Spread of disease and prevention methods
Aedes aegypti is a vector for transmitting several tropical fevers. Only the female bites for blood, which she needs to mature her eggs. To find a host, these mosquitoes are attracted to chemical compounds emitted by mammals, including ammonia, carbon dioxide, lactic acid, and octenol. Scientists at the USDA Agricultural Research Service have studied the specific chemical structure of octenol to better understand why this chemical attracts the mosquito to its host. They found the mosquito has a preference for "right-handed" (dextrorotatory) octenol molecules.
The yellow fever mosquito can also contribute to the spread of reticular cell sarcoma among Syrian hamsters.
The Centers for Disease Control and Prevention traveler's page on preventing dengue fever suggests using mosquito repellents that contain DEET (N, N-diethylmetatoluamide, 20% to 30%). It also suggests:
- Although Aedes aegypti mosquitoes most commonly feed at dusk and dawn, indoors, in shady areas, or when the weather is cloudy, "they can bite and spread infection all year long and at any time of day."
- The mosquitoes prefer to breed in areas of stagnant water, such as flower vases, uncovered barrels, buckets, and discarded tires, but the most dangerous areas are wet shower floors and toilet tanks, as they allow the mosquitos to breed in the residence. Research has shown that certain chemicals emanating from bacteria in water containers stimulate the female mosquitoes to lay their eggs. They are particularly motivated to lay eggs in water containers that have the correct amounts of specific fatty acids associated with bacteria involved in the degradation of leaves and other organic matter in water. The chemicals associated with the microbial stew are far more stimulating to discerning female mosquitoes than plain or filtered water in which the bacteria once lived. Once a week, females scrub off eggs sticking to wet containers, seal and/or discard them.
- Wear long-sleeved clothing and long trousers when outdoors during the day and evening.
- Use mosquito netting over the bed if the bedroom is not air conditioned or screened, and for additional protection, treat the mosquito netting with the insecticide permethrin.
Insect repellants containing DEET (particularly concentrated products) or p-menthane-3,8-diol (from lemon eucalyptus) were effective in repelling Ae. aegypti mosquitoes, while others were less effective or ineffective in a scientific study. The Centers for Disease Control and Prevention article on "Protection against Mosquitoes, Ticks, & Other Arthropods" notes that "Studies suggest that concentrations of DEET above approximately 50% do not offer a marked increase in protection time against mosquitoes; DEET efficacy tends to plateau at a concentration of approximately 50%".
Mosquito control is currently the best method for disease prevention. This primarily includes source reduction, pesticide spraying for larval control and "fogging" for adult control, or the use of mosquito traps like the lethal ovitrap.
Although the lifespan of an adult Ae. aegypti is two to four weeks depending on conditions, the eggs can be viable for over a year in a dry state, which allows the mosquito to re-emerge after a cold winter or dry spell.
The preference for biting humans is dependent on expression of the odorant receptor AeegOr4.
New research is looking into the use of a bacterium called Wolbachia as a method of biocontrol. Studies show that invasion of Ae. aegypti by the endosymbiotic bacteria allows mosquitos to be resistant to the certain arboviruses such as dengue fever and Zika virus strains currently circulating.