Health column: July and August peak time for mosquito-borne illnessI hate deer flies! It seems they are usually very bad around the beginning of July and I thought I was going to get lucky and avoid them this summer. But seems they are just a little late this year.
By: Ann Busche, For the Budgeteer News
I hate deer flies! It seems they are usually very bad around the beginning of July and I thought I was going to get lucky and avoid them this summer. But seems they are just a little late this year; perhaps another result of our cold spring? I was swarmed by them last weekend as I attempted to get some work done outside.
The challenge is that not only does it hurt when they bite, but usually my entire hand will get fairly swollen if I’m bit on a finger, for example.
I started to wonder why we hear so much about mosquitoes and not much about deer flies, yet they are both interested in us because they want to suck our blood.
Seems deer flies and mosquitoes both develop in wet areas like swamps and ponds, pretty much anywhere there is standing water. Both are attracted to a potential meal through the carbon dioxide given off by warm-blooded animals.
While insect repellents that contain DEET will deter a mosquito, seems deer flies aren’t very impressed, or repelled by DEET, so the best defense is covering up bare skin. While mosquitoes don’t hesitate to follow you indoors, deer flies generally don’t go into structures, so another way to avoid getting bit is to just stay indoors.
The big difference between these swarming, nasty, blood sucking insects is that deer flies don’t transmit disease to humans, and mosquitoes do.
While there is some evidence that a deer fly in the western part of the U.S. can transmit bacteria that impacts small animals, especially rabbits, I didn’t find anything about transmission of disease to humans. No disease transmission to humans, no public health concerns, and no warnings to take precautions to avoid being bitten.
So, while deer fly bites hurt and may cause bite site swelling, they are more a nuisance than a health risk.
Mosquito bites do potentially pose a health risk and the most common disease transmitted by mosquitoes in Minnesota is West Nile Virus. Minnesota’s first case of WNV was found in 2002 and since then there have been 535 cases reported, including 16 fatalities. The first case in Minnesota for 2013 was reported recently.
Most people infected with WNV will experience either no symptoms or very mild flu-like symptoms. Symptoms of West Nile fever include:
• sudden onset of high fever, generally greater than 102 degrees
• severe headache
• pain: sore throat, backache, joint pain, muscle aches
However, a small percentage of people (less than 1 percent) can develop
severe symptoms consistent with encephalitis, which is a swelling of the brain. Symptoms of West Nile encephalitis are:
• changes in mental status
• sensitivity to light
• altered reflexes
• seizures (less frequent)
So, while chances of contracting West Nile encephalitis are very small, it is a serious illness and public health officials are recommending the following actions to avoid mosquito bites:
• Use a repellent containing up to 30 percent DEET; these are safe and effective.
• The repellent permethrin will kill mosquitoes but this repellent is sprayed onto clothing, not skin. Clothing sprayed with permethrin should be allowed to dry before wearing it.
Other repellents on the market contain picaridin or oil of lemon eucalyptus. Regardless of the repellent used, it’s important to following the directions on the label.
• Minimize the time outdoors during dawn and dusk as these are the prime feeding times of mosquitoes.
The peak time for mosquito-borne illness is July and August, so we are just beyond the midpoint of the peak season. Kind of a “good news, bad news” situation because as mosquito season draws to the close, so does our precious summertime.
Source: Minnesota Department of Health; www.health.state.mn.us
Ann Busche is the director of Public Health and Human Services for St. Louis County. Contact her at 726-2096 or email: firstname.lastname@example.org