraying insecticides.

In addition to monitoring and testing birds, several states–including Delaware, New Jersey, New York, Pennsylvania and Virginia– are using “sentinel chickens,” or flocks of chickens in various locations that are tested routinely for the virus.

Chickens have long been used to detect the various strains of encephalitis prevalent in the United States because they are susceptible to the virus but it doesn’t make them sick or kill them. The West Nile virus is expected to have a similar effect according to William Meredith, a Delaware Mosquito Control Section official.

What distinguishes this year’s West Nile virus detection effort is the amounts of money states are spending to prevent the virus from threatening their residents.

Pennsylvania leads the way with $9.8 million allocated to control the disease. Most of that amount, $8 million, is reserved for spraying insecticides if necessary. According to Richard McGarvey, Pennsylvania Department of Health spokesperson, the remaining $1.8 million is mainly for start-up costs of the program.

Before this year, Pennsylvania had no program for monitoring, screening or testing mosquitoes. Because local governments in Pennsylvania also had nothing in place before this year for monitoring, screening or testing mosquitoes, the state is completely funding all aspects of local mosquito-control programs.

“Is it a lot? Yes. But we want to make sure we’re doing it right,” McGarvey said.

Even states such as Connecticut, Delaware, Maryland, New Jersey, New York and Virginia, that traditionally monitor mosquitoes for other types of encephalitis (or at least did so last year because of West Nile) are budgeting extra money for mosquito control and surveillance.

Connecticut, for example, is spending $1.5 million to beef up its program, much more than the $200,000 the state typically spends for mosquito trapping and testing.

New Jersey is more than doubling its regular mosquito-control budget to spend a total of more than $1 million dollars from state coffers. New York’s state budget calls for an additional $2.5 million to be spent on West Nile response.

“I don’t recall in the last 25 years that I’ve been working in this area as much manpower being put into surveillance as for the West Nile virus,” said Theodore Andreadis, chief medical entomologist at the Connecticut Agricultural Experiment Station.

In addition to increasing mosquito-control budgets, states are also getting help from the federal government. The Centers for Disease Control have awarded grants totaling $2.7 million to 17 states, Washington, D.C. and New York City.

The maximum grant is $200,000 per state, and so far the maximum has been allocated to Connecticut, New Jersey and New York.

Among the other states receiving grants from the CDC for help in warding off the West Nile virus are Alabama, Delaware, Florida, Georgia, Louisiana, Maryland, Massachusetts, Mississippi, North Carolina, Pennsylvania, Rhode Island, South Carolina, Texas and Virginia.

Because the virus is so new, many states lack the equipment and trained personnel to test for the virus within the state. Part of what CDC is funding is enhancements to state laboratories so the virus can be tested for in-state and identified and contained sooner.

“One of the problems we had last fall is that all states had to send specimens to be tested to [CDC] labs in Colorado or Madison, Wisconsin. That clearly built in delays in terms of gathering information,” said Stephen Ostroff, M.D., associate director for the National Center for Infectious Disease at the CDC.

Delaware is using $47,000 of its $70,500 CDC grant to equip its state lab to test for the virus.

Other state preparations include:

  • Connecticut will double its mosquito traps to maintain a total of 72 trapping locations. All 36 of the new traps will be added in lower Fairfield and New Haven counties where dead crows were found last year.
  • Delaware is adding 10 more stations containing sentinel chickens to the 12 it already has, and it will add another 10 more insect traps to catch and test adult mosquitoes to the 22 that are currently in place.
  • New Jersey will test chickens in all 21 counties this year. Normally, mosquito control programs are left up to counties, which did not all have sentinel chickens last year.
  • New York, where each county handles its own public health and mosquito control, is preparing a statewide response plan, which outlines what counties should be doing to prepare for the virus’ return. New York City, which is spending $4.5 million of its own money on West Nile response, will have mosquito traps and sentinel chicken flocks in all five boroughs, and the city’s Department of Environmental Protection will use “mosquito fish,” or larvae-eating fish at catch basins, waste treatment plants and other breeding sites for mosquitoes.
  • Pennsylvania is using its Department of Aging to educate seniors, who are more at risk for the disease, about the West Nile virus. To get their program up and running, the Keystone State has created 500 mosquito monitoring sites scattered around the state with an emphasis on the New Jersey and New York borders.

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