Information about the west nile virus

About
Disclaimer
 

Mosquitoes got you itching? Browse around here for some remedies. We have reviews of different mosquito traps and an educational resource about mosquitoes, and what you can do to avoid being bitten.

About West Nile

West Nile virus belongs to a group of disease-causing viruses known as flaviviruses,
which are spread by insects, usually mosquitoes. West Nile virus represents an
emerging infectious disease in the United States and Canada. Most human infections
are mild, causing fever, headache, and body aches, often accompanied by a skin rash,
and swollen lymph glands. If the virus crosses the blood-brain barrier however,
it can cause life-threatening encephalitis (inflammation of the brain) or meningitis
(inflammation of the lining of the brain and spinal cord). Recent cases have indicated
that West Nile virus can also be transmitted through blood transfusion or organ
transplant. In addition, it appears West Nile virus can be transmitted from mother
to child before birth and through breast milk.

How Do People Get Infected With West Nile Virus:


The principle route of human infection with West Nile virus is through the bite
of an infected mosquito. Mosquitoes become infected when they feed on infected
birds, which may circulate the virus in their blood for a few days. The virus eventually
finds its way into the mosquito's salivary glands. During subsequent blood meals,
the virus may be injected into humans and animals, where it can multiply and cause
illness.

The first step in the transmission cycle of West Nile virus occurs when a mosquito
bites an infected bird. The virus primarily cycles between mosquitoes and birds,
infected female mosquitoes can transmit West Nile virus to incidental hosts, including
humans, when taking a blood meal. Crows are commonly associated with the virus
because they are highly susceptible to infection, but scientists have identified
at least 75 other infected bird species.

The Spread of West Nile:

The West Nile virus was first isolated in Uganda in 1937. It emerged in the Western
Hemisphere for the first time in the New York City area in 1999. Although health
officials hoped, the virus would not survive the first winter, in early spring 2000
it re-emerged in birds and mosquitoes and spread to other parts of the eastern United
States and Canada.

Between 1999 and 2001, West Nile virus caused 18 deaths and sickened 131 other people.
By the summer of 2002, the virus had spread west and south. As of December 20,
2002, Canadian and US health departments have reported 3,852 cases of West Nile
virus in people, resulting in 241 deaths in 2002. Preliminary numbers published
by the US Centers for Disease Control indicate more than 8,900 reported human cases
of West Nile virus in 2003, resulting in more than 210 deaths. Of the 8900 cases
reported, 68% were reported as West Nile Fever (milder disease), 30% were reported
as West Nile meningitis or encephalitis (severe disease), 2% were clinically unspecified.
Researchers continue to monitor and test birds and mosquitoes throughout the United
States and Canada for evidence of the virus.

Top 5 states with greatest number of reported cases (Jan. 1, 2003 to Dec. 17, 2003):


State Reported Cases Reported Deaths
Colorado 2,477 45
Nebraska 1,831 22
South Dakota 1,013 14
Texas 598 33
North Dakota 507 4

Please note, the dramatic difference is death rates in the 2003 figures would seem
to suggest that there are wide discrepancies in the levels of monitoring and testing
to confirm West Nile virus cases in humans across different states. In is generally
assumed that the number of actual cases is significantly higher than the reported
numbers as many symptoms of West Nile can be mild and mimic other illnesses, and
may therefore go unreported.