Aedes aegypti

Aedes aegypti, the yellow fever mosquito, is a mosquito that can spread dengue fever, chikungunya, Zika fever, Mayaro and yellow fever viruses, and other disease agents. The mosquito can be recognized by white markings on its legs and a marking in the form of a lyre on the upper surface of its thorax. This mosquito originated in Africa, but is now found in tropical, subtropical and temperate regions throughout the world. 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 United States Department of Agriculture (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: 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.