By Sara Rider
We all know that annoying whine: the high-pitched, slightly modulating sound that tells us there’s a six-legged insect nearby who thinks we’re the next entrée. If mosquito bites weren’t annoying enough, for over 15 years, they have increasingly carried the threat of an illness that is usually mild, but can occasionally turn very severe: West Nile virus.
According to the Mayo Clinic, West Nile virus is spread by infected mosquitoes. Most people who get infected don’t experience any symptoms. About 20 percent of those who are infected experience only minor symptoms and a mild infection called West Nile fever.
“Most people who are infected do not develop any symptoms,”agrees Wil Foadey, M.D., a physician at Premier Family Physicians. “Doctors typically don’t see most cases, because people who are infected often don’t consult their physician.”But for a few people—an estimated one percent of all those infected—West Nile virus can be truly life-threatening, according to the Mayo Clinic.
Headaches and fever—or something worse
In 2012, the last year with finalized statistics, there were 153 cases of West Nile virus in Travis County, according to the Austin/Travis County Health and Human Services Department (HHSD). Some 73 people were hospitalized, and six people died. People affected ranged in age from 11 years old to 91. This was a significant increase in reported cases from the prior nine years, and no fatalities had occurred since 2007, reports HHSD. But despite the hospitalizations and fatalities in 2012, when a bite from an infected mosquito results in West Nile fever, symptoms are usually fairly mild.
“Sometimes it looks like the flu,”says Dr. Foadey. “In most people, you will see flu symptoms, especially headaches, fever and chills, nausea, vomiting, body aches, joint pain. Sometimes that’s why people don’t even go to see their doctors, because they think they just have the flu.”
Symptoms can progress and worsen
“Only a few people will develop severe symptoms like confusion, paralysis, trouble walking or problems with vision,”explains Dr. Foadey. “Those are symptoms that make you think outside the box as a physician: what could be causing them? If it’s in the summer months, and the patient tells you they’ve been exposed to mosquitoes, then you have to think about the possibility of West Nile virus.”
Other symptoms of this more serious version of West Nile virus can include high fever, severe headache, a stiff neck, and even convulsions or partial paralysis, according to the Mayo Clinic.
“If you have severe symptoms, then you have to consider hospitalization,”says Dr. Foadey. “The patient can develop encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes surrounding the brain and spinal cord).”
While a mild case of West Nile fever is usually over in a few days, the symptoms of encephalitis or meningitis can linger for weeks. “Some people will have paralysis or trouble breathing,”explains Dr. Foadey. “With severe cases, you need to do more invasive treatments and watch out for brain swelling, because that’s obviously dangerous and can be deadly.”
What’s your personal risk?
West Nile virus first appeared in the United States in 1999. It has now spread to all the contiguous 48 states. It is most common during the summer months, says Dr. Foadey. The Mayo Clinic reports that overall risk depends on the time of year, with the majority of cases occurring between July and September. But as HHSD points out, our local risk can be greater since mosquitoes are present in Central Texas all year, with the highest concentrations occurring from April through September.
In addition to time of year, your personal health plays a large role in determining your personal risk. “If someone is very healthy, they could get bitten but never be symptomatic,”says Dr. Foadey. “Or if they did have symptoms, they would be so mild that most people would never go to the doctor.”
But if someone is not in good health, the risk increases. “People who are older or in bad health, or people who are immuno-suppressed are at a higher risk of the more severe forms of the disease,”explains Dr. Foadey. “And the very young are also at risk.”
In addition, the Mayo Clinic advises that people who work outside or people who spend a lot of time outdoors are at higher risk just because their exposure to mosquitoes may be increased.
Steps to prevention
Because mosquitoes are basically part of life in Central Texas for six months out of the year, prevention becomes even more important.
“Avoiding the times of day during which mosquitoes feed—specifically dusk and dawn—is very important,”says Dr. Foadey. “If you’re outside during these times, it’s important to wear long sleeves and use insect repellant.”
HHSD also advises checking your yard regularly for containers that may hold water and emptying them. According to HHSD, it can take less than a week for mosquitoes to develop in standing water.
The Mayo Clinic also advises unclogging roof gutters and changing the water in your birdbaths at least weekly. When infants and children are outside, they also advise covering strollers or playpens with mosquito netting.
“The most important thing is prevention—all of the steps you can take to reduce your exposure to mosquitoes,”says Dr. Foadey. “But the next important thing is to recognize the symptoms. If you know that you’ve been bitten by mosquitoes and if you develop a flu-like illness, you need to consult your doctor.”
That consultation becomes even more important if your “summer flu”starts showing signs of more severe problems. “If you have neurological symptoms like confusion, difficulty walking or difficulty breathing, then it’s definitely time to see your doctor,”says Dr. Foadey. “It’s hard to stay away from mosquitoes in the summer months, but if you have any of the symptoms of West Nile, it’s time to get some help.”