West Nile-like virus in New York
William Ventura, Ph.D
Professor
Pace University
Bedford Road
Pleasantville, New York, 10570
fax: (530) 706-6259
http://www.oocities.org/RainForest/Andes/3804/
wventura@fsmail.pace.edu
Welcome to Dr. Bill's page. I would like to present a short synopsis of events in lower New York State focusing primarily on September/October, 1999.
To date, around 38 people (primarily the elderly) have become ill. Several have died (less than 10), with what was first diagnosed as St. Louis Encephalitis-related illnesses. This diagnosis was later changed to complications due to West Nile-like virus infection. This latter condition leads to flu-like symptoms such as aches and pains, headache, high fever, and can in severe cases lead to hemorrhagic fever and convulsions. In most cases the patient recovers with moderate care.
It is especially relevant to point out that the Summer of 1999 was one of the hottest and driest in recent memory in the southern region of New York State. Many elderly were overcome with heat-related problems, and many were hospitilized.
AN IMMEDIATE QUESTION TO BE CONSIDERED IS:
DID THIS DEHYDRATING-PRODUCING SUMMER MAKE THE AFFECTED INDIVIDUALS MORE SUSCEPTIBLE TO ATTACK BY THE WEST NILE-LIKE VIRUS?
Following the hot summer, the area being discussed was hit by Hurricane Floyd. One of the consequences of Floyd was heavy rains causing severe erosion and flooding. In addition to people becoming ill, many birds - particularly crows - were found dead during the two week period following the activities of Hurricane Floyd. Subsequent examination of these birds confirmed the presence of the virus. But, to date, no report has been presented that the virus actually killed the birds.
Officials in our region made the decision based on human illness and bird deaths to immediately being spraying insecticide to kill Culex mosquitos. Reason given, these mosquitos are being infected by the birds and passing on the West Nile-like virus to humans. No consideration given to possibility that ticks may be transmitting the virus to humans.
The responsible officials in the New York City area decided to spray MALATHION over their area. The responsible officials in the Westchester County area chose a pyrethrin derivative, SUMITHRIN (Anvil), as their spray of choice.
Reason given, Anvil is less dangerous than Malathion and not as harmful to fish or humans. If ticks are involved in the transmission of this virus - neither spray would be effective in destroying them.
Please note that Culex mosquitos, the culprit suspected of spreading the virus to humans, tend to be less active when the temperature hovers around 50 degrees F or below. Currently, Northern Westchester is not being sprayed with evening temperatures hovering around 40 degrees. Spraying will occur in northern Westchester County when the temperature reaches 50 degrees F. In addition, local Fire Departments are also distributing DEET products to invididuals who wish to repel mosquitos.
Here are some points for your consideration:
1. Malathion is primarily a nerve poison that is dangerous to people wh! o have respiratory problems.
2. Malathion is extremely toxic to fish and spraying it over water sources is prohibited by the DEC.
3. New York City residents were not provided with the specific formulation of the malathion product sprayed in their areas.
4. People were informed that malathion is safe but they should cover swing sets, lawn furniture and stay indoors with windows kept shut.
5. The residents of Westchester County, New York were informed that a chrysanthemum chemical derivative - sumithrin (Anvil) was not only safer than malathion and would degrade in less than eight hours when in direct sunlight.
6. Over 200 fish were found dead in Rye, New York (Westchester County) after Anvil spraying in the area.
7. The MSDS sheet for Anvil clearly states that this insecticide is extremely toxic to fish and should not be sprayed over water areas - the Westchester County area being sprayed is a primary watershed region for New York C! ity area.
8. Anvil is a contact poison and unless it hits the mosquito directly via spray, or the mosquito lands in the poison, it will not kill the insect.
9. Anvil spraying in Northern Westchester County has been delayed for three days October 5 ,6 and 7, 1999, because of the threat of rain in the region.
10. The overnight temperatures expected in this region for the next week (October 7 through 13, l999 when primary spraying will occur with Anvil) is expected to be around 40 degrees F.
11. Due to a delay of three days, several apple orchards have been able to gather data that suggests Anvil should not be sprayed on fruit. They were lucky for the 3 day delay and they have been informed their apple trees will not be sprayed. In addition, the delay has caused the responsible officials to state - no watershed area will be sprayed.
THANKS GOD OR NATURE FOR THE DELAY SO CALMER HEADS CAN PREVAIL.
12. There is no question that, if human populations are at risk for infection with a dangerous virus, then appropriate measures should be taken including spraying with potentially harmful chemicals. However, it is unclear how many individuals with respiratory illnesses, such as asthma, will be more adversely affected by the sprays than possible infection by the virus.
13. It is still unclear if the virus killed the birds, and indeed that the Culex mosquito is spreading the disease to humans.
The environmental consequences of the spraying with Malathion and Anvil will be determined over the next several months as more information is gathered. It is important, however, for all decision makers to weigh the risks and benefits, use information gathering procedures, and use the scientific method to come up with the best decision possible.
The decision makers are already hinting at the possibility of respraying the entire region in the Spring of 2000.
As of November 22, 1999, a total of nine Westchester, New York residents were affected. Across the metropolitan area, the virus is suspected of causing sickness in 61 people (possibly killing seven).
SCIENTISTS DEBATE WHICH MOSQUITO MAY BE THE CULPRIT.
In a newspaper article written by Pamela Weber-Leaf,(The Journal News, 2/1/2000, page 4B), scientists in New York, New Jersey and Connecticut are debating which mosquito may carry the west nile virus.
Mosquitos suspected: Culex pipiens and Aedes vexans.
Culex pipiens - only species found in New York state with the virus. Culex pipiens favors bird hosts and prefers stagnant water to lay eggs.
Aedes vexans can also carry virus and virus isolated from a swampy region just south of Hackensack Meadowlands in New Jersey. The Aedes vexans is a very aggressive, human-biting mosquito.
TO DATE, NO ONE KNOWS WHICH SPECIES OF MOSQUITO CAUSED THE 61 CASES (INCLUDING 7 DEATHS) IN THE AFFECTED REGIONS.
Updates will be added to this site as they develop.
