Research and analysis

Global high consequence infectious disease events: summary July 2023

Updated 25 April 2024

Interpreting this report

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

The report 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.

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, 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. Past 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 primary HCIDs

Contact HCIDs

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 (first reported in 2016, with the latest case reported in 2022).
Sources and routes of infection	• bite from, or crushing of, an infected tick • contact with the blood, tissues or body fluids of infected humans or animals
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
Risk rating	Low – rarely reported in travellers.
Recent cases or outbreaks	Between January and 29 July 2023, a total of 715 suspected CCHF cases, including 78 deaths were reported in Afghanistan by the World Health Organization (WHO). Associated deaths were reported from 18 provinces, with more than half of these reported from Kabul and Balkh provinces. Afghanistan reported 103 confirmed CCHF cases, including 15 deaths, during 2022. On 9 July 2023, media reported one case of CCHF in the Akhaltsikhe region of Samtskhe Javakheti, Georgia. Twelve cases, including one death, have been reported so far in 2023. In 2022, 47 confirmed cases were recorded in Georgia, including 3 deaths. In Iran, on 4 July 2023, media reported that health authorities had registered 19 cases of CCHF nationally since the beginning of the year, including one death. The Iraqi Ministry of Health reported 377 cases of CCHF, including 53 deaths, from the start of the year to 12 July 2023. On 26 July 2023, media reported a further case in a 5-year-old child in Diyala Province. On 27 July 2023, media reported a further 8 cases of CCHF, including 2 deaths. On 5 July 2023, a fatal case of CCHF was reported in the state of Gujarat, India. According to the media, Gujarat reported 5 confirmed cases of CCHF in 2022. As of 10 July 2023, 9 confirmed cases of CCHF were reported by the media since the beginning of 2023 in Kazakhstan. 2 cases were confirmed in the Sauran Region, and one confirmed case each was reported from Ordabasy, Otyrar, Tolebi, Keles, Maktaaral and Zhetysay regions and in the city of Turkestan. On 30 July 2023, media reported one case of CCHF (fatal) in a 27-year-old woman from the village of Kučica in Plakkovica, Karbinci Municipality, North Macedonia. Only one laboratory-confirmed case has been reported in the country (in 2010) since the first detection of CCHF in 1971. In Pakistan, on 20 July 2023 media reported 8 cases of CCHF in Khyber Pakhtunkhwa province, including the death of an Afghan national. On 18 July 2023, media reported 23 cases of CCHF in the Balochistan Health Department in 2023, with 2 cases undergoing treatment. In Russia, on 29 July 2023 media reported 25 cases of CCHF in the North Caucasus region since the beginning of the 2023 tick season. In Dagestan, one fatal case was noted. On 28 July 2023, media reported a fatal case of CCHF in Senegal in a 69-year-old Mauritanian national. The first case of CCHF in Mauritania was reported in February 2022, with 5 cases since – 3 of which recovered and 2 died. On 13 July 2023, media reported 2 CCHF-associated deaths within the Sivas region of Turkey. A total of 5 deaths were reported from the start of the year to 13 July 2023 in the region. Confirmed case numbers of CCHF in Turkey are unclear. On 7 July 2023, media reported 41 cases of CCHF, including 22 hospitalisations, and 2 CCHF deaths in Çorum Province.

Ebola virus disease (EVD)

Geographical risk areas	Map of countries which have reported EVD cases up to January 2023.
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
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).
Risk rating	Very low – other than during the West Africa outbreak, exported cases are extremely rare.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in July 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	Three travel-related cases reported in 2022. Prior to this, 13 imported cases had been reported since 1971, 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	Since the start of the outbreak on 9 September 2022 and up to 2 July 2023, Liberia has reported a total of 80 laboratory-confirmed cases of Lassa fever, including 23 deaths (case fatality rate 28.8%). Between 1 January and 23 July 2023, Nigeria has reported 1,009 confirmed and 6,597 suspected Lassa fever cases. Among confirmed cases, 171 deaths have been reported (case fatality rate of 16.9%). The number of confirmed cases and deaths reported in 2023 is higher compared to the equivalent 2022 period (857 cases including 169 deaths).

Marburg virus disease (MVD)

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. Outbreaks were reported for the first time in Equatorial Guinea in February 2023 and in Tanzania in March 2023.
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.
Risk rating	Very low – globally, 5 travel-related exported cases have previously been reported in the literature.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in July 2023.

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.
Risk rating	Very low (UKHSA risk assessment).
Recent cases or outbreaks	No confirmed or suspected human cases were reported in July 2023.

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 and the US in 2022, and in the UK in 2022 and 2023. The first human cases of avian influenza A(H5N1) (clade 2.3.4.4b) were reported from South America in 2023, from Ecuador and Chile.
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	As of July 2023, 5 detections were reported in the UK, one in 2022 and 4 in 2023.
Risk rating	Very low (UKHSA risk assessment).
Recent cases or outbreaks	On 14 July 2023, UKHSA reported the detection of 2 asymptomatic, human cases of influenza A(H5N1) in poultry workers in England, as a result of an asymptomatic testing programme for people in contact with infected birds. This brings the total number of A(H5N1) cases reported in 2023 to 4. UKHSA has not detected evidence of human-to-human transmission. One case was reported in the UK during 2022.

Middle East respiratory syndrome (MERS-CoV)

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.
Risk rating	Very low (UKHSA risk assessment).
Recent cases or outbreaks	A case of MERS-CoV was confirmed in the United Arab Emirates on 10 July 2023, after a patient was admitted to hospital on 8 June 2023. No secondary cases were reported. Prior to this, the last reported case of MERS-CoV from the United Arab Emirates was in November 2021. Including the case reported in July 2023, the United Arab Emirates has reported 94 cases of MERS-CoV, including 12 deaths (case fatality rate of 13%) since July 2013.

Mpox (Clade I only)

Geographical risk areas	Central Africa including, Central African Republic, Cameroon, the Democratic Republic of the Congo, Gabon and Congo.
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	In June 2022, the Advisory Committee on Dangerous Pathogens (ACDP) recommended that the strain of monkeypox virus (MPXV) largely responsible for the global outbreak (Clade IIb, B.1 lineage) should no longer be classified as an HCID. In January 2023, the ACDP recommended that all Clade II MPXV should no longer be classified as an HCID. No cases of Clade I mpox have been reported in the UK. Between 2018 and 2021, 7 cases of mpox were identified in the UK which would no longer be classified as HCID mpox, but were treated as HCID cases at the time: 4 of the cases were imported from Nigeria, 2 cases were household contacts and one case was a healthcare worker involved in the care of an imported case.
Risk rating	Very low – no known importations of Clade I mpox into the UK.
Recent cases or outbreaks	Sequencing data is rarely available for mpox cases reported from endemic African countries where clade I MPXV is known to circulate. Of these countries, confirmed mpox cases have been reported from the Democratic Republic of the Congo (DRC), with 75 confirmed cases (0 deaths) reported in July 2023. So far during 2023, 555 confirmed cases, including 2 deaths, have been reported from the DRC.

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.
Risk rating	Exceptionally low/negligible – no travel-related infections in the literature.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in July 2023.

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 the 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.
Risk rating	Exceptionally low/negligible – no known current outbreaks globally.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in July 2023.

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 imported cases related to the 2002 outbreak.
Risk rating	Exceptionally low/negligible – 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.
Risk rating	Exceptionally low/negligible – one travel-related case was identified in Belgium in 2020.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in July 2023.

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.
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 July 2023.

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) • person to person via body fluids
UK experience 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	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.
Risk rating	Exceptionally low/negligible – not known to have occurred in travellers.
Recent cases or outbreaks	On 10 July 2023, media reported one fatal case of SFTS in an individual who came into contact with a stray cat on Jeju Island, South Korea. From the beginning of the year and as of 27 July 2023, there have been 59 cases of SFTS reported by the South Korea Disease Control and Prevention Agency, with most cases reported from South Gyeongsang (9 cases) and Gyeonggi (8 cases) provinces.

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.
Risk rating	Very low – rare cases in travellers have been reported.
Recent cases or outbreaks	No reports of hantavirus infection caused by Andes virus have been identified in July 2023. However, cases in which the type of hantavirus was not specified have been reported from the Andes virus risk area of Chile. 5 cases of hantavirus, including one death, were reported from the Ñuble region on 17 July 2023. The Ñuble region reported a total of 5 cases and 2 deaths throughout 2022.

Avian influenza A(H5N6) virus

Geographical risk areas	Mostly China. New strain reported 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 in the UK.
Risk rating	Very low – not known to have occurred in travellers (UKHSA risk assessment).
Recent cases or outbreaks	In China, one new case of avian influenza A(H5N6) was reported on 24 July 2023. The case involved a 64-year-old male living in Guilin, Guangxi Province, who raised domestic poultry prior to a symptom onset on 3 July 2023. The case was admitted for treatment the following day in a critical condition. From 2014 to 24 July 2023, 85 human cases of avian influenza A(H5N6) have been reported by Mainland China health authorities.

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 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 in the UK.
Risk rating	Very low – human cases are rare, and severe disease even rarer.
Recent cases or outbreaks	No confirmed or suspected human cases were reported in July 2023.

Authors of this report

Emerging Infections and Zoonoses Team, UKHSA