On August 23rd of 1999, the first ever case of the West Nile virus in the western hemisphere was reported in Queens, a borough of New York City. A statistical cluster of eight elderly people who were diagnosed with West Nile fever died of encephalitis (brain inflammation). Around that same time and place, many dead crows were noticed throughout the city by various citizens and health professionals. Some of the exotic birds at the Bronx Zoo were also found dead. The West Nile virus is especially dangerous to elderly people and infants, as risk factors for contracting the disease include suppressed or weakened immune systems.
Authorities called the Center for Disease Control (CDC), who came over to investigate the matter. They found that the West Nile virus had been contracted by birds throughout the area, including crows, robins, ducks, and eagles. Horses are also known to be susceptible, but birds are the animal most commonly infected with the West Nile virus. By the end of that summer, there were 56 confirmed cases of humans infected with the West Nile virus in New York. However, as the CDC reminds us, those are only the cases that showed symptoms serious enough for people to seek medical help.
West Nile fever is caused by the West Nile virus, which is carried and transmitted by mosquitoes. Four out of five humans who are infected with the West Nile virus show few or no symptoms. Less than one percent of cases of West Nile virus are severe and result in neurological damage.
Currently, no vaccine against the West Nile virus exists, nor is any medical treatment available. The best method of reducing the risk of infection is adequate mosquito control. This could involve the use of screens, sheer curtains, protective clothing, mosquito repellants, and getting rid of standing water where mosquitoes might breed, such as in old tires, upturned buckets, abandoned swimming pools, and shallow holes in the ground that form puddles when it rains.
Signs of the West Nile virus include fever, headaches, fatigue, muscle pain, nausea, vomiting and rashes. In other words, flu-like symptoms. One in five infected people show these signs. Illnesses associated with West Nile virus include West Nile fever, West Nile neuroinvasive disease, West Nile virus encephalitis, West Nile meningitis, West Nile meningoencephalitis, West Nile poliomyelitis, West Nile reversible paralysis, non-neurologic complications, and skin lesions such as rashes.
The West Nile virus was first identified in Uganda in 1937. Until the mid-1990s, the disease was only sporadic, and confined to certain areas of the world. Then came an outbreak in Algeria in 1994. Then there was an outbreak in Romania in 1996. Then came the New York City outbreak of 1999, from where the West Nile virus spread across America and up into Canada, and south into the tropics of Latin America. Now, the West Nile virus has spread across the world.
In 2012, the United States experienced one of its worst epidemics of West Nile virus, when 286 people died of it.