Infectious disease surveillance and monitoring for animal and human health: summary October 2024
Updated 24 April 2025
© Crown copyright 2025
This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.
Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.
This publication is available at https://www.gov.uk/government/publications/emerging-infections-monthly-summaries/infectious-disease-surveillance-and-monitoring-for-animal-and-human-health-summary-october-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.
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 |
| Clade I mpox) | African Region | Update |
| Marburg virus disease | Rwanda | Update |
Avian influenza A(H5N1) – United States
Event summary
On 29 October 2024, the United States Centres for Disease Control and Prevention (US CDC) reported that 36 confirmed human cases of avian influenza A(H5) have been detected in the United States since the start of the year. 15 cases were associated with exposure to infected poultry, 20 cases were associated with exposure to infected dairy cattle, and 1 case had no determined exposure source.
The first presumed human infections in California and Washington states were reported on 3 October 2024 and 20 October 2024, respectively. The first 2 cases in California experienced mild symptoms including conjunctivitis, and tested positive for avian influenza A(H5). The cases were not linked to each other, but both had occupational exposure to infected dairy cattle in the Central Valley (California first reported cases of avian influenza A(H5N1) in dairy cattle in August 2024). Samples from the first two cases were sequenced as avian influenza A(H5N1) clade 2.3.4.4b viruses, genotype B3.13, closely related to viruses isolated from infected dairy cattle. Since the initial report, and as of 29 October 2024, 16 confirmed avian influenza A(H5N1) cases in humans in California (all who had been exposed to infected cattle) have been reported. In Washington, the first human cases of avian influenza A(H5) were confirmed in 2 poultry cull workers on an affected Franklin County farm. Samples from the human cases tested positive for avian influenza A(H5N1) clade 2.3.4.4b viruses, genotype D1.1 (this genotype has not been circulating in dairy cattle, but has been circulating in poultry and wild birds). Since the initial report, and as of 29 October 2024, 6 cases of avian influenza A(H5) have been reported in Washington state. The cases experienced mild conjunctivitis and some also reported mild upper respiratory symptoms.
Incident assessment
The Department for Environment, Food and Rural Affairs and the Animal and Plant Health Agency assess the risk of avian influenza A(H5N1) in livestock in Great Britain (GB) as very low. As avian influenza A(H5N1) clade 2.3.4.4b genotype B3.13 has not been detected in GB, the zoonotic transmission risk to people in contact with infected animals in the UK is also considered very low. Currently, there are no indicators of increasing risk to human health. The Food Standards Agency assess the risk of avian influenza A(H5N1) clade 2.3.4.4b genotype B3.13 exposure to UK consumers, through imported US dairy products, to be very low.
Since 2021, and up to the end of October 2024, 5 human detections of avian influenza A(H5N1) clade 2.3.4.4b have been reported in the UK. These detections were associated with exposure to infected birds, with human cases being either asymptomatic or presenting with mild symptoms. For further information on avian influenza viruses, see UKHSA’s avian influenza webpage.
Clade I mpox – African Region
Event summary
On 14 August 2024, the World Health Organization declared a Public Health Emergency of International Concern (PHEIC) in response to the surge of clade I mpox cases in the Democratic Republic of the Congo (DRC), with spread to neighbouring African countries.
The countries reporting clade I mpox in the African Region (Figure 1) include:
• the DRC (8,607 confirmed cases and 1,049 deaths, as of 28 October 2024)
• Burundi (1,287 confirmed cases and no deaths, as of 26 October 2024)
• the Central African Republic (CAR) (57 confirmed cases and 1 death, as of 4 October 2024)
• the Republic of the Congo (RoC) (22 confirmed cases and no deaths as of 25 October 2024)
• Rwanda (26 confirmed cases and no deaths as of 27 October 2024)
• Uganda (288 confirmed cases and 1 death as of 30 October 2024)
• Kenya (14 cases and 1 death as of 17 October 2024)
• Gabon (which has reported clade Ia mpox cases in the past) reported 2 cases and no deaths as of 25 October 2024, but the clade type was not confirmed.
Figure 1. Geographical distribution of mpox clades in the African Region. Data from the WHO.
The number of mpox cases in the African Region has increased in October 2024, driven mainly by cases reported from the DRC, Burundi, and Uganda, as seen in Figure 2. In the DRC, North and South Kivu provinces are currently reporting the most cases. On 3 October 2024, media reported that both clades Ia and Ib mpox were circulating in Kinshasa, with outbreaks being driven predominantly by sexual contact.
In Uganda, an initial rise in mpox cases early in October 2024 was linked to fishing communities in Nakasongola district, specifically an area with a high concentration of local bars and lodging places frequented by the fishing community. Other mpox hotspots in Uganda included Kampala and Wakiso districts. As of 30 October 2024, only 31.7% of cases in Uganda were reported in known contacts of a confirmed case, suggesting undetected transmission chains in the country.
Figure 2. The epidemiological curve for confirmed cases of clade I mpox in the African Region. Data was collated from official and media sources with a cutoff date of 31 October 2024.
An mpox vaccination campaign was launched on 5 October 2024 to support key at-risk groups in Equateur, North Kivu and South Kivu provinces, though uptake was reportedly slow. The vaccination focus was initially on frontline health workers, close contacts of mpox cases and immunocompromised individuals. The second vaccination phase, which began on 26 October 2024, targeted people at high risk of mpox virus exposure, including sex workers and people in contact with cases. The DRC is expecting 3 million doses of the LC16m8 vaccine for use in children, and on 29 October 2024, Bavarian Nordic announced a clinical study investigating the MVA-BN mpox/smallpox vaccine in children aged 2-to-11-years-old. For context, as of 5 October 2024, 70% of the 988 deaths reported in the DRC were in children under 5-years-old. In Burundi, children under 15-years-old also made up the majority of the confirmed mpox cases (51.9%).
Clade Ib mpox continued to spread outside the African Region in October 2024, with the first imported cases reported in Germany and the United Kingdom. Germany reported their first clade Ib mpox case on 22 October 2024, in a 30 to 40-year-old man with travel history to Rwanda between September to early October. The case reported sexual contact as a possible exposure and developed symptoms and sought medical care upon return to Germany. The Robert Koch Institut assesses the risk of clade I mpox to the health of the German population as low.
The United Kingdom reported their first case of clade Ib mpox on 30 October 2024, in an individual in London who had recently travelled to countries in Africa experiencing community transmission of clade Ib mpox. The risk of clade Ib mpox, as assessed by UKHSA, remains low.
Incident assessment
During October 2024, the epidemic in the African Region has continued to deteriorate with an increase in cases in the DRC, Burundi and Uganda (and deaths in the DRC). Travel-associated clade Ib mpox cases were also reported outside of the African Region for the first time in Germany and the United Kingdom.
In early August 2024, the WHO classified the risk associated with mpox in eastern DRC and neighbouring countries as high, and the risk in areas of the DRC where mpox is endemic as high. The WHO states that the mpox outbreak in Africa may continue to evolve due to multiple factors. For example:
• There is evidence that there is likely under-detection of cases and under-reporting of local transmission with reported cases that have no epidemiological links.
• Reported cases have been identified in multiple locations within each country.
• Emergency responses in each country have been disparate with varying levels of resource allocation and support from in-country and global partners.
• Clade I mpox is reportedly being transmitted through sexual contact within key populations, further accelerating its spread.
Several studies were published in October 2024 that described the epidemiology of mpox introduction and analysis of circulating mpox using whole genome sequencing. These included:
• an epidemiological analysis of confirmed mpox cases in Burundi, between 3 July and 9 September 2024
• a description of cases with clade Ib in Burundi between July and 20 August 2024
• a descriptive genetic sequencing analysis of mpox clade I in the Republic of the Congo.
The World Health Organization Global Advisory Committee on Vaccine Safety also published a statement in October 2024 on the safety of the mpox vaccines for use in high-risk groups.
As of October 2024, one case of clade I mpox has been reported in the UK. In the UK, at the time of writing, clade I mpox is considered a high consequence infectious disease (HCID), for which there are established processes for the isolation and contact management of a HCID case. There are a range of robust public health, clinical, infection prevention and control measures available for HCIDs, which can be adapted for use, as necessary.
Marburg virus disease - Rwanda
Event summary
On 27 September 2024, the Rwandan Ministry of Health reported confirmed cases of Marburg virus disease (MARD) in health facilities in Kigali. This was the first report of MARD in Rwanda. Between 27 September and 30 October 2024, 66 confirmed cases and 15 deaths (case fatality rate (CFR) of 23%) were reported. 49 confirmed cases have recovered. As of 30 October 2024, 5,913 diagnostic tests had been carried out and 1,618 vaccine doses had been administered.
Guidelines issued by the Ministry of Health on 29 October 2024 included: the restriction of hospital visitors and caregivers; healthcare facilities admitting suspected MARD patients had to apply strict infection prevent control measures; MARD fatalities were not permitted to have a funeral wake or home vigil; funeral services for MARD fatalities could not be attended by more than 50 people; and open-casket viewings were not permitted in homes, churches or mosques.
On 20 October 2024, Rwanda’s Minister for Health stated an index case had been identified with a high probability, linked to a zoonotic origin. The first generated draft genomes indicated a close evolutionary relationship to a strain of Marburg virus observed during a 2014 outbreak of MARD in Uganda, and to samples previously isolated from bats in the region. The sequences from 2014, sequences from bats in the region, and sequences from the current outbreak shared a single zoonotic origin, and phylogenetic analysis showed 4 identical viral sequences. Whilst some mutations were identified, none were markers for increased transmissibility or severity.
As of 31 October 2024, the Sabin Vaccine Institute had delivered approximately 2,700 doses of its investigational Marburg virus vaccine (ChAd3-MARV) to Rwanda. As of 30 October 2024, 1,618 vaccine doses have been administered. On 15 October 2024, the WHO reported that Rwanda had started the world’s first clinical trial investigating the safety and efficacy of Remdesivir for the treatment of MARD cases.
Incident assessment
There have been 18 outbreaks of MARD recorded by the WHO, including the first outbreak in Germany in 1967.
The WHO assesses the risk of this outbreak as very high at the national level, high at the regional level, and low at the global level.
On 7 October 2024, the United States (US) Department of Health and Human Services outlined its response to the current MARD outbreak through on-the-ground support, US preparedness and travel advice, vaccines and therapeutics and research. On 23 October 2024, the US Embassy in Kigali reported that the US will provide an additional US$ 7 million toward Rwanda’s response to the MARD outbreak.
To date, no cases of MARD have been reported 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 |
|---|---|
| Oropouche fever | Brazil and Ecuador |
| West Nile virus (WNV) | Multi-country |
| Circulating vaccine derived polio virus | Multi-country |
| Cholera | Multi-country |
| Dengue | Multi-country |
Oropouche fever
As of 20 October 2024, the Brazilian Ministry of Health recorded 8,264 cases of Oropouche fever in 2024. Most cases were reported in the Amazonas Province (3,231 cases). In comparison, 832 confirmed cases of Oropouche fever were reported in Brazil in 2023.
The Pan American Health Organization reported Ecuador’s first Oropouche fever cases for 2024 on 15 October 2024, detected through a retrospective analysis of dengue-negative samples by the National Institute of Public Health Research. The two laboratory-confirmed cases presented with symptoms on 11 June and 17 July 2024, had no travel history, and were not epidemiologically linked. Neither case required hospitalisation and both have fully recovered.
West Nile virus (WNV)
From 1 January to 23 October 2024, 1,657 cases of West Nile virus (WNV) have been reported from 19 countries in Europe. Italy and Greece have reported the majority of cases with 384 and 297 cases, respectively. WNV infection in humans is a notifiable disease at the European Union/European Economic Area level. WNV has a wide geographical distribution in Europe due to the presence of the native Culex pipiens mosquito, the most common and competent member of the Culex mosquito genus (which is the major vector of WNV).
On 24 October 2024, the first locally acquired human case of West Nile virus was reported in Poland. The virus was first detected in birds in Warsaw and the surrounding areas in August 2024.
Circulating vaccine derived polio virus (cVDPV)
During October 2024, the Global Polio Eradication Initiative (GPEI) reported one cVDPV2-positive environmental sample from the Barcelona metropolitan area, Catalonia, Spain, with collection in September 2024. This is the first time cVDPV2 has been reported in Spain.
One confirmed case of cVDPV2 was reported by Senegal’s Ministry of Health on 15 October 2024, in an unvaccinated individual. This is the first report for Senegal in 2024. Senegal did not report any cVDPV2 cases in 2023.
An alert for the detection of cVDPV3 in wastewater samples in French Guiana was issued by the WHO Pan American Health Organisation on 14 October 2024. The GPEI reported that 3 cVDPV3-positive environmental samples were collected from Cayenne province in French Guiana in May, June and August 2024. Further analysis showed that the genetic sequence of a sample detected on 26 June 2024 was not genetically related to any previously identified VDPV3 strains, including those that circulated in other countries between 2021 and 2022. This suggests that it might not have spread from a known source.
Cholera
During October 2024, 37,363 new cholera cases and 395 associated deaths were reported from 19 countries and territories across 4 WHO regions. This is a 32% decrease in cases and a 48% decrease in deaths compared to September 2024. Most cases were reported in the Eastern Mediterranean Region (28,878 cases and 236 deaths across 6 countries) followed by the African Region (8,264 cases and 159 deaths across 11 countries).
The Comoros initially declared a cholera outbreak on 2 February 2024, which had entered a control phase. However, cases were reported again on 14 September 2024, on the island of Grand Comore. 198 cases and 3 deaths have been reported in the Comoros between 14 September and 13 October 2024.
There is an ongoing outbreak of cholera in Sudan that began in August 2024, with 23,736 cases and 672 deaths reported in 2024 as of 12 October 2024. There have reportedly been difficulties delivering aid supplies to cholera-affected areas due to ongoing conflict within the country.
Dengue
In October 2024, dengue serotype 3 (DENV-3) was detected in a confirmed case in Amazonas state, Brazil for the first time since 2009. This case was detected on 9 October 2024 with the state government issuing an epidemiological alert on 10 October 2024 calling for increased attention to dengue patient sampling and testing.
Between 20 and 26 October 2024, the state of Florida, US, recorded 5 new locally acquired dengue cases, bringing the state total to 55 cases since the beginning of 2024. Recent dengue cases in Florida’s Tampa Bay area are possibly due to the after-effects of recent hurricanes which flooded the area and left standing water suitable for mosquito breeding.
Europe experienced a rise in autochthonous dengue cases in October 2024. Italy reported 657 confirmed cases of dengue between 1 January and 22 October 2024, of which 200 cases were autochthonous infections. Outbreaks are ongoing in the Marche region with 133 locally acquired cases recorded in the towns of Fano and Pesaro between 4 September and 14 October 2024, and in the Emilia-Romagna region with 35 cases recorded in 2024 as of 15 October (both outbreaks were of dengue serotype DENV-2). Sporadic cases of serotype DENV-1 and DENV-3 have also been recorded in other regions of Italy.
In the Provence-Alpes-Côte d’Azur region of France, the regional health agency issued an alert on 30 September 2024 after the detection of 11 cases of locally acquired dengue in the municipality of Vallauris. Mosquito control orders were initiated and reinforce surveillance measures introduced to detect and eliminate breeding sites and potentially infected adult mosquitoes to prevent further spread of dengue.
Publications of interest
Oropouche fever
In 2024, there was a rapid expansion of Oropouche fever cases across South America. Research has suggested that the epidemic isolate had higher replication efficiency, was more virulent than a historical strain of Oropouche virus (OROV), and that individuals with previous immunity had a lower neutralising capacity. Additionally, another paper reported that phylodynamics, phylogeography, and ecological niche modelling strongly suggests OROV expanded to non-endemic areas beyond the Amazon Basin via a combination of short and long distance dispersal events. Both papers emphasise the need for surveillance in informing public health response, both molecular and environmental.
The expansion of cases in endemic countries in South America has led to OROV infections in travellers returning to Europe, with this paper highlighting the risk of spread via global interconnectedness with South America through examples including the Olympic Games in Paris and religious pilgrimages. Another paper also found that replication-competent OROV was detected in the semen of a returning traveller for 16 days after symptom onset, raising concerns for the risk of sexual transmission of the virus.
Mpox
Both clade Ia and Ib mpox are circulating in the Democratic Republic of the Congo. Clade Ia mpox cases generally arise from zoonotic spillover events, whereas clade Ib – which is believed to have emerged in September 2023 - is associated with human-to-human transmission, notably through sexual contact. Mpox virus genomes implicated in sustained human-to-human transmission have been shown to be predominated by APOBEC3-type mutations (a type of human enzyme that induces mutations during viral genome replication). A phylogenetic analysis of 115 mpox genomes from Kinshasa have shown that most mutations in both subclades are APOBEC3 linked, suggesting that the clade Ia outbreak in Kinshasa resulted from sustained human-to-human transmission following a zoonotic introduction. This is a significant departure from traditional transmission pathways of clade Ia mpox.
Novel pathogens and diseases
Jeilongviruses
Jeilongviruses (part of the Paramyxoviridae family) have a wide host range, having been detected in rodents, bats and hedgehogs. Jeilongviruses have previously been found in Africa, Asia, Europe, and South America. In 2021, a domestic cat brought home a dead mouse to a virology researcher in Florida, US, and the subsequent discovery and characterisation of a novel Jeilongvirus was described in this paper. This is the first Jeilongvirus detected in the US. The virus was genetically distinct from others in the genus, and virus replication studies performed in various cell lines indicate it has broad cellular and host species tropisms.
Coronaviruses
Coronaviruses have received significant attention since the high-profile outbreaks of SARS, MERS and COVID-19.Bats are a key reservoir for alpha- and betacoronaviruses. This paper conducted sampling and sequencing of coronaviruses in bats in Yunnan province between March 2020 and August 2021, discovering five novel coronaviruses with high genetic diversity. The study also suggested that bat coronaviruses undergo frequent recombination events, and that alphacoronaviruses are more prone to cross-species transmission across different bat families and genera. This could indicate higher spillover risk.
Further reading
Iquitos Virus in Traveler Returning to the United States from Ecuador
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