Please note that not all cases of disease or outbreaks are reported; some outbreaks may only be reported if they occur outside of the usual recognised risk area or season, or they have been reported in greater than usual numbers. See 'About Outbreaks' tab below for further detail.

For further information on red, amber and green alert categories, see About Outbreaks tab.

28 May 2026
USA

Mpox in USA

Since November 2024, and as of 22 May 2026, 20 cases of clade I mpox have been reported in the United States. Clade Ib mpox has been sequenced from clade I cases in the US. Please see our Topics in Brief article for further information on mpox.

7
Take extra precautions
27 May 2026

Measles in Japan

As of 20 May 2026, a total of 498 measles cases have been reported in Japan for 2026. Please see our Topics in Brief article for further details on measles.

Take usual precautions
22 May 2026

Dengue in New Caledonia

As of 21 May 2026, a total of 1,786 dengue cases have now been reported in New Caledonia since January 2026. Please see our Topics in Brief article for further details on dengue.

2
Take usual precautions
20 May 2026
Australia + Northern Territory

Murray Valley encephalitis in Australia

On 19 May 2026, local health authorities in the Northern Territory reported two deaths from Murray Valley encephalitis. Both cases were reported from Alice Springs, one in April and the other in May 2026. Travellers should avoid mosquito bites.

Take usual precautions

MERS-CoV in France and Saudi Arabia

Between January 2025 and 29 April 2026, there have been 19 human cases of MERS reported – 17 reported by the Kingdom of Saudi Arabia, and two reported by France in December 2025 in individuals who had travelled to the Middle East. Please see our Topics in Brief article for further details on MERS-CoV.

Take usual precautions
15 May 2026

Measles in Mexico

As of 7 May 2026, a total of 10,049 cases of measles have been reported in 2026. Please see our Topics in Brief article for further details on measles.

Take usual precautions
11 May 2026

Hantavirus in Argentina

As of 25 April 2026, 101 confirmed cases of hantavirus infection and 32 deaths have been reported in Argentina during the 2025/2026 season. Cases have been reported in the following provinces: Buenos Aires, Salta, Santa Fe, Chubut, Río Negro, Entre Ríos and Jujuy. Please see UKHSA guidance for more details on hantavirus.

3
Take usual precautions
06 May 2026

Measles in Bangladesh

As of 5 May 2026, a total of 5,467 confirmed measles cases and 41,793 suspected cases with 259 deaths have been reported in Bangladesh for 2026. Please see our Topics in Brief article for further details on measles.

3
Take usual precautions
06 May 2026

Dengue in Tonga

As of 5 May 2026, a total of 56 confirmed dengue cases have now been reported in Tonga. The highest number of cases have been reported from Tongatapu Island. Dengue virus serotype 2 (DENV-2) has been confirmed. Please see our Topics in Brief article for further details on dengue.

1
Take usual precautions
01 May 2026

Mpox in Luxembourg

Between April 2025 and March 2026, one clade I mpox case was reported in Luxembourg. This is the first clade I mpox case reported in Luxembourg. Please see our Topics in Brief article for further details on mpox.

Take extra precautions

NaTHNaC regularly review and update information on disease outbreaks and other health issues that may affect the UK traveller. You can search the information by disease or by country in our Outbreak Surveillance section.

The information comes from a wide variety of sources and can be used along with the Country Information section of our website where you will find recommendations on vaccines, malaria and other risks for each country (where relevant).

Please note that not all cases of disease or outbreaks are reported. In some countries, there may be limited surveillance and reporting processes in place so information can be difficult to obtain. Some diseases may only be reported if they occur outside of the usual recognised risk area or season, or they have been reported in greater than usual numbers. Outbreaks of those diseases included in the UK childhood vaccination programme are not usually reported unless the outbreak is unusual or unexpected.

The information presented in the disease surveillance reports is collated from a variety of sources, including government bodies, international organisations and the media. The verification status of each report is clearly indicated. Verified reports are confirmed by official sources. Some unverified reports are included to ensure timely dissemination of information and where possible we will try to substantiate these reports, although confirmation may not always be possible. Unverified reports may be subject to change, misreporting and may later prove to be unsubstantiated. They should not therefore be regarded as official.

Where available, a web link is provided to the original information source. We cannot accept responsibility for the sites to which it links, or for the information found on those sites. Linking to outside sites does not in any way imply endorsement of these sites. If you wish to use the following content for official purposes, please refer to the original sources of information.

Key to NaTHNaC alert level feature

LEVEL 1: GREEN
Take usual precautions
Follow standard protective measures, as recommended for this destination, disease or situation. Be aware that advice may change and check for updates.
LEVEL 2: AMBER
Take extra precautions
Follow any additional precautions recommended. Be alert and check regularly for changes in advice about this ongoing situation. Advice may be relevant for all travellers or apply to a specific group of travellers.
LEVEL 3: RED
FCDO advise against travel
The Foreign, Commonwealth & Development Office (FCDO) advise against travel on health grounds. This may mean avoiding non-essential travel, or all travel, follow the FCDO advice for details. Please note we do not report on FCDO safety and security alerts. Travellers should check the FCDO travel advisories for their destination for this information.

Alert categories are based on the situation at the time of publication. They will not be routinely updated unless outbreak information or a news item is updated.