Research and analysis

Global high consequence infectious disease events: summary November to December 2022

Updated 28 March 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 section 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 includes 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. Currently, all diseases are classified in one of three categories: Low, Very low and Exceptionally low.

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. Spain has also reported locally acquired cases (first reported 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	Two cases have been reported in individuals who have travelled to the UK from Afghanistan in 2012 and Bulgaria in 2014
Likelihood assessment	Low – rarely reported in travellers.
Recent cases or outbreaks	As of 31 December 2022, Afghanistan had reported 103 confirmed and 286 suspected CCHF cases during 2022. There have been 15 associated deaths. In November 2022, media in Iran reported that there had been 78 cases of CCHF and 9 deaths since 21 March 2022. Mauritania reported 4 confirmed cases of CCHF, including 2 deaths, between 29 August and 25 December 2022. As of 27 November, media had reported 59 cases of CCHF in Russia in 2022. Uganda reported 6 confirmed cases of CCHF, including 2 deaths, between 12 July and 13 December 2022.

Ebola virus disease (EVD)

Geographical risk areas	Map of countries which have reported EVD cases.
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	Four 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	On 20 September 2022, an outbreak of EVD caused by Sudan ebolavirus was declared in Uganda. The last case was confirmed on 27 November. A total of 142 confirmed (55 deaths) and 22 probable cases (22 deaths) were reported. The outbreak was declared over on 11 January 2023.

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. 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 common imported viral haemorrhagic fever (VHF) but importations to the UK are still rare.
Recent cases or outbreaks	In December 2022, one confirmed case of Lassa fever was reported in Guinea in the Health District of Gueckedou. As of 18 December, Nigeria had reported 1,038 confirmed Lassa fever cases, 7,981 suspected cases and 183 deaths (among confirmed cases) in 2022. During the equivalent 2021 time period, 454 confirmed cases, 4,273 suspected cases and 92 deaths (among confirmed cases) were reported. In 2022, as of 1 December, 67 confirmed Lassa fever cases and 22 deaths had been reported in Liberia (case fatality rate of 32.8%). In 2021, 25 confirmed cases and 16 deaths were reported (case fatality rate of 64.0%).

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. Cases were reported in Ghana for the first time in July 2022.
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 reported cases in the UK .
Likelihood assessment	Very low – globally, 5 travel-related exported cases have previously been reported in the literature.
Recent cases or outbreaks	No reports of confirmed or suspected human cases were identified between November and December 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 reports of confirmed or suspected human cases were identified between November and December 2022.

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 reported in Spain, the UK and the US 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	One UK case reported in 2022.
Likelihood assessment	Very low (UKHSA risk assessment).
Recent cases or outbreaks	In November 2022, a human case of avian influenza A(H5N1) was reported in Guangxi, China. The case developed symptoms on 22 September and died on 18 October. The case reported having exposure to live domestic poultry before symptom onset. Since 2005, 54 human cases of avian influenza A(H5N1) have been reported in mainland China.

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 or consumption of raw camel milk
UK experience to date	Five cases in total – 3 imported cases (2012, 2013 and 2018), 2 secondary cases in close family members of the case in 2013, 3 deaths.
Likelihood assessment	Very low (UKHSA risk assessment).
Recent cases or outbreaks	No reports of confirmed or suspected human cases were identified between November and December 2022.

Mpox (monkeypox) virus (clades I, IIa and IIb non-B.1 lineages only)

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 mpox skin lesions or scabs • coughing or sneezing of an individual with an mpox rash • consumption of contaminated bushmeat
UK experience to date	Between 2018 and 2021, 7 cases of mpox were identified in the UK: 4 of the cases were imported from Nigeria, 2 cases were household contacts and 1 was a case in a healthcare worker involved in the care of an imported case. Since May 2022, mpox cases with no recent travel to endemic countries have been reported in the UK, as part of the global mpox outbreak in non-endemic countries. In June 2022, the virus associated with this outbreak (which falls within Clade IIb), was declassified as a HCID following review by the Advisory Committee on Dangerous Pathogens (ACDP) and agreement by the UK 4 nations public health agencies (see HCID status of mpox). See UKHSA mpox outbreak: epidemiological overview and WHO Emergency situation reports for further information about the outbreak. In the UK, 8 cases infected with non-B.1 lineages of mpox virus have been identified by genomic sequencing since the start of the global mpox outbreak in non-endemic countries.
Likelihood assessment	Very low – before the start of the global mpox outbreak in 2022, there were 8 recorded importations of mpox in non-endemic countries since 2018. These cases were in travellers to Israel (one case), Singapore (one case), the US (2 cases) and the UK (4 cases).
Recent cases or outbreaks	Mpox cases have been reported from several endemic countries during 2022 (all data as of 21 December 2022): Cameroon has reported 18 confirmed cases, including 3 deaths. The Central African Republic has reported 8 confirmed cases, including 2 deaths. The Democratic Republic of the Congo (DRC) has reported 277 confirmed cases, including 198 deaths. Ghana has reported 107 confirmed cases, including 4 deaths. Liberia has reported 3 confirmed cases and no deaths. Nigeria has reported 704 confirmed cases, including 7 deaths. The Republic of the Congo has reported 5 confirmed cases, including 3 deaths.

Nipah virus

Geographical risk areas	South East Asia. Predominantly in Bangladesh and India. 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
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	Bangladesh reported 3 cases of Nipah virus infection during 2022.

Pneumonic plague (Yersinia pestis)

Geographical risk areas	Predominantly sub-Saharan Africa but also Asia, North Africa, South America, Western US. Endemic in Madagascar, Peru, and DRC.
Sources and routes of infection	• flea bites • close contact with infected animals • close 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	In December 2022, media reported 5 deaths due to plague in Madagascar. One additional case, reported to have had pneumonic plague, has recovered.

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 particles • direct contact with contaminated environment
UK experience to date	Four cases related to the 2002 outbreak.
Likelihood assessment	Exceptionally low – no cases have been reported since 2004.
Recent cases or outbreaks	No confirmed or suspected human cases reported globally 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	In December 2022, the media reported a case of Argentine haemorrhagic fever in the province of Buenos Aires, Argentina.

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 reports of confirmed or suspected human cases were identified between November and December 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. Cases have also been reported in Taiwan, Thailand, Myanmar and Vietnam. 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 reports of confirmed or suspected human cases were identified between November and December 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	As of 17 December, 16 confirmed hantavirus cases had been reported in the province of Buenos Aires, Argentina, in 2022. The type of hantavirus is not reported. As of 25 November, 25 confirmed hantavirus cases and 6 deaths had been reported in Chile during 2022. In December 2022, the media reported 3 additional cases in Los Ríos Region and one additional case in Aysén Region. The type of hantavirus is not reported. In total, 37 hantavirus cases were reported in Chile during 2021.

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	No reports of confirmed or suspected human cases were identified between November and December 2022.

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 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 reported)
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 reports of confirmed or suspected human cases were identified between November and December 2022.

Authors of this report

Alethea Charlton, Bláthnaid Mahon, Michael Reynolds