Mosquito Bites

Is the resulting injury from a mosquito sting, which could produces from a local inflammatory reaction to, after an incubation period, a vector-borne disease, such as malaria, dengue, leishmaniasis, and yellow fever, among others. The mosquito bites its victims (humans or animals) because it is a hemophagus insect (use blood for feed and for its reproductive cycle). Their ability to bite is given by the prosbocis (an extended mouth structure). In the female mosquitoes, the piercing mouthparts allow them to draw blood into their alimentary tract. Many substances that make them able to bite practically being few or none perceived by the victim (anesthetics) and substances that make efficient the extraction of blood (anticoagulants) are secreted from salivary glands of the mosquitoes. Mosquitoes that transmit disease-caus-ing pathogens (parasites, viruses, or bacteria) belong taxonomically to the suborder Nematocera (order Diptera), and particularly to the family Culicidae.

In this family are located the two most medically important mosquito subfamilies: Anophelinae and Culicinae. The species of Anopheles (Anopheles gambiae, darlingi, dirius, and funestus, among others) belong to the first one, being the vector of the most worldwide important parasitic disease, malaria. The species of Aedes (mainly Aedes aegypti, africanus, simpsoni, and albopictus) and Culex (Culex pipiens, sitiens, quinquefasciatus, univittatus, and restuans, among others) belong to the second one, being the vectors of dengue and yellow fever, and of other viral and parasitic diseases such as viral encephalitis (such as Venezuelan and Western equine encephalitis, Japanese encephalitis, and St. Louis encephalitis), West Nile virus, and filariasis, among others, respectively. In the case of yellow fever, the mosquitoes Haemagogus and Sabethes (also subfamily Culicinae members) are the most important vectors in the sylvatic cycle of disease.

The risk associated with mosquito bites could be assessed in different ways; but derived from the study of malaria transmission, the entomological inoculation rate describes the number of infecting bites that a person received per night (but can be calculated in other time scales). To properly perform and analyze this, medical entomologists conduct entomological surveillance studies, using different methods of catching anopheline mosquitoes, such as human landing catches, light traps, a double net, a calf-baited trap, and collection of resting mosquitoes on vegetation, among others. These studies allow to public health authorities to perform a guided-vectorial control to reduce transmission of malaria and other vector-borne diseases in the areas where these diseases are prevalent or endemic.

Other families in which its members could lead to a disease as a result of mosquito bites include the sand flies (family Psychodidae, subfamily Phlebotominae), the family Simulidae, and the family Ceratopogonidae.

Leishmaniasis, bartonellosis, and papatasi fever, among others, are diseases transmitted by sand fly bites (Phlebotomus, Sergentomyia, and Lutzomyia).

River blindness is a parasitic disease (produced by a filarial called Onchocerca volvulus) that is transmitted by a mosquito bite by species of Simulium (family Simulidae). Similarly, other filarial parasites, species of Mansonella, are transmitted by mosquitoes of the family Ceratopogonidae: Culicoides, Forcipomyia, Austroconops, and Leptoconops.

In any case, thinking of a local inflammatory reaction to an important mosquito-transmitted disease, the exposure to mosquito bites should be avoided. [Page 1139]Personal protection against mosquito bites is based on the use of topical repellents, the use of long clothing to reduce exposed skin, and the use of insecticide sprays, vaporizers, and nets, among others.

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