Tropical diseases threaten New York

November 3, 1999

By Lucy Chubb

As New York City health officials struggle to curb the spread of encephalitis among its citizens, Physicians for Social Responsibility warned on September 21 that outbreaks of this and other mosquito-borne diseases will be on the rise if global warming remains on its current path.

Infectious diseases such as encephalitis, malaria and yellow fever will become prevalent in regions beyond the tropics, according to the group, as greenhouse gases continue to increase in the atmosphere and the Earth warms.

Three elderly people have died in New York City from the St Louis strain of encephalitis. The St Louis strain causes inflammation of the brain that is almost always induced by a virus carried by mosquitoes. Normally, encephalitis is not deadly and can be treated, but it can be fatal to those with a weakened immune system.

The issue, according to Dr Cathey Falvo, program director for International and Public Health at New York Medical College, who is also a member of the Physicians for Social Responsibility board, is whether the disease-causing microbes that are carried by mosquitoes will be able to survive through the winter.

The Culex mosquitoes that spread diseases like malaria and encephalitis are prevalent in many areas but do not always carry disease. For an outbreak to occur in the United States, the microbes that cause illness must be carried in from other countries, and conditions must be right for the microbes to remain alive and for the mosquitoes that spread them to flourish.

These microbes die when they are exposed to colder temperatures. This is why in New York City officials have pledged to spray pesticides until the first frost, since the cold weather would kill the microbes and preclude the need to continue spraying.

Falvo believes that the agreements made in Rio de Janeiro and Kyoto regarding global warming need to be implemented as soon as possible. She also advocates government incentives to conserve energy, the promotion of alternative energies such as wind and solar and discretion when it comes to exporting energy technology. For instance, Western nations should first suggest renewable solar or wind technologies to developing countries, rather than offering hydroelectric or nuclear energy technology at the outset.

Falvo is hopeful about new studies being conducted to harness the power of ocean currents to generate electricity, though this research is in its infancy.

Considering the New York City encephalitis problem, Falvo suggests that the infrastructure responding to outbreaks of mosquito-borne diseases ought to improve.

For example, the Culex mosquito responsible for the spread of encephalitis prefers long, hot and dry spells before it breeds. It would be helpful, she said, if there were someone at the health department knowledgeable about insects and their life cycles who could predict that there might be an outbreak. These weather conditions conducive to the breeding of the Culex existed on the East Coast for most of the summer.

Some of the steps that could have been taken include warning citizens about the possibility of an outbreak, encouraging them to wear insect repellent and suggesting the use of window screens if people choose not to run their air conditioning or don't have it.

With such cautionary tactics, the controversial spraying of the pesticide Malathion could have been avoided, at least to some extent. While she is concerned about the use of pesticides, Falvo does admit that there is not always a better choice, and that the use of pesticides in New York City probably could not have been avoided under the circumstances.

[Copyright 1999, Environmental News Network, All Rights Reserved.]

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