Research and analysis

Infectious disease surveillance and monitoring for animal and human health: summary July to September 2023

Updated 25 April 2024

Interpreting this report

The UK Health Security Agency’s (UKHSA) Emerging Infections and Zoonoses (EIZ) team uses an integrated horizon scanning approach, which combines information on both human and animal health, to identify and assess outbreaks and incidents of new and emerging infectious diseases globally. For further information about the EIZ team’s horizon scanning process, please see our Epidemic intelligence activities.

This summary provides an overview of incidents (new and updated) of public health significance, which are under close monitoring. The incidents are divided into 2 sections: Notable incidents of public health significance and Other incidents of interest. For each notable incident of public health significance, an incident assessment is provided, based on the EIZ team’s interpretation of the available information.

The report also includes a section that focuses on Novel pathogens and diseases and a final Publications of interest section, which contains new publications relevant to emerging infections.

For more information, or to sign up to the distribution list to receive an email alert when new reports are published, please contact epiintel@ukhsa.gov.uk

Notable incidents of public health significance

Summary of incidents

Disease or infection	Location	New or update since the last report
Dengue	Bangladesh	Update
Nipah virus infection	India	New

Dengue – Bangladesh

Event summary

An increase in dengue cases and associated deaths have been reported across Bangladesh in 2023. Between 1 January and 30 September 2023, the government of Bangladesh reported 203,406 dengue cases, including 989 associated deaths (case fatality rate (CFR) of 0.5%), with 83,222 cases (41%), including 639 deaths (65%) reported from Dhaka City (CFR of 0.8%) (Figure 1). This represents the highest number of dengue cases reported in Bangladesh during comparable reporting periods, since 2000 (Figure 2). In 2023, although female cases made up 39% of total cases (79,763 cases) up to 30 September 2023, they accounted for 56% of total associated deaths (557 deaths).

Figure 1. Dengue case numbers and deaths by reporting month in Bangladesh in 2023, as of 30 September 2023

Government of the People’s Republic of Bangladesh Management Information System. Accessed: 18 October 2023.

Figure 2. Cumulative number of dengue cases and deaths reported in Bangladesh, 2018 to 2023 (as of 30 September 2023)

Government of the People’s Republic of Bangladesh Management Information System. Accessed: 18 October 2023.

*Data available for 2020 is limited due to the COVID-19 pandemic

Several other countries across Asia have reported an increase in dengue cases in 2023, including:

• Taiwan, with 17,292 dengue cases and 42 deaths between January and 30 October 2023
• Malaysia, with 89,474 cases and 65 deaths between January and 30 September 2023
• Thailand, with 102,202 cases and 98 deaths between January and 27 September 2023

Incident assessment

On 11 August 2023, the World Health Organization (WHO) assessed the risk of dengue in Bangladesh at the national level as ‘high’. This was due to the increasing number of cases and deaths with the peak not yet reached, the high CFR compared to previous years, and the increasing geographical distribution of cases. In addition, dengue virus serotype-2 (DENV-2) has been identified as the main circulating serotype, following 4 years of DENV-3 as the leading serotype. A dengue vaccine has not been approved in Bangladesh.

Bangladesh receives a large volume of international tourists, and the possibility of travellers acquiring the disease and contributing to its further spread outside the country cannot be ruled out.

While severe disease in a case is possible, transmission risk within the wider UK population is negligible given the lack of established vector populations necessary for transmission. Given the small number of travel-associated infections imported into the UK annually, current processes for the diagnosis of cases, previous experience in treatment and the use of appropriate therapeutics, the risk to the UK remains very low.

Nipah virus infection – India

Event summary

Between 12 and 15 September 2023, 6 laboratory-confirmed cases of Nipah virus infection, including 2 deaths, were reported by the Government of Kerala. All confirmed cases were reported from Kozhikode District, in males aged between 9 and 45 years. All cases were epidemiologically linked to the index case, which included both family members and hospital contacts.

A multisectoral coordination and response was activated by national and state authorities to contain the spread of the outbreak. As of 27 September 2023, a total of 1,288 contacts were identified. The source of the initial infection remains under investigation. Genomic analysis carried out by the National Institute of Virology in Pune identified the virus as the Indian Genotype or I-Genotype, which is similar to the Nipah virus strain found in Bangladesh.

Incident assessment

WHO states that this outbreak was not entirely unexpected; this is the sixth Nipah virus outbreak to be reported in India, and the third outbreak to be reported in Kozhikode District. The Kerala Government rapidly established response measures to contain the spread of the outbreak, and public health teams and healthcare workers in the affected district have previous experience in managing similar outbreaks.

To date, there have been no reported cases of Nipah virus in the UK. While severe disease in a case is possible, transmission within the wider UK population is highly unlikely as there are established processes for the isolation and contact management of high consequence infectious diseases (HCID) cases. There are a range of robust public health, clinical, infection prevention and control measures available for HCID, which can be adapted for use as necessary.

Other incidents of interest

Summary of other incidents

Disease/infection	Location
Anthrax	multi-country
Avian influenza	China UK
Plague (bubonic)	Mongolia China
Crimean-Congo haemorrhagic fever	multi-country
Cholera	multi-country
COVID-19	multi-country
Dengue	Europe
Hantavirus	multi-country
Lassa fever	Nigeria Liberia Benin
Malaria	USA
Measles	multi-country
MERS-CoV	Saudi Arabia
Mpox	global summary
Polio	multi-country
Swine influenza	USA Netherlands
West Nile virus	Europe USA
Yellow fever	multi-country
Zika virus	multi-country

Anthrax

Between July and September 2023, sporadic cases of anthrax have been reported from multiple countries. In July 2023, media reported 93 confirmed cases of anthrax in the Gunungkidul Regency of Indonesia. The outbreak began in early July 2023, when the fatal index case slaughtered cows, suspected to be infected with anthrax and distributed the meat to residents of their village.

Russia experienced multiple regional outbreaks of anthrax. On 11 September 2023, media reported 9 laboratory-confirmed cases of anthrax in the Voronezh Region. Eight confirmed cases were reported from the Bogucharsky District, linked to a dairy farm, and one case from Kantemirovsky District in a farm worker who slaughtered an infected animal. On 6 July 2023, media reported 5 cases of anthrax in Tuva, in individuals who had slaughtered and consumed meat from an infected horse.

Sporadic cases of anthrax have also been reported in Kazakhstan (11 confirmed cases), Kyrgyzstan (6 cases) and Romania (2 cases).

Avian influenza A(H5N6)

China reported 3 avian influenza A(H5N6) cases between July and September 2023.

On 24 July 2023, Hong Kong’s Centre for Health Protection of the Department of Health reported a human case of avian influenza A(H5N6) from mainland China. The case is a 64-year-old male living in Guilin City, Guangxi Province, who had exposure to domestic poultry. The case had a symptom onset on 3 July 2023 and was hospitalised on 4 July 2023 in a serious condition.

On 23 August 2023, a case of avian influenza A(H5N6) involving a 27-year-old female was reported from Dazhou City, Sichuan Province. The case developed symptoms on 20 July 2023 and was admitted to hospital on 22 July 2023. The source of infection and the clinical outcome of the case is not known.

On 27 September 2023, a fatal human case of avian influenza A(H5N6) in Chongqing Municipality, Sichuan Province, was also reported. The case was a 68-year-old male who had exposure to live domestic poultry. He developed symptoms on 5 August 2023, was hospitalised on 10 August 2023 where he died on 20 August 2023.

Avian influenza A(H5N1)

On 14 July 2023, UKHSA reported that there have been 2 new asymptomatic human detections of avian influenza A(H5N1) identified through the surveillance programme of individuals with direct exposure to infected birds. Since the programme was launched in March 2023, and as of 10 July 2023, there have been 4 human avian influenza A(H5N1) detections (all asymptomatic), out of 144 individuals tested in the UK.

Avian influenza A(H9N2)

On 21 July 2023, the Chinese Centre for Disease Control and Prevention reported a case of human infection with avian influenza A(H9N2) in Guangxi Province. The case had onset of illness on 22 June 2023, was hospitalised with pneumonia on 25 June 2023 and has since recovered. The case had exposure to backyard poultry although environmental samples tested negative for influenza A(H9) viruses.

China reported one new human case of avian influenza A(H9N2), in Sichuan Province, on 7 August 2023, in a 4-year-old girl who had a symptom onset of 7 August 2023. The case had mild symptoms, was not hospitalised and has since recovered. The case had exposure at a live poultry market.

Bubonic plague

Between July and September 2023, 5 cases of bubonic plague were reported. On 8 August 2023, media reported a case of bubonic plague from Mongolia’s capital, Ulaanbaatar, following the consumption of infected marmot meat. Five contacts were isolated for follow-up. On 30 August 2023, media reported a fatal case of bubonic plague in the Govi-Altai region of Mongolia; no further details were provided. 

On 15 August 2023, a familial cluster of 3 cases of bubonic plague was reported in Xilin Gol Meng, Inner Mongolia Autonomous region, China. The first case was confirmed on 7 August 2023 with the remaining 2 cases confirmed on 12 August 2023.

Crimean-Congo haemorrhagic fever (CCHF)

CCHF is endemic in Africa, the Balkans, the Middle East and western and south-central Asia. The WHO Eastern Mediterranean Region remains the most affected region, reporting the highest number of cases.

Between 1 January and 30 September 2023, 1,115 CCHF cases, including 105 deaths, have been reported across Afghanistan. The CCHF-associated deaths were reported from 15 provinces, more than half of which were from Kabul (48, 45.7%) and Balkh (15, 14.3%) provinces. The number of newly reported cases has been decreasing since 2 September 2023.

On 31 July 2023, media reported 505 cases of CCHF, including 64 deaths, across Iraq. In response to rising number of reported cases, the Iraqi Ministry of Agriculture announced the launch of a national awareness campaign to eliminate tick vectors from agricultural buildings and livestock, with the aim of controlling the disease across all governates.

On 22 August 2023, media reported there had been 28 CCHF cases reported in Quetta Province, Pakistan. 

As of 29 July 2023, media reported there had been 25 cases of CCHF, including one death, reported in the North Caucasus Russia in 2023.

Also in July 2023, North Macedonia reported its first confirmed CCHF case in more than 50 years. Two cases were reported including one death. The first case was admitted to a health clinic in Skopje, on 25 July 2023, where they presented with symptoms typical of haemorrhagic fever.

On 4 July 2023, media had reported 19 cases of CCHF, including one death, in Iran since the start of 2023. CCHF is endemic in Kazakhstan and media reported 9 confirmed cases of CCHF in the region of Turkestan on 10 July 2023.

As of 30 September 2023, 8 cases of CCHF including 3 deaths had been reported from 5 regions in Senegal. Cases were reported from:

• Dakar (3 cases, 2 deaths)
• Fatick (2 cases, one death)
• Louga (one case)
• Tambacounda (one case)
• Kédougou (one case)

CCHF is endemic in Senegal, with confirmed cases detected annually in recent years.

Cholera

Since the beginning of 2023, 28 countries have reported cholera cases, globally. The overall capacity to respond to multiple and simultaneous outbreaks remains strained due to a global lack of resources, including shortages of the oral cholera vaccine and cholera supplies, as well as overstretched public health and medical personnel. WHO continues to assess the risk of cholera at the global level as very high.

The WHO African Region remains the most affected region. Within this region, 17 countries have reported cholera cases since the beginning of 2023. As of 30 September 2023, 191,885 cases (85,541 confirmed cases; 106,609 suspected) and 2,990 deaths (CFR of 1.6%) had been reported. The most affected countries include:

• Malawi (42,920 cases; 1,260 deaths)
• Mozambique (34,667 cases; 144 deaths)
• Democratic Republic of the Congo (DRC) (36,084 cases; 303 deaths)
• Ethiopia (23,652 cases; 299 deaths)
• Cameroon (20,672 cases; 487 deaths)
• Somalia (13,243 cases; 33 deaths)
• Nigeria (2,860 cases; 84 deaths)

The outbreaks in many southeast African countries, including Kenya (8,801 cases; 145)  Zimbabwe (4,226 cases; 118 deaths), South Africa (1,471 cases; 2 deaths) and Burundi (1,038 cases; 9 deaths), appear to have stabilised since the beginning of September 2023.

Sudan is the latest country to report a cholera outbreak in the African region. On 26 September 2023, the Sudan Ministry of Health reported the first suspected cases from Khater village, Gedaref state. This outbreak is occurring amid an ongoing humanitarian crisis, with over 80% of the health facilities in the country out of service. The most recent cholera outbreak reported in Sudan occurred in 2019, where 346 cases and 11 deaths were reported from Blue Nile, Sennar and Khartoum states.

Other notable outbreaks have been reported from the WHO Eastern Mediterranean region, including Afghanistan (144,543 cases; 73 deaths), Syria (103,123 cases; 3 deaths) and Somalia (12,681 cases; 30 deaths). Several factors have likely contributed to the resurgence of cholera in the region, including climate change, conflict and political instability, weak health systems, increased population movement, poor water and sanitation infrastructure and low awareness among the public.

COVID-19

By the end of September 2023, over 770 million confirmed COVID-19 cases and over 6 million deaths had been reported globally. Over 13.5 billion vaccine doses had been administered globally, as of 27 September 2023. According to WHO, reported cases are not an accurate representation of infection rates due to the reductions in testing and reporting globally. Among countries reporting, the number of reported cases and deaths have declined, with over 685,000 new cases and over 1,900 new deaths reported during the 28-day period of 28 August to 24 September 2023; a decrease of 55% and 34%, respectively, compared to the previous 28 days (31 July to 27 August 2023).

On 17 August 2023, the WHO SARS-CoV-2 virus evolution advisory group added BA.2.86 as a variant under monitoring due to it having a large number of spike mutations present. As of 18 September 2023, 48 BA.2.86 sequenced cases had been reported in England, 6 cases had been reported from Scotland and none from Wales or Northern Ireland.

As of 28 September 2023, 262 detections of BA.2.86 from 12 countries in the European Union (EU) and European Economic Area (EEA), as well as 11 countries outside the EU and EEA had been reported. A Lancet study indicated that BA.2.86 has a significantly lower infectivity rate than the B.1.1 and EG.5.1 variants.

Dengue

Dengue is not endemic in mainland EU and EEA, with most cases being reported in travellers to countries where dengue is known to circulate. In areas of the EU and EEA where the competent vectors are established, and when environmental conditions are favourable, viraemic travel-related cases may generate a local transmission of the virus. Between July and September 2023, locally acquired cases of dengue have been reported in Italy (49 cases), France (31 cases, including 2 probable cases), and Spain (1 case). Further details on the locally acquired cases in Italy can be found in a recent publication.

Hantavirus

On 24 August 2023, media had reported 691 human cases of hantavirus in Bashkiria, Russia, since the start of 2023.

On 26 August 2023, media had reported 36 cases of hantavirus including 2 deaths in Panama so far in 2023. The province of Los Santos reported the highest number of cases (26 cases), while 6 and 4 cases were reported from Herrera and Coclé, respectively.

Between July and September 2023, sporadic human cases of hantavirus were reported in the USA, including New Mexico (one case), Nevada (one case) and Washington (one case).

On 11 September 2023, media reported there had been 14 cases of hantavirus recorded in Bolivia: Tarija (3 cases), Santa Cruz (4 cases), La Paz (4 cases) and Cochabamba (3 cases).

In Chile, 36 hantavirus cases, including 6 deaths, had been reported so far this year, as of 16 August 2023. A higher number of cases were reported in Chile during the first 9 months of 2023 than in the whole of 2022 (32 cases and 7 deaths).

Since the start of the year and as of 26 September 2023, the media have reported a total of 10 confirmed cases of hantavirus including 3 deaths in Argentina. Seven cases were reported from the department of Orán (3 from the city of San Ramón de Orán, one from Pichanal and one from Colonia de Santa Rosa), another case from Buenos Aires with a history of travel to Bolivia and 2 cases from General San Martín (one from Embarcación and one in Tartagal).

For all cases listed above, the type of hantavirus was not specified.

Lassa fever

By the end of September 2023, Nigeria had reported 1,081 confirmed, 9 probable, and 7,554 suspected cases of Lassa fever. Among confirmed cases, 182 deaths have been reported (CFR of 16.8%). The number of confirmed cases up to the end of September 2023 remains higher (n=1,081) when compared to the same period in 2022 (n= 933). However, the CFR is lower (16.8% vs 19.1% in the same period in 2022).

As of 24 September 2023, Liberia has reported 94 confirmed cases of Lassa fever, including 27 deaths (CFR of 29%).

Lassa fever is endemic in Benin and on 6 September 2023, media reported 6 cases, including one death, in the Parakou municipality.

Malaria

After being declared malaria-free in 1970 by WHO, 8 cases of locally acquired Plasmodium vivax malaria were reported in the USA between 18 May and 17 August 2023. These were the first cases to be reported nationally since 2003. Seven cases were reported in Florida and one case in Texas. Case surveillance, mosquito surveillance and control activities, and public outreach and education activities were conducted in both states. The US Centers for Disease Control and Prevention (CDC) stated that the risk of locally acquired malaria in the USA remains very low.

Measles

Large outbreaks of measles continue to be reported globally, mostly across the African, Middle East and Asian regions. From July to September 2023, countries reporting the highest number of measles cases included the DRC (234,825 cases as of 3 September 2023), Yemen (25,935 cases as of 22 June 2023) and Chad (8,984 cases as of 6 August 2023). There are also ongoing outbreaks in Cameroon  Zambia, Kyrgyzstan and Central African Republic.

From 1 January to 31 July 2023, a total of 695 measles cases were reported by 17 countries to The European Surveillance System (TESSy), with the majority of cases being reported by:

• Austria (151 cases)
• Germany (28 cases)
• Belgium (26 cases)
• Poland (25 cases)
• France (20 cases)
• Italy (10 cases)

In Romania, 460 cases of measles had been reported as of August 2023. A recent study found the D8 measles variant in Romania for the first time, among the increasing measles cases in 2023.

Middle East respiratory syndrome (MERS-CoV)

On 29 August 2023, WHO reported that between 13 September 2022 and 12 August 2023, the Ministry of Health of the Kingdom of Saudi Arabia (KSA) had registered 3 confirmed cases of MERS-CoV, including 2 associated deaths. Of the 3 cases, 2 had a history of contact with dromedary camels and all 3 cases had a history of consumption of raw camel milk in the 14 days prior to the onset of symptoms.

Since the first report of MERS-CoV in KSA in 2012, human infections have been reported from 27 countries, in all 6 WHO regions. Of the reported 2,605 cases, most MERS-CoV cases (2,196; 84%) have been reported from KSA. Of the 937 deaths reported from 27 countries, 856 (91%) have been reported from KSA.

Mpox

As of 26 September 2023, 90,818 laboratory-confirmed and 663 probable cases of mpox, including 157 deaths, have been reported to WHO from 115 member states across all 6 WHO regions. Most cases reported in the 4 weeks leading to 26 September 2023 were notified from the Western Pacific Region (51.9%) and the South-East Asia Region (18.1%)

Detection of cases of mpox acquired within the UK were first confirmed in England in May 2022. The outbreak has mainly been in gay, bisexual, and other men who have sex with men without documented history of travel to endemic countries. In 2023, up to 31 August 2023, there had been a total of 50 cases of mpox reported in the UK. Of these, 48 were in England (22 cases were presumed to have acquired mpox in the UK), one imported case in Scotland and one case in Wales.

Polio

Wild polio virus type 1 (WPV1)

Between 1 January and 26 September 2023, 7 cases of WPV1 were reported to the Global Polio Eradication Initiative from Afghanistan (5 cases) and Pakistan (2 cases). This is a reduction from 27 cases reported in the equivalent 2022 period. WPV1 is endemic in Afghanistan and Pakistan.

Circulating vaccine derived polio virus (cVDPV)

As of 19 September 2023, 265 cases of cVDPV (types 1 and 2) had been reported globally since 1 January 2023. This is a decrease of 609 cVDPV1 and cVDPV2 cases reported during the same period in 2022.

Collectively, 76 cases of cVDPV type 1 were reported from the DRC (60 cases), Madagascar (13 cases) and Mozambique (3 cases).

In total, 189 cases of cVDPV type 2 were reported from:

• DRC (85 cases)
• Chad (33 cases)
• Nigeria (24 cases)
• Central African Republic (11 cases)
• Mali (6 cases)
• Guinea (5 cases)
• Kenya (5 cases)
• Benin (3 cases)
• Indonesia (3 cases)
• Somalia (3 cases)
• Burkina Faso (2 cases)
• Côte d’Ivoire (2 cases)
• Tanzania (2 cases)
• Yemen (2 cases)
• Israel (one case)
• Burundi (one case)
• Zambia (one case)

Swine influenza

There were 3 human cases of swine influenza reported in the USA between July and September 2023. The first case, reported on 26 July 2023, was reported as a presumptive positive swine influenza A(H3)v infection.

Diagnostic testing conducted by the CDC was inconclusive, likely due to the specimen tested not having a high enough viral load. However, investigations revealed the case was exposed to pigs within 10 days prior to onset of illness at an agricultural fair in Michigan, where swine influenza A was detected among pigs. On 31 July 2023, a human case of swine influenza A(H1N2)v occurred in a person who had attended different agricultural fairs in Michigan with exposure to pigs. Neither of these cases detected in Michigan were hospitalised.

On 22 September 2023, media reported a human case of swine influenza A(H1N2)v in Montana, USA. Prior to the onset of illness, the case visited an agricultural fair. The patient sought medical care on 5 August 2023, but was not hospitalised.

On 2 September 2023, WHO was notified of one confirmed human case of swine influenza A(H1N1)v virus, in North Brabant Province, Netherlands. This is the first human case of swine influenza A(H1N1)v reported in the Netherlands in 2023. The case had no underlying medical conditions and no history of occupational exposure to animals. The patient had onset of symptoms on 20 August 2023; no further cases were detected and WHO assessed the risk of detecting additional cases associated with this event as low.

West Nile virus (WNV)

Between July 2023 and 27 September 2023, EU and EEA countries reported 566 human cases of West Nile virus (WNV), of which the top 3 most affected countries were:

• Italy (280 cases; 17 deaths)
• Greece (143 cases; 19 deaths)
• Romania (63 cases; 9 deaths)

During the current 2023 WNV transmission season, human cases of WNV infection were reported for the first time ever from Gironde, Charente-Maritime, Alpes-Maritimes, Charente, Gard and Vaucluse in France; Sömmerda in Germany; Ioannina and Kastoria in Greece; Imperia, Taranto and Lecce in Italy; and Barcelona, Cáceres, Huelva and Valencia in Spain.

In EU-neighbouring countries, 83 human cases of WNV infection were reported: 82 in Serbia and one in North Macedonia. No deaths related to WNV infections were reported by EU-neighbouring countries. Although the intensity of WNV circulation is expected to decrease in October, the weather conditions in most of the affected areas are still favourable for vector-borne transmission. Therefore, more human cases are expected in the coming weeks.

As of 26 September 2023, 1,419 human cases of WNV had been reported this year across 44 states in the USA. Of the total cases, 923 were neuroinvasive WNV cases. Colorado and California states have reported the most cases of WNV so far in 2023.

Yellow fever

As of 2023, 34 countries in Africa and 13 countries in Central and South America are either endemic for, or have regions that are endemic for, yellow fever. Nigeria, Liberia and Guinea have reported the most cases between July and September 2023.

In Liberia, between the beginning of July 2023 and 30 September 2023, 25 new suspected cases of yellow fever were reported, bringing the cumulative total to 86 suspected cases of yellow fever.

As of 31 August 2023, 1,819 cases and 21 deaths were reported across 36 states in Nigeria. By the end of July 2023, most cases were reported from Bauchi and Katsina states. A decreasing trend in case numbers has been observed since 2 July 2023.

On 21 September 2023, the Guinea Ministry of Health reported 178 cases of yellow fever (45 confirmed cases; 4 deaths) from Dabola district, Faranah region. A previous yellow fever outbreak occurred in Guinea in December 2020: 48 suspected cases, including 14 deaths, reported from 3 regions: Boké, Kankan and Kindia.

Zika virus

As of 30 September 2023, 3,284 confirmed cases of Zika virus were reported throughout the region of the Americas:

• 3,202 from Brazil as of 26 August 2023
• 50 in Panama
• 22 in Mexico
• 7 from Bolivia
• 3 from Peru

On 24 September 2023, Cambodia’s Ministry of Health reported a single case of Zika virus in a 7-year old female from Baray District, Kampong Thom Province. This was the first case reported in Cambodia in 2023.

Novel pathogens and diseases

Coronavirus

A recent study investigated the diversity and abundance of viruses within bats sampled from Yunnan province, China. It also examined the potential for viral spillover into animals and humans. The authors identified 5 viral species that have potential to be pathogenic to humans or livestock. This included a novel recombinant SARS-like coronavirus closely related to both SARS-CoV and SARS-CoV-2. In vitro assays indicate that this virus can utilise the human ACE2 receptor, potentially increasing its risk of emergence.

Echarate virus

Phleboviruses are globally distributed and can be transmitted by phlebotomine sandflies, mosquitoes, or ticks. In a recent study, the authors report on the identification of a novel phlebovirus variant isolated from a patient with acute febrile illness in Peru. As clinical symptoms of infection caused by phleboviruses can also be characteristic of diseases such as dengue and malaria, this can result in misdiagnoses. Thus, continued acute febrile illness surveillance is necessary to detect novel and emerging pathogens.

Publications of interest

COVID-19

During the COVID-19 pandemic, WHO developed an evidence-based alert system, which assessed public health risk on a weekly basis. The system covered 237 countries, territories, and areas from May 2021 to June 2022 for the early identification of situations where healthcare capacity may become overstretched. Since June 2021, the system supported the release of more than $27 million from WHO emergency funds, over 450,000 rapid antigen diagnostic testing kits and over 6,000 oxygen concentrators. While the system was developed for COVID-19, a similar system could be used for future outbreaks and emergencies, with necessary adjustments to parameters and indicators.

Ebolavirus

There is currently no approved vaccine for Sudan ebolavirus. In a recent phase 1 clinical trial of a monovalent chimpanzee adenovirus vector vaccine against Sudan ebolavirus (cAd3-EBO S), antibodies were induced in 78% of participants by 2 weeks, increasing to 85% by 4 weeks (from a sample size of 40 individuals). Additionally, antibodies persisted to 48 weeks in 82% of participants. The vaccine candidate was found to be safe and tolerable suggesting its potential for emergency deployment in Sudan ebolavirus outbreaks.

Another study investigated the potential use of a dual-target vaccine, YF17D-vectored Ebola vaccine candidate (YF-EBO), which uses ebolavirus glycoproteins on a yellow fever virus (YF17D) backbone. The vaccine candidate was shown to be safe and immunogenic in mouse models, eliciting antibodies specific to both ebolavirus and yellow fever virus. This study shows the potential of YF-EBO to simultaneously contribute to the control of yellow fever and Ebola virus disease (EVD) outbreaks through routine immunisation programs, as both diseases often share endemicity, particularly in the African region.

In July 2023, the US Food and Drug Administration approved Ervebo, a vaccine for the prevention of EVD caused by Zaire ebolavirus, in individuals aged 12 months to 17 years. The European Commission also approved Ervebo for use in this cohort in September 2023. Ervebo has been approved for use in individuals 18 years of age and older since December 2019.

Taï Forest virus (TAFV) is a lesser-known ebolavirus that can cause lethal infection in chimpanzees, with one human case reported to date. A recent study developed a vesicular stomatitis virus (VSV)-based vaccine expressing the TAFV glycoprotein (VSV-TAFV) as the viral antigen. The vaccine was able to illicit the development of antigen-specific binding neutralising antibodies, and T cell responses in nonhuman primates against TAFV. The study provides evidence of VSV-TAFV eliciting protection against TAFV following a singular dose, highlighting its potential for further development.

Lyme borreliosis

A recent phase 1, randomised, clinical trial for a novel 3 dose multivalent OspA-based Lyme borreliosis vaccine (VLA15), found the vaccine to be safe and well tolerated, eliciting an immunogenic response in healthy adult participants. This first in-human trial showcased evidence that VLA15 was immunogenic against OspA serotypes 1 - 6, most prevalent in Northern America and Europe, with some species also found in Asia, signifying its potential for use globally. These findings support the further development of VLA15 to prevent Lyme borreliosis, the most common tick-borne disease in North America and Europe.

Borrelia bavariensis is one of several genospecies of the B. burgdorferi sensu lato complex associated with Lyme disease and is widely distributed across Europe and Asia. A recent study confirmed the presence of B. bavariensis infected Ixodes ricinus ticks in the UK at sites near King’s Lynn and Carlisle, suggesting a broad but low distribution of B. bavariensis in the UK. The authors emphasise that the detection of B. bavariensis in the UK is not unexpected given its distribution in temperate regions of the northern hemisphere and its adaptation to woodland rodents and hedgehogs found in the UK. No human B. bavariensis infection has been reported in the UK.

Malaria

A recent randomised controlled phase 3 trial in Mali and Burkina Faso found that seasonal vaccination with the RTS,S/AS01E vaccine combined with seasonal malaria chemoprevention (SMC), in children aged 5 years and under is a more effective intervention when given over a 5 year period in comparison to the RTS,S/AS01E vaccine or SMC alone. Study results found a 66.8% decrease in hospital admissions for severe malaria, a 65.9% decrease for malarial anaemia, and 68.1% decrease for blood transfusions. Importantly, the study also found a 66.8% decrease in deaths caused by malaria in this age group when compared to the SMC treatment alone, supporting the use of this regime to reduce the burden of malaria in endemic regions.

Mpox

The DRC has the highest burden for mpox cases, globally. A study in the DRC evaluated the use of a Luminex-based serological assay, alongside traditional polymerase chain reaction (PCR) investigations, and found that additional mpox cases were identified when compared to using PCR alone. As a result, additional mpox infections were detected across 14 further health zones in the DRC, with 23 additional outbreaks between 2013 and 2022 identified, increasing the sample positivity rate from 33.9% (PCR alone) to 48.2% (PCR and serology (223 out of 463 samples). This study highlights the need to develop rapid point-of-care tests that can be used in remote areas to rapidly diagnose mpox cases.

Usutu virus

In 2020, Usutu virus (USUV) was detected in wild birds in Greater London for the first time. Additional cases have been detected in Greater London in subsequent years, as confirmed by whole genome sequencing, suggesting that the virus is overwintering in the UK. In July 2023, quantitative PCR and genome sequencing detected USUV in 2 dead birds; one was found in Greater London and the second in rural Cambridgeshire. This is the first confirmed detection of the virus in the UK outside the Greater London area. The risk to public health from USUV is considered low in the UK.

Further reading

Bhanja Bandavirus

Detection of Bhanja Bandavirus in Patients with Neuroinvasive Disease of Unknown Etiology in Croatia.

Crimean-Congo haemorrhagic fever

Detection of the Crimean–Congo Hemorrhagic Fever Virus Genome in Questing Ixodes spp. and Haemaphysalis spp. in the Periurban Forestry Areas of Istanbul: Has a New Biorisk Emerged?

Ebola virus

Atypical Ebola virus disease in a rhesus macaque.

Nipah virus

Tackling a global epidemic threat: Nipah surveillance in Bangladesh, 2006–2021.

Severe fever with thrombocytopenia syndrome

Emerging Tick-Borne Dabie bandavirus: Virology, Epidemiology, and Prevention.

Simian malaria

Simian malaria: a narrative review on emergence, epidemiology and threat to global malaria elimination.

Related resources

1. High consequence infectious diseases monthly summaries

2. National flu and COVID-19 surveillance reports

3. Avian influenza (influenza A H5N1): technical briefings

4. Avian influenza (bird flu) in Europe, Russia and the UK reports

5. Bird flu (avian influenza): latest situation in England updates

6. Human Animal Infections and Risk Surveillance (HAIRS) group risk assessments and statements

7. Animal and Plant Health Agency (APHA) monitoring of disease in livestock and poultry monthly reports

Authors of this report

UKHSA’s Emerging Infections and Zoonoses team epiintel@ukhsa.gov.uk