Climate change is here, and along with warmer temperatures, mosquitoes are breeding faster and more often than they usually do. Normally, the worst a mosquito can do is give you an itchy bite. Some mosquitoes can, however, transmit deadly viruses that can lead to hospitalisation and even death. The most common mosquito-borne disease in the world is a fever called dengue, also named “break-bone fever”. Dengue fever is endemic (always present within a specific area) to many countries that lie within the tropical and sub-tropical belt.
Dengue fever causes flu-like symptoms that usually last for 2-7 days. In severe cases, it can cause internal bleeding, painful joints, and organ damage. If an individual is reinfected with dengue, the result is most likely to be fatal. The incubation period is short, with symptoms appearing within 4-10 days after the mosquito bite. Currently, there are no known treatments, and the best doctors can do is manage the symptoms. The World Health Organization (WHO) has so far licensed only two vaccines, the Dengvaxia and the Qdenga.
Aedes aegypti (yellow fever mosquito) and Aedes albopictus (Asían Tiger mosquito) are the two main culprits behind the spread of dengue. They are urban mosquitoes and can be identified by the white stripes on their back and legs.
Worldwide, the reported number of dengue cases in 2023 was 6.5 million, which almost doubled to 12 million in 2024. Roughly 257 million people live in these endemic regions, where the incidence rate is expected to continue to rise. So, what has caused these numbers to spike?
Mosquitoes like warmer, wetter weather. When it’s warm, these mosquitoes tend to grow and breed faster and replicate the virus in their gut more effectively, leading to a higher viral load. They are even known to bite more aggressively in hotter temperatures. Global warming also means that summers are getting longer, allowing more time for these mosquitoes to breed.
With rising temperatures, more regions across the globe are becoming habitable for these mosquitoes. Areas in south-east Asia and southern America (parts of Brazil and Peru) are expected to face the brunt of this increase. Dr. Erin Mordecai, an associate professor of biology from Stanford University, says “We looked at data on dengue incidence and climate variation across 21 countries in Asia and the Americas and found that there is a clear and direct relationship between rising temperatures and rising infections.”
Even areas such as the United States and Europe, where dengue fever is usually not seen, are seeing an increase in cases. Since dengue is not endemic in these regions, it is therefore a “brand new” disease, with the people residing in these regions having no innate immunity.
Scientists predict that if we don’t stop climate change, dengue cases will continue to rise, and millions more will get sick. Urbanisation, global travel, extreme weather patterns, and improper trash disposal all further contribute to this spread. We must act fast to limit climate change before it’s too late!
References:
https://cosmosmagazine.com/health/body-and-mind/climate-change-is-driving-the-rise-in-dengue-cases
https://news.stanford.edu/stories/2025/01/waste-reduction-a-key-defense-against-rising-dengue-cases
https://news.un.org/en/story/2023/07/1138962
https://www.nature.com/articles/s41467-023-43954-0
https://www.sciencedirect.com/science/article/pii/S2468042723000428