Deadly viruses could be reaching the UK on planes and in travellers’ luggage, experts warn, as international travel drives a “concerning” rise in infections such as chikungunya and oropouche. The first UK case of oropouche has been detected in travellers returning from Brazil, while chikungunya cases among holidaymakers continue to surge.
Simon Clarke, professor of cellular microbiology at the University of Reading, said the trend reflects a growing appetite among Britons for travel to warmer, equatorial regions. “While oropouche is mainly found in the Amazon and chikungunya in sub-tropical regions, they are spreading,” he said. Both viruses have already appeared in the United States and Europe, with sporadic outbreaks reported in France and Italy.
Paul Hunter, professor of medicine at the University of East Anglia, warned of a small risk of “airport-associated infections,” where infected mosquitoes arrive on planes and escape. He stressed that any infection spreading to previously unexposed populations is concerning. Chikungunya, transmitted by mosquito bites, causes sudden fever and severe joint pain, which can persist for months or even years. In rare cases, it can cause organ damage or be fatal, particularly among the very young, the elderly, or people with underlying health conditions.
Between January and June 2025, the UK recorded 73 chikungunya cases, primarily in London, compared with 27 cases for the same period last year. Most were linked to travel to Sri Lanka, India, and Mauritius. While the mosquitoes that transmit the disease are not established in the UK, locally acquired infections elsewhere highlight the potential risk. Experts warn that cases are likely to rise during the remaining weeks of the mosquito season.
Chikungunya outbreaks are increasing globally, with surges on Indian Ocean islands such as Reunion, Mayotte, and Mauritius, as well as more than 10,000 cases reported in China since June 2025. Foshan, a city in southern Guangdong province, has implemented Covid-style lockdowns and insecticide spraying to curb the virus, with 12 other cities in the province, as well as Hong Kong and Taiwan, reporting infections. Since early 2025, 16 countries have reported 240,000 cases and 90 deaths, according to the European Centre for Disease Prevention and Control.
Two chikungunya vaccines are approved for use in the UK and available at private travel clinics. Experts urge travellers to take precautions, including insect repellent, covering the skin, and using treated bed nets. Dr Philip Veal, consultant in public health at UKHSA, said: “Chikungunya can be a nasty disease, and we’re seeing a worrying increase in cases among travellers returning to the UK. Symptoms usually improve in a few weeks, but joint pain can last months or longer.”
The UKHSA has also reported the first imported cases of oropouche in travellers from Brazil. The virus, dubbed “sloth fever,” circulates among primates, sloths, and birds, and is transmitted to humans by midges and mosquitoes. It causes flu-like symptoms including fever, headaches, joint and muscle pain, chills, nausea, and vomiting, and in severe cases, can lead to brain inflammation such as encephalitis or meningitis. There is no vaccine or specific treatment, but fatalities are extremely rare. Travel-associated cases are now appearing across Europe, with the first cases reported in Spain, Italy, and Germany in 2024.
Francois Balloux, professor of computational systems biology at UCL, noted a marked increase in both chikungunya and oropouche in endemic regions. “Neither could circulate in the UK due to the absence of vectors, but travellers are being infected overseas and returning home,” he said.
Health officials also report a rise in travel-related cholera in the UK, with eight cases in the first half of 2025, compared with just one in 2024, mostly linked to travel to India and Ethiopia. Meanwhile, dengue cases have decreased by 67% across England, Wales, and Northern Ireland, and only four cases of zika have been reported this year.
Experts warn that rising global temperatures and continued international travel may increase the risk of mosquito-borne viruses reaching the UK, and they urge travellers to remain vigilant and take preventative measures.
