Research and analysis

Global high consequence infectious disease events: summary October 2021

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 high consequence infectious diseases (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. 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 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 confirmed cases (ex-Afghanistan 2012, ex-Bulgaria 2014).
Likelihood assessment	Low. Rarely reported in travellers (23 cases in world literature).
Recent cases or outbreaks	No confirmed or suspected cases of CCHF were reported in October 2021.

Ebola virus disease

Geographical risk areas	Sporadic outbreaks in Western, Central and Eastern Africa.
Sources and routes of infection	• contact 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 8 October 2021, the Democratic Republic of Congo’s Ministry of Health announced a new outbreak of Ebola virus disease in Béni health zone, North Kivu Province. As of 31 October 2021, there have been 8 confirmed (6 deaths) and 3 probable (all fatal) cases.

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	Fourteen cases since 1971, all ex-West Africa.
Likelihood assessment	Low. Overall, Lassa fever is the most common imported viral haemorrhagic fever (VHF) but is still rare (a total of 35 imported cases reported globally since 1969).
Recent cases or outbreaks	In Nigeria, there have been 3,419 suspected and 401 confirmed cases of Lassa fever in 2021, as of 24 October. A total of 79 deaths have been reported, with a case fatality rate of 19.7%. This is lower than the number of cases reported in the equivalent 2020 period (5,931 suspected, 1,116 confirmed cases and 239 deaths, with a case fatality rate of 20.6%). In Liberia, from January 2021 to 23 October 2021, a total of 117 suspected cases were reported, of which 16 (13.6%) were confirmed. There were 10 deaths among the confirmed cases (case fatality rate of 62.5%). In Guinea, 8 confirmed cases including 7 deaths (case fatality rate of 87.5%) have been reported this year, as of 21 October 2021. The last case was confirmed on 19 September 2021.

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 of Marburg virus disease were reported in October 2021.

Airborne HCIDs

Avian influenza A(H7N9) virus (Asian lineage)

Geographical risk areas	All 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 October 2021.

Avian influenza A(H5N1) virus

Geographical risk areas	Human cases predominantly in South East Asia, but also Egypt, Iraq, Pakistan, Turkey and Nigeria. Highly pathogenic H5N1 in birds much more widespread, including in the UK.
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 October 2021.

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	Five 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 October 2021. So far in 2021, there have been 14 cases of MERS-CoV identified globally. Of these cases, 13 were in Saudi Arabia and one in the United Arab Emirates.

Monkeypox virus

Geographical risk areas	West and Central Africa.
Sources and routes of infection	• 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 have been only 4 cases of monkeypox reported in the UK, including 3 cases previously imported from Nigeria (2 in September 2018 and 1 in December 2019). One other 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.
Recent cases or outbreaks	There have been no updates on monkeypox cases in Nigeria since the previous report. As of 30 September, 79 suspected and 23 confirmed cases have been identified in 2021. No deaths have been reported. During 2020, there were 8 confirmed cases in total. In the Democratic Republic of the Congo (DRC), 2,703 cases and 71 deaths associated with monkeypox were reported between 1 January and 30 September 2021.

Nipah virus

Geographical risk areas	Outbreaks in Bangladesh and India. South East Asia at risk.
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	On 4 September 2021, the Kerala State Health department reported an isolated case of Nipah virus disease in Kozhikode district, Kerala, India. The case, a 12-year-old boy, developed symptoms on 29 August and died on 5 September. No further cases were reported. On 16 October 2021, Kerala State was declared free of Nipah virus after no new cases had been reported in the previous 42 days. Bangladesh has retrospectively updated the number of Nipah virus cases reported in 2020 to include an additional case, bringing the total for 2020 to 7 cases and 4 deaths. In 2021, 2 cases have been reported up until the end of October, with no deaths.

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	There have been no updates on the plague outbreak in Ituri province, DRC since the September report. As of 12 September 2021, 118 suspected plague cases and 13 deaths have been reported in 2021. In 2020, 461 suspected and 31 deaths were reported in the province. As of 17 October, Madagascar has reported 41 suspected cases of pulmonary plague including 19 confirmed cases and 6 deaths. Plague is endemic to Madagascar, where 200 to 700 cases are reported each year.

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	Four 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). Limited to the provinces of Buenos Aires, Cordoba, Santa Fe, Entre Rios 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: travel-related cases have never been reported.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in October 2021.

Bolivian haemorrhagic fever (Machupo virus)

Geographical risk areas	Bolivia. Limited to the Department of Beni, municipalities of the provinces Iténez (Magdalena, Baures and Huacaraje) and Mamoré (Puerto Siles, San Joaquín and San Ramón).
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 October 2021.

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 of SFTS were reported in October 2021.

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 October, no confirmed or suspected cases of Andes virus have been reported in 2021. Media reports of a fatal case of hantavirus infection in Araucanía, Chile in October brought the total cases reported in 2021 in this region to 6, with 2 deaths. The strain of hantavirus was not specified.

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	Three human cases of avian influenza A(H5N6) were reported in mainland China in October 2021. This brings the total number of cases reported so far in 2021 to 24. From 2014 to the end of October 2021, a total of 50 human cases have been reported in mainland China.

Avian influenza A(H7N7) virus

Geographical risk areas	Sporadic occurrence in birds across mainland 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 October 2021.