Your Guide to
Neglected Tropical Diseases

Dengue and chikungunya are viral infections that spread through the yellow fever mosquito (Aedes aegypti) and the Asian tiger mosquito (Aedes albopictus). The diseases share similar initial symptoms, making them difficult to distinguish. Both cause sudden high fever, severe headache, muscle pain, and rashes. The key difference lies in their main complications: dengue's hallmark is severe bleeding and shock in about 1 in 20 cases, while chikungunya is known for debilitating joint pain that can persist for months or years.

About 1 in 4 people infected with dengue develop symptoms, often including high grade fever, pain behind the eyes, and severe body aches, which is why the disease is sometimes called "breakbone fever." On the other hand, most people infected with chikungunya are symptomatic, exhibiting severe joint pain affecting multiple joints and sometimes having a stooped posture that gave the disease its name (from "that which bends up" in the Makonde language).

Most people with either disease recover within a week, although joint pain from chikungunya can last much longer. People infected with dengue a second time face a higher risk of severe disease. Death is rare for both diseases (less than 1% with proper care), and newborns and older adults face the highest risk of severe complications.

Both diseases spread through bites from the same species of female mosquitoes, which bite during daylight hours. After feeding on an infected person, the virus replicates inside the mosquito for several days before the mosquito can transmit it to others. The mosquitoes breed in standing water and water tanks around homes.

This shared transmission cycle means prevention strategies for one disease effectively prevent the other. Neither disease spreads directly from person-to-person, although transmission can rarely occur from mother to infant during pregnancy (especially around the time of delivery for chikungunya), and through blood transfusion or organ transplantation.

Geographic scope:

• Both diseases are found in tropical and subtropical regions worldwide and often occur in the same areas.
• Both diseases are present or have been reported in more than 100 countries across Africa, the Americas, Asia, and Europe.
• Both are spreading to previously unaffected areas, including parts of Europe.
• Dengue transmission peaks during and after rainy seasons, while chikungunya tends to occur in sporadic outbreaks.

Population affected:

• Dengue causes far more cases globally (hundreds of millions of infections annually), resulting in thousands of deaths per year.
• Over 14 million dengue cases reported in 2024 (Source: WHO).
• Dengue cases have been rapidly increasing in recent years, with Asia carrying the majority of the global burden.
• Approximately half the world's population is now at risk.
• Chikungunya affects tens of millions of people annually, with hundreds of thousands experiencing chronic long-term joint pain.

Neither disease has a cure. Treatment focuses on rest, fluids, and acetaminophen for fever and pain. Aspirin and ibuprofen increase bleeding risk. Most people recover within a week, although chikungunya joint pain may persist for months or years. Warning signs of severe dengue require hospitalization.

Since both diseases are spread by the same mosquitoes, prevention strategies are identical and center on avoiding bites and eliminating breeding sites. Protection includes insect repellent, long-sleeved shirts and pants, screens, and mosquito nets. Daytime protection is essential as these mosquitoes are active during daylight hours. Eliminating standing water around homes (e.g., emptying containers and covering water storage tanks) reduces mosquito breeding sites. Vaccines exist but with limitations.

Currently, QDENGA® is the only WHO-recommended vaccine for children aged 6-16, with other candidates still under evaluation. For chikungunya, VIMKUNYA is available for people aged 12+, and is used mainly for those who travel to outbreak areas and laboratory workers.