( )The principal urban vector is the Aedes aegypti mosquito. The vector is a small, black-and-white, highly domesticated mosquito that has adapted to humans preferring to feed on them during daylight hours and lay their eggs in a warm and humid environment of artificial containers and around houses. Eggs can resist long periods of desiccation (more than a year) what facilitate the survival of the mosquito during adverse climatic conditions.( ) A.aegypti is an efficient epidemic vector of dengue virus because of its feeding behavior. The female aedes has a special tendency to bite and suck the human blood, because it requires as a source of proteins to lay eggs. The female mosquitoes generally disrupt the feeding process at the person's movement and often return to the same or a different person to continue feeding, and can transmit virus to more than one individual in a single cycle.( ) In all of these species, dengue virus may be transmitted from infected female to her offspring. However, most mosquitoes become infected when they ingest blood from a person experiencing an acute dengue virus infection. After an infected person is bitten by an infective mosquito, the virus undergoes an extrinsic incubation period of 8 to 12 days.( ) Virus replication occurs in different tissues of the insect and after replication in salivary glands, the infected mosquitoes can consequently transmit the virus to uninfected persons. After an extrinsic incubation period of 3 to 14 days (average, 4 to 7 days), while the person may experience the onset of dengue ́s symptoms, dengue viruses may circulate in the peripheral blood and if A. aegypti mosquitoes bite the ill person, those mosquitoes may become infected.( ).
The dengue virus (DENV) consists of four antigenic ally closely related virus serotypes called DENV-1, DENV-2, DENV-3 and DENV-4.( ) All types cause dengue fever. Infection with one serotype induces a life-long protective to the homologous serotype but confers only partial and transient protection against subsequent infections by the others serotypes.