The UK Health Security Agency (UKHSA) has warned that climate change is significantly altering the landscape of vector-borne diseases in the UK by creating favorable conditions for the organisms that carry them.
Climate Change Reshaping UK Risk of Vector-Borne Diseases
Rising Trends in Local and Imported Infections
While the overall risk to the public in England remains low, Professor Lea BerrangFord, Deputy Director of the Centre for Climate & Health Security at UKHSA, stated that the risk picture is changing due to urbanization, the globalization of trade and travel, and climate change. This shift is evident in both imported and locally acquired cases.
Imported cases of malaria to the UK have reached their highest level in 20 years, and infections such as dengue fever are steadily moving northwards. Domestically, Lyme disease—a bacterial infection spread by tick bites—remains the most common locally acquired vector-borne infection in England. According to the first annual One Health Vector-Borne Disease Surveillance report published by the UKHSA, the Department for Environment, Food and Rural Affairs (Defra), and the Animal and Plant Health Agency (APHA), there were 1,168 laboratory-confirmed acute cases of Lyme disease reported in 2025. This represents an increase from the 959 cases reported in 2024.
Emerging Mosquito and Virus Threats
Although no locally acquired mosquito-borne infections were reported in England in the 2025 surveillance data, officials highlight a growing risk from specific viruses. The Usutu virus is now considered endemic in birds and mosquitoes in south-east England, and in 2025, it was detected in wild birds in Scotland for the first time. Additionally, the West Nile virus was first detected in UK mosquitoes in samples collected in 2023.
Mojca Kristan, an assistant professor in medical entomology at the London School of Hygiene and Tropical Medicine, noted that while there are roughly 30 native mosquito species in the UK, invasive species capable of carrying viruses like dengue fever are already well-established in Europe. Kristan warned that climate change makes Britain a more attractive place for mosquitoes to survive and thrive
.
Impact on Primary Healthcare and Public Health
The changing environment is already impacting frontline healthcare. Higher temperatures may lead people to spend more time outdoors with less clothing, increasing susceptibility to bites. Between April and June 2025, Boots reported that consultations for infected insect bites through the Pharmacy First scheme doubled. NHS England data showed these consultations peaked in July 2025 with 91,527 cases, 78% of which resulted in the supply of medicine.
To manage these emerging threats, the UKHSA has updated its national contingency plans for West Nile virus and invasive Aedes mosquitoes in England.
Vector Distribution and Environmental Factors
The prevalence of vectors is often tied to specific environmental conditions. The primary vector for Lyme disease, Ixodes ricinus, is found in higher densities in woodlands and areas where deer are present. While central England has fewer ticks due to lower deer populations, the presence of deer is not believed to increase the proportion of infected ticks.
The broader European context shows a similar trend of diseases moving into temperate regions following global temperature spikes. An example is the bluetongue virus, which infects ruminants such as goats, cattle, and sheep. Originally endemic to the tropics and subtropics, the virus migrated to the Mediterranean and Southern Europe in the late 1990s and later moved into Central and Northern Europe. Between 2007 and 2010, 28 European countries reported over 58,000 unexpected outbreaks of the disease.
Current surveillance efforts now utilize a “One Health” approach, combining data from human, animal, and environmental health sectors to identify new hotspots and spot threats sooner, according to government officials.
