Mosquitoes, Ticks, and Warming Climates: A Deadly Mix
- Md. Jannatul Naeem Jibon
- Jun 2
- 3 min read
The impacts of climate change are spreading fast and hitting harder than ever, largely fueled by greenhouse gas emissions from burning fossil fuels. Since 1900, the Earth’s average temperature has already risen by 1.1°C — and most of that warming has happened just in the past 50 years.
This rise in temperature doesn’t just affect the weather; it’s also shaking up the natural world in ways that matter for human health. Warming influences how disease-carrying organisms (and the pathogens they carry) behave, develop, and spread. It also affects the populations and behaviors of the animals that host these diseases.
But wait, what exactly are vectors?
Vectors are living creatures — often insects — that carry and pass on infectious pathogens from one host to another, sometimes from animals to humans and sometimes between humans. Many of these vectors are blood-feeding insects like mosquitoes or ticks. Here’s how it works: when they take a blood meal from an infected host, they ingest the disease-causing microorganisms. After the pathogen multiplies inside them, the vector can pass it on to the next host they bite. And once a vector becomes infectious, it usually stays that way for the rest of its life, spreading the pathogen with each new bite.

What Are Vector-Borne Diseases?
Vector-borne diseases are illnesses in humans caused by parasites, viruses, or bacteria that are spread through vectors — those tiny carriers we talked about earlier, like mosquitoes and ticks. Some well-known examples include malaria, dengue, schistosomiasis, human African trypanosomiasis, leishmaniasis, Chagas disease, yellow fever, Japanese encephalitis and onchocerciasis.
These diseases are no small problem: they make up over 17% of all infectious diseases worldwide and are responsible for more than 700,000 deaths every year. Malaria, for example, affects an estimated 249 million people globally each year and causes over 608,000 deaths — most heartbreakingly, many of these are young children under the age of five. The disease spreads through the bite of Anopheles mosquitoes. On the other hand, dengue is the world’s most common viral vector-borne disease, spread by Aedes mosquitoes. Right now, more than 3.9 billion people across 132 countries are at risk of dengue, leading to around 96 million symptomatic cases and 40,000 deaths every year.
Vector-Borne Diseases and Climate Change
According to the Intergovernmental Panel on Climate Change (IPCC), there’s high confidence that vector-borne diseases have already been on the rise in recent decades — and the future doesn’t look any easier. If we don’t step up our efforts to adapt and improve control strategies, diseases like malaria, dengue, Lyme disease, and West Nile virus are projected to increase even more over the next 80 years.
So, what’s going on?
Climate change has a big impact on the delicate balance between pathogens (like parasites, viruses, and bacteria), the vectors that carry them, and the animals that serve as hosts. As temperatures rise, many disease-carrying insects are expanding their range — moving into higher altitudes and broader latitudes — and the seasons when they’re active are lasting longer. Therefore, as the planet warms, the window for disease transmission widens, and we can expect to see even more cases unless action is taken.
To protect global health, we must act now — strengthening strategies and adapting to climate change to reduce the rising threat of vector-borne diseases.
References
IPCC. (2022). Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change.
Thomson, M. C., & Stanberry, L. R. (2022). Climate Change and Vectorborne Diseases. New England Journal of Medicine. https://doi.org/10.1056/NEJMra2200092
WHO. (2024). Vector-borne diseases. https://www.who.int/news-room/fact-sheets/detail/vector-borne-diseases
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