Dengue Fever

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Dengue is the most common infection transmitted by mosquitoes in human beings, which in recent years has become a major international public health problem. It is usually found in tropical and subtropical regions around the world. The incidence of dengue has grown dramatically around the world in recent decades. Over 40% of the world's population is now at risk from dengue. World Health Organization currently estimates that there may be 50–100 million dengue infections worldwide every year.
The first confirmed outbreak of dengue fever in Pakistan was in 1994, but a sudden rise in cases and the annual epidemic trend first occurred in Karachi in November 2005. Since 2010, Pakistan has been experiencing an epidemic of dengue fever that has caused …show more content…

Hyperendemicity may occur due to the cocirculation of multiple virus serotypes in the same city. Humans become infected with dengue viruses due to the the bite of an infective mosquito (Gubler, 1998). The principal vector of dengue virus is Aedes agypti which is a domesticated mosquito and prefers to lay eggs in artificial water containers found in and around residential areas, for example, old automobile tires, flower vases, refrigerator trays, coolers and trash. The adult mosquitoes prefer to rest indoor and feed on humans mostly during daylight hours. The two peak timings of biting of this mosquito are early morning and in the afternoon before dusk. The female mosquitoes disrupts the feeding process at the slightest movement but returns to the same or a different person after few moments to continue feeding process. Female Aedes aegypti mosquitoes often feed on several persons during their single blood meal and therefore have tendency to transmit dengue virus to multiple persons in a short time (Putnam etal., 1995 ; Scott etal., 1997) After transmission of virus from insect to human during biting, the virus undergoes 3 to 14 days incubation period after which the person may experience symptoms of dengue fever. During this period dengue virus circulates in the peripheral blood and during this stage if any other Aedes aegypti mosquito bites the ill person then that mosquito may also become infected and subsequently transmits the virus to other uninfected person (Gubler,

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