Dr. William P. Ventura
Pace University
Pleasantville, N.Y. 10570
AS OF JUNE 19,2000 - MORE PRECISE TESTS INDICATE RESULTS FROM ONE CHICKEN WERE NOT POSITIVE FOR WEST NILE VIRUS. CITY HOLDS SPRAYING.
WEST NILE VIRUS
The West Nile Virus first appeared in New York City in the Fall of 1999. Seven people died and 62 were hospitalized.
The City has set up 14 flocks of test chickens (each flock has 6 or 7 chickens).
Every week the chickens blood is tested for the presence of antibodies against the west nile virus.
The test used is an indirect fluorescent antibody test. The sample of chicken blood is added to a slide that contains cells infected with West Nile.
This technique does not isolate the West Nile Virus, hence the indirect aspect of the test.
To date, ONE chicken tested positive.
To date tests performed on 350 pools of mosquitoes and more than 90 dead birds have all come up NEGATIVE.
In 1999, the City sprayed Malathion, an organophosphate type of insecticide.
This year they want to use Resmethrin.
Resmethrin is a synthetic pyrethroid similar to the sumithrin sprayed in Westchester County, New York.
The EXTOXNET information on Resmethrin indicates it can cause numbness, itching, burning, and tingling sensations with skin exposure.
Exposure by any route may include incoordination, twitching, loss of bladder control, and seizures.
Resmethrin may also cause eye irritation.
Pyrethroids such as resmethrin may cause adverse effects on the central nervous system. Long-term feeding studies have shown increased liver and kidney weights and adverse changes in liver tissues.
ECOLOGICAL EFFECTS
Resmethrin is slightly toxic to birds;
Highly toxic to fish;
Highly toxic to bees.
Resmethrin breaks down in the presence of light and humidity. Its half-life in the environment is 15 minutes.
Fish toxicity studies 96 hour LC50 studies show that resmethrin is toxic to
- mosquito fish (7 microgram/liter);
- redswamp crawfish- Procambarus clarkii (resmethrin with piperonyl butoxidc) (0.00082 microgram/liter);
- bluegill sunfish (0.75 to 2.6 microgram/liter);
- coho salmon (1.7 microgram/liter);
- channel catfish 16.6 microgram/liter).
The half-lives for elmination of several pyrethroids by trout are greater than 48 hours; while elimination half-lives for birds and mammals range from 6 to 12 hours.
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