The Impact of West Nile Virus on Humans (or Why We Should Worry)
West Nile virus can infect humans, but there are more drastic ways that it affects our lives. The virus normally lives in birds and is transmitted among them and other animals by mosquitoes. There is no other definite method of transmission, and people do not have to worry about contracting the virus through contact with infected humans or animals. Hundreds of species of birds and many mammals, including several endangered species, are vulnerable to the virus. Many domestic animals are also susceptible, but the virus does not create any symptoms in most of them. There is no way of getting rid of the virus once an animal has been infected, but a vaccine for horses has recently been approved by the USDA. There are also vaccines for preventing infection in humans being worked on by several companies.
West Nile virus can infect humans, but infection is not the only way that it affects our daily lives. Several other animal species can also become infected by the virus, so special care should be taken to protect our wildlife, our livestock, and even our pets.
West Nile virus is transmitted from birds to other animals through a vector, one of forty-three species of mosquito. Scientists have also found West Nile virus in ticks in Africa and Asia (Lee, 2003), but there has been no evidence that the ticks can also act as a vector for the virus. People cannot catch West Nile virus from any other animals, so becoming ill from the virus should not be the main concern of humans regarding the virus.
However, if a human does become infected with West Nile virus, it is unlikely that it will produce any symptoms. Usually, only people over the age of 50 or very young children area develop symptoms because their immune systems are failing with age or are not completely developed, respectively. About 20% of people develop mild symptoms, including fever, nausea, and swollen lymph nodes, within a couple weeks of being bitten by an infected mosquito. Only one out of 150 infected humans display more
WNV’s Impact on Humans 2
serious symptoms, such as high fever, disorientation, vision loss, numbness, and paralysis. Because West Nile is a virus, it cannot be cured by antibiotics. People who display serious symptoms are given supportive treatment, which may include intravenous fluids and respiratory support until they recover (CDC, 2004).
Animals found in the wild are also susceptible to West Nile virus. It is fatal to up to 285 species of birds, which are the reservoirs that the virus normally lives in (CDC, 2005). Members of the avian family Corvidae, which includes crows, ravens, magpies, and jays (CDC, 2003), are especially vulnerable to West Nile virus, as seen during the 1999 New York epidemic, when hundreds of crows died from the virus. Other animals that have been found carrying the virus include squirrels, chipmunks, skunks, and bats (Lee, 2003). Although humans do not have to worry about...