The Mosquito and Global Warming

 

By Trish Elliott

 

One of the many side effects of global warming may be the increase in the size and range of the pesky, disease-carrying mosquito.

 

Let’s face it, most people hate mosquitos. The welt we get when we have a “mosquito bite” is actually an allergic reaction to their saliva, but mosquitos can ruin backyard barbeques, camping trips, and quiet nights, as we swat at these fast-moving insects. But their more serious affect is as carriers of deadly diseases.

There are more than 3,000 species of mosquitoes, all of whom are  carnivores, but the members of three bear primary responsibility mosquito05for the spread of human diseases. Anopheles mosquitoes are the only species known to carry malaria, and also transmit filariasis (also called elephantiasis) and encephalitis.

Culex mosquitoes carry encephalitis, filariasis, and the West Nile virus.

Aedes mosquitoes, of which the voracious Asian tiger is a member, carry yellow fever, dengue, and encephalitis.

Unlike other mosquitoes that tend to only come out at certain times, the Asian-tiger variety will bite all day long, making it hard to avoid the bug. Their eggs are also much stronger than the average mosquito and are tough enough to survive the cold.

The black-and-white striped bug was brought to Texas 30 years ago in a tire shipment. Since then, it has spread to 27 states.

“It’s a beautiful mosquito because it’s very well adapted to what it does,” said entomologist Joseph Conlon, a technical adviser for the American Mosquito Control Association. “If you look at it, it’s a very intensely black mosquito with white striping on it. It’s very pretty.”

The insect is particularly effective at spreading illness, and Conlon said that these bugs can infected with as many as 30 known diseases in a laboratory, including West Nile virus and Dengue fever. They have been found to spread six-to-seven diseases worldwide and transmit five within the United Sates.

In fact, this insect has a history of causing epidemics and is blamed for causing the Chikungunya epidemic on the French Island of La Reunion between 2005 to 2006. Two-hundred-sixty-six thousand people became infected with the virus, and 254 of them died, according to the Centers for Disease Control and Prevention.

Mosquitoes use exhaled carbon dioxide, body odors and temperature, and movement to hone in on their victims. Only female mosquitoes have the 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.

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.

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.

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Source: Baret News Wire