As much of the country swelters under the extreme heat of late summer, people head outdoors in the evenings to gain relief from warm living rooms and bedrooms. Taking advantage of late twilights, neighbors may linger for extended conversations or do the outside work made impossible by daytime heat. While most know to swat away mosquitoes, few may be aware that this season--like none before it--is rife with potential for the West Nile virus. Cases have been increasing across the country this year, with more dangerous complications than are usually seen. Worse yet, peak mosquito season is just now upon us. Here's what you need to know about this disease and how to prevent it.
West Nile basics
The West Nile virus is a fairly recent arrival to the United States; the first cases were documented in 1999. Spread by the bite of infected mosquitoes, West Nile is a febrile (fever-inducing) illness that can cause encephalitis (inflammation of the brain) and meningitis (inflammation of the brain and spinal cord). However, most people infected with West Nile develop neither disease and, in fact, show no symptoms at all.
West Nile symptoms
Traditionally, about 20% of people infected with the West Nile virus develop symptoms of illness anywhere between two and 14 days after having been bitten. These symptoms include:
Most of these people recover without any further medical problems, although they may feel particularly fatigued for months afterward.
West Nile complications
Usually, only about one percent of those with West Nile develop meningitis or encephalitis. Those most at risk for these complications are people over the age of 60 and those with medical conditions such as diabetes, high blood pressure, cancer, or kidney disease. Approximately 10 percent of individuals who develop these complications die.
What makes this season different
This year cases of West Nile are not only sharply increasing across the United States, but they are also producing complications in more patients than usual. The Centers for Disease Control reports that as of August 25, 2015, West Nile virus infections are present in 44 states and the District of Columbia. In all, 303 people have become ill. Of those people, 173 have been diagnosed with encephalitis or meningitis--that's a whopping 57 percent. Because mosquito season runs from late spring until the first freezing temperatures of fall, these numbers are likely only to increase over the next several weeks.
Two reasons for increased cases
There are two divergent reasons for the increase in West Nile cases this year.
Drought-stricken areas are seeing dramatically more West Nile cases because, with few sources of natural water, mosquitoes are concentrated in fewer areas, spreading the virus among their cramped populations. For example, a record number of people died from West Nile last year in California, a state hard hit by extreme drought.
Areas with abundant rainfall are, paradoxically, also home to many West Nile cases. More natural water sources mean an explosion in the mosquito populations there. This summer, many states experienced record rainfall such as Texas, Oklahoma, Arkansas, and Nebraska. This year four people have died from West Nile in Texas, with much of the season still to go; last year six deaths were recorded.
What you can do
To avoid getting bitten by mosquitoes carrying the West Nile virus, wear long sleeves, pants, and long socks when practical. Spray exposed skin with a repellent that contains DEET or other approved insecticides. If possible, avoid going outdoors between dusk and dawn.
Aggressive pest control is a must to prevent mosquitoes from breeding in your yard. Diligently search out and empty every source of standing water; even a trace of rainwater in a bucket is enough for the insects to breed. Make this a neighborhood effort so that others' yards don't support mosquito breeding either. Pest control of all sorts will help improve everyone's health.
Lastly, monitor your health. Note if you are bitten by a mosquito, and then watch for signs of West Nile. Because the symptoms of the disease are similar to the flu, you could miss it if you're not paying attention; then, if complications arise, you'll be caught completely unaware.
Though this season is a particularly extreme one for a potentially deadly disease, you can take measures to protect yourself from West Nile.