Wednesday, August 29, 2012

Prevention is Key for West Nile Virus

The end of August is West Nile Virus season in the United States and this year has been a bad one with the most reported infections and deaths from the disease.  By August 30 there were a total of 1,590 cases nationally with 66 deaths, according to the Center for Disease Control (CDC).  That is a 40% rise in just one week!

 For West Nile Virus, birds are the vector.  Mosquitoes who bite infected birds can  pass the virus on to humans.  The virus is amplified over the summer in bird populations and hotter than normal temperatures this summer may be a factor in the increased cases we are seeing this year.  It is not spread by human-to-human contact or from other animals to humans.

West Nile Virus is spread by the bite of an infected Northern House Mosquito (Culex pipiens). It was first discovered in 1999 and since that time over 30,000 people have been sickened by the disease.  According to the CDC, 75% of this year’s serious cases have been reported from 5 states (Texas, Louisiana, South Dakota, Oklahoma and Mississippi) and almost half of all cases have been reported from Texas.  So far this year 34 cases have been found in California.

Most people who are bit by West Nile Virus carrying mosquitoes will have no symptoms at all.  For the ones who do become ill, the infection is usually mild.  Flu-like symptoms can appear 3-14 days after a bite and include:
  • Fever
  • Aching muscles and head ache
  • Swollen lymph glands
  • Skin rash

Four out of five people will never know they are infected and will have immunity for life from West Nile Disease.  But people over age 50 are at the highest risk for developing severe West Nile Disease.  Healthy, active older adults who spend time working and exercising outdoors can develop severe disease.  Also people who are immune-suppressed or are fighting off other illnesses can get extremely ill with West Nile Virus and even die.

 The severe symptoms include high fever, encephalitis, headache, neck stiffness, vision loss, convulsions and even paralysis.

To diagnose West Nile Virus, the doctor will do a blood test or a cerebrospinal tap to test for antibodies to the virus.  A 2nd blood test is needed two to three weeks later to confirm the diagnosis.

There is no treatment for West Nile infection and there is no vaccine.  All the care is supportive.

Here are some tips to protect against West Nile Virus:
  1. Eliminate standing water including flower pots, plastic containers, wading pools, and roof gutters. Fill birdbaths with fresh water at least once a week.  Mosquitoes are aquatic and they must have standing water to develop from egg to adult.
  2. Wear light colored clothing, long sleeve shirts or long pants, especially in the evening when mosquitoes are most active.  Mosquitoes are attracted to dark colors.
  3. Mosquitoes are attracted to sweat and perfumes. 
  4. Use mosquito repellent if outdoors, especially from dusk to dawn.  Sprays and lotions containing DEET are the most effective but use products with 30% or less DEET and for children use 15% or less.  Oil of lemon eucalyptus, a plant-based repellent is also effective.  Repellents don’t kill mosquitoes; they just make you less attractive.
  5. Sonic repellants do not work but smoke pots and citronella candles can help.

Remember this:  The chance of becoming ill from West Nile Virus is quite low.  But if you are older and will be outdoors in a mosquito-infested area, make sure you protect yourself with clothing and chemical repellants.  There is no treatment so prevention is key.

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