Research and analysis

Global high consequence infectious disease events: summary February 2022

Updated 25 April 2024

Interpreting this report

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

It is divided into 2 sections covering all the defined HCID pathogens. The first contains contact and airborne HCIDs that have been specified for the HCID Programme by NHS England. The second section contains additional HCIDs that are important for situational awareness.

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

Likelihood assessment

Included for each disease is a ‘likelihood assessment’ – the likelihood of a case occurring in the UK – based on past UK experience and the global occurrence of travel-associated cases. There are currently 3 categories: Low, Very Low and Exceptionally Low.

When considering clinical history, it is important to remember that cases can and do occur outside of the usual distribution area. It is not possible to assess accurately the risk of cases presenting to healthcare providers in England but taken together it is inevitable that occasional imported cases will be seen.

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 in HCID identification.

Incidents of significance of primary HCIDs

Contact HCIDs

Crimean-Congo haemorrhagic fever (CCHF)

Geographical risk areas	Endemic in Africa, the Balkans, the Middle East and Asia. First locally acquired case in Spain in 2016 (HAIRS risk assessment).
Sources and routes of infection	• bite from or crushing of an infected tick • contact with blood or tissues from infected livestock • contact with infected patients, their blood or body fluids
UK experience to date	2 confirmed cases (ex-Afghanistan 2012, ex-Bulgaria 2014).
Likelihood assessment	Low. Rarely reported in travellers (23 cases in world literature).
Recent cases or outbreaks	In Mauritania, 5 cases of CCHF including 2 deaths were reported during February 2022.

Ebola virus disease

Geographical risk areas	Sporadic outbreaks in Western, Central and Eastern Africa
Sources and routes of infection	• contact with or consumption of infected animal tissue (such as bushmeat) • contact with infected human blood or body fluids
UK experience to date	4 confirmed cases (1 lab-acquired in the UK in 1976, 3 healthcare workers associated with West African epidemic 2014 to 2015).
Likelihood assessment	Very Low. Other than during the West Africa outbreak, exported cases are extremely rare.
Recent cases or outbreaks	No confirmed or suspected cases were reported in February 2022.

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 rodent • inhalation of aerosols of excreta from an infected rodent • contact with infected human blood or body fluids
UK experience to date	3 travel-related cases reported in 2022 (see below). Prior to this, 13 imported cases had been reported since 1971, all in travellers from West Africa.
Likelihood assessment	Low. Overall, Lassa fever is the most commonly imported viral haemorrhagic fever (VHF) but is still rare.
Recent cases or outbreaks	The UK reported 3 cases of Lassa fever including one death in February 2022. The first case had travelled to Mali in late 2021, where Lassa fever is endemic. The second and third cases were family members of the first case and had not travelled to Mali. In Nigeria, there have been 2,433 suspected and 540 confirmed cases of Lassa fever between 1 January and 27 February 2022. A total of 98 deaths have been reported amongst confirmed cases, resulting in a case fatality rate of 18.1%. This is higher than the number of cases reported during the same period in 2021 (959 suspected, 136 confirmed cases and 31 deaths amongst confirmed cases; case fatality rate of 22.8%). Togo reported one confirmed (fatal) case of Lassa fever in February 2022, in the Oti-South district. Lassa fever is endemic in Togo, where sporadic cases and outbreaks have been reported every few years since 2016. Liberia has reported 16 suspected and 17 confirmed cases of Lassa fever (including 5 deaths) in 2022, as of 28 February. In 2021, 112 suspected and 24 confirmed cases (15 deaths) were reported as of 21 November.

Marburg virus disease

Geographical risk areas	Sporadic outbreaks have previously been reported in Central and Eastern Africa. A human case was reported in August 2021 in Guinea; this was the first case to be identified in West Africa.
Sources and routes of infection	• exposure in mines or caves inhabited by Rousettus bat colonies • contact with infected human blood or body fluids
UK experience to date	No known cases in the UK.
Likelihood assessment	Very Low. Globally, 5 travel-related cases have previously been reported in the literature.
Recent cases or outbreaks	No confirmed or suspected cases were reported in February 2022.

Airborne HCIDs

Avian influenza A(H7N9) virus

Geographical risk areas	All reported human infections have been acquired in China.
Sources and routes of infection	• close contact with infected birds or their environments • close contact with infected humans (no sustained human-to-human transmission)
UK experience to date	No known cases in the UK.
Likelihood assessment	Very Low (UKHSA Risk Assessment).
Recent cases or outbreaks	No confirmed or suspected human cases were reported in February 2022.

Avian influenza A(H5N1) virus

Geographical risk areas	Human cases predominantly in South East Asia, but also Egypt, Iraq, Pakistan, Turkey and Nigeria. A human case was reported for the first time in England in 2022.
Sources and routes of infection	• close contact with infected birds or their environments • close contact with infected humans (no sustained human-to-human transmission)
UK experience to date	No known cases in the UK.
Likelihood assessment	Very low (UKHSA Risk Assessment).
Recent cases or outbreaks	No confirmed or suspected human cases were reported in February 2022.

Middle East respiratory syndrome (MERS)

Geographical risk areas	The Arabian Peninsula: Yemen, Qatar, Oman, Bahrain, Kuwait, Saudi Arabia and United Arab Emirates.
Sources and routes of infection	• airborne particles • direct contact with contaminated environment • direct contact with camels
UK experience to date	5 cases in total: 3 imported cases (2012, 2013 and 2018), 2 secondary cases in close family members of the second case, 3 deaths.
Likelihood assessment	Very low (UKHSA Risk Assessment).
Recent cases or outbreaks	No confirmed or suspected human cases were reported in February 2022.

Monkeypox virus

Geographical risk areas	West and Central Africa.
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 monkeypox skin lesions or scabs • coughing or sneezing of an individual with a monkeypox rash
UK experience to date	To date, there have been 7 cases of monkeypox reported in the UK. In May 2021, a case of monkeypox was identified with prior travel from Delta State, Nigeria. Two family members were subsequently identified as having monkeypox. Prior to these 3 cases, there were 4 previous cases of monkeypox reported in the UK, including 3 cases imported from Nigeria (2 in September 2018 and 1 in December 2019). One additional case, in 2018, was a healthcare worker who acquired infection following contact with contaminated bed linen.
Likelihood assessment	Very low. Reported outside Africa for the first time in 2018. Since 2018, 8 importations of human cases of monkeypox have been reported in non-endemic countries in travellers to Israel (1 case), Singapore (1 case), the US (2 cases) and the UK (4 cases).
Recent cases or outbreaks	Nigeria reported 9 suspected and 4 confirmed cases of monkeypox between 1 January and 28 February 2022. No deaths were recorded. From September 2017 to 28 February 2022, a total of 525 suspected cases have been reported. In the Democratic Republic of the Congo (DRC), 542 cases including 29 deaths were reported between 1 January and 20 February 2022. In the same period of 2021, there were 569 cases and 17 deaths. In total, 3,091 cases including 83 deaths were reported in 2021. Cameroon reported a monkeypox outbreak in December 2021. As of 17 February 2022, 22 suspected and 3 confirmed cases (2 deaths) have been reported. Monkeypox is reported sporadically in Cameroon, with more than half of regions reporting at least one case between 2020 and 2022.

Nipah virus

Geographical risk areas	South East Asia. Recent outbreaks in Bangladesh and India.
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
UK experience to date	No known cases in the UK.
Likelihood assessment	Exceptionally low. No travel-related infections in the literature.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in February 2022.

Pneumonic plague (Yersinia pestis)

Geographical risk areas	Predominantly sub-Saharan Africa but also Asia, North Africa, South America, Western US.
Sources and routes of infection	• flea bites • close contact with infected animals • contact with human cases of pneumonic plague
UK experience to date	Last outbreak in the UK was in 1918.
Likelihood assessment	Exceptionally low. No travel-related infections in the literature.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in February 2022.

Severe acute respiratory syndrome (SARS)

Geographical risk areas	Currently none. Two outbreaks originating from China in 2002 and 2004.
Sources and routes of infection	• airborne particles • direct contact with contaminated environment
UK experience to date	4 cases related to 2002 outbreak.
Likelihood assessment	Exceptionally low. Not reported since 2004.
Recent cases or outbreaks	No confirmed or suspected human cases reported since 2004.

Incidents of significance of additional HCIDs

Argentine haemorrhagic fever (Junin virus)

Geographical risk areas	Argentina (central). Endemic to the provinces of Buenos Aires, Córdoba, Santa Fe and La Pampa.
Sources and routes of infection	• direct contact with infected rodents • inhalation of infectious rodent fluids and excreta • person-to-person transmission has been documented
UK experience to date	No known cases in the UK.
Likelihood assessment	Exceptionally low. One travel-related case was identified in Belgium in 2020.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in February 2022.

Bolivian haemorrhagic fever (Machupo virus)

Geographical risk areas	Bolivia – cases have been identified in the departments of Beni (Mamoré, Iténez and Yucuma provinces) and Cochabamba (Cercado province).
Sources and routes of infection	• direct contact with infected rodents • inhalation of infectious rodent fluids and excreta • person-to-person transmission has been documented
UK experience to date	No known cases in the UK.
Likelihood assessment	Exceptionally low. Travel-related cases have never been reported.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in February 2022.

Lujo virus disease

Geographical risk areas	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) • person-to-person via body fluids
UK experience to date	No known cases in the UK.
Likelihood assessment	Exceptionally low. A single travel-related case has been reported. No cases have been reported anywhere since 2008.
Recent cases or outbreaks	No confirmed or suspected human cases reported since 2008.

Severe fever with thrombocytopenia syndrome (SFTS)

Geographical risk areas	Mainly reported from China (south-eastern), Japan and Korea. First ever cases reported in Vietnam and Taiwan in 2019. Serological evidence of SFTS in Pakistan.
Sources and routes of infection	• presumed to be tick exposure • person-to-person transmission described in household and hospital contacts, via contact with blood or bloodstained body fluids
UK experience to date	No known cases in the UK.
Likelihood assessment	Exceptionally low. Not known to have occurred in travellers.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in February 2022.

Andes virus (Hantavirus)

Geographical risk areas	Chile 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
UK experience to date	No known cases in the UK.
Likelihood assessment	Very Low. Rare cases in travellers have been reported.
Recent cases or outbreaks	No confirmed or suspected cases of Andes virus were reported in February 2022.

Avian influenza A(H5N6) virus

Geographical risk areas	Mostly China. New strain in Greece in March 2017, and subsequently found in Western Europe in birds.
Sources and routes of infection	Close contact with infected birds or their environments.
UK experience to date	No known cases.
Likelihood assessment	Very low. Not known to have occurred in travellers (UKHSA risk assessment).
Recent cases or outbreaks	In February 2022, 6 human cases of avian influenza A(H5N6) were reported in mainland China, bringing the total number of human cases reported so far in 2022 to 14. Since 2014, 71 human cases have been reported in mainland China, 31 of which were reported in 2021.

Avian influenza A(H7N7) virus

Geographical risk areas	Sporadic occurrence in birds across Europe and the UK. A human case was reported in Ireland in 1996, 89 cases were reported in the Netherlands in 2003, and 3 human cases of conjunctivitis associated with H7N7 were reported in Italy in 2013.
Sources and routes of infection	• close contact with infected birds or their environments • close contact with infected humans (no sustained human-to-human transmission)
UK experience to date	No known cases.
Likelihood assessment	Very low. Human cases are rare and severe disease even rarer.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in February 2022.