Mosquitoes can act as vectors for many disease-causing viruses and parasites. Infected mosquitoes carry these organisms from person to person without exhibiting symptoms themselves. Mosquito-borne diseases include:
- Viral diseases, such as yellow fever, dengue fever and chikungunya, transmitted mostly by Aedes aegypti. Dengue fever is the most common cause of fever in travelers returning from the Caribbean, Central America, and South Central Asia. This disease is spread through the bites of infected mosquitoes and cannot be spread person to person.
Severe dengue can be fatal, but with good treatment, less than 1% of patients die from dengue.[60]
- The parasitic diseases collectively called malaria, caused by various species of Plasmodium, carried by mosquitoes of the genusAnopheles
- Lymphatic filariasis (the main cause of elephantiasis) which can be spread by a wide variety of mosquito species[61]
- West Nile virus is a concern in the United States, but there are no reliable statistics on worldwide cases.
- Eastern equine encephalitis virus is a concern in the eastern United States.
- Tularemia, a bacterial disease caused by Francisella tularensis, is variously transmitted, including by biting flies. Culex and Culiseta are vectors of tularemia, as well as arbovirus infections such as West Nile virus.[62]
Potential transmission of HIV was originally a public health concern, but practical considerations and detailed studies of epidemiological patterns suggest that any transmission of the HIV virus by mosquitoes is at worst extremely unlikely.[63]
Various species of mosquitoes are estimated to transmit various types of disease to more than 700 million people annually in Africa, South America, Central America, Mexico, Russia, and much of Asia, with millions of resultant deaths. At least two million people annually die of these diseases, and the morbidity rates are many times higher still.
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.[64]
No comments:
Post a Comment