News
Vector-borne diseases: researching and developing sustainable solutions to tackle a global health risk
Vector-borne diseases are infectious diseases generally transmitted by insects and hematophagous (blood-sucking) parasites. The prevalence and spread of vector-borne diseases are rising at an alarming rate, and they currently represent a major threat to human health. This increase is a consequence of significant changes at planetary level including climate change, international travel and global trade. Vector-borne diseases are also now a reality in mainland France. The Institut Pasteur is leading several initiatives and projects involving research, surveillance and innovative methods to improve understanding and respond more effectively to these emerging threats.
Read on to find out about some recent developments that reveal new insights into a vector that is a key focus of scientific research – the mosquito.
• Chikungunya, dengue, Zika – what are the risks in mainland France?
In 2025, more than 830 people who had not traveled to tropical regions were infected with chikungunya or dengue in mainland France. The number of locally acquired cases is rising each year, and the tiger mosquito is to blame – as Louis Lambrechts, Head of the Institut Pasteur's Insect-Virus Interactions Unit, explains.
• Mosquitoes: unlocking the black box of virus transmission
In 2025, several early-career scientists were selected to lead new research groups at the Institut Pasteur, and Sarah Merkling was one of them. She has led the Insect Infection and Immunity five-year group (G5) since January 2026.
• Cassandra Koh: One mosquito, billions of viruses – a daunting task
She spent her childhood on the island of Borneo, completed her PhD in Australia and arrived in Paris without speaking a word of French. Cassandra Koh, a virologist at the Institut Pasteur, has got mosquitoes under her skin – scientifically speaking.
As a specialist in the mosquito virome, she is exploring largely uncharted territory, namely the billions of viruses hosted by these insects, with the aim of understanding how the next disease outbreaks might emerge.
We meet a scientist who pairs curiosity with rigor and a passion for science with a deep appreciation for French cuisine.
• Mosquitoes Under Surveillance
Since one year, the Ema-Tigre project (Emergence of Vector-Borne Diseases Linked to the Tiger Mosquito) has been monitoring the spread of mosquito-borne viruses in France. Rachel Bellone, scientist in the Arbovirus and Vector Insects Unit, explains how the network is organized around three main areas of focus.
Watch the YouTube video “Mosquitoes Under Surveillance” (in French)
• The "Lettre de l'Institut Pasteur": The invisible assassin
As announced in the newsletter on May 11, the latest issue of the quarterly newsletter for Institut Pasteur donors – the "Lettre de l'Institut Pasteur" (LIP) – contains a special report on “The invisible assassin.”
Read the latest issue of the LIP (in French)
• Mosquitoes and ticks – the ultimate biological weapons
Dengue, chikungunya, Zika, Lyme disease, malaria and leishmaniasis are all what are known as vector-borne diseases, with a specific mode of transmission that sets them apart from infections like influenza or COVID-19. They require a living vector – a mosquito, sandfly or tick –, which hosts pathogens (viruses, bacteria and parasites), allows them to develop, then transfers them to humans via a bite. These vectors serve as mobile incubators, making the diseases they host particularly resistant to conventional health measures. The impact is huge – vector-borne diseases account for more than 17% of all infectious diseases and claim more than 700,000 lives worldwide every year.