More than 4 billion people live in dengue-endemic areas and about 400 million cases occur each year, making dengue the most rapidly spreading mosquito-borne viral disease. In the last 50 years, the incidence of cases has increased 30 times, and cases have moved from rural to urban areas. The highest number of dengue cases was recorded in 2023, affecting over 80 countries.
Although dengue is found worldwide in subtropical and tropical areas, the World Health Organization (WHO) reports that Asia represents ~70% of the global burden of disease. There is a trend of increasing numbers of cases and geographical expansion. The Americas reported their highest number of cases in 2024 at 12 million cases. Much of this may be due to the expanding environment of the most important vector, the Aedes aegypti mosquito.
Greater than 70% of the world's population, most at risk for dengue, live in Asia and the Pacific region. The dengue epidemic is spreading to more of the Southeast region, and new countries have become endemic foci. Case fatality rates of 3–5% have been seen in rural areas of India, Indonesia, and Myanmar, while the worldwide fatality rate averages 1%.
