Dengue is not directly a communicable disease in the sense that it cannot spread from person to person like a cold or the flu. However, it is transmitted through the bite of an infected mosquito, primarily Aedes aegypti and, to a lesser extent, Aedes albopictus.
How Dengue Spreads
While direct human-to-human transmission doesn't occur, the following process explains how dengue spreads:
- Mosquito Bite: A mosquito bites a person infected with the dengue virus.
- Virus Incubation: The virus incubates within the mosquito for a period (typically 8-12 days) before it can be transmitted.
- Transmission to New Host: The infected mosquito then bites a healthy person, transmitting the dengue virus.
- Infection Cycle: The newly infected person develops dengue fever, and if another mosquito bites them during this period, that mosquito becomes infected, continuing the cycle.
Role of Humans in Dengue Transmission
- Amplification of the Virus: Infected humans act as reservoirs for the dengue virus. While the virus cannot spread directly from person to person, an infected person provides the virus to mosquitoes.
- Geographic Spread: Humans can carry the dengue virus across geographical boundaries, potentially introducing it to new areas where competent mosquito vectors exist. This is particularly relevant during the period when the virus is actively circulating in their bloodstream.
Factors Influencing Dengue Transmission
- Mosquito Population: The abundance of Aedes mosquitoes directly affects the risk of dengue transmission.
- Climate: Warm, humid climates are ideal for mosquito breeding and survival, increasing dengue risk.
- Urbanization: Densely populated urban areas with poor sanitation provide ample breeding grounds for mosquitoes.
- Travel: International travel can introduce new strains of dengue virus to different regions.
Prevention of Dengue
Since dengue is mosquito-borne, prevention focuses on mosquito control and personal protection:
- Mosquito Control:
- Eliminate mosquito breeding sites (standing water in containers, tires, etc.).
- Use insecticides to kill mosquitoes and larvae.
- Introduce mosquito predators (e.g., fish in water tanks).
- Personal Protection:
- Use insect repellent containing DEET, picaridin, or IR3535.
- Wear long sleeves and pants, especially during peak mosquito activity (dawn and dusk).
- Use mosquito nets, especially while sleeping.
- Install screens on windows and doors.
Therefore, while dengue is not a directly communicable disease, the role of mosquitoes as vectors makes it an infectious disease spread through a biological agent.
