Dengue is transmitted by the mosquito, Aedes aegypti, which acts as the vector in transmitting the dengue virus.
The mosquito gets infected by the dengue virus when it bites a person who has dengue or DHF. For about a week the virus multiplies inside the mosquito, after which it bites a healthy person, who soon develops symptoms of dengue fever.
Mosquito bites Dengue infected person
Dengue Virus multiplies inside the mosquito for a week
Mosquito bites healthy person
Dengue cannot spread directly from person to person.