By Zheng Qi 2021-02-17

Dengue, a mosquito-borne viral infection found across tropical and subtropical regions worldwide, is one of the fastest-growing global public health challenges of our time, with its global incidence skyrocketing by an astonishing 30-fold over the past half-century. This rapid expansion has transformed dengue from a geographically limited concern into a widespread threat, with current estimates suggesting that between 50 to 100 million infections occur annually across more than 100 endemic countries, placing nearly 4 billion people — close to half of the world’s population — at constant risk of exposure. The disease is caused by any one of four closely related but immunologically distinct virus serotypes known as DEN-1, DEN-2, DEN-3, and DEN-4, each of which can trigger the full spectrum of illness, from mild unnoticed cases to life-threatening complications.

The primary transmission route of dengue is through the bite of an infected female Aedes mosquito, most commonly Aedes aegypti and, to a lesser extent, Aedes albopictus. Unlike many other mosquito-borne diseases that peak during dusk and dawn, Aedes mosquitoes are aggressive daytime feeders, meaning people remain vulnerable during daylight hours, especially in urban and semi-urban environments where these mosquitoes thrive in small artificial water containers, discarded tires, flowerpots, and uncovered water storage tanks. When a mosquito bites a person already infected with dengue, it picks up the virus and, after an incubation period of 8–12 days, becomes capable of transmitting the virus to every new person it bites for the rest of its lifespan, creating rapid chains of local transmission during rainy seasons or in densely populated areas with inadequate waste management.

Most dengue infections are either asymptomatic or cause only a mild, flu-like illness that often goes undiagnosed, with symptoms that may include sudden high fever, severe headache, pain behind the eyes, muscle and joint aches (giving rise to its historical nickname “breakbone fever”), nausea, vomiting, and a distinctive skin rash that appears a few days after the fever starts. These symptoms typically last for 2–7 days, and most patients recover fully with rest, hydration, and supportive care. However, in a small but significant proportion of cases — particularly during a second infection with a different dengue serotype — the illness can progress unpredictably to severe dengue, a dangerous complication characterized by plasma leakage, severe bleeding, organ impairment, and shock. This critical phase usually begins just as the initial fever starts to subside, catching many families and health workers off guard, and it requires immediate hospitalization for careful fluid management and intensive monitoring to prevent fatal outcomes.

The most effective way to lower your personal risk of dengue is through consistent, round-the-clock protection against mosquito bites, especially during daytime hours when Aedes mosquitoes are most active. This includes wearing long-sleeved clothing, using EPA-approved insect repellents on exposed skin, installing window and door screens, and sleeping under insecticide-treated bed nets in high-risk areas. Community-wide efforts to eliminate mosquito breeding sites by regularly emptying, covering, or treating standing water containers are equally crucial for breaking local transmission cycles. With no specific antiviral treatment currently available and only limited dengue vaccines approved for use in certain age groups and settings, prevention through vector control and bite avoidance remains the cornerstone of global dengue management strategies.

Edited by: Secretariat of the Asia-Pacific Network for Drug and Diagnostics Innovation
Produced by: Zheng Qi
Reviewed by: Zhang Haobing
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