Easter holidaymakers have been warned to take precautions against mosquitos after a surge in a tropical virus being detected in Britain.

The UK Health Security Agency reports that cases of chikungunya virus increased by 43% last year and is being detected here at its highest levels since 2014. The infection is transmitted to humans by Aedes mosquitoes and causes sudden, high fever and severe, often debilitating, joint pain that can last for months. In rare cases it can be fatal.

The data shows it is caught abroad between April and September and health officials are stressing the importance of protecting against biting insects during Easter and spring travel. The UKHSA also said malaria cases detected back in the UK dropped slightly in 2025, but remain high.

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Dr Philip Veal, consultant in public health at the UKHSA, said: "For some people chikungunya can be a prolonged and nasty disease and we continue to see cases in travellers returning to the UK, particularly from parts of Asia and the Indian Ocean region.

“While this mosquito-borne infection is rarely fatal, it can cause severe joint and muscle pain, headaches, sensitivity to light and skin rashes. Thankfully, symptoms usually improve within a few weeks, but joint pain may last for months or longer. So, it is essential to take precautions against mosquito bites when travelling.”

The latest UKHSA Travel-associated Infections Report published today shows 160 chikungunya cases were reported in 2025, up from 112 cases the previous year. Most cases are linked to recent holidays to India, Sri Lanka and Bangladesh. There are two chikungunya vaccines that have recently been approved for use in the UK and are available privately from travel clinics, following an assessment by a healthcare professional.

Separate UKHSA data shows imported malaria cases remain high despite a decrease in diagnoses to 1,629 in 2025 from 1,812 in 2024. Most cases were reported during the late spring and summer travel months between May and October.

Malaria is potentially fatal but almost entirely preventable when prevention measures such as antimalarial tablets are taken correctly. Health chiefs say travellers should follow travel advice for their destination, which may include antimalarials and mosquito bite avoidance measures.

Dr Dipti Patel, director of the National Travel Health Network and Centre, said: "If you’re travelling over Easter or spring, it’s important that you prepare before you travel, and take precautions against mosquito bites. Simple steps such as using a DEET based insect repellent, covering-up your skin and sleeping under insecticide-treated bed nets can greatly reduce the risk.

“Before you travel, check the Travel Health Pro website for the latest advice on your destination. If chikungunya is a risk at your destination, you may wish to discuss the suitability of chikungunya vaccination with a travel health clinic."

Chikungunya is spread by Aedes aegypti and Aedes albopictus mosquitoes. The odd ones are detected in the UK after travelling over on lorries from abroad but conditions are not right for them to breed. This means their populations are not established so there is currently no risk of onward transmission of chikungunya in the UK.

Travellers are advised to consult their general practice, pharmacist or travel clinic between four and six weeks before travel for personalised advice.