Almost anyone who spends time outdoors is familiar with the high-pitched whine of a mosquito. Pesky and irritating, their bites sting and itch. Campers and hikers take for granted that these buzzy biters are a part of outdoor recreation. But savvy people use repellents containing DEET to discourage mosquitoes.
Until the last few years the danger of mosquito-borne human diseases in Texas has been fairly low, but things are changing. Of course, we all were vaguely aware that in Mexico, Central and South America mosquitoes carry a variety of diseases. Now we have to add many areas of the United States. Coastal areas especially, and rain-soaked or flooded areas of Texas are favorite breeding grounds for mosquitoes. And the diseases they transmit to people have names most of us have never heard: Chikungunya, Zika, West Nile, and Dengue.
According to the CDC (Centers for Disease Control), Chikungunya is usually not fatal but symptoms include rash, fever, joint and muscle pain and swelling and headaches. The joint pain can be very severe and disabling, sometimes lasting for months.
Zika virus has been making headlines for several years because in pregnant women it can enter the developing fetus, causing a severe birth defect called microcephaly in which the developing child has brain damage and a very small head. It may also be born dead.
West Nile virus often produces no symptoms. But about 20% of infected people may develop headaches, body aches, joint pains, vomiting, diarrhea or rash. Approximately 1% will have a very serious illness such as encephalitis or meningitis. Sometimes the disease symptoms take months or years to cease. A few victims will have life-long debilitating conditions.
Dengue symptoms include high fever, severe headache, pain behind the eyeball, joint and muscle pain, rash, nausea and vomiting. But symptoms usually end in two to three weeks.
None of these diseases are curable in the usual sense. Doctors can only treat the symptoms.
How do mosquitoes transmit disease? They do it quite well, thank you. Using special razor-sharp probes, they penetrate the skin and insert a hollow tube that allows them to suck up blood.
After insertion, the mosquito maneuvers its mouth parts until if finds a blood vessel. Then it injects saliva containing an anticoagulant so that the blood meal doesn’t clot and plug up their plumbing, ending the meal prematurely. The blood thinner also causes itching and the saliva contains disease viruses.
Interestingly, some people are more attractive to mosquitoes than others. For example, what’s your blood type? People with Type O blood are most likely to be bitten. Those with Type A are least likely.
Sweating during exercise releases lactic acid which increases your attraction. Eating salty and potassium-rich foods like bananas and avocados also makes us more desirable.
Interestingly, what we call body odor and think of as stinky and repelling, is like ringing a dinner bell for mosquitoes.
Even breathing calls in the sneaky biters as we release carbon dioxide when we exhale. But there’s not much you can do about that. Not breathing while hiking isn’t a viable solution, something you’ll find out if you try holding your breath more than about a minute or two.
Taking prevention a step farther, it is very important to get rid of puddles or other rain water accumulated in old tires and junk items that hold water. These are prime breeding areas for mosquitoes. “Dry and drain” should be your bywords.
Apply repellents containing DEET (chemical name, N,N-diethyl-meta-toluamide) to all exposed skin surfaces. But be aware that DEET can damage plastics including eye glass frames and lenses. Also minimize bare skin and hopefully your outdoor recreation activities will be a pleasant part of our fields and forests, without any unpleasant sequels.
Dr. Risk is a professor emeritus in the College of Forestry and Agriculture at Stephen F. Austin State University in Nacogdoches, Texas. Content © Paul H. Risk, Ph.D. All rights reserved, except where otherwise noted. Click firstname.lastname@example.org to send questions, comments, or request permission for use.