West Nile virus (WNV) is spread through the bite of an infected mosquito. It was first discovered in Uganda in 1937. Mosquitoes become infected when they bite and feed on infected birds, and they in turn bite humans, spreading the disease. The virus was first discovered in the United States in 1999, and has spread throughout the U.S. Since then, it has also been found in the Middle East, Asia and Africa. West Nile virus has also been found to be spread through blood transfusions, breastfeeding and organ transplantation.
Time Frame and Risk Factors
After an individual is bitten, symptoms tend to appear between three to 14 days, with mild symptoms lasting between three to six days. Severe symptoms like encephalitis may linger on for weeks, or permanently. Risk of infection is highest between July and September in the United States, according to the Mayo Clinic. Individuals with weakened immune systems, those who spend time outdoors and those over the age of 50 are at the highest risk of infection.
Complications
According to the National Institutes of Health, one of the main complications of West Nile virus is encephalitis, or inflammation of the brain. This may lead to permanent brain damage or death. Another complication is permanent muscle weakness, which is similar to the crippling disease polio.
Symptoms
According to the Centers for Disease Control and Prevention, 80 percent of people infected with West Nile virus have no symptoms. The mild form of the disease, called West Nile fever, has several symptoms. They include nausea, vomiting, back pain, fever, abdominal pain, sore throat, lack of appetite, muscle aches, headache and diarrhea. The severe form of the disease is rare, and symptoms include stiff neck, convulsions, disorientation, muscle jerking, lack of coordination, partial paralysis, high fevers and severe headaches.
Treatment of Effects
West Nile virus has no specific treatment as it is a viral infection, and antibiotics do not kill viruses. Bed rest and treatment of symptoms is helpful, while hospitalization is required in more serious cases. West Nile virus research is being done on the drug Ribavirin, which as of 2010 is used to treat hepatitis C, according to the U.S. National Library of Medicine. Studies are also being done with interferon therapy, which uses immune cells to treat encephalitis.
Prevention
Prevention begins with reducing mosquito populations. Standing water is a breeding ground and should be eliminated as much as possible. This includes emptying unused swimming pools, changing water in bird baths regularly, unclogging roof gutters and removing old tires that may hold rain water. Application of insect repellent DEET is also effective and prevents bites. It is also advisable to avoid going out during the dawn and dusk hours, and to wear long-sleeved shirts and long pants to prevent bites.
