Mosquitoes and the Diseases they Carry

Poisonous snakes, deadly scorpions, mosquitoes. If the last word does not seem to be
potentially deadly, you are mistaken. Mosquitoes have been responsible for killing more
people than all the wars. Today, two to three million people will die from malaria. Tens of
millions will die or become disabled from other mosquito transmitted diseases. Amazing that
such a tiny insect can do so much damage.

While malaria is relatively uncommon in the United States, although it does occur, approximately half of the world’s population is susceptible to malaria. In the United States, the threat of developing encephalitis from mosquitoes is much higher than the threat of developing malaria. Encephalitis, meningitis and many other diseases can develop from the bites of virus infected mosquitoes. The West Nile, St. Louis encephalitis, LaCrosse (California) encephalitis, and Eastern equine and Western equine encephalitis are a few of the viruses that can be contracted.

Diptera, or flies, are the group of insects known as Mosquitoes. In fact, in Spanish, mosquito means “little fly”. Flies are distinguished from other types of insects by their two wings. Diptera means “two wings”. Mosquitoes differ from other types of flies by its proboscis (long tubular “mouths” for sucking up fluids) and their hair-like scales which cover the body.

Female mosquito’s only live a few weeks or months. Males life span is even shorter usually only reaching one week. Mosquitoes hatch from eggs laid in damp places that have, or have had, standing water. Their eggs hatch into larvae. These larvae lie just beneath the water’s surface and breathe through tubes on the end of their bodies. Microscopic organisms found in the water supply their food. Mosquitoes thrive in water containing leaves or sewage which help generate food for the developing mosquito larvae.

Larvae develop into comma-shaped pupae in about a week. While in the pupal stage, mosquito do not feed. Within three days the pupa usually transform into an adult mosquito. The standard mosquito life cycle has a few exceptions. Larvae of some mosquito species eat the larvae of other species.

Only female mosquitoes bite. They can be very particular about whose blood they consume. Most species have their own preference. Males do not bite and feed on nectar and other plant juices. Mosquitoes can detect carbon dioxide exhaled by their hosts and can sense body chemicals, such as the lactic acid in perspiration. Mosquitoes are attracted to some people more than others. Many times one person will have multiple bites while someone next to them have none.

Mosquitoes can fly more than 20 miles from their original water source. Mosquitoes only fly about 4 miles an hour, not exactly fast. They look for movement of dark objects. Once it finds you and lands, it inserts its proboscis and probes for blood vessels beneath the skin. Once it finds a vessel, the mosquito injects saliva which contains an anticoagulant. This helps to facilitate a steady flow of blood. This injection of saliva is how malaria parasites or the encephalitis virus are transmitted.

Currently, the West Nile virus is the most common disease transmitted by mosquitoes and other biting flies and ticks. West Nile virus arrived in the United States in 1999. Recently, Illinois had the most West Nile cases with 884 and 67 deaths.

There are several versions of the encephalitis virus, also carried by mosquitoes. The St. Louis, Eastern and Western Equine, and California Encephalitis are some of the different versions of the virus. The reservoirs for these viruses vary from birds to mammals.

What can you do to reduce the population of mosquitoes and protect yourself? Repellents with “deet” work well to defend against mosquito bites. Your local health department can help by spraying susceptible areas to decrease the larvae population. Any areas with standing water such as birdbaths, containers, brush with many leaves and debris, should be drained and cleaned. By eliminating the breading grounds, you help protect yourself and the surrounding area from these potentially dangerous insects.