As the summer holiday season begins, the UK Health Security Agency (UKHSA) is reminding travellers to take precautions against travel-associated infections overseas. UKHSA has today published provisional data for England, Wales and Northern Ireland on specific selected travel associated infections including mosquito-borne infections (dengue, Zika, chikungunya and malaria) and enteric fever (typhoid and paratyphoid fever).
Mosquito-borne infections can cause fever, headache, muscle and joint pain, nausea and vomiting, and can be serious although some people experience no symptoms at all. Typhoid and paratyphoid are serious but preventable illnesses caused by Salmonella bacteria, usually spread through contaminated food or water, News Cover reports, citing the UK government's official website.
Travellers can protect themselves against these infections by taking steps to avoid mosquito bites, including using insect repellent, covering exposed skin and sleeping under a treated bed net where needed, as well as practising good food and water hygiene and getting vaccinations and malaria prevention tablets where appropriate.
The latest imported dengue data shows that a total of 137 cases were reported in England from January to June 2026. South-East Asia and South Asia remain the most common regions of exposure, with 27 cases linked to travel to Thailand and 19 to the Maldives.
A total of 8 Zika virus cases were reported from January to June 2026. This already exceeds the 7 cases recorded in 2025. Indonesia was the most frequently reported country of exposure, accounting for four of the eight cases in 2026 so far. Notably, only one travel-associated case linked to Indonesia had been reported between 2014 and 2025, which occurred in 2024.
Although Zika rarely causes serious illness in most people, it poses a significant risk during pregnancy as it can be passed to the unborn baby and can cause birth defects. There is no vaccine or treatment, so avoiding mosquito bites is the most effective form of protection.
A total of 59 chikungunya cases were reported from January to June 2026, with Sri Lanka being the most commonly reported country of travel, accounting for 18 cases.
Meanwhile, 557 malaria cases were reported in England, Wales and Northern Ireland from January to May 2026. Malaria is potentially fatal but almost entirely preventable when antimalaria tablets are taken correctly.
Today’s data shows that cases of dengue and Zika continue through spring and into the summer, with dengue recording its highest 2026 monthly total in June, and Zika cases reported throughout this period. This follows the pattern seen in previous years, where mosquito-borne infection cases are commonly reported during the spring and summer travel months.
In addition to mosquito-borne infections, a total of 287 travel-associated enteric fever cases (typhoid and paratyphoid fever) were reported from January to June 2026. The highest number of enteric fever cases is recorded between May and October in recent years, with September seeing a peak of 118 cases in 2025. These are serious but preventable illnesses caused by Salmonella bacteria, usually spread through contaminated food or water.
With the summer holiday season now underway, cases are expected to continue to rise and UKHSA is reminding travellers to take appropriate precautions before and during their trip.
