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Interpreting this report

The report provides updates on known, high-consequence infectious disease (HCID) events around the world as monitored byÌýthe UK Health Security Agency’s (UKHSA) epidemic intelligence activities.

The report is divided into 2 sections covering all the definedÌýHCIDÌýpathogens. The first section contains contact and airborneÌýHCIDsÌýthat have been specified for theÌýHCIDÌýprogramme by NHS England. The second section contains additionalÌýHCIDsÌýthat are important for situational awareness.

Each section contains information on known pathogens and includes descriptions of recent events. If an undiagnosed disease event occurs that could be interpreted as a potentialÌýHCID, a third section will be added to the report.

Events found during routine scanning activities that occur in endemic areas will briefly be noted in the report. Active surveillance, other than daily epidemic intelligence activities, of events in endemic areas will not be conducted (for example, actively searching government websites or other sources for data on case numbers).

The target audience for this report is any healthcare professional who may be involved inÌýHCIDÌýidentification, treatment and management.

Risk rating

Included for each disease is a current risk rating based on the probability of introduction to the UK and potential impact on the UK public.ÌýPast UK experience and the global occurrence of travel-associated cases are also considered. Currently, all diseases are classified into one of 3 categories: Low, very low and exceptionally low/negligible.

Incidents of significance of primaryÌýHCIDs

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Crimean-Congo haemorrhagic fever (CCHF)

Geographical risk areas	Endemic in Africa, the Balkans, the Middle East and western and south-central Asia. Cases have also been reported in Russia and Georgia. Spain has previously reported locally acquired cases (, with the ).
Sources and routes of infection	• bite from, or crushing of, an infected tickÌý • contact with the blood, tissues or body fluids of infected humans or animals
UKÌýexperience to date	Two cases have been reported in individuals who have travelled to the UK from and .
Risk rating	Low – rarely reported in travellers.
Recent cases or outbreaksÌý	Between 1 January and 27 April 2024, the World Health Organization (WHO) reported , from Afghanistan. CCHF was confirmed in 5 out of 93 cases from 4 provinces, including Kabul, Balkh, Kapisa and Paktika. (case fatality rate (CFR) of 9.2%). On 26 April 2024, the . In 2023, Senegal reported 7 CCHF cases, including 2 deaths (CFR of 28.6%) from 6 regions. On , health authorities reported a confirmed case of CCHF in Salamanca, north-western Spain. The case, an elderly male, was reportedly bitten by a tick. that the case died on 1 May 2024. .

Ebola virus disease (EVD)

Geographical risk areas	Map of countries which have reported EVD cases up to January 2023. No outbreaks of EVD have since been reported.
Sources and routes of infection	• contact with blood, tissues or body fluids of infected animals, or consumption of raw or undercooked infected animal tissue • contact with infected human blood or body fluids
UKÌýexperience to date	Four confirmed cases (one lab-acquired in the UK in 1976, 3 healthcare workers associated with West African epidemic 2014 to 2015).
Risk rating	Very low – other than during the West Africa outbreak, exported cases are extremely rare.
Recent cases or outbreaksÌý	No confirmed or suspected human cases were reported in April 2024.

Lassa fever

Geographical risk areas	Endemic in sub-Saharan West Africa.
Sources and routes of infection	• contact with excreta, or materials contaminated with excreta from an infected rodentÌý • inhalation of aerosols of excreta from an infected rodentÌý • contact with infected human blood or body fluids
UKÌýexperience to date	. Prior to this, 8 imported Lassa fever cases had been reported since 1980, all in travellers from West Africa.
Risk rating	Low – overall, Lassa fever is the most common imported viral haemorrhagic fever (VHF) but importations to the UK are still rare.
Recent cases or outbreaks	Between 1 January 2024 and 14 April 2024, . This is an ongoing outbreak since January 2022. Between 1 January and 28 April 2024, , with confirmed cases reported from 28 states. 156 deaths were reported among confirmed cases (CFR of 18.2%). This is an increase in suspected cases and deaths compared to the equivalent period in , including 148 deaths among confirmed cases (CFR of 17.0%), were reported.

Marburg virus disease (MVD)

Geographical risk areas	Sporadic outbreaks have previously been reported in Central and Eastern Africa. A human case of MVD was reported in ; this was the first case to be identified in West Africa. for the first time in July 2022. MVD outbreaks were reported for the first time in and in .
Sources and routes of infection	• exposure in mines or caves inhabited by Rousettus bat colonies • contact with infected human blood or body fluids
UKÌýexperience to date	ÌýNo reported cases in the UK.
Risk rating	Very low – globally, 5 travel-related exported MVD cases have previously been reported in the literature.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in February or April 2024.

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Avian influenza A(H7N9) virus

Geographical risk areas	All reported human infections have been .	Ìý
Sources and routes of infection	• close contact with infected birds or their environmentsÌý • close contact with infected humans (no sustained human-to-human transmission)	Ìý
UKÌýexperience to date	No known cases in the UK.	Ìý
Risk rating	ÌýVery low (UKHSAÌýrisk assessment).	Ìý
Recent cases or outbreaks	No confirmed or suspected human cases were reported in April 2024.	Ìý

Avian influenza A(H5N1) virus

Geographical risk areas	Human cases have been predominantly reported in South East Asia, but also in Egypt, Iraq, Pakistan, Turkey and Nigeria. Human cases (clade 2.3.4.4b) were and the , and and 2023. The first human cases of avian influenza A(H5N1) (clade 2.3.4.4b) were reported from South America in 2023, from and . Since October 2023, several human cases of clade 2.3.2.1c have been reported in .
Sources and routes of infection	• close contact with infected birds or their environments • close contact with infected humans (no sustained human-to-human transmission)
UKÌýexperience to date	As of September 2023, 5 detections were reported in the UK, and 4 in 2023.
Risk rating	ÌýVery low (UKHSAÌýrisk assessment).
Recent cases or outbreaks	On , the WHO was notified of a laboratory confirmed human case of avian influenza A(H5N1). The case had exposure to dairy cattle presumed to be infected with avian influenza A(H5N1). The patient developed , their sole symptom, on 27 March 2024. They were treated with a course of antivirals and recovered fully. This case is associated with an in dairy cattle within the United States.

Middle East respiratory syndrome (MERS-CoV)

Geographical risk areas	The Arabian Peninsula – Bahrain, Jordan, Iraq, Kingdom of Saudi Arabia, Kuwait, Oman, Qatar, United Arab Emirates, Yemen. Evidence has also been reported in Iran and Kenya.
Sources and routes of infection	• airborne particles • direct contact with contaminated environmentÌý • direct contact with camels or consumption of raw camel milk
UKÌýexperience to date	– 3 imported cases (2012, 2013 and 2018), 2 secondary cases in close family members of the case in 2013, 3 deaths.
Risk rating	ÌýVery low (UKHSAÌýrisk assessment).
Recent cases or outbreaks	No confirmed or suspected human cases were reported in April 2024.

Mpox (Clade I only)

Geographical risk areas	Central Africa including, .
Sources and routes of infection	• close contact with an infected animal (in an endemic country) or an infected person • contact with clothing or linens (such as bedding or towels) used by an infected person • direct contact with mpox skin lesions or scabs • coughing or sneezing of an individual with an mpox rash • consumption of contaminated bushmeat
UKÌýexperience to date	No cases of Clade I mpox have been reported in the UK.
Risk rating	ÌýVery low – no known importations of Clade I mpox into the UK.
Recent cases or outbreaks	Sequencing data is often not available for mpox cases reported from endemic African countries where Clade I mpox is known to circulate. Therefore, we report below all reported mpox cases from these countries, regardless of whether the samples have been sequenced or clade-tested. In 2024, as of 4 April, . Cameroon reported 113 mpox cases (27 confirmed), including one death, in 2023. Between 1 January and 21 April 2024, the , including 331 deaths (CFR of 5.7%), from 19 of 26 provinces. (14,434 cases, including 728 deaths). In the Republic of the Congo, were reported from 5 departments, as of 28 April 2024. The Republic of the Congo declared a mpox epidemic on . During 2023, 95 mpox cases, including 5 deaths were reported.

Nipah virus

Geographical risk areas	South East Asia, predominantly in . Cases have also been reported in Malaysia and Singapore.
Sources and routes of infection	• direct or indirect exposure to infected bats • consumption of contaminated raw date palm sap • close contact with infected pigs or humans
UKÌýexperience to date	ÌýNo known cases in the UK.
Risk rating	Exceptionally low/negligible – no travel-related infections in the literature.
Recent cases or outbreaks	No confirmed cases of Nipah virus infection were reported in April 2024.

Pneumonic plague (Yersinia pestis)

Geographical risk areas	Predominantly . Endemic in Madagascar, Peru, andÌýthe DRC.
Sources and routes of infection	• flea bitesÌý • close contact with infected animalsÌý • close contact with human cases of pneumonic plague
UKÌýexperience to date	Last outbreak in the UK was in 1918.Ìý
Risk rating	Exceptionally low/negligible
Recent cases or outbreaksÌý	No confirmed cases of pneumonic plague were confirmed in April 2024.

Severe acute respiratory syndrome (SARS)

Geographical risk areas	Currently none. Two historical outbreaks originating from China in 2002 and 2004.
Sources and routes of infection	• airborne particlesÌý • direct contact with contaminated environment
UKÌýexperience to date	related to the 2002 outbreak.
Risk rating	Exceptionally low/negligible
Recent cases or outbreaks	No confirmed or suspected human cases reported globally since 2004.

Incidents of significance of additionalÌýHCIDs

Argentine haemorrhagic fever (Junin virus)

Geographical risk areas	(central). Endemic to the provinces of Buenos Aires, Córdoba, Santa Fe and La Pampa.
Sources and routes of infection	• direct contact with infected rodentsÌý • inhalation of infectious rodent fluids and excretaÌý • person-to-person transmission has been documented
UKÌýexperience to date	ÌýNo known cases in the UK.
Risk rating	Exceptionally low/negligible – was identified in Belgium in 2020.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in April 2024.

Bolivian haemorrhagic fever (Machupo virus)

Geographical risk areas	Bolivia – (Mamoré, Iténez and Yucuma provinces) and Cochabamba (Cercado province).
Sources and routes of infection	• direct contact with infected rodentsÌý • inhalation of infectious rodent fluids and excretaÌý • person-to-person transmission has been documented
UKÌýexperience to date	ÌýNo known cases in the UK.
Risk rating	Exceptionally low/negligible – travel-related cases have never been reported.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in April 2024.

Lujo virus disease

Geographical risk areas	A single case acquired in Zambia led to a cluster in South Africa in 2008.
Sources and routes of infection	• presumed rodent contact (excreta, or materials contaminated with excreta of infected rodent)Ìý • person to person via body fluids
UKÌýexperience to date	No known cases in the UK.
Risk rating	Exceptionally low/negligible – a single travel-related case has been reported. No cases have been reported anywhere since 2008.
Recent cases or outbreaks	Exceptionally low / negligible – a single travel-related case has been reported. No cases have been reported anywhere since 2008.

Severe fever with thrombocytopenia syndrome (SFTS)

Geographical risk areas	Mainly reported from China (south-eastern), Japan and Korea. Cases have also been reported in , , and . Serological evidence of SFTS in .Ìý
Sources and routes of infection	• presumed to be tick exposureÌý • person-to-person transmission described in household and hospital contacts, via contact with blood or bloodstained body fluids
UKÌýexperience to date	No known cases in the UK.
Risk rating	Exceptionally low/negligible – not known to have occurred in travellers.
Recent cases or outbreaks	On , media reported that South Korea had recorded its first confirmed case of SFTS in 2024. The case was reported in Sangju, Gyeongsangbuk-do Province. On , a second SFTS was reported by the media from Jeju City, Jeju Province.

Andes virus (Hantavirus)

Geographical risk areas	ÌýChile and Southern Argentina.
Sources and routes of infection	• rodent contact (excreta, or materials contaminated with excreta from an infected rodent) • person-to-person transmission described in household and hospital contacts
UKÌýexperience to date	ÌýNo known cases in the UK.
Risk rating	Very low – rare cases in travellers have been reported.
Recent cases or outbreaks	On , media reported one laboratory confirmed fatal case of hantavirus in El Bolson, Río Negro Province, Argentina. As of , Chile’s Ministry of Health has reported 2 confirmed cases of hantavirus in April. The cumulative case count for 2024 is currently 13 confirmed cases and 2 deaths (CFR of 15.4%). The type of hantavirus was not specified for any of the above cases.

Avian influenza A(H5N6) virus

Geographical risk areas	Mostly China. New strain reported in , and subsequently found in Western Europe in birds.Ìý
Sources and routes of infection	Close contact with infected birds or their environments.Ìý
UKÌýexperience to date	ÌýNo known cases in the UK.Ìý
Risk rating	Very low – not known to have occurred in travellers (UKHSAÌýrisk assessment).
Recent cases or outbreaks	No confirmed or suspected human cases were reported in April 2024.

Avian influenza A(H7N7) virus

Geographical risk areas	Sporadic occurrence in birds across mainland Europe and the UK. in 1996, in 2003, and in 2013.
Sources and routes of infection	• close contact with infected birds or their environmentsÌý • close contact with infected humans (no sustained human-to-human transmission reported)Ìý
UKÌýexperience to date	ÌýNo known cases in the UK.
Risk rating	ÌýVery low – human cases are rare, and severe disease even rarer.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in April 2024.

Authors of this report

Emerging Infections and Zoonoses Team, UKHSA