Causes, prevention of West Nile Virus explained
Summer is the season for outdoor activities and mosquitoes. Standing water from recent rains are a breeding ground for mosquitoes and possibly West Nile Virus.
Named after the West Nile region of Uganda where the virus was first identified, West Nile Virus (WNV) is spread to people by the bite of a mosquito infected with the virus. It's usually considered a virus of birds, but people can be accidental hosts.
Mosquitoes become infected by biting a bird that carries the virus. WNV is not spread from person to person or directly from birds to humans.
In people, the disease usually causes only a mild illness, but may cause encephalitis (swelling of the brain), meningitis (swelling of the lining of the brain), or even death in rare cases.
More severe infections are seen in the elderly and those with a weakened immune system.
Horses and other animals can be infected with the virus from the bite of an infected mosquito. Most horses recover but there have been some deaths.
There were two documented cases where WNV was transmitted through a blood transfusion. While more than 2.5 million blood donations have been screened for WNV since last summer, a low risk exists of potential transmission.
Symptoms, treatment
Most people infected with WNV do not become ill. People with a mild infection may experience fever, headache, eye pain, muscle aches, joint pain, a rash on the trunk, and swollen lymph nodes.
In severe cases, symptoms include severe muscle weakness, inflammation of the brain, paralysis, and coma.
Symptoms usually occur three to 15 days after a WNV-infected mosquito bites a person. Being bitten by an infected mosquito will not necessarily make a person sick. Most people who are infected have no symptoms or only a mild illness.
Prior infection of WNV is thought to provide lifelong immunity to the virus.
There is no specific treatment for the infection. A physician may prescribe medications to relieve the symptoms of the illness. In severe cases, hospitalization may be required.
A vaccine against the virus does not exist at this time for humans. There is a vaccine available for horses.
Preventing mosquito bites will prevent WNV infection. Personal protection and reducing mosquito populations will minimize the chance of developing WNV infection when it is present in an area.
Personal protective measures to reduce or prevent mosquito bites include limiting time spent outdoors at dusk and dawn when mosquitoes are active, wearing long sleeve shirts and long pants when outdoors, using insect repellents containing DEET when outdoors, and screening homes to prevent mosquito entry.
Reducing mosquito populations also will reduce mosquito bites. Eliminating standing, stagnant water where mosquitoes breed is a good way to reduce the mosquito population.
Any container or area where water can collect is a potential breeding ground for mosquitoes such as unused tires, buckets, toys, clogged, gutters, birdbaths, and livestock tanks. Turning out the water or replacing existing water every three days will interrupt the mosquito life cycle. Also, the use of lavicides with Bti in these areas of stagnant and standing water has shown to be extremely effective in eliminating mosquitoes.
Mosquitoes most likely to carry the virus will not breed in fresh water or running water.
For more information, contact Marion Health Department at 620-382-2550 or 888-305-8848 or Kansas Department of Health and Environment web site at www.westnileks.com.
