Mosquito summary - HECC Chapter 8: climate and vector-borne diseases
Source: gov.uk (2025-03-06)

Chapter 8 of the HECC report examines how climate change may have an impact on ticks and tick-borne diseases, potentially changing associated public health risk.

CCHS navigation menu: CCHS homepage (https://www.gov.uk/government/organisations/the-centre-for-climate-health-security)Topic: health impacts (https://www.gov.uk/government/collections/health-impacts) Vector-borne disease: mosquitoes (https://www.gov.uk/government/collections/mosquitoes)Part of: learning about mosquitoes

Important resources for HECC chapter 8:
- Mosquito summary chapter 8: climate and vector-borne diseases
- Chapter 8 full report (pdf) (https://www.gov.uk/government/publications/climate-change-health-effects-in-the-uk#:~:text=Chapter%208%3A%20Direct%20and%20indirect%20effects%20of%20climate%20change%20on%20vectors%20and%20vector%2Dborne%20diseases%20in%20the%20UK)
More content:
- Full HECC report (https://www.gov.uk/guidance/health-effects-of-climate-change-hecc-report)
Summary

Vector-borne diseases (VBDs) are illnesses caused when parasites, viruses or bacteria are spread to humans and animals by blood-feeding arthropods (vectors). These include mosquitoes, ticks, midges, sand-flies and fleas. The presence, distribution and seasonality of vectors, as well as the pathogens they carry, are influenced by both weather and climate. This chapter of the Health Effects of Climate Change (HECC) report describes how the public health risk posed by vector-borne diseases could change in the UK under a high warming scenario.

Both the increased rainfall and warmer temperatures caused by climate change are impacting the distribution of UK mosquitoes. Mosquito densities in the UK are driven by the availability of flooded habitat, and extreme rainfall and flooding events can create new habitats. Warmer temperatures benefit vectors by speeding up their development, as well as increasing their rates of both survival and biting. The development rate of pathogens in mosquitoes also increases with temperature up until a threshold, after which they decline. A warmer climate can change vector distribution by making areas that were previously unsuitable for vector survival, suitable.

While climate is an important influence on vector distribution, other factors contributing to this include trade and travel, which increase risks of non-native vectors being imported, as well as land use changes which can create or destroy vector habitats.

There are 36 species of mosquitoes in the UK. Some types of mosquitoes that are a cause for concern under a changing climate include Culex modestus and Culex pipiens for their potential to transmit West Nile virus (WNV) and in the case of the latter type also its potential to transmit Usutu virus. Anopheles mosquitoes are also potential vectors of Plasmodium malaria in the UK.

There is also concern about the introduction and establishment of invasive mosquito species in the UK, such as Aedes albopictus. These can transmit diseases such as dengue, chikungunya and Zika, and which therefore poses a significant risk to public health. Based on climate modelling, the area around London is already suitable for the establishment of this invasive mosquito, and it is expected that most of England could also be suitable by the 2040s and 2050s, with London becoming suitable for endemic dengue transmission by the 2060s under high warming scenarios. Once a non-native species has become established, it is very difficult to eradicate it. Surveillance is therefore very important for identifying the presence of new species early enough to remove them.