We are rapidly approaching the peak season for West Nile virus that occurs from August through mid-September. The West Nile virus is found primarily in birds, but can be transmitted to humans by mosquitoes that have bitten an infected bird. Then, when the mosquito bites a human, the virus is transmitted via the mosquito’s salivary glands.
About 25 percent of people who become infected will actually become ill with West Nile fever, but only 1 in 230 will develop severe disease associated with infection of the brain and spinal cord. The majority of people who become infected will never develop symptoms and therefore never know they ever had it. The body’s immune system does a fantastic job of eliminating the infection, but some individuals are at higher risk than others including people over 50, advanced cancer patients and individuals taking immune-suppressing medications.
West Nile fever occurs 2 to 15 days after exposure to the virus. Symptoms include fever, headache, fatigue, body aches, loss of appetite, rash, vomiting, diarrhea and abdominal pain. Symptoms can last from a few days to longer than a month, with fatigue often lingering longer than other symptoms.
The more severe disease involving the brain and spinal cord can be life threatening and 10 percent of those with neurological involvement die. Symptoms include headache, neck rigidity, fever, disorientation, seizures, coma, muscle weakness and paralysis. Full recovery is less than 40 percent.
Diagnosis can be made with blood tests or cerebrospinal fluid (from around the spinal cord and brain). There is not a specific treatment for West Nile virus, but the best way to avoid contracting the virus is to avoid mosquito bites with these basic measures:
Be extra cautious during dawn and at dusk when mosquitoes are most active.
Use long sleeves and long pants and clothing treated with permethrin.
Consider using insect repellents containing DEET, picardin and lemon eucalyptus oil.
If you or any of your loved ones have symptoms suggesting West Nile virus, see your healthcare provider immediately. If you would like more information about West Nile risks in your local area, go online to diseasemaps.usgs.gov/wnv_co_mosquito.html.
Dr. Laurie Marbas is a family physician at Grand River Hospital and Medical Center in Rifle.