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West Nile Virus is the mosquito-borne infection we don't hear much about, but that hasn't gone away. The Centers for Disease Control report that as recently as 2013 the virus and related arborviruses continued to cause severe neuroinvasive infections.
West Nile Virus is the most common of a group of viruses that also includes La Crosse virus, Jamestown Canyon virus, Powassan virus, eastern equine encephalitis, California serogroup virus, and St. Louis encephalitis virus. All of these viruses attack the central nervous system in birds, mammals such as horses, and humans.
Nationwide, there were 1,267 cases of the virus in humans, with 51% of infections reaching the brain. Most commonly the virus struck people 70 years of age and older, and 9% of people who contracted virus died of the infection. The average age of persons who died of West Nile Virus infections was 78 years.
Here are frequently asked questions and answers about the West Nile Virus.
Was the West Nile Virus brought to this country by West Nile terrorists?
No. The West Nile Virus seems to have arrived with a mosquito in an airplane in 1995. The first cases of the disease in North America were detected in New York City, and it has been spreading westward since. Currently the infection is found in all 48 continental states of the United States, although it has not yet been reported in Alaska or Hawaii.
Is West Nile Virus always deadly?
No. Only about 1% of people who are infected with the virus develop serious symptoms such as meningitis, and many may not ever be diagnosed as having the disease. In people over the age of 50, however, up to 10% may develop a condition known as flaccid paralysis, and deaths in infected people over the age of 70 are not unusual.
How does someone catch West Nile Virus?
The West Nile Virus is spread by mosquitoes, although there is some evidence it may also be contracted by handling wild bird droppings. Because the disease is usually transmitted by mosquitoes, cases seldom occur before June or after November in the Northern Hemisphere.
Is the United States the only country affected by the virus?
No, cases have been noted in Africa, as well as in Israel, Russia, Algeria, France, Romania, and the Czech Republic.
What are the symptoms of West Nile Virus infection?
Three to six days after a bite from a mosquito carrying the infection, there may be headache, backache, eye pain, rash, nausea, vomiting, loss of appetite, and/or fatigue. Fever is relatively rare, occurring in only about 1 in 5 cases.
Severe cases can cause a blister-like red rash on the trunk, arms, and legs.
The most severe symptoms of the disease usually do not appear for about a week after the first symptoms from the infection.