PERIOD OF COMMUNICABILITY

The female Ae. aegypti usually becomes infected with the dengue virus when it takes a blood meal from a person during the acute febrile (viremia) phase of dengue illness.

After an extrinsic incubation period of 8 to 10 days, the mosquito becomes infected. The virus is transmitted when the infected female mosquito bites and injects its saliva into the wound of the person bitten. The cycle of dengue continues by this process. Dengue begins abruptly after an intrinsic incubation period of 4 to 7 days (range 3—14 days). There is also evidence of vertical transmission of dengue virus from infected female mosquitoes to the next generation.