Thursday, April 24, 2003
April showers bring Spring flowers - and mosquitoes
LOOKING AHEAD by Wally Dobelis
As the Winter hardships subside and nice Spring weather makes outdoor joys accessible to New Yorkers, season-appropriate problems arise. Not like terrorism, the war and SARS, not as in "Houston, I have a..." they are nevertheless real.
My current concern is the little- recognized and rapidly spreading West Nile Virus, borne by an insect well known to local park frequenters, the mosquito. The onset of warm weather brings out the mosquitoes, a few of them WNV infected, who will lay their eggs in trash-filled puddles, rain-filled discarded containers and old tires in abandoned lots, such as those in East Village (check around 12th Street). Gutters filled with decaying leaves, water in dog bowls and birdbaths, flower pot saucers left for more than a few days are their ideal breeding grounds. Note that a clean and chlorinated swimming pool is safe.
The risk increases when we seek relief in the country, where both rain and the spring thaws have left ample wetlands. Cleanup is indicated, as is cautious avoidance of the wetlands until they dry up. As for prevention of bites, repellent sprays help, DEET -based prays are the safest. When going out for a walk between dusk and dawn, the active hours for mosquitoes, wear light and loose-fitting apparel that covers the body (the insects can bite through tight clothes). Spray the clothing with DEET. Although it has been considered safe since its discovery some 50 years ago by the US Army and Department of Agriculture, be cautious in using the spray on bare skin, stay with short-term protective preparations. The May 2003 issue of Consumers Reports lists nine sprays, with their rated hours of use, for both mosquitoes and Lyme ticks. Speaking of the latter, cutting the bright early Spring lawn short and keeping it that way is another way reventing exposure to Lyme disease, keeping both the mice ant ticks down. That's important when our cats and dogs gambol outdoors.
Why this alarm about the WNF? Well, there are the growing numbers and exposures. While there were over 18,000 cases of Lyme Disease reported in 2002, only the Northeast and a couple of Midwest states are actively at risk, while the count of laboratory-positive West Nile cases in the same year has grown to 4,156, affecting 40 states of the US, with 284 deaths. The figures are those published by the Atlanta-based national CDC (Centers for Disease Control and Prevention). That is extreme growth for a disease unknown in the US until 1999, when an outbreak of encephalitis (inflammation of the brain) with 88 cases and 9 deaths in the metropolitan NY, NJ and CT alerted us that a little known African and Asian affliction had reached our shores.
The mosquito that may carry the virus is the common Culex, or house variety. The symptoms are those of flu, with mild fever. About 80 percent of those affected do not know that they have had it. Only about one in 150 of the victims becomes seriously ill. As of the moment there are no cures for the WNF, patients are made comfortable until the fever goes away. The risk of major impact increases with age and past history of suppressed immune systems. Most victims are over 50 years old.
What is the reported vicious insect-bird cycle that brings the disease to us? Well, mosquitoes hibernate. When the warmth of the spring wakes up the infected females, they hunt for blood, the meal they need to lay eggs. Birds are the most common source, and those thus infected in Spring pass the virus to new generations of mosquitoes. The virus is deadly to some species of avians, particularly ravens, magpies, crows and jays. Birds, by roosting together, can infect others. Some 90 percent of dead crows in the NY area tested in 1999-2000 have been found to be WNF carriers. Dead birds or animals found should not be touched, and should be reported to local health authorities.
The CDC has issued warnings about this explosive epidemic that has virtually wiped out the crows and blue-jays in some parts of this country, and killed 1/3 of the 15,000 horses known to have been infected. According to research performed on household pets, dogs are safe and cats may have a brief illness from which they will recover. Neither species is likely to transmit the disease.
Spraying programs, such as those of 1999-2000 in NYC that produced great fears of the side effects, are up to the municipalities. Pesticides malathion and naled should be avoided; pyrethroid, a fast acting synthetic that breaks down quickly, has been found to be the best.
Wally Dobelis thanks CDC, the US Geological Survey and, especially, Consumer Reports .
As the Winter hardships subside and nice Spring weather makes outdoor joys accessible to New Yorkers, season-appropriate problems arise. Not like terrorism, the war and SARS, not as in "Houston, I have a..." they are nevertheless real.
My current concern is the little- recognized and rapidly spreading West Nile Virus, borne by an insect well known to local park frequenters, the mosquito. The onset of warm weather brings out the mosquitoes, a few of them WNV infected, who will lay their eggs in trash-filled puddles, rain-filled discarded containers and old tires in abandoned lots, such as those in East Village (check around 12th Street). Gutters filled with decaying leaves, water in dog bowls and birdbaths, flower pot saucers left for more than a few days are their ideal breeding grounds. Note that a clean and chlorinated swimming pool is safe.
The risk increases when we seek relief in the country, where both rain and the spring thaws have left ample wetlands. Cleanup is indicated, as is cautious avoidance of the wetlands until they dry up. As for prevention of bites, repellent sprays help, DEET -based prays are the safest. When going out for a walk between dusk and dawn, the active hours for mosquitoes, wear light and loose-fitting apparel that covers the body (the insects can bite through tight clothes). Spray the clothing with DEET. Although it has been considered safe since its discovery some 50 years ago by the US Army and Department of Agriculture, be cautious in using the spray on bare skin, stay with short-term protective preparations. The May 2003 issue of Consumers Reports lists nine sprays, with their rated hours of use, for both mosquitoes and Lyme ticks. Speaking of the latter, cutting the bright early Spring lawn short and keeping it that way is another way reventing exposure to Lyme disease, keeping both the mice ant ticks down. That's important when our cats and dogs gambol outdoors.
Why this alarm about the WNF? Well, there are the growing numbers and exposures. While there were over 18,000 cases of Lyme Disease reported in 2002, only the Northeast and a couple of Midwest states are actively at risk, while the count of laboratory-positive West Nile cases in the same year has grown to 4,156, affecting 40 states of the US, with 284 deaths. The figures are those published by the Atlanta-based national CDC (Centers for Disease Control and Prevention). That is extreme growth for a disease unknown in the US until 1999, when an outbreak of encephalitis (inflammation of the brain) with 88 cases and 9 deaths in the metropolitan NY, NJ and CT alerted us that a little known African and Asian affliction had reached our shores.
The mosquito that may carry the virus is the common Culex, or house variety. The symptoms are those of flu, with mild fever. About 80 percent of those affected do not know that they have had it. Only about one in 150 of the victims becomes seriously ill. As of the moment there are no cures for the WNF, patients are made comfortable until the fever goes away. The risk of major impact increases with age and past history of suppressed immune systems. Most victims are over 50 years old.
What is the reported vicious insect-bird cycle that brings the disease to us? Well, mosquitoes hibernate. When the warmth of the spring wakes up the infected females, they hunt for blood, the meal they need to lay eggs. Birds are the most common source, and those thus infected in Spring pass the virus to new generations of mosquitoes. The virus is deadly to some species of avians, particularly ravens, magpies, crows and jays. Birds, by roosting together, can infect others. Some 90 percent of dead crows in the NY area tested in 1999-2000 have been found to be WNF carriers. Dead birds or animals found should not be touched, and should be reported to local health authorities.
The CDC has issued warnings about this explosive epidemic that has virtually wiped out the crows and blue-jays in some parts of this country, and killed 1/3 of the 15,000 horses known to have been infected. According to research performed on household pets, dogs are safe and cats may have a brief illness from which they will recover. Neither species is likely to transmit the disease.
Spraying programs, such as those of 1999-2000 in NYC that produced great fears of the side effects, are up to the municipalities. Pesticides malathion and naled should be avoided; pyrethroid, a fast acting synthetic that breaks down quickly, has been found to be the best.
Wally Dobelis thanks CDC, the US Geological Survey and, especially, Consumer Reports .
# posted by Wally Dobelis @ 3:03 PM 
