#Nosocomial #outbreak of #Lassa fever in Conakry, #Guinea, 2022

 

Abstract

Background

Lassa fever (LF) is endemic in Guinea, with high seroprevalence in the forest region. However, clinical cases have been only anecdotally reported. In August 2022, a nosocomial outbreak occurred at a private clinic in the capital Conakry, an area previously considered low risk.

Methods

Suspected cases were confirmed by real-time RT-PCR within 24 hours. Viremia was monitored during hospitalization, and whole-genome sequencing was performed in-country within 13 days of outbreak detection. Outbreak investigation involved rodent testing in the home village of the suspected primary case.

Results

Six cases were laboratory-confirmed, five of which were healthcare workers of the clinic. The case fatality rate was 16.7%. Viral RNA remained detectable in blood of survivors for a median of 26 days (IQR 24-41) post disease onset. Epidemiological investigations identified a suspected primary case, who had died of a febrile disease compatible with Lassa fever, had contact with all secondary cases, and had a travel history from Kissidougou area. Three near-complete and one partial Lassa virus genomes were recovered from the secondary cases, which phylogenetically clustered with genomes from central Guinea. Consistent with a common transmission source, the four genomes were almost identical. Rodent testing revealed a new reservoir area in eastern-central Guinea.

Discussion

This outbreak highlights the vulnerability of healthcare settings in low-prevalence areas of West Africa to nosocomial Lassa virus transmission due to human mobility. Facilitated by capacity building programs for viral hemorrhagic fevers, rapid diagnosis, genomic analysis, and ecological assessment enabled an efficient outbreak response and control.

Source: 

Link: https://academic.oup.com/jid/advance-article/doi/10.1093/infdis/jiag229/8661158

____

Mapping #global emergence of #pathogens with #epidemic and #pandemic #potential to inform and accelerate pandemic #prevention, #preparedness, readiness and response

 

Abstract

Introduction 

Increasing occurrence of epidemics and pandemics and concurrent emergence of different pathogens calls for multi-sectoral, multi-pathogen preparedness actions. Data on various factors that drive emergence of diverse pathogens can inform evidence-based preparedness by identifying geographies at-risk. When leveraging evidence within a One Health approach, multiple pathogens can be addressed simultaneously, thereby strengthening countries pandemic preparedness efforts. 

Methods 

For seventeen priority pathogens (avian influenza viruses, zoonotic coronaviruses including COVID-19, hemorrhagic fever viruses including Ebola, Henipaviruses, and arboviruses including yellow fever and Zika), we identified global evidence on animal reservoirs, vectors, environmental suitability, and reported human cases. We discriminated geospatially recorded pathogen detections from a background sample and constructed maps using these datasets to generate an evidence-based assessment of emergence risk globally. 

Results 

Seventeen pathogen-specific assessments were combined into a global composite map. Sub-Saharan Africa and South Asia have evidence supporting emergence risk for the greatest number of pathogens (included areas at-risk of all pathogens) and scored highest when strength-of-evidence weightings were factored. The Americas had the lowest tally of considered pathogens. Environmental suitability analyses received the highest weights, reservoir ranges the lowest. 

Discussion 

Preparedness and readiness must consider the range of global biological threats. Our methodology is capable of incorporating changing evidence on emergence potential for multiple pathogens to identify geographies at higher risk with different pathogen combinations. Our maps can contribute to existing decision-support structures, guiding shared interventions and strategic allocation of resources for spillover prevention and pandemic preparedness, thereby enhancing local response capacities applying a multidisciplinary approach.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

This work was concluded in 2024 and supported by the United States Agency for International Development (USAID) before January 22, 2025, the Germany Agency for International Cooperation (GIZ) and the Government of France.

Source: 

Link: https://www.medrxiv.org/content/10.64898/2026.03.20.26347940v1

____

Post-discharge #sequelae of #Lassa fever #survivors in #Nigeria: an analysis of the LASCOPE prospective cohort

 

Summary

Background

Lassa fever is one of the most important viral haemorrhagic fevers, yet post-discharge sequelae remain inadequately characterised. Previous studies have been limited by small sample sizes and unsystematic assessments. We aimed to describe post-discharge sequelae in Lassa fever survivors and explore the effect of disease severity on sequelae patterns.

Methods

LASCOPE was a prospective study of patients with PCR-confirmed Lassa fever hospitalised at Federal Medical Centre Owo, Owo, Nigeria, between April 23, 2018, and Feb 17, 2023. All patients who provided informed consent were included, with no age restriction. Severe disease was defined as the presence of at least one of the following during the acute phase: National Early Warning Score version 2 score of 7 or higher, Kidney Disease Improving Global Outcomes stage 2 or higher, or Lassa virus PCR Ct value of less than 25. At hospital discharge, follow-up of survivors was planned for day 60 after admission, or before that, based on medical need. A systematic symptom assessment was done at each visit. The main outcome was clinical remission, defined as complete absence of symptoms. Other outcomes were post-discharge death, symptom incidence, and prevalence of symptoms over time. Subgroup analyses were performed by age group (children aged <18 years or adults aged ≥18 years) and disease severity (severe or not severe).

Findings

Of 882 survivors (median age 32 years [IQR 22–46], 459 [52%] female and 423 [48%] male), post-discharge data were available for 807 (91%), with a total of 2603 person-months of follow-up. For three of 807 survivors with post-discharge information, only the vital status was collected. 736 (91%) of 807 reached clinical remission, with a median time to clinical remission of 19 days (95% CI 16–23) post discharge. The most frequently reported symptoms were asthenia (158 [20%] of 804), headache (148 [18%]), and post-exertional malaise (123 [15%]). Hearing symptoms were reported by only 17 (2%) of 804 survivors, which was substantially lower than previous studies. Disease severity did not affect time to remission. Six (1%) survivors died after hospital discharge.

Interpretation

Patient-reported symptoms suggest good recovery with few hearing or neurosensory disorders in most survivors of Lassa fever. Future research would benefit from extended follow-up periods and standardised diagnostic assessments, including objective audiometry, to further characterise the full spectrum of post-Lassa fever complications.

Funding

Institut National de la Santé et de la Recherche Médicale, University of Oxford, EU, UK Department for International Development, Wellcome Trust, French Ministry of Foreign Affairs, Agence Nationale de Recherches sur le SIDA et les Hépatites Virales, and French National Research Institute for Sustainable Development.

Source: 

Link: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(26)00057-5/abstract?rss=yes

____

#Marburg virus disease - #Ethiopia [End of the Outbreak] (#WHO, Jan. 26 '26)

 

{Excerpt}

26 January 2026

Situation at a glance

On 26 January 2026, the Ministry of Health of Ethiopia declared the end of the Marburg virus disease (MVD) outbreak. 

This declaration came after two consecutive incubation periods (a total of 42 days) since the last person confirmed with MVD died and was given a safe and dignified burial, in accordance with WHO recommendations on 14 December 2025. 

As of 25 January 2026, a cumulative total of 19 cases, including 14 confirmed (including nine deaths) and five probable cases (all deaths), were reported. 

A total of 857 contacts listed for monitoring all had completed their 21-day follow-up as of 25 January 2026. 

WHO, through its country office and partners, provided technical, operational and financial support to the government to contain this outbreak.

Description of the situation

On 14 November 2025, after the laboratory confirmation of suspected viral hemorrhagic fever (VHF) cases in Jinka town, South Ethiopia Regional State, Ethiopia, the Ministry of Health of Ethiopia declared an outbreak of Marburg Virus Disease (MVD). 

Molecular testing conducted by the National Reference Laboratory at the Ethiopian Public Health Institute (EPHI) identified Marburg virus (MARV) in patient samples. 

This was the first time Ethiopia was reporting a MVD outbreak.

The first known case was an adult from Jinka town who developed symptoms on 23 October. 

The patient presented to the General Hospital the following day with vomiting, loss of appetite, and abdominal cramps. 

As of 25 January 2026, a cumulative total of 14 confirmed cases, including nine deaths (Case Fatality Rate (CFR) 64.3%) and five probable cases, all of whom had died, were reported by the Ministry of Health from Jinka, Malle and Dasench woredas in South Ethiopia Region and Hawassa in Sidama Region.

As of 25 January 2026, a total of 857 contacts were listed who completed 21 days of follow-up, 760 from the South Ethiopia Region and 97 from the Sidama Region. 

As of 5 January 2026, 3800 samples were tested for the virus.

On 26 January 2026, after two consecutive incubation periods (a total of 42 days), without a new confirmed case reported, after the last confirmed case died and was given a safe and dignified burial, on 14 December 2025, the Ministry of Health of Ethiopia declared the end of the MVD outbreak, as per WHO recommendations.

(...)

Source: 

Link: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON592

____

From #pandemic #influenza to novel #coronaviruses: emerging infectious diseases of the 21st century

 

Highlights

• Global mobility, climate pressures, and ecological change drive emerging infections.

• Highly pathogenic influenza strains, including H5N1, pose ongoing spillover risks and pandemic potential.

• SARS, MERS, and COVID-19 illustrate the pandemic potential of novel coronaviruses.

• Nipah, Ebola, Pteropine orthoreovirus and Zika remain high-impact threats for global health security.

• Mass gatherings can amplify transmission risks of emerging high-consequence viruses.

• Strengthened surveillance, diagnostics, and One Health strategies are essential for pandemic preparedness.

Abstract

Emerging infectious diseases have risen significantly in the twenty-first century as ecological disruption, climate change, expanding human–animal interfaces, and global mobility intensify opportunities for pathogen transmission. This review synthesizes historical and contemporary evidence across viral, bacterial, fungal, and parasitic threats to characterize how diverse pathogens emerge and spread. Foundational events such as the 1918 influenza pandemic, mid-century influenza pandemics, the emergence of HIV/AIDS, and the eradication of smallpox provide context for understanding modern disease dynamics. In recent decades, coronaviruses including SARS, MERS, and SARS-CoV-2, pandemic H1N1, avian influenza subtypes, and major arboviruses such as dengue, chikungunya, Zika, West Nile virus, and yellow fever have demonstrated the rapidity with which zoonotic pathogens can disseminate globally. Viral hemorrhagic fevers including Ebola, Marburg, Lassa, and Crimean–Congo hemorrhagic fever remain critical threats, especially in regions with limited health-care capacity. Concurrently, antimicrobial resistance, the emergence of Candida auris, and the climate-driven expansion of endemic mycoses involving Histoplasma, Coccidioides, and Blastomyces highlight the increasing importance of fungal pathogens. Parasitic diseases such as artemisinin-resistant malaria, zoonotic trypanosomiasis, and expanding Leishmania transmission reflect shifting ecological conditions. These patterns are shaped by intersecting drivers including deforestation, wildlife trade, agricultural intensification, urban crowding, conflict, and rapid microbial evolution that enable spillover and sustained transmission. Although advances in genomic surveillance, metagenomic diagnostics, mRNA vaccines, monoclonal antibodies, and broad-spectrum antivirals have strengthened global response capacity, substantial gaps persist in equity, surveillance, and access to countermeasures. Strengthening One Health systems and resilient public health infrastructures is essential to anticipate and mitigate emerging infectious threats.

Source: 

Link: https://www.sciencedirect.com/science/article/abs/pii/S0732889326000271?via%3Dihub

____

An #mRNA #vaccine encoding the #Ebola virus glycoprotein induces high neutralizing #antibody titers and provides strong protection against lethal infections in mouse models

 

Abstract

Ebola virus (EBOV) is the causative agent of Ebola disease (EBOD), a viral hemorrhagic fever with a notably high case fatality rate. Current treatments for EBOD are limited to monoclonal antibodies or two licensed viral vector vaccines, a recombinant vesicular stomatitis virus (rVSV)-vectored vaccine or an adenovirus and modified vaccinia Ankara regimen. However, comparisons of protection, efficacy, and durability with alternative nucleotide platforms remain understudied. Here, we evaluated the immunogenicity of an mRNA vaccine expressing the EBOV glycoprotein (GP) in parallel with rVSV- and DNA-based vaccine platforms. The mRNA EBOV-GP vaccine, formulated in lipid nanoparticles, elicited significantly higher levels of total IgG and neutralizing antibody titers compared to the rVSV-EBOV-GP vaccine. Linear antibody epitope analysis indicated a preference for targeting the mucin-like domain in EBOV-GP1 following rVSV-based vaccination, while the mRNA platform distinctly targeted the internal fusion loop of EBOV-GP2. After characterizing the immunogenicity of the mRNA vaccine, two models of EBOD were used to demonstrate its protective efficacy: a surrogate rVSV-based challenge model of EBOD using type-I interferon deficient C57BL/6 mice and infection of BALB/c mice with authentic mouse-adapted EBOV. In both studies, the EBOV mRNA vaccine fully protected the mouse cohorts against morbidity and mortality. Additionally, the EBOV mRNA vaccine produced greater neutralizing antibody titers compared to the DNA EBOV-GP vaccine. These results suggest that an mRNA vaccine expressing EBOV-GP can induce robust, functional humoral responses that are protective against EBOD, warranting further development as an alternative to, or as part of a vaccine strategy including, viral vectored vaccines.

Source: Frontiers in Immunology, https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2025.1682418/full

____

#Genomic Insights into #Marburg Virus Strains from 2023 and 2025 #Outbreaks in Kagera, #Tanzania

 

Abstract

Marburg virus (MARV) is the primary cause of Marburg virus disease (MVD), a severe hemorrhagic fever with a high case-fatality rate. The first reported MVD outbreak in Tanzania occurred in 2023, followed by a second outbreak in 2025, both within the Kagera region. During those MVD outbreaks, 174 suspected cases were identified; of those, 10 were laboratory confirmed. After complete genome assembly and bioinformatic analyses, we found the MARV strains of the 2023 and 2025 outbreaks to be closely related and clustered with MARV strains that caused outbreaks in Rwanda (2024) and Uganda (2014). The sequences from both MVD outbreaks in Tanzania showed >99.71% nucleotide identity, suggesting a possible single spillover event followed by limited human-to-human virus transmission. Further ecologic studies are essential to identify potential spillover events, but our findings indicate that closely related MARV strains circulate in Kagera, Tanzania, posing a risk for future outbreak recurrence.

Source: 

Link: https://wwwnc.cdc.gov/eid/article/32/1/25-1314_article

____

#Lassa fever #symptomatology, viral dynamics, and host immune response (PREPARE): a prospective, observational cohort study in #Liberia

 

Summary

Background

Lassa virus (LASV) is a persistent threat to public health in west Africa and beyond. LASV is endemic in west Africa and each year it is responsible for an estimated 2·7 million infections, 23 700 hospitalisations, and 5000 deaths. With over 32 reported cases of Lassa fever imported into non-endemic countries—one-third of which were fatal—the importance of enhanced detection and management of Lassa fever extends beyond west Africa.

Methods

The prevalence, pathogenesis, and persistence (PREPARE) study was a prospective cohort study among patients admitted to two hospitals in a hyperendemic area of Liberia. Any patients aged 5 years or older with a febrile illness were eligible to enrol and be tested for Lassa fever. The study aimed to measure the prevalence of LASV infection and assess the signs and symptoms, LASV viral replication kinetics, and LASV-specific IgM and IgG responses longitudinally among adults and children with laboratory-confirmed Lassa fever.

Findings

From July 10, 2018, to Aug 12, 2024, a total of 435 participants were enrolled, including 362 admitted with a febrile illness and 73 who were directly admitted with clinical suspicion for Lassa fever. Lassa fever was diagnosed by plasma LASV RT-PCR in 41 (11%) of 362 febrile participants and 47 (64%) of 73 participants directly admitted with suspected Lassa fever, resulting in a total of 88 cases of confirmed Lassa fever. At entry, anorexia (71 [81%] of 88 vs 178 [51%] of 347), severe fatigue or weakness (63 [72%] vs 178 [51%]), and nausea or vomiting (39 [44%] vs 95 [27%]) were more likely to be reported by participants with Lassa fever than by participants who tested LASV RNA negative. Among the participants with Lassa fever, 11 (13%) of 88 died after admission. Mental status changes, seizures, acute kidney failure, hyperkalaemia, and metabolic acidosis were more frequent in patients with Lassa fever who died than in patients who survived. Median cycle threshold values at study entry for glycoprotein complex gene (GPC) or polymerase gene (L) were lower in those who died (GPC cycle threshold 22·4 [IQR 20·0–27·9]; L cycle threshold 21·7 [19·0–27·7]) than in those who survived (GPC cycle threshold 31·5 [28·0–33·9]; L cycle threshold 32·3 [28·0–33·9]). Among the 70 participants with Lassa fever who consented to longitudinal follow-up through their hospitalisation, seven died and these participants tended to have lower cycle threshold values and lower IgM and IgG LASV responses compared with survivors.

Interpretation

In a region of Liberia where it is endemic, Lassa fever is a prevalent cause of morbidity and mortality. Several symptoms were more likely in those with Lassa fever but overlap with those caused by other common infectious diseases. Compared with survivors, those who died during hospitalisation for Lassa fever tended to have evidence of organ dysfunction along with higher viral loads at study entry and during follow-up and lower antibody levels during their illness, suggesting a muted humoral immune response might be a factor in the development of severe Lassa fever.

Funding

US National Institute of Allergy and Infectious Diseases and National Institutes of Health.

Source: 

Link: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(25)00725-X/abstract?rss=yes

____

#Serological evidence of concurrent #Lassa virus and #SARS-CoV-2 #exposure in #Ghana- a cross-sectional study

 

Abstract

Background

The COVID-19 pandemic has exposed vulnerabilities in infectious disease surveillance, especially in West Africa where endemic viruses including Lassa fever persist. The overlapping clinical symptoms of these two infections create diagnostic challenges and the possibility of undetected co-infections.

Methods

A retrospective cross-sectional study was conducted using archived serum samples from a nationwide SARS-CoV-2 seroprevalence survey in Ghana. 434 samples across six regions were tested for SARS-CoV-2 total antibodies (IgG/IgM) using the WANTAI ELISA kit and Lassa virus IgG using ReLASV Pan-Lassa-NP-IgG ELISA.

Results

SARS-CoV-2 antibody prevalence was 64.29% (n = 279) and Lassa virus IgG prevalence was 20.28% (n = 88). Of the cohort of subjects who were seropositive for SARS-CoV-2, 20.79% were also seropositive for LASV IgG. Multivariate analysis revealed household size as a strong risk factor of dual exposure. Individuals from medium-sized households (4–6 persons) (aOR = 8.78, 95% CI: 1.18–65.56, p = 0.034) and large households (≥ 7 persons) (aOR = 12.90, 95% CI: 1.99–83.40, p = 0.007) had significantly increased odds of dual seropositivity compared to small households. Regional variations were observed, with Greater Accra showing significantly lower odds of dual seropositivity (aOR = 0.13, 95% CI: 0.03–0.51, p = 0.004) compared to Ashanti Region.

Conclusion

This study provides serological evidence of SARS-CoV-2 and Lassa virus concurrent exposure in Ghana during the COVID-19 pandemic. This finding suggests large household size as a key driver of dual viral exposure and calls for integrated surveillance systems and targeted interventions in large household settings to reduce concurrent transmission of viruses with pandemic potential.

Source: 

Link: https://link.springer.com/article/10.1186/s12879-025-12385-1

____

#Ebola virus disease - #DRC: End of the Outbreak Declared (#WHO D.O.N., Dec. 1 '25)

 

{Summary}

Situation at a glance

On 1 December 2025, the Ministry of Health (MoH) of the Democratic Republic of the Congo (DRC) declared the end of the Ebola virus disease (EVD) outbreak which had been declared on 4 September 2025. 

The end was declared after two consecutive incubation periods (a total of 42 days) since the last person confirmed with EVD tested negative for the virus and was discharged on 19 October 2025. 

A total of 64 cases (53 confirmed, 11 probable), including 45 deaths (CFR 70.3%), were reported from six health areas in Bulape Health Zone, Kasai Province. 

WHO and partners provided technical, operational and financial support to the government to contain the outbreak. 

This is the country’s 16th outbreak of Ebola. 

Although the outbreak has been declared over, health authorities are maintaining surveillance to rapidly identify and respond to any re-emergence. 

Risk communication and community engagement activities will continue to provide accurate information, monitor and address community feedback and rumours, and support efforts to reduce stigma toward individuals affected by the outbreak.

(...)

Source: 

Link: https://www.who.int/emergencies/disease-outbreak-news/item/ebola-virus-disease---democratic-republic-of-the-congo

____

DREF #Operation: #Ethiopia #Marburg #Outbreak 2025 (MDRET039) (IFRC, Dec. 1 '25)

 

Description of the Event

Date when the trigger was met: 12-11-2025

What happened, where and when?

-- On 14 November 2025, the Federal Ministry of Health (FMOH), in collaboration with the Ethiopian Public Health Institute (EPHI), issued a press release declaring an outbreak of Marburg virus disease in the South Region of Ethiopia. 

-- As of 26 November 2025, 78 laboratory tests have been conducted, of which twelve confirmed cases, including seven confirmed deaths, have been reported, three cases remain probable. 

-- Of the twelve confirmed cases, five are currently alive, three on treatment, and two discharged. 

-- More than 300 contacts have been identified and are under active follow-up. 

-- Given the high fatality potential and rapid transmissibility of Marburg, (MVD) an immediate and coordinated public health response is essential. 

- Early detection, isolation, contact tracing, and community sensitization are critical to prevent further spread by strengthening infection prevention and control (IPC) in health facilities, ensuring the safety of health workers, mobilizing rapid response teams (RRTs), and effective risk communication are key priorities at this stage.

-- An urgent response is warranted due to the potential for rapid local and cross-regional transmission, and significant public health threat associated with hemorrhagic fevers. 

-- Delayed intervention could result in high morbidity and mortality, community panic and overburdening of the health system. 

-- Immediate action will help contain the outbreak source, interrupt transmission chains, and protect both the affected population and health workers while laboratory confirmation and epidemiological investigations continue.

Source: 

Link: https://reliefweb.int/report/ethiopia/dref-operation-ethiopia-marburg-outbreak-2025-mdret039

____

#Ethiopia, #Prevention and #Control Activities for the #Marburg Virus Disease Have Been Strengthened and Are Ongoing (MoH, Nov. 26 '25): 73 confirmed/probable/suspected cases so far

 

The Ministry of Health and the Ethiopian Public Health Institute (EPHI) have released a press statement containing updated information regarding the Marburg virus disease.

They stated that laboratory tests have confirmed the occurrence of Marburg virus disease in the Southern Ethiopia Region. 

Up to now, 73 suspected individuals have been tested; among them, 6 patients have died due to the virus, as confirmed by the EPHI reference laboratory. Five additional patients are currently receiving treatment.

It was also noted that 349 people who had contact with the confirmed cases are under follow-up, and 119 of them have already completed their isolation period.

Dr. Mekdes Daba, Minister of Health, expressed condolences for those who lost their lives due to the virus and extended sympathy to their families, relatives, and friends.

She further explained that isolation centers have been established in affected areas, trained personnel are deployed, and essential medical supplies are being organized to provide strengthened medical care to patients. 

Additionally, Ethiopia is working with countries that previously experienced Marburg outbreaks to exchange expertise, learn from their experience, and access treatments and vaccines that have yielded positive results, ensuring they become available in the country for patients.

Dr. Mesay Hailu, Director of the Ethiopian Public Health Institute, confirmed that isolation centers, medical services, and trained staff are prepared should new cases appear. 

He added that even in regions where no cases have been detected, preparedness activities are underway. 

Screening procedures have also been strengthened at airports, border points, and other entry/exit locations.

Anyone who shows symptoms of the disease is urged to report immediately to the nearest health facility or call the toll-free numbers 8335 or 952. These hotlines also provide additional information and counseling services about the disease.

Source: 

Link: https://www.moh.gov.et/marburg-response

____

Assessing #Ebola virus circulation in the Tshuapa province (#DRC): A #OneHealth #investigation of wildlife and #human interactions

 

Abstract

The wildlife reservoir and spillover mechanisms of Ebola virus remain elusive despite extensive research efforts in endemic areas. This study employed a One Health approach to examine the virus’ circulation in wildlife and the associated human exposure risks in the Tshuapa province of the Democratic Republic of the Congo. We screened 1049 samples from 919 animals, predominantly small mammals, collected in 2021, and 380 samples from inhabitants of Inkanamongo village, the site of an Ebola virus disease outbreak in 2014. These samples were screened for evidence of current (RNA) or past (IgG antibodies) Ebola virus infections. We also conducted interviews with 167 individuals in the surrounding districts to assess their interactions with wildlife. While no Ebola virus RNA was detected in the wildlife samples, anti-orthoebolavirus IgG antibodies were found in 13 bats and 38 rodents. Among the human participants, 120 individuals had IgG antibodies against at least 1 orthoebolavirus antigen, with 12 showing seropositivity for 2 antigens of the same orthoebolavirus, despite not having a prior Ebola disease diagnosis. Furthermore, the majority of respondents reported frequent visits to the forest to hunt a variety of wild animals, particularly ungulates and rodents, which could account for occasional viral spillovers. The absence of active Ebola virus circulation in wildlife may reflect seasonal patterns in reservoir ecology, as those observed in bats. Similarly, seasonal human activities, such as hunting and foraging, may result in periodic exposure risks. These findings highlight the importance of continuous, multidisciplinary surveillance to monitor changes in seasonal spillover risks.

Author summary

Since its discovery in 1976 in the Democratic Republic of Congo (DRC), Ebola virus (EBOV) has caused more than 20 outbreaks in humans, with fatality rates as high as 90%. While the virus is believed to have an animal origin, naturalist reservoir and the mechanisms of transmission to humans remain poorly understood. Gaining insight into which species may harbour the virus and how transmission occurs is essential to predict and prevent future outbreaks. In this study, we investigate EBOV exposure in wildlife and humans in a region of the DRC with a documented history of outbreaks. Although we did not detect active infection in animals, we found serological evidence of prior exposure in several bat and rodent species, as well as among local residents. Interviews with community members revealed frequent contact with wildlife through hunting and handling, practices that could elevate the risk of animal-to-human transmission. These findings offer new clues about possible EBOV reservoirs and highlight the role of human behaviours in facilitating facilitate spillover events. Our results underscore the need for continued, integrated surveillance to improve understanding of Ebola virus ecology and to help reduce the risk of future Ebola outbreaks in endemic regions.

Source: 

Link: https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1013628

____

#Marburg virus disease - #Ethiopia (#WHO, D.O.N., Nov. 21 '25)

 

{Excerpts}

Situation at a glance

On 12 November 2025, WHO noted a press release from the Ethiopian Ministry of Health (MoH), and the Ethiopian Public Health Institute (EPHI), announcing suspected viral hemorrhagic viral fever (VHF) in Jinka town, South Ethiopia Regional State, Ethiopia. 

On 14 November 2025, the Ministry of Health of Ethiopia confirmed that the cases previously reported as suspected VHF were Marburg virus disease (MVD). 

Molecular testing conducted by the National Reference Laboratory at EPHI identified Marburg virus (MARV) in patient samples. 

As of 20 November 2025, 33 laboratory tests have been conducted, of which six confirmed cases, including three deaths, have been reported. 

Of the six confirmed cases, three are currently alive and on treatment. 

In addition to the lab-confirmed cases, a further three epidemiologically linked cases could not be tested; all three are deceased and recorded as probable cases. 

A total of 206 contacts have been identified, and contacts are under active follow-up. 

The number of contacts will continue to change as the response evolves. 

The source of the infection has not yet been identified. 

This marks the first confirmed outbreak of MVD in the country. 

Initial investigation by the one health team in Ethiopia show the presence of the natural host of the virus, fruit bats, in the area. 

MVD is a severe, often fatal illness, transmitted from bats to humans, and clinically similar to Ebola virus diseases. 

The disease has a case fatality ratio of up to 88%, but it can be much lower with good and early patient care. 

Under the leadership of the MoH, WHO is working alongside the Ethiopian response teams to enhance coordination, surveillance (including outbreak investigation, contact tracing, and alert management), case management, infection prevention and control measures, laboratory capacity, risk communication and community engagement. 

WHO assesses the public health risk posed by the outbreak as high at the national level, moderate at the regional level and low at the global level. 

Ethiopia is facing concurrent emergencies and multiple disease outbreaks, including of cholera, measles, dengue, which results in stretched health capacity.

Description of the situation

As of 20 November 2025, 33 laboratory tests have been conducted, of which six confirmed cases, including three deaths, have been reported. Of the six confirmed cases, three are currently alive and on treatment. In addition to the lab-confirmed cases, a further three epidemiologically linked cases could not be tested; all three are deceased and recorded as probable cases. A total of 206 contacts have been identified, and contacts are under active follow-up. The number of contacts will continue to change as the response evolves.

Clinically, patients have presented with high-grade fever, headache, vomiting, abdominal pain, and watery or bloody diarrhoea. Haemorrhagic manifestations, including nose bleeding and vomiting blood were observed in five cases, consistent with multi-organ failure.

As this is the first time Ethiopia is reporting MVD, WHO recommends that samples be shared with a reference laboratory for inter-laboratory comparison.

(...)

WHO risk assessment

This is the first confirmed MVD outbreak in Ethiopia.  The public health risk posed by the MVD outbreak is assessed as high at the national level due to several concerning factors:

-- The outbreak involves six laboratory-confirmed cases; there have been a total of six deaths and there are three confirmed cases under treatment.

-- All deaths involved unsupervised burials, posing a risk of potential additional community transmission.

-- The presence of healthcare workers among the confirmed cases suggests potential occupational exposure risks within health facilities.

-- Although investigations are ongoing, information on the source of the outbreak, geographical extent and epidemiology is limited.

-- Although no international transmission has been confirmed to date, the potential risk for spread remains. The affected area, Jinka, while distant from Ethiopia’s capital or major international airports, is connected by road transportation networks, including to neighbouring Kenya and South Sudan. Therefore, the public health risk posed by this event is assessed as moderate at the regional level. It is considered low at the global level.

(...)

Source: 

Link: https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON585

____

#Ethiopia confirms first #outbreak of #Marburg virus disease (#WHO AFRO, Nov. 15 '25)

 

14 November 2025

Addis Ababa—Ethiopia’s Ministry of Health has confirmed an outbreak of Marburg virus disease in the South Ethiopia Region, the first of its kind in the country, following laboratory testing of samples from a cluster of suspected cases of viral haemorrhagic fever.

Genetic analysis by the Ethiopia Public Health Institute revealed that the virus is of the same strain as the one that has been reported in previous outbreaks in other countries in East Africa. 

A total of nine cases have been reported in the outbreak that has affected Jinka town in the South Ethiopia Region.

The national authorities are scaling up response including community-wide screening, isolation of cases, treatment, contact tracing and public awareness campaigns to curb the spread of the Marburg virus, which is in the same family of viruses that cause Ebola virus disease.

The World Health Organization (WHO) and partners are supporting the government as it intensifies response to halt the spread of the virus and end the outbreak. A team of responders with expertise in viral haemorrhagic fever outbreak response has been deployed along with medical supplies and equipment.  

Marburg virus disease is a severe and often fatal illness caused by the Marburg virus. The disease is transmitted to humans from fruit bats and spreads among people through direct contact with bodily fluids of infected individuals or contaminated materials.

Initial symptoms include high fever, severe headache, muscle aches and fatigue. Many patients develop severe bleeding within a week of onset. Although several promising candidate medical countermeasures are currently undergoing clinical trials, there is no licensed therapeutic or vaccine for effective management or prevention of Marburg virus disease. However, early access to supportive treatment and care – rehydration with oral or intravenous fluids – and treatment of specific symptoms, improve survival.  

In the African region, previous outbreaks and sporadic cases have been reported in Angola, the Democratic Republic of the Congo, Ghana, Kenya, Equatorial Guinea, Rwanda, South Africa, Tanzania and Uganda.

Source: World Health Organization, Regional Office for Africa, https://www.afro.who.int/countries/ethiopia/news/ethiopia-confirms-first-outbreak-marburg-virus-disease

____

#Africa #CDC #Statement on Suspected Viral #Haemorrhagic #Fever in Jinka, Southern Region, #Ethiopia (Nov. 14 '25)

 

13 November 2025, Addis Ababa – The Africa Centres for Disease Control and Prevention (Africa CDC) is closely monitoring reports of a suspected viral haemorrhagic fever (VHF) in Jinka, Southern Region, Ethiopia.

On 12 November 2025, the Ethiopia Public Health Institute (EPHI) notified Africa CDC of eight suspected cases, with clinical samples collected and submitted to the National Reference Laboratory for further testing. As investigations continue, no confirmed aetiology has yet been established.

From London where he was on official mission, the Director General of Africa CDC, H.E. Dr. Jean Kaseya had a call the same day with the Ethiopian Minister of Health H.E. Dr. Mekdes Daba to congratulate her for early detection and the transparency that characterized Ethiopia when there is a public health event, and to extend the support from Africa CDC and the entire continent to quickly contain that.

During the Africa CDC Weekly Press Briefing on Health Emergencies held on 13 November 2025, H.E. Dr. Jean Kaseya, highlighted this event and briefed Member States on preliminary information and response readiness.

The Africa CDC in-country team continues to engage closely with national authorities and provide technical support. Africa CDC will continue working with the Government of Ethiopia and partners and will issue timely updates as more information becomes available and laboratory results are confirmed, and additional assistance will be mobilised as required

###

Source: ReliefWeb, https://reliefweb.int/report/ethiopia/africa-cdc-statement-suspected-viral-haemorrhagic-fever-jinka-southern-region-ethiopia

____

Safety, tolerability, and immunogenicity of INO-4500, a synthetic #DNA-based #vaccine against #Lassa virus, in a phase 1b clinical trial in healthy Ghanaian adults

 

Abstract

Background: 

Lassa fever (LF) is an acute viral hemorrhagic illness endemic to West Africa, with no licensed vaccines or targeted treatments available, highlighting a critical gap in global health preparedness. T cell-mediated immunity plays a central role in viral control and survival. Synthetic DNA vaccines offer a promising strategy to induce both humoral and cellular immunity against LF.

Methods: 

A Phase 1b, randomized, double-blind, placebo-controlled trial was conducted to assess the safety, tolerability, and immunogenicity of INO-4500, a DNA vaccine encoding the Lassa virus (Josiah strain) glycoprotein precursor (GPC). A total of 220 healthy adults were randomized to receive either 1 mg or 2 mg of INO-4500 (intervention), or placebo, administered intradermally (ID) followed by electroporation (EP) at Day 0 and Week 4. Safety was evaluated through Week 48. Primary immunogenicity endpoints included humoral and cellular immune responses at multiple timepoints post-vaccination.

Results: 

INO-4500 was well tolerated, with no Grade 3 or higher treatment-emergent adverse events (TEAEs) deemed to be related to the intervention; 88.6% of all TEAEs were Grade 1. No cases of attributable hearing loss were reported. INO-4500 groups demonstrated statistically significant increases in Lassa virus GPC-specific binding antibodies at Weeks 6 and 12 compared to placebo, with the 2 mg group eliciting the strongest responses. T cell responses remained elevated above baseline through Week 48 in both INO-4500 groups, indicating durable cellular immunity.

Conclusions: 

DNA vaccine INO-4500 was well tolerated and elicited durable humoral and cellular immune responses in healthy adults. These findings support further clinical development of INO-4500 as a potential preventive vaccine to reduce LF-associated morbidity and mortality in endemic regions.

Clinical Trial Registration: https://clinicaltrials.gov, identifier NCT04093076

Source: Frontiers in Immunology, https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2025.1658549/full

____

Joint #FAO / #WHO / #WOAH Rapid #Risk #Assessment of Rift Valley fever (#RVF) in #Senegal and #Mauritania: Implications for Public Health and Animal Health (Oct. 24 '25)

 

{Excerpt}

Risk statement

This risk assessment is based on the current epidemiological and epizootic situation of Rift Valley fever (RVF) in Senegal and Mauritania, from 20 September through 8 October 2025.

The risk assessment was conducted separately for each country. However, the findings indicate that the level of risk is the same for both countries across all levels, for both human and animal health.  

During this period, Senegal reported 119 confirmed human RVF cases, including 16 deaths, resulting in a case fatality rate (CFR) of 13.4%. Cases were recorded across eight health districts in three regions of Senegal, with the majority in Saint-Louis Region with 110 cases (92%) followed by Louga (four cases) and Matam (one case). 

The affected districts in Saint-Louis Region: Podor, Richard-Toll, Dagana, and Saint-Louis are located along the northern border with Mauritania along the Senegal River.  

The most affected age groups were 15- 35 years, accounting for 69 cases (58%), and 35-60 years with 34 cases (29%), with 77 % of cases occurring in males. 

Hemorrhagic symptoms were reported in 22 cases (18%) of which 13 resulted in death.  

Animal infections resulting in abortions and livestock mortality were also reported. 

On 23 September, 1122 blood samples and four abortion samples were collected from small ruminant herds in villages where human cases were reported. 

Of these, 36 samples tested positive across six herds. 

By 30 September, a total of 27 confirmed animal cases, two deaths have been reported to the World Organisation for Animal Health (WOAH) through the World Animal Health Information System (WAHIS). 

As of that date, five animal outbreaks have been confirmed in Saint-Louis Region, with four additional outbreaks expected to be included in a forthcoming follow-up report currently in draft.  

RVF is endemic in Senegal, with previous outbreaks affecting both humans and animals. 

The last confirmed human case before this outbreak occurred in January 2025 in Touba, located in the Diourbel region, while the last recorded human case in Saint-Louis region occurred in 2022.   

Between 27 September and 5 October 2025, Mauritania reported 17 confirmed human RVF cases, including eight deaths, resulting in a CFR of 47%. 

Cases were recorded across seven districts in five regions (wilayas), three of which have international borders: Assaba which borders Mali to the south, Brakna and Trarza both bordering Senegal along the Senegal River. 

Of 66 samples tested, the positivity rate was 25.7%.  

Multiple active outbreaks in animals have also been reported. According to the Ministry of Animal Resources of Mauritania, as of 6 October, 17 outbreaks across eight regions, with 86 out of 307 samples testing positive. 

The first animal cases, involving goats and camels, were reported in August 2025. A total of 39 clinical animal cases (including 16 deaths in two dromedaries and 14 goats) were reported in Aioun, Hodh-Gharbi region and Timbedra, Hodh-Charghi region, both are located in southeastern Mauritania near the Mali border, and in Maghta Lahjar, Brakna region, in central Mauritania.  

In Brakna region alone, 233 animal cases and 55 deaths have been reported to WOAH by 3 October 2025. 

Affected animals include sheep, goats, camels and cattle.  

RVF is endemic in Mauritania. The last major outbreak occurred in 2022, with 47 confirmed human cases, including 23 deaths (CFR 49%), mostly among animal breeders in nine of 15 regions. 

The virus also affected animals such as cattle, camels, and small ruminants, with sample positivity rates of around 24% tested during that outbreak period.  

The current outbreak in Senegal and Mauritania is unusual in both its magnitude and severity. It involves multiple districts in border regions, particularly along the Senegal River, increasing the risk of cross-border transmission between Senegal and Mauritania. 

In Mauritania, the outbreak also extends to eastern regions bordering Mali, raising concerns about potential regional spread beyond the Senegal River basin.  

A notably high proportion of severe and haemorrhagic cases has been reported. In Senegal, 18% of confirmed human cases presented with haemorrhagic symptoms, with 13 cases resulting in death.  

The situation is particularly concerning in Mauritania, where the CFR has reached 47%, reflecting both the severity of illness and potential gaps in early detection and clinical management. 

Further information is needed to better understand the factors contributing to this high fatality rate. 

Possible contributing factors include delayed access to adequate care, shortage of essential medical products and supplies and underreporting of mild cases, which may result in disproportionate detection of severe cases. However, additional factors should also be investigated.  

(...)

Source: World Health Organization, https://www.who.int/publications/m/item/joint-fao-who-woah-rapid-risk-assessment-of-rift-valley-fever-(rvf)-in-senegal-and-mauritania--implications-for-public-health-and-animal-health

____

Chapter One - #Mucosal #Sudan virus #infection results in a lethal disease in #ferrets with previous #Lloviu virus infection not providing cross-protection

Abstract

Sudan virus (SUDV) causes highly lethal outbreaks of hemorrhagic disease throughout Africa, but there has yet to be an approved vaccine or therapeutic to combat this public health threat. The most common route of natural exposure to filoviruses is through mucosal contact which greatly impacts initial viral replication. Historically, SUDV animal models used an intramuscular infection route. Here, we sought to further characterize an animal model using mucosal challenge routes and compared the impact that intramuscular, intranasal, or aerosol exposure had on SUDV pathogenicity in a ferret model. We determined that the route of infection did not significantly impact overall SUDV pathogenicity; only subtle changes were detected in magnitude of viremia and oral viral shedding. Additionally, we sought to determine if preexisting Lloviu virus (LLOV) immunity could protect ferrets from lethal SUDV infection. We found that the previous immunity elicited by LLOV infection was not sufficient to protect ferrets from lethal SUDV disease. In conclusion, our results indicate that the infection route has minimal effect on overall pathogenicity of SUDV in ferrets and that prior LLOV infection does not elicit a cross-protective immune response to SUDV.

Source: Advances in Virus Research, https://www.sciencedirect.com/science/article/abs/pii/S0065352725000077?via%3Dihub

____

#Epidemiology and Genetic Characterization of Distinct #Ebola #Sudan #Outbreaks in #Uganda

Abstract

Background. 

Sudan virus (SUDV) has caused multiple outbreaks in Uganda over the past two decades, leading to significant morbidity and mortality. The recent outbreaks in 2022 and 2025 highlight the ongoing threat posed by SUDV and the challenges in its containment. This study aims to characterize the epidemiological patterns and phylogenomic evolution of SUDV outbreaks in Uganda, identifying key factors influencing transmission and disease severity. 

Methods. 

We conducted a retrospective observational study analyzing epidemiological and genomic data from SUDV outbreaks in Uganda between 2000 and 2025. Epidemiological data were collected from official sources, including the Ugandan Ministry of Health and the World Health Organization, supplemented with reports from public health organizations. Genomic sequences of SUDV were analyzed to investigate viral evolution and identify genetic variations associated with pathogenicity and transmissibility. 

Results. 

The 2022 outbreak involved 164 confirmed cases and a case fatality rate (CFR) of 33.5%, with significant geographic variation in case distribution. The 2025 outbreak, still ongoing, was first detected in Kampala, with evidence of both nosocomial and community transmission. Phylogenomic analysis revealed the presence of two main genetic groups, representing Sudan and Uganda, respectively. The genetic variability of the Ugandan cluster is higher than that observed in Sudan, suggesting a greater expansion potential, which aligns with the current outbreak. Epidemiological findings indicate that human mobility, weaknesses in the health system, and delays in detection contribute to the amplification of the outbreak. 

Conclusions. 

Our findings underscore the importance of integrated genomic and epidemiological surveillance in understanding SUDV transmission dynamics. The recurrent emergence of SUDV highlights the need for improved outbreak preparedness, rapid response mechanisms, and international collaboration. Strengthening real-time surveillance and enhancing healthcare system resilience are critical to mitigating the impact of future outbreaks.

Source: Infectious Disease Reports, https://www.mdpi.com/2036-7449/17/3/44

____