Long quote from the article in the Worcester Telegram and Gazette

State set to attack deadly Nile virus

Saturday, March 18, 2000
By John J. Monahan
Telegram & Gazette Staff
         State officials are preparing a rapid response plan, which includes
widespread spraying of pesticides, in the event a mosquito-borne outbreak of
the deadly West Nile Virus occurs this spring in Massachusetts.
         The preparations come on the heels of advisories from the Centers
for Disease Control and Prevention in Atlanta for the Eastern Seaboard
states, including all of New England, to come up with plans for the
surveillance and control of possible outbreaks of the virus.
         Federal officials hope the states can reduce the likelihood, or at
least contain, a possible outbreak of the virus that hit New York City last
summer.
         State health officials say that in about a week they will begin
sampling mosquito larvae across Massachusetts for signs of the virus. If it
is located, they may immediately resort to widespread application of a
natural larvicide called BT to kill off immature mosquitoes before they turn
into adults.
         If further monitoring determines that maturing mosquitoes and birds
migrating back to New England are carrying the virus, the officials say they
may have to go to more intensive widespread applications of pesticides across
large areas in the state.
         In addition to aerial fogging with the pesticide Malathion, which
was done throughout the New York City area last summer, urban drainage
systems also may be treated with pesticides or larvicides to kill mosquitoes.
         The virus, which had not previously been seen in the Western
Hemisphere, turned up in New York City last summer. The outbreak was noticed
after large numbers of birds around Central Park were found dead from the
virus.
         Aerial fogging of the New York City area helped keep to 47 the
number of people who contracted the disease. Four residents died from the
virus.
         The West Nile Virus is carried by birds and can be transmitted to
humans by mosquitoes that feed on the infected birds, then bite humans. It is
uncertain how the virus might act in the United States, which has far
different wildlife patterns and climates than the Middle East, where the
virus originated.
         Massachusetts officials expect to learn the answers to key questions
in the first weeks of April, when migrating birds and mosquito larvae can be
examined for the virus.
         Barbara G. Warner, the associate director of the Massachusetts
Department of Public Health laboratory who is helping to coordinate the
statewide investigation, said officials need to quickly determine if the
virus has survived the winter, and, if so, how prevalent it is along the
Atlantic and Gulf coasts.
         So far the virus has not been found in Massachusetts, but it was
found last year in Connecticut and in wintering mosquitoes in the New York
City drainage system in January and February.
         Massachusetts was included in the recommended surveillance and
response area because it is in an area where transmission is likely to occur
this spring because of bird migration patterns.
         “What we don't know is how that organism behaves in this part of the
world,” said Brad C. Mitchell, director of the state Pesticide Control Board.
         Although birds tend to die from the virus, which could limit
continuation of the outbreak that occurred in New York, scientists still need
to monitor birds to determine if the disease has spread during the winter and
spring migrations of birds.
         “This may have been a one shot deal in New York last year, but we
are monitoring it and preparing for the worst,” Mr. Mitchell said.
         The state already monitors and kills mosquitoes in Southeastern
Massachusetts to protect against the spread of eastern equine encephalitis.
         However, because a different mosquito species that is more likely to
live in urban areas is believed to carry the West Nile virus, the monitoring
and control plans for the disease are being expanded across the state. Urban
areas included in the plans include Worcester, Springfield and Boston.
         “Where we spray would depend on where it is isolated,” Mr. Mitchell
said. If the state identifies potential “hot spots” early in mosquito larva,
then a mosquito larvicide called BT, a natural toxin, could be used. BT kills
mosquito larva but its toxicity is limited.
         If the virus is later found in adult mosquitoes, other, stronger
pesticides may have to be used, Mr. Mitchell said.
         Ms. Warner said the public can take precautions, guarding against
mosquito bites by wearing long pants and long-sleeved shirts and using
mosquito repellent.
         Mr. Mitchell emphasized that residents should take steps to
eliminate standing water around their homes to reduce breeding by mosquitoes.
         He said residents do not have to worry about contracting the virus
from birds.
         Before applying any larvicide or resorting to widespread use of
pesticides, state officials would weigh the environmental risks posed by the
chemical applications and the risks posed by the virus.
         “I have no doubt that if it is determined there is significant risk,
there will be prompt action,” Mr. Mitchell said.
         Mr. Mitchell said it is hoped that applying larvicide would be
sufficient to curb the problem. However, larvicide may not be adequate,
because it is difficult to spray the substance into covered areas where
mosquitoes lives.
         If Malathion is applied from airplanes, he said, it would be applied
in the form of a light fog and cover large areas.
         “None of us want to see it reach that point,” Mr. Mitchell said.
© 2000 Worcester Telegram & Gazette
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