Research and analysis

Infectious disease surveillance and monitoring for animal and human health: summary September 2024

Updated 24 April 2025

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.

Epidemiological updates for diseases classified as a high consequence infectious disease (HCID) are published in UKHSA’s HCID monthly summary, unless they are considered a notable incident of public health significance, in which case a more detailed summary will be provided in this report.

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
Avian influenza A(H5N1) United States Update
Marburg virus disease Rwanda New

Avian influenza A(H5N1) – United States

Event summary

In United States, 14 confirmed human cases of avian influenza A(H5) were reported between April and 27 September 2024. Of these, 9 cases reported exposure to infected poultry, while 4 cases were exposed to infected dairy cattle and the source of exposure in the most recent case has not been determined.

 On 6 September 2024, the United States Centers for Disease Control and Prevention reported a human case of avian influenza A(H5) in the state of Missouri. This is the 14th human case of avian influenza A(H5) in the US during 2024, and the first human case of avian influenza A(H5) with no immediate known animal exposure. The case, an adult with existing comorbidities, presented with symptoms of chest pain, nausea, vomiting, diarrhoea, and weakness. The case was hospitalised as a result of underlying medical conditions, received treatment with influenza antivirals and recovered. A household contact of the case was also ill at the same time, but was not tested, and has since recovered. A second close contact (a health care worker) developed mild symptoms and tested negative for influenza.

As of 27 September 2024, 94 contacts of the case were reported, including 7 (1 household, 6 healthcare workers) that reported respiratory symptoms. No contacts tested positive for avian influenza A(H5N1).

Incident assessment

Globally, between 1 January 2003 and 27 September 2024, 904 human infections with avian influenza A(H5N1), including 464 deaths (case fatality rate (CFR) of 51.3%), have been reported.

The World Health Organization (WHO) assesses the current public health risk of human cases of avian influenza A(H5) as low. Human infections with avian influenza A(H5) are rare and mostly associated with exposure to infected poultry or contaminated environments. No evidence of sustained human-to-human transmission has previously been reported.

In the UK, as of 30 September 2024, 5 human infections with avian influenza A(H5N1) have been reported. The risk of avian influenza A(H5) infection to UK residents is considered very low, although may be higher for those with exposure to potentially infected poultry and/or their contaminated environments.

Marburg virus disease - Rwanda

Event summary

On 27 September 2024, the Rwanda Ministry of Health officially declared an outbreak of Marburg virus disease (MARD). According to the WHO, blood samples were taken from suspected cases and tested positive for Marburg virus by real-time reverse transcription polymerase chain reaction (RT-PCR). As of 29 September 2024, 26 confirmed cases and 8 deaths (CFR of 31%) have been reported from 7 districts. More than 70% of confirmed cases are healthcare workers from 2 health facilities in Kigali. As of 29 September 2024, 300 contacts are being followed up with further contact tracing ongoing, and the source of the outbreak remains under investigation.

One contact reportedly travelled to Belgium and appropriate response measures were undertaken by Belgian public health authorities. The contact did not become symptomatic, completed the 21-day monitoring period and remained healthy.

Incident assessment

The is the first outbreak of MARD detected in Rwanda. A high proportion of cases are healthcare workers, highlighting a significant risk of nosocomial transmission. Cases have been reported across 7 districts, including in areas that border the Democratic Republic of the Congo (DRC), Tanzania and Uganda, highlighting a risk of potential spread to bordering countries. Cases have also been reported in Kigali, which is well connected with an international airport and road networks to other cities in East Africa. The Government of Rwanda, the WHO and other partners have implemented response measures, including a public hotline for symptom reporting, ongoing epidemiological investigation, contact tracing, case isolation, risk communication and community sensitisation.

On 30 September 2024, the WHO assessed the risk of this outbreak as very high at the national level, and low at the global level.

As of 30 September 2024, no cases of MARD have been recorded in the UK. Whilst international travel routes exist between the UK and Rwanda, imported viral haemorrhagic fever cases in travellers returning from endemic areas are rare. There is a range of robust clinical, infection prevention and control measures if a case of MARD were to be imported into the UK, which can be adapted for use as necessary.

Summary of other incidents

Disease or infection Location
Anthrax Kazakhstan
Avian influenza A(H9N2) Ghana and China
Chikungunya Multi-country
Cholera Multi-country
Dengue Multi-country
Influenza A(H1N1)v Vietnam
Oropouche fever Multi-country
Rabies United States
West Nile virus (WNV) Europe

Anthrax

On 3 September 2024, media reported 4 suspected human cases of anthrax in Uyghur Region, Kazakhstan. The cases were reportedly involved in the slaughter of sick animals. Samples of meat products from the slaughter were collected from the homes of the cases, and soil samples were collected from the slaughter site for laboratory analysis. On 5 September 2024, media reported that the anthrax was confirmed in the samples.

Avian influenza A(H9N2)

On 20 September 2024, the WHO reported the first confirmed human case of avian influenza A(H9N2) in Ghana. The case, a child under 5 years of age from Upper East region, became symptomatic on 5 May 2024 with a cough, fever and sore throat. On 7 May 2024, the case received medical care at a local hospital, where an initial diagnosis of an influenza-like illness was made. Initially, a sample from the case tested PCR positive for avian influenza A(H3N2), although this was subsequently confirmed on whole genome sequencing as avian influenza A(H9N2) by the WHO. The case had no known exposure to poultry or any sick person with similar symptoms prior to onset of symptoms. No further human cases of avian influenza A(H9N2) associated with this case were identified in the community. Respiratory samples collected from close contacts tested negative.

In China, on 17 September 2024, the Centre for Health Protection reported a confirmed human case of avian influenza A(H9N2) in a 3-year-old female from Guangdong Province, with a symptom onset date of 12 August 2024. The report provides no further information regarding exposures, follow-up, or contacts.

Chikungunya

In Brazil, between 1 January and 27 September 2024, 258,202 cases of chikungunya and 177 associated deaths were registered. The number of chikungunya cases detected in Brazil in 2024 has been significantly higher than in 2023. Between 1 January and 31 December 2023, 158,060 cases and 122 associated deaths were reported. The number of cases peaked in epidemiological week 9 of 2024 (ending 2 March 2024) and steadily declined afterwards.

 In Réunion, the first autochthonous case of chikungunya was reported on 23 August 2024. This was the first chikungunya case registered since 2014. As of 20 September 2024, 6 autochthonous cases have been reported in Saint-Gilles-Les-Bains. In response, the Regional Health Agency for La Réunion implemented public health measures and vector control strategies including elimination of mosquito breeding sites, active case search, community sensitisation and distribution of repellents to priority areas.

Cholera

Globally, 439,724 cholera cases and 3,432 deaths were recorded between 1 January and 29 September 2024 across 5 WHO regions. The number of cholera related deaths reported in 2024 represents a 126% increase compared to 2023. However, the number of reported cases is 16% lower than in 2023. According to the WHO, the increase in mortality may be attributed in part to factors such as conflict in certain locations experiencing cholera outbreaks, which has led to compromised access to healthcare, extensive flooding that has damaged critical infrastructure, and insufficient medical facilities in some areas.

In September 2024, 47,234 cases and 583 cholera related deaths were reported from 14 countries. The Eastern Mediterranean Region reported the highest number of cases, with 41,424 cases across 5 countries. This was followed by the African Region (5,710 cases in 7 countries) and the South-East Asia Region (100 cases in 2 countries).

 In Yemen, the International Rescue Committee reported that 163,000 suspected cholera cases and 519 deaths have been recorded between March 2024 and 23 September 2024. The current cholera outbreak has been exacerbated by flooding and humanitarian crisis.

Dengue

In the Central African Republic, on 10 September 2024 the Ministry of Health declared an outbreak of dengue. According to the WHO, from 13 July to 7 September 2024, 13 confirmed cases were reported. Three districts in the capital city, Bangui, have been affected and 2 serotypes (DENV-1 and DENV-2) have been detected.

In France, between 1 January and 25 September 2024, 68 locally acquired dengue cases across 10 departments were reported. The cases were registered in Var (36 cases), Vaucluse (18 cases), Pyrénées-Orientales (4 cases), Alpes-Maritimes (3 cases), Drôme (2 cases), and Hérault (2 cases).

On 9 September 2024, media reported an autochthonous outbreak of dengue in the Tarragona area, Catalonia, Spain. A total of 5 cases were reported and include 2 symptomatic cases who were hospitalised and discharged, one symptomatic case not requiring hospitalisation, and 2 asymptomatic cases. Autochthonous dengue cases have been reported in Catalonia in previous years (for example, 2018, 2019 and 2023).

Between 1 January and 24 September 2024, Italy’s Higher Institute of Health reported 500 cases of dengue (436 travel associated, 64 locally acquired cases) and no deaths.

In the Philippines, media reported that 208,965 cases of dengue and 546 deaths were registered between 1 January and 6 September 2024. According to the media article, the number of cases reported in 2024 is 68% higher when compared to the same period during 2023.

 In Trinidad and Tobago, media reported that 1,315 confirmed dengue cases and 16 deaths were recorded from 1 January to 9 September 2024. In 2023, 132 dengue cases were reported in Trinidad and Tobago.

Swine influenza A(H1N1)

On 4 September 2024, the WHO reported the first fatal human case of swine influenza A(H1N1)v virus in Vietnam. The case was a 70-year-old female resident of Son La province, who had underlying medical conditions. The case presented with symptoms of fever, fatigue, and loss of appetite following return from a month-long stay in Hung Yen province. The case was hospitalised on 1 June 2024 and was initially diagnosed with pneumonia, before being transferred to another hospital for treatment until her death on 11 June 2024. Test results on samples taken on 5 June 2024 confirmed influenza A virus using a RT-PCR test with an undetermined subtype. On 1 August 2024, genomic sequencing results confirmed swine influenza A (H1N1)v. The source of the case’s infection remains unknown. No respiratory illnesses were reported in the contacts of the case and there were no outbreaks among livestock in the area around the case’s residence.

Oropouche fever

In Brazil, between 1 January and 22 September 2024, 7,992 cases of Oropouche fever were recorded. In comparison, 831 confirmed cases were reported in 2023. According to the Pan American Health Organization, Brazil has recorded 11 foetal deaths, 3 spontaneous miscarriages, and 4 cases of congenital anomalies, thought to be related to Oropouche virus (OROV) infection.

Rabies

In Canada, on 6 September 2024, Brant County Health Unit (BCHU) confirmed a human case of rabies in a resident of Brantford-Brant. This is the first ever detection of human rabies in Brantford-Brant, and the first detection in Ontario since 1967. According to BCHU, the case is suspected to have been exposed to a bat in the Gowganda area of the Timiskaming region. Close contacts were assessed and offered rabies post-exposure prophylaxis.

West Nile virus (WNV)

In Europe, between 1 January and 25 September 2024, 907 human WNV cases were reported from 18 countries. The cases were recorded in Albania, Austria, Bulgaria, Croatia, Czechia, France, Germany, Greece, Hungary, Italy, Kosovo, North Macedonia, Romania, Serbia, Spain, Slovakia, Slovenia, and Turkey. Italy and Greece reported the majority of cases, with 233 and 189 cases respectively.

Publications of interest

Mpox

In this study, the authors provided a detailed review of a case of clade Ib monkeypox virus (MPXV) in Kinshasa, DRC. The case, an adult female, presented on 1 July 2024 with mpox like lesions. The case reported no zoonotic exposure, however, did report occasional sexual contact with a friend in Kinshasa before lesions appeared. The friend developed a rash while in South Africa, 3 days after the case became symptomatic. Sequences from the case clustered with MPXV clade Ib sequences from mpox cases in South Kivu province. The detection of the case in Kinshasa, a city with multiple air transport routes, poses a risk of further spread to neighbouring countries.  

In another study, authors evaluated the effectiveness of 5 commercially available MPXV-specific lateral flow devices (LFDs) in assessing both mpox infection and vaccine-derived immunity and diagnosis for use in field settings. The authors state that although all the LFDs had high specificity, all the tests had less than 56% specificity. The authors conclude that considerations should be made, and validations should be carried out to confirm the reliability and accuracy of these LFD tests.

In this study, the researchers used publicly available data from outbreak investigations of MPXV clade I in the DRC to estimate key epidemiological parameters such as incubation period and generation time, which are important for modelling and monitoring disease transmission.

Oropouche virus (OROV)

In this study, authors aimed to assess the epidemiology of OROV infections and compare occurrence to other arboviruses including dengue, chikungunya, and Zika virus disease. The authors carried out a systematic review and meta-analysis of available studies on OROV infections, calculating pooled detection rates for anti-OROV antibodies and virus detection. They concluded that OROV prevalence is likely underestimated in South America, highlighting its potential as a global threat and emphasising the importance of a One Health approach for prevention.

Zoonotic spillover

Farmed fur animals may harbour emerging zoonotic pathogens. Authors in this study investigated the viral diversity within these animals, focusing on their zoonotic spillover potential. A total of 125 virus species were characterized from 461 individual fur animals. Among these, 36 viruses were novel, and 39 were identified as potentially high-risk for cross-species transmission. Results of the study highlighted the presence of coronaviruses, influenza A subtypes, Japanese encephalitis virus and Mammalian orthoreovirus in the farmed fur animals. The authors suggest that fur farms could be significant hubs for viral transmission between animals and humans.

Novel pathogens and diseases

Wetland virus

This study reports on a newly discovered tick borne Orthonairovirus, Wetland virus (WELV), detected in Northern China which caused febrile illness in several human cases. Following detection, active hospital-based surveillance was conducted to determine the prevalence of WELV in febrile cases who had tick bites. WELV is a member of the orthonairovirus genus which includes Crimean–Congo hemorrhagic fever virus, Dugbe virus, Nairobi sheep disease virus, Songling virus, Yezo virus and Tacheng tick virus, which cause mild to severe haemorrhagic illnesses in humans.

Further reading

Serological evidence of zoonotic filovirus exposure among bushmeat hunters in Guinea

Epidemiology and global spread of emerging tick-borne Alongshan virus

Novel Epidemiologic Features of High Pathogenicity Avian Influenza Virus A(H5N1) 2.3.3.4b Panzootic: A Review

WHO global framework to define and guide studies into the origins of emerging and re-emerging pathogens with epidemic and pandemic potential

Clinical Management of Hospitalized Patients With High-Consequence Infectious Diseases in England

Epidemiological description of Marburg virus disease outbreak in Kagera region, Northwestern Tanzania

A coordinated research roadmap - Mpox virus: Immediate research next steps to contribute to control the outbreak

Presumed Transmission of 2 Distinct Monkeypox Virus Variants from Central African Republic to Democratic Republic of the Congo

The resurgence of monkeypox: Epidemiology, clinical features, and public health implications in the post-smallpox eradication era

Fatal Oropouche Virus Infections in Nonendemic Region, Brazil, 2024

Oropouche Fever, Cuba, May 2024

Manual for plague surveillance, diagnosis, prevention and control

Preclinical Development of a Novel Zika Virus-like Particle Vaccine in Combination with Tetravalent Dengue Virus-like Particle Vaccines

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