On May 30, the WHO released a new report on the global dengue situation to raise awareness of this public health threat across all continents.
As of April 30, 2024, more than 7.6 million dengue cases had been reported to the WHO in 2024, including 3.4 million confirmed cases, over 16,000 severe cases, and more than 3,000 deaths. This increase has been particularly pronounced in the Americas Region, where the number of cases had already exceeded seven million by the end of April 2024, surpassing the annual rate of 4.6 million cases in 2023.
The risk of dengue is similar across all regions, countries, and within countries. Factors associated with an increasing risk of dengue epidemics and spread to new countries include:
- Early onset and longer duration of dengue transmission seasons in endemic areas;
- Changing distribution and increasing abundance of vectors (Aedes aegypti and Aedes albopictus);
- Consequences of climate change and periodic weather phenomena (El Niño and La Niña events) leading to heavy rainfall, humidity, and rising temperatures that favor vector reproduction and virus transmission;
- Changes in circulating serotypes within a country affecting population immunity;
- Fragile health systems amid political and financial instability in countries facing complex humanitarian crises and large-scale population movements hindering public health response;
- Movement of infected people and goods that could carry vector mosquitoes.
Currently, 90 countries have active dengue transmission in 2024, and not all have been reflected in formal reports. Additionally, many endemic countries lack robust detection and reporting mechanisms, underestimating the true global dengue burden.
Given the current scale of dengue outbreaks, the potential risk of further international spread, and the complexity of factors affecting transmission, the overall global risk is still considered high, making dengue a continued global public health threat.
Geographical distribution of dengue cases as reported to WHO from January to April 2024*
Co-circulation of Dengue, Chikungunya, and Zika Viruses
There is considerable overlap in the geographic distribution of dengue, chikungunya, and Zika viruses, all transmitted by Aedes mosquitoes and sharing some clinical features that can lead to misdiagnoses and erroneous reports in the absence of differential laboratory tests. Surveillance data during large “presumed dengue” outbreaks may mistakenly include cases of one or both of the other diseases.
So far in 2024, more than 250,000 cases of chikungunya and nearly 7,000 cases of Zika virus disease have been reported to the WHO. Figure 3 shows countries/territories/areas with evidence of current or previous circulation of at least two of the three viruses.
Countries, territories or areas with previous or current local mosquito-borne transmission of more than one Aedes-borne virus (dengue, chikungunya and Zika) as of 30 April 2024
