ÌÇÐÄÊÓƵ

Aedes aegypti and Aedes albopictus mosquitoes are vectors of multiple diseases including dengue, chikungunya and Zika, posing a public health risk to populations within their native range.

A study in PLOS Global Public Health describes the detection of invasive mosquito eggs in the United Kingdom in 2023 and 2024, suggesting an increasing incidence of importation of these species. The work was led by Colin Johnston at the Center for Climate and Health Security, UK Health Security Agency, Porton Down, Salisbury, United Kingdom and colleagues.

Historically, Ae. aegypti and Ae. albopictus were limited to subtropical and tropical regions; however, Ae. albopictus has now established populations across parts of southern and central Europe, demonstrating its ability to survive in temperate climates. Rising temperatures and milder winters may increase northward incursions of invasive species, putting new populations at risk of disease transmission.

In order to monitor and limit the presence of invasive mosquito species, the UK Health Security Agency (UKHSA) worked with partners to conduct surveillance activities from 2020-2025. Surveillance teams set ovitraps at seaports, airports, and transport hubs on highways in England, Wales, and Northern Ireland. The traps were monitored every two weeks from June to October every year of the surveillance efforts, and the mosquito species were identified using morphological and molecular techniques, working with Edge Hill University.

Through surveillance efforts, Ae. aegypti eggs were detected in a freight storage facility near London Heathrow Airport in September 2023. In August 2024, Ae. albopictus was detected for the first time since 2019 in Kent, England at a motorway service station.

According to the authors, "While there is currently no evidence that Ae. albopictus or Ae. aegypti are widely established in the UK, without timely action, the UK faces the risk of invasive mosquito populations becoming established. As we have demonstrated here, proactive measures enhance resilience against emerging vector-borne disease risks".

The authors add, "The UK Health Security Agency's surveillance has detected isolated incursions of invasive mosquito species, including Aedes aegypti and Aedes albopictus, also known as the tiger mosquito. While these mosquitoes are not currently established in the UK, their detection highlights the importance of ongoing, enhanced surveillance to reduce the risk of mosquito-borne diseases. UKHSA continues to work with local authorities, landowners and partners to ensure a swift and coordinated response.

Both Aedes aegypti and the tiger mosquito are globally important vectors of diseases such as dengue and chikungunya. The UKHSA's MEZE group, alongside adult mosquito surveillance and citizen science projects, enhances our ability to detect and respond to new introductions. Although recent findings suggest a low current risk to public health, repeated detections underscore the need for continued vigilance, robust monitoring networks, and early intervention to prevent these invasive species from becoming established in the UK.

Lead author Johnston, Senior Medical Entomologist, UKHSA, adds, "What stood out during this surveillance was how dynamic and responsive our work needs to be. Each detection triggered enhanced local surveillance and control measures, and the fact that no further specimens were found suggests these were isolated incursions. Working with a wide variety of organizations and individuals was very rewarding. The collaborative efforts between UKHSA, local authorities and landowners were key to rapidly mobilizing and preventing the establishment of invasive mosquitoes."