Dengue, Chikungunya and Zika

UK Status

Dengue cases in the UK are usually linked to travel. UK agencies keep a close watch because both capable species have now been detected in Britain: Aedes albopictus, found as eggs in Kent on several occasions since 2016, and Aedes aegypti, found breeding at homes in east London in September 2026.

Does the east London finding change my dengue risk?

While it does imply that the climate of the UK is becoming more suitable for establishment of these invasive mosquitoes, it does not change the practical risk to the public. Dengue virus does not circulate in the UK, so a mosquito here has nothing to pick up and pass on. Transmission would need several concurrent conditions: an established mosquito population, an infected person, and their meeting during a biting time and season. The UKHSA has assessed the risk from the finding as very low and has overseen treatment of the site. See our page on the species for what more information.

What Exactly Is Dengue?

Dengue is a mosquito-borne viral disease that is common in many tropical and subtropical regions. It is one of the major diseases that public health teams watch when talking about mosquito spread and climate suitability.

Global and Climate Context

Dengue is one of the fastest-growing vector-borne diseases globally. UK and European surveillance matters because research has identified parts of Europe at increasing risk, and public-health teams want to spot changes early rather than wait for outbreaks. In that context, invasive mosquitoes such as Aedes albopictus and Aedes aegypti are watched closely.

Symptoms to Know

Dengue can cause fever, headache, aches, fatigue, and sometimes rash. Severe illness is less common but can be serious. Travel-related illness should be assessed promptly if symptoms develop after a trip.

Public Advice

For UK residents, the main practical steps are bite prevention when travelling, checking for symptoms after travel, and supporting surveillance that helps detect changing risk early. UKHSA's vector-borne disease work is aimed at exactly that kind of early warning.

Chikungunya

Chikungunya is spread by the same mosquitoes as dengue, mainly Aedes aegypti and Aedes albopictus. Both have now been detected in the UK, however, chikungunya is not currently a risk in this country. The risk for this virus is still concentrated in travelers to places where the disease is endemic or where outbreaks are occurring.

Cases in returning travellers have been rising. UKHSA recorded 59 cases between January and June 2026, with Sri Lanka the most common country of travel for illnesses.

Symptoms

A sudden fever, almost always with joint pain, which is the feature that commonly separates it from dengue in most people's experience. Muscle pain, headache, nausea, fatigue and a rash are common too. The joint pain can be severe, and although it usually settles within days or weeks, in some people it can last considerably longer.

Vaccines

Two chikungunya vaccines are now approved in the UK on the advice of the Joint Committee on Vaccination and Immunisation: IXCHIQ for adults aged 18 to 59, and Vimkunya from age 12. Neither is routine. Both are bought privately through travel clinics after an assessment, and whether either is appropriate depends on where you are going and your own health, so ask a travel health professional rather than assuming.

Zika Virus

Zika is carried by the same Aedes mosquitoes, so the UK risks are similar: no local transmission, and cases only in people returning from more affected areas.

Zika is different from dengue and chikungunya in two ways that matter. Most infections cause mild illness or none at all, so people often do not know they have had it. But it can also pass from a pregnant woman to her baby, and it can be passed on sexually, which is why the travel advice below covers partners as well as travellers.

Why it matters in pregnancy

Infection during pregnancy can cause birth defects including microcephaly and problems with the baby's brain development. UKHSA puts the risk at roughly 4 to 6% of babies born to women infected while pregnant.

If you are travelling

If you are pregnant, postpone non-essential travel to areas with ongoing outbreaks and endemic transmission. Check the country you are going to on NaTHNaC's country pages, as risks change over time.
After returning, avoid becoming pregnant for 2 months if you travelled alone, or 3 months if your partner travelled as well or instead. Use condoms as well as other forms of contraception during this time.
Avoiding bites is the only real protection, since there is no vaccine and no specific treatment. See the mosquito bite prevention guide.