Urgent warning as cases of mosquito virus causing 'sudden fever' rise in UK
The UK Health Security Agency (UKHSA) has also detected the first cases of the emerging disease oropouche virus in the UK, all of which were linked to travel from Brazil
Health officials are urging holidaymakers to protect themselves against mosquito bites due to an increase in chikungunya cases among travellers returning from overseas. The UK Health Security Agency (UKHSA) has also identified the first instances of the emerging oropouche virus in the UK, all linked to travel from Brazil.
Chikungunya, a virus transmitted through mosquito bites, presents symptoms such as sudden fever and joint pain. According to the UKHSA, while most people recover within a fortnight, the joint pain can persist for months or even years in some individuals.
Although serious complications are rare, the disease can be fatal in exceptional cases, especially among the very young, the elderly, or those with pre-existing health conditions. The latest report on travel-associated infections from the UKHSA reveals that there were 73 reported cases of chikungunya from January to June 2025, a significant increase from the 27 cases reported during the same period the previous year.
The majority of these cases were associated with travel to Sri Lanka, India, and Mauritius. All cases were reported in England, predominantly in London.
Currently, there is no risk of onward transmission of chikungunya in the UK, as the two species of mosquito that transmit the disease are not established here, according to UKHSA. The illness primarily occurs in Africa and Asia, particularly southern Asia, although cases have been reported in Europe and parts of North America.
However, this year has seen outbreaks in the Americas and Asia, with surges in China and the Indian Ocean islands of Reunion, Mayotte and Mauritius.
Steps to prevent 'nasty disease'
Dr Philip Veal, a consultant in public health at UKHSA, warned: "Chikungunya can be a nasty disease and we're seeing a worrying increase in cases among travellers returning to the UK. 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.
"It is essential to take precautions against mosquito bites when travelling. Simple steps, such as using insect repellent, covering up your skin and sleeping under insecticide-treated bed nets can greatly reduce the risk."
Two chikungunya vaccines are approved for use in the UK and are available to purchase following an assessment at a private travel clinic.
Oropouche detected in UK
The first UK cases of oropouche virus, which is spread by midge bites, have also been detected by UKHSA. All three cases were associated with travel to Brazil.
The illness, which resembles the flu, can cause symptoms such as fever, headaches, joint pain, muscle pain, chills, nausea and vomiting. Officials have urged anyone who becomes unwell with these symptoms after travelling to affected areas, including parts of Central and South America and the Caribbean, to seek urgent medical advice.
According to the World Health Organisation (WHO), before late 2023, the oropouche virus was mostly reported near the Amazon rainforest area. However, in 2024, locally transmitted cases of the disease were reported in Brazil, Bolivia, Colombia, Cuba, Guyana, Peru and the Dominican Republic.
The UKHSA report also indicates an increase in travel-associated cholera cases in the UK, with eight cases in the first half of the year compared to just one in 2024. Most cases were associated with travel to India and Ethiopia.
There was also a 67% decrease in the number of dengue cases reported in England, Wales and Northern Ireland from January to June, and there were just four cases of zika virus during the period, down from nine in 2024.