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In the summer of '99, mosquitoes carrying the West Nile Virus killed seven, hospitalized 55 and infected more than 1,900 in the Northern Queens area of New York.
On August 12, 1999 a normally healthy, active 60 year old man was admitted to Flushing Hospital Medical Center, with a 104 degree temperature, having suffered weeks of weakness and fatigue just prior to this. Soon there were six more cases such as this one. The common
thread...all had spent a period of time outdoors just before the onset of their symptoms. None of these seven survived the virus.
Other reports included cases of 22 infected horses on Long Island, thirteen of which died, or were euthenized. The Bronx Zoo lost 27 captive birds and counting. Over 10,000 crows and free-flying birds had succumb to the WNV.
At the time of the outbreak, NYC had no mosquito surveillance or prevention programs in effect. Following this, the city and the Centers
for Disease Control began a wide range spraying, (via helicopter and truck) of Malthion, an organic pesticide, which attacks the nervous systems of flying insects and fish. This was supposed to arrest the propagation of
infected mosquitoes, but it did not.
An infected bird or birds, illegally entering the United States are believed to be the origin of the WNV in the NYC area. The cycle of outbreak begins with the infected bird. When a mosquito pierces the skin of a victim, to get blood, it draws up the virus. Then upon repeating
this process with yet another victim, it's saliva, containing the virus, immediately flows into the puncture. The WNV is then passed on.
The West Nile Virus belongs to the family of viruses that cause yellow fever, Japanese B encephalitis, St. Louis encephalitis and Murray Valley encephalitis.
It causes a range of symptoms and maladies from, varying levels of body aches, headache, fever, nausea, weakness and fatigue, to the most
serious...encephalitis, inflammation of the brain, which can be fatal.
Though the CDC states that the virus usually runs it's course in most people with little or no effects, the elderly and the very young are
most susceptible, as their immune systems are either immature or depressed.
This virus was first isolated in Uganda's West Nile Province in 1937...hence, the name. It has since been responsible for epidemics in South Africa, Algeria, France, Romania and last year killed 50 in Russia. Of 450 reported cases of viral meningitis in Bucharest, Romania in July of 2000, 89% were confirmed as the WNV.
During a United States subcommittee hearing on global health risks in October, 1999, Dr. Durland Fish, a medical entomologist and associate
professor at the Yale University School of Medicine testified: "The introduction of a foreign insect-borne virus, never before seen in
the Western Hemisphere, is a public health threat unprecedented in modern times. It is reminiscent of the introduction of yellow fever and bubonic
plague in past centuries." Dr. Fish had previously given a similar warning in 1982, hoping this would challenge the government to put in
place a program to address this issue, but his words fell on deaf ears.
As more and more reports came in of sick and dying crows, the S.P.C.A.'s and various departments of health began testing sick and dying birds in various cities and states, to find the source of this sudden phenomenon. The CDC was called in for a final verdict, and sure
enough...it was confirmed. West Nile Virus.
The slowness of detection and confirmation of the virus, could be attributed to the only method of testing available, which took up
to four days for results. Due to the onslaught of suspected infection, a new technique called real-time polymerase chain reaction was developed.
This is a virus specific test, able to detect the most minute amounts of WNV in cerebrospinal fluid within 5 hours.
On April 26, 2000 CNN reported that 17 states, Alabama, Connecticut, Delaware, Florida, Georgia, Louisiana, Massachusetts, Mississippi,
Pennsylvania, Maryland, New York, New Jersey, North Carolina, Rhode Island, South Carolina, Texas and Virginia, received $2.7 million to
create surveillance programs for detecting areas where this virus could propagate.
It is feared that birds heading South for the Winter, will carry the WNV to areas not yet effected. It is also apparent that there has to be
a grand scale effort to curb this epidemic around the world. Subsequently, the Centers for Disease Control has called for global surveillance of this virus.
WHAT CAN YOU DO ?
There are actually many steps you can take to reduce mosquito populations around your home and community and thereby lessen the risk of infection.
1.) Remove outside objects, such as discarded tires and empty buckets as anything that will hold standing water is a perfect breeding ground for mosquitoes.
2.) Drain water from roof gutters.
3.) Keep swimming pools clean, chlorinated and covered when not in use.
4.) Change water in bird baths every other day.
5.) Report property owners who fail to comply with these standards.
6.) Wear long sleeve shirts and long pants outdoors, especially in and around tall grasses and bush. Mosquitoes are most active at dawn,
dusk and evenings.
7.) Apply a safe insect repellent to all exposed skin, as well as spraying clothing, as mosquitoes can penetrate most fabrics. Be especially
careful using bug repellent on very young children. Read all warnings before applying.
8.) Before a backyard or activity in a damp wooded area, use an environmentally safe fogger or bomb to kill and/or keep mosquitoes away.
It is important to note that cooling temperatures do not negate taking necessary steps to reduce breeding areas for mosquitoes, as infected
larvae can remain dormant over the Winter months, only to reinfect, the following Spring and Summer.
INFORMATION IN PRINT:
(1) Hubalek Z, Halouzka J. West Nile fever: a reemerging mosquito-borne
viral disease in Europe. Emerg Inf Dis 1999; 5: 643-50.
(2) Briese T, Jia XY, Huang C, Grady LJ, Lipkin WI. Identification of a
Kunjin/West Nile-like flavivirus in brains of patients with New York
encephalitis. Lancet 1999; 354: 1261-62.
(3) Calisher CH, Karabatsos N, Dalrymple JM, et al. Antigenic relationships
between flaviviruses as determined by cross-neutralization tests with
polyclonal antisera. J Gen Virol 1989; 70: 37-43.
(4) Berthet FX, Zeller HG, Drouet MT, Rauzier J, Digoutte JP, Deubel V.
Extensive nucleotide changes and deletions within the envelope glycoprotein
gene of Euro-African West Nile viruses. J Gen Virol 1997; 78: 2293-97.
(5) Poidinger M, Hall RA, Mackenzie JS. Molecular characterization of the
Japanese encephalitis serocomplex of the flavivirus genus. Virology 1996;
218: 417-21.
Emerging Diseases Laboratory, Departments of Microbiology and Molecular
Genetics, Anatomy and Neurobiology, Neurology, University of California,
Irvine, CA 92697-4292, USA (Yi-Yu Jia MD, T Briese PhD, I Jordan PhD,
Prof W I Lipkin MD); Department of Zoology, University of Oxford,
South Parks Road, Oxford, UK (A Rambaut DPhil); Department of Biological
Chemistry, University of California, Irvine, CA (H C Chi PhD);
Department of Microbiology and Parasitology, University of Queensland,
Brisbane, Australia (J S Mackenzie PhD, R A Hall Ph.D., J Scherret MSc)
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