Few animals on Earth evoke the antipathy that mosquitoes do. Their itchy, irritating bites and nearly ubiquitous presence can ruin a backyard barbecue or a hike in the woods. They have an uncanny ability to sense our murderous intentions, taking flight and disappearing milliseconds before a fatal swat. And in our bedrooms, the persistent, whiny hum of their buzzing wings can wake the soundest of sleepers.
Beyond the nuisance factor, mosquitoes are carriers, or vectors, for some of humanity’s most deadly illnesses, and they are public enemy number one in the fight against global infectious disease. Mosquito-borne diseases cause millions of deaths worldwide every year with a disproportionate effect on children and the elderly in developing countries.
There are more than 3,000 species of mosquitoes, but the members of three bear primary responsibility for the spread of human diseases. Anopheles mosquitoes are the only species known to carry malaria. They also transmit filariasis (also called elephantiasis) and encephalitis. Culex mosquitoes carry encephalitis, filariasis, and the West Nile virus. And Aedes mosquitoes, of which the voracious Asian tiger is a member, carry yellow fever, dengue, and encephalitis.
Mosquitoes transmit disease in a variety of ways. In the case of malaria, parasites attach themselves to the gut of a female mosquito and enter a host as she feeds. In other cases, such as yellow fever and dengue, a virus enters the mosquito as it feeds on an infected human and is transmitted via the mosquito’s saliva to a subsequent victim.
Mosquitoes use exhaled carbon dioxide, body odors and temperature, and movement to home in on their victims. Only female mosquitoes have the mouth parts necessary for sucking blood. When biting with their proboscis, they stab two tubes into the skin: one to inject an enzyme that inhibits blood clotting; the other to suck blood into their bodies. They use the blood not for their own nourishment but as a source of protein for their eggs. For food, both males and females eat nectar and other plant sugars.
Impact on the Ecosystem
The only silver lining to that cloud of mosquitoes in your garden is that they are a reliable source of food for thousands of animals, including birds, bats, dragonflies, and frogs. In addition, humans are actually not the first choice for most mosquitoes looking for a meal. They usually prefer horses, cattle, and birds.
All mosquitoes need water to breed, so eradication and population-control efforts usually involve removal or treatment of standing water sources. Insecticide spraying to kill adult mosquitoes is also widespread. However, global efforts to stop the spread of mosquitoes are having little effect, and many scientists think global warming will likely increase their number and range.
Using Mosquito Repellant
The most effective way to avoid getting sick from viruses spread by mosquitoes when at home and during travel is to prevent mosquito bites.
Mosquito bites can be more than just annoying and itchy. They can spread viruses that make you sick or, in rare cases, cause death. Although most kinds of mosquitoes are just nuisance mosquitoes, some kinds of mosquitoes in the United States and around the world spread viruses that can cause disease.
Mosquitoes bite during the day and night, live indoors and outdoors, and search for warm places as temperatures begin to drop. Some will hibernate in enclosed spaces, like garages, sheds, and under (or inside) homes to survive cold temperatures. It is best to consult with a pest control expert to ensure that measures have been taken to prevent mosquito spawning. In northern California Mosquito season starts in the summer and continues into fall.
- Use insect repellent: When used as directed, Environmental Protection Agency (EPA)-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women. Use an EPA-registered insect repellentwith one of the following active ingredients:
- Oil of lemon eucalyptus (OLE)
- Para-menthane-diol (PMD)
- Cover up: Wear long-sleeved shirts and long pants.
- Keep mosquitoes outside: Use air conditioning, or window and door screens. If you are not able to protect yourself from mosquitoes inside your home or hotel, sleep under a mosquito bed net.
Methods used to prevent the spread of disease, or to protect individuals in areas where disease is endemic, include:
- Vector control aimed at mosquito control or eradication
- Disease prevention, using prophylactic drugs and developing vaccines
Prevention of mosquito bites, with insecticides, nets, and repellents.
- Since most such diseases are carried by “elderly” female mosquitoes, some scientists have suggested focusing on these to avoid the evolution of resistance.