#Ebola disease caused by #Bundibugyo virus - #DRC (WHO, August 28 '26): 5,794 cases and 2,786 deaths

 

Situation at a glance

    Since the last Disease Outbreak News was published on 14 August 2026, the outbreak has spread from 54 to 60 health zones. 

    The number of affected provinces stands at six out of 26 provinces of the country: Bas-Uélé, Haut-Uélé, Ituri, North Kivu, South Kivu, and Tshopo. 

    Six additional health zones reported cases since the last update - Ganga and Viadana health zones in Bas-Uélé province, Biena, Manguredjipa, and Mutwanga in North Kivu, and Tshopo health zone in Tshopo province. 

    As of 26 August 2026, a total of 5794 confirmed cases, including 2786 deaths, have been reported, corresponding to a crude case fatality ratio (CFR) of 48.1%. 

    These figures demonstrate a substantial increase in the scale and geographic extent of the outbreak over the past three months. 

    The crude case fatality ratio of 48% underscores the severity of the disease and ongoing challenges related to timely case detection, access to and quality of clinical care, and effective interruption of viral transmission. 

    Delays in recognizing cases increase the likelihood of onward transmission within households, communities and healthcare facilities. 

    The outbreak remains a public health emergency of international concern, following the advice of Emergency Committee meeting convened on 18 August.

Description of the situation

    Since the previous Disease Outbreak News was published on 14 August 2026, additional confirmed cases and deaths of BVD have been reported only in the Democratic Republic of the Congo.  

    Cumulatively as of 26 August 2026, 5815 confirmed cases have been reported: 5794 in the Democratic Republic of the Congo (including two cases diagnosed in the Democratic Republic of the Congo and subsequently treated in Germany), 20 in Uganda and one in France. 

    A total of 2788 deaths have been reported, including two in Uganda. 

    As of 26 August, at least 1314 patients have recovered, including 1293 in the Democratic Republic of the Congo, 18 in Uganda, two in Germany and one in France.  

    As of 27 August, the 42-day enhanced monitoring period, as per international guidance, has been completed in both France and Uganda.  

    The continuing intensity of transmission in the Democratic Republic of the Congo means that the risk of further exportation across international borders remains. 

    Entry and exit health screening and surveillance measures are in place at airports, ports and official land border crossings; however, movement through informal border crossing routes may occur, presenting an ongoing risk of virus exportation, importation and onward transmission. 

    Therefore, cross‑border collaboration, and sustained surveillance and preparedness are essential to prevent further regional spread and ensure an effective public health response. 

    On 27 August, vaccination of health care workers using the Ervebo vaccine was initiated in the Democratic Republic of the Congo in some areas, including in Kisangani, Tshopo province. 

    Although Ervebo is a safe vaccine, and effective against Ebola virus disease, it is not known whether it provides protection against the Bundibugyo virus in humans. 

    Thus, starting a clinical trial of the vaccine, alongside this wider use, is key to provide important new evidence and inform future use of the vaccine. 

    The second IHR Emergency Committee meeting regarding the epidemic of Ebola Bundibugyo virus disease in the Democratic Republic of the Congo took place on 18 August. 

    Following the advice of the Committee, the Director-General agreed that the ongoing outbreak remains a Public Health Emergency of International Concern, and issued updated temporary recommendations to countries. 

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Democratic Republic of the Congo  

    Since 14 August 2026 when the last Disease Outbreak News was published, an additional 1129 confirmed cases, including 602 confirmed deaths, have been reported in the Democratic Republic of the Congo. 

    Although part of this increase likely reflects expanded surveillance, enhanced laboratory testing, improved diagnostic capacity, and periodic data backlog reconciliation, the sustained rise in number of cases and deaths are the result of continued transmission and substantial outbreak expansion. 

    As of 26 August 2026, a total of 5794 confirmed cases, including 2786 deaths (CFR 48.1%), have been reported in the Democratic Republic of the Congo. 

    To date, 1293 patients have recovered. 

    Cases have been reported from 60 health zones (HZ) across six provinces. Ituri has 28 health zones affected out of 36, followed by North Kivu (15/34), Haut-Uélé (6/13), Tshopo (7/23), South Kivu (1/34) and Bas Uélé (3/11). 

    The most recently affected province, Bas-Uélé, started reporting cases since 12 August. 

    The most recently affected health zones are Biena and Manguredjipa in North Kivu province. 

    As of 26 August, of the 60 affected health zones, 81 new confirmed cases were reported in the last 24 hours from 19 health zones in Ituri, North Kivu, Haut-Uélé, and Tshopo provinces. Ituri remains the epicentre of the outbreak, with 4802 confirmed cases reported since the start of the outbreak, including 52 new confirmed cases reported in the last 24 hours, as of 26 August. 

    Nord-Kivu is the second most affected province, with a cumulative number of 775 confirmed cases, including 22 reported in the last 24 hours, as of 26 August. The highest CFR (68%) in this outbreak has been reported from North Kivu province; the reasons for this high CFR are under investigation. 

    The number of individuals requiring contact monitoring has also increased substantially as the outbreak has expanded. As of 26 August, the proportion of contacts followed up in the last 24 hours is at 82.3% (22 091 seen out of 26 850 to follow up). The large number of contacts reflects the scale of potential exposure within affected communities. 

    The outbreak is unfolding in a conflict-affected humanitarian context marked by insecurity, armed violence, and large-scale displacement. 

    More than 26 million people face acute food insecurity, and an estimated one million internally displaced people live in Ituri Province alone. Insecurity and displacement disrupt access to health care and essential services, restrict access for response teams, and impede surveillance, case investigation and contact follow-up. 

    Overcrowding, limited water, sanitation and hygiene services, and restricted access to healthcare in mining communities, informal settlements and sites for internally displaced people further hinder early detection, infection prevention, and appropriate care. These conditions also make it harder to implement response measures consistently and to reach affected populations.  

Figure 2: Number of confirmed Bundibugyo virus disease cases in the Democratic Republic of the Congo, by date of notification, as of 26 August 2026

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Figure 3: Number of deaths among confirmed Bundibugyo virus disease cases in the Democratic Republic of the Congo by date of notification, as of 26 August 2026

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    Between 18 May and 28 August 2026, enhanced public health intelligence conducted by WHO identified 76 Ebola-related signals across 23 countries and territories, supporting rapid verification, risk assessment and information sharing with national authorities through IHR National Focal Points. Most signals, 92% (70/76), including suspected cases among travellers and health-care workers and reports circulating in public sources, were subsequently ruled out through investigation and laboratory testing. The remaining six were confirmed as Ebola events. 

Epidemiology

    Bundibugyo virus disease (BVD) is a severe Ebola disease caused by the Bundibugyo virus, one of the Orthoebolavirus species. It is a zoonotic disease, with fruit bats suspected to be the natural reservoir. 

    

    Human infection is thought to occur through close contact with the blood or secretions of infected wildlife, such as bats or non-human primates, and it subsequently spreads from person-to-person through direct contact with the blood, secretions, organs, or other bodily fluids of infected individuals or contaminated surfaces and materials. Transmission is particularly amplified in health-care settings when IPC measures are inadequate and during unsafe burial practices involving direct contact with deceased individuals. 

    The incubation period for BVD ranges from two to 21 days, and infected individuals are not infectious until symptom onset. Early symptoms such as fever, fatigue, muscle pain, headache, and sore throat are non-specific, which complicates clinical diagnosis and can delay detection. These symptoms then progress to gastrointestinal symptoms, organ dysfunction, and, in some cases, haemorrhagic manifestations. 

    CFRs in the past two BVD outbreaks, reported in Uganda and in the Democratic Republic of the Congo in 2007 and 2012, were 30% and 50%, respectively. 

    Differentiating BVD from other endemic febrile illnesses such as malaria is challenging without laboratory confirmation using PCR or antigen- or antibody-based assays. Outbreak control relies on rapid case identification, isolation and care, contact tracing, safe burials and strong community engagement, as no approved vaccines or specific treatments currently exist for BVD. 

    Since first detected in May 2026, this BVD outbreak has rapidly evolved into a large and geographically expanding epidemic in the Democratic Republic of the Congo, with sustained transmission, high mortality and an increasing risk of further international spread. The current outbreak is the second documented Bundibugyo virus disease outbreak in the country, after the 2012 outbreak, and the largest Ebola disease outbreak ever recorded in the Democratic Republic of the Congo irrespective of Ebola virus species. The population at greatest risk of exposure is concentrated in communities living in and moving through areas with active transmission.  

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WHO risk assessment

    On 14 August 2026, WHO reassessed the risk of the outbreak of BVD to incorporate newly available information. The risk for countries sharing land borders with the Democratic Republic of the Congo was separated from the risk for other countries in the African Region. 

    The risk in the Democratic Republic of the Congo was assessed as very high due to ongoing transmission and the continued expansion of the outbreak into new health zones, increasing the potential for further national and regional spread. The main considerations supporting this assessment include the substantial increase in the number of cases and considerable geographic extension of the outbreak since the previous risk assessment, and potential further increase in CFR as additional deaths are investigated and outcomes are established. In addition, reported transmission among healthcare workers, ongoing conflict and insecurity, laboratory capacity constraints, and absence of licensed vaccine or specific antiviral treatment were also considered as factors maintaining the very high risk. 

    The risk for countries sharing land borders with the Democratic Republic of the Congo was again assessed as high due to sustained population mobility linked to cross-border trade and mining activities, variation in capacities and experience of BVD response, and variable levels of readiness. Uganda, the Central African Republic and South Sudan are of particular concern for importation given their proximity, high population mobility and connectivity with areas of the Democratic Republic of the Congo currently experiencing intense transmission. For the Central African Republic and South Sudan, these risks are further compounded by high humanitarian needs, population displacement, insecurity and underlying limitations in health-system capacity. 

    The risk for the rest of the African region and at the global level was again assessed as low. 

(...)

Source: 

Link: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON616

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#Fatal case of respiratory #diphtheria in an unvaccinated #child in #Italy (ECDC, August 28 '26)

 

{Excerpt from ''Weekly Communicable Disease Threats Report, Week 35, 22–28 August 2026''}

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Overview:

Summary

    ° On 20 August 2026, media sources reported a fatal case of diphtheria  in Palermo, Sicily, involving a four-year-old {girl}. According to media  reports, the case manifested initial symptoms, including fever, reduced  appetite and vomiting between 10 and 11 August. The patient's condition  deteriorated progressively, with the development of high fever and respiratory  distress on 15 August. Owing to the worsening clinical presentation, the child was  hospitalised in the intensive medical care unit.

    ° Despite receiving organ-supportive treatment and diphtheria antitoxin, the patient died on 20 August. The child had not been vaccinated against diphtheria. 

    ° Clinical specimens were submitted to Italy's National Institute of Health (Istituto Superiore di Sanità, ISS) for laboratory confirmation of suspected  diphtheria. On 25 August, the ISS confirmed the detection of  Corynebacterium diphtheriae and identified the presence of the diphtheria  toxin gene, indicating infection with a toxigenic strain capable of causing  respiratory diphtheria.

    ° A second probable case was reported in a four-year-old cousin of the  first case, who was admitted to hospital with milder symptoms. According to  media reports, the child had been previously vaccinated against diphtheria.  The patient is being managed in isolation and is reported to be in a stable clinical condition.

    ° Local health authorities have initiated an epidemiological investigation, including contact tracing and active monitoring of contacts to  identify potential additional cases and limit further transmission.

    ° Public health measures have also been implemented, including  chemoprophylaxis of contacts and vaccination of the siblings of the first case. 

    ° Media sources have reported that 10 additional family members have tested positive for C. diphtheriae. These individuals were reported to be  vaccinated and in good clinical condition.

    ° However, as of 25 August, no additional cases besides the two described  above have been reportedofficially by local health authorities.

Background

    ° Diphtheria is a vaccine-preventable bacterial disease caused by  Corynebacterium diphtheriae.

    ° Transmission can occur from person to person through respiratory  droplets, direct contact with respiratory secretions, contact with exudate from  infected skin lesions or contaminated surfaces. 

    ° Infection may present as respiratory or cutaneous diphtheria.  Asymptomatic infection is also common, particularly in highly vaccinated  populations. The pathogenicity of C. diphtheriae is primarily related to the  production of the diphtheria toxin, which can cause local tissue damage, severe  systemic complications and even death. 

    ° Diphtheria is largely preventable through vaccination, and  unvaccinated or under-vaccinated individuals are at  higher risk of severe  disease and death. 

    ° Without timely diagnosis and treatment, respiratory diphtheria  can be  life-threatening, especially in unvaccinated, young children.

    ° Diphtheria remains a relatively rare disease in the EU/EEA due to high  vaccination coverage. In 2022, a large multi-country outbreak was recorded,  primarily affecting migrants and asylum seekers, with limited evidence of spread  to the general population. Reported cases declined in subsequent years, although  sporadic cases and localised transmission continue to occur, particularly among  vulnerable populations, including migrants, people experiencing homelessness,  and unvaccinated or under-vaccinated individuals.

ECDC assessment:

    ° The probability of widespread transmission of diphtheria in the general  population in the EU/EEA is considered low, due to high levels of  population immunity achieved through routine vaccination programmes. The  impact on the general population is also assessed as low, as high vaccination coverage reduces the risk of severe disease and death. Therefore, the  overall risk to the general population in the EU/EEA is considered low.

    ° Nevertheless, sporadic cases and localised clusters may occur in  settings where vaccination coverage is suboptimal or where conditions facilitate  transmission, such as overcrowded environments and settings with poor hygiene.  Imported cases may also occur among individuals travelling from endemic  geographical areas. Severe disease is more likely among susceptible groups,  including unvaccinated or under-vaccinated individuals, young children, older  adults, and immunocompromised individuals.

    ° Achieving and sustaining high vaccination coverage in the population is  crucial to prevent serious or fatal disease. In the event of cases, rapid clinical  recognition, prompt laboratory confirmation, timely administration of appropriate  treatment, and the identification and management of close contacts are essential to reduce morbidity, mortality, and onward transmission.

Actions:

    ° ECDC continues to monitor this event through epidemic intelligence activities and is liaising with the relevant national public health authorities to  collect additional information on the case and ongoing contact tracing and contact follow-up activities.

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Source: 

Link: https://www.ecdc.europa.eu/en/publications-data/communicable-disease-threats-report-22-28-august-week-35

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#Global Respiratory #Virus #Activity: Weekly #Update (WHO, August 28 '26)

 

{Excerpt, from Weekly Epidemiological Record}

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    The findings below are based on surveillance conducted through the WHO Global Influenza Surveillance and Response System (GISRS). 

    More details can be found on the Global Influenza Programme's surveillance and monitoring page.

Overview

    ° In week 33 2026, influenza positivity was below 10% and SARS-CoV-2 activity remained low globally. 

    ° During the past few weeks, influenza positivity remained just below 10% overall in the tropical areas and southern hemisphere temperate and subtropical areas. 

    ° RSV positivity also remained low globally.

Influenza

    ° Globally, influenza detections remained low in week 33 with influenza A and B viruses detected in similar proportions.

    ° In the southern hemisphere, influenza percent positivity was elevated (>10%) in one country in Temperate South America. 

    ° Percent positivity was over 30% in one country in Oceania where a medium increase in activity was observed.

    ° In the northern hemisphere, influenza percent positivity was elevated (>10%) in some countries in Central America and the Caribbean, Tropical South America, Western Africa, Western, Southern and South-East Asia and in single countries in Middle Africa, South West and Northern Europe and Eastern Asia. 

    ° Percent positivity was over 30% in single countries in Tropical South America, Western and Eastern Africa and Southern Asia. 

    ° Increases in activity were observed in some countries in Central America and the Caribbean and Southern Asia and in single countries in Tropical South America, Western, Eastern and Middle Africa, South West Europe and Western Asia.

    ° In the zones with elevated positivity, influenza A(H3N2) was predominant in South West Europe, Eastern Africa, Eastern Asia and Oceania; influenza A(H1N1)pdm09 was predominant in Western, Southern and South-East Asia and influenza B was predominant in Tropical and Temperate South America. 

    ° Influenza A and B were codominant in Central America and the Caribbean and Western Africa and influenza A(H1N1)pdm09 and influenza A(H3N2) were codominant in Middle Africa.

SARS-CoV-2

    ° Globally, SARS-CoV-2 positivity remained stable and low across most reporting countries, with elevated positivity (>10%) reported in countries in Central America and the Caribbean and in single countries in Tropical South America, Southern and South-East Asia. 

    ° Small increases in activity were observed in countries in Central America and the Caribbean, Northern Europe and in a single country in Southern Asia.

Respiratory Syncytial Virus (RSV)

    ° RSV positivity was elevated (>10%) in a few countries in Central America and the Caribbean, Tropical and Temperate South America and in a single country in Southern Asia. 

    ° Percent positivity was over 30% in a single country in Temperate South America. 

    ° Small increases in activity were observed in two countries in Central America and the Caribbean. 

    ° RSV and influenza activity were both elevated in single countries in Temperate South America and Southern Asia.

Severity assessment

    ° The severity assessments here are reported from countries, areas and territories. 

    ° Assessments for transmissibility can be reported based on syndromic parameters and/or influenza-specific parameters. 

    ° In the southern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as low (1) and moderate (1); transmissibility using syndromic data was reported as moderate (1). 

    ° In the northern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as below seasonal threshold (11) and low (2); transmissibility using syndromic data was reported as below seasonal threshold (8). 

    ° Influenza-specific transmissibility was reported as moderate in one country in the tropical areas.

Current update: Global Respiratory Virus Activity: Weekly Update N° 592

All past updates: Global respiratory virus updates

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Source: 

Link: https://www.who.int/publications/journals/weekly-epidemiological-record/wer101-34

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Modeling the #impact of respiratory disease #outbreaks on the #US #agricultural #workforce

 

Abstract

Background: 

Emerging respiratory disease outbreaks pose a major threat to food production systems. Agricultural workers face health disparities that amplify their susceptibility to respiratory pathogens, yet the consequences for worker health and food production remain poorly understood. 

Methods: 

We developed a household-structured susceptible-infectious-recovered (SIR) transmission model to compare disease dynamics between agricultural workers and the general U.S. population across six regions. We simulated outbreaks across a range of epidemiological scenarios and assessed productivity losses in California for three labor-intensive crops (oranges, iceberg lettuce, strawberries) with different harvest seasonalities. 

Results: 

We show that, for a baseline reproduction number of R0 = 2.0, the peak disease prevalence among agricultural workers is 1.41-1.69 times higher than that of the general population across regions, and final outbreak sizes are 1.29-1.42 times higher. Household structure accounts for 54%-68% of the disease disparity. Peak productivity losses range from 0.50%-0.63% across crops, translating to millions in lost potential revenue. At higher transmissibility and severity (R0 = 3 and assuming all infections are symptomatic), losses are 2.4 times higher. 

Conclusions: 

Household crowding may lead to disproportionate respiratory disease burden among agricultural workers that is exacerbated by vaccination and obesity disparities, highlighting the need for targeted outbreak preparedness and mitigation strategies in the agricultural sector to maintain food system resilience and support public health in these communities.

Competing Interest Statement

The authors have declared no competing interest.

Source: 

Link: https://www.medrxiv.org/content/10.64898/2026.03.31.26349871v2

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#USA, #Wastewater Data for Avian #Influenza #H5 (US CDC, August 28 '26)

 

{Excerpt}

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A(H5) detections in the past week

Time Period: August 16, 2026 - August 22, 2026

    -- A(H5) Detection: 3 site(s) (0.7%)

    -- No Detection: 437 site(s) (99.3%)

    -- No samples: 72 site(s)

{Click on Image to Enlarge}

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Source: 

Link: https://www.cdc.gov/wastewater/emerging-viruses/h5.html?

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Seasonal #surveillance in #humans in 2026 for #WNV #infection (ECDC, August 28 '26): 877 cases so far, of which 428 in #Italy

 

{Summary}

Week 35, 2026 | Produced on 27 August 2026 at 12:45, based on data submitted up until and including 26 August 2026.

Current situation

    ° Since the beginning of the 2026 transmission season, and as at 26 August, 124 areas affected by West Nile virus (WNV) have been identified in 15 countries across Europe.

    ° These areas are located in: 

        § Italy (55), 

        § Greece (17), 

        § Romania (15), 

        § France (13), 

        § Serbia (six), 

        § Spain (four), 

        § North Macedonia (three), 

        § Croatia (two), 

        § Germany (two), 

        § Albania (one), 

        § Austria (one), 

        § Cyprus (one), 

        § Hungary (one), 

        § Kosovo* (one) and 

        § the Netherlands (one).

    ° This week, 25 areas are reported as affected for the first time this season. (...).

    ° The 15 countries have reported 877 locally acquired human cases of WNV infection: 

        § Italy (428 cases), 

        § Greece (222 cases, of which eight with unknown place of infection), 

        § Spain (79 cases), 

        § North Macedonia (49 cases), 

        § Romania (45 cases), 

        § France (28 cases), 

        § Serbia (11 cases), 

        § Croatia (three cases), 

        § the Netherlands (three cases), 

        § Austria (two cases), 

        § Cyprus (two cases), 

        § Germany (two cases), 

        § Albania (one case), 

        § Hungary (one case) and 

        § Kosovo* (one case)

(...)

Source: 

Link: https://www.ecdc.europa.eu/en/west-nile-fever/surveillance-and-disease-data/disease-data-ecdc

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Chinese #Taipei - High pathogenicity avian #influenza #H5N1 viruses (Inf. with) (#poultry) - Immediate notification

 

    ° A recurrence of high pathogenicity avian influenza (HPAI) subtype H5N1 (clade 2.3.4.4b) was detected in native chickens at a slaughterhouse in Taipei City, Chinese Taipei. 

    ° On August 8, clinical signs were identified during postmortem inspection by the resident veterinarian, who immediately notified the Local Animal Disease Inspection Authority of Taipei City. 

    ° On the same day, diagnostic samples were collected and sent to the National Reference Laboratory; concurrently, the other 25 native chickens from the same source were depopulated and placed in frozen storage. 

    ° Following official confirmation of the positive case on August 10, the frozen carcasses were destroyed on August 11, with cleaning and disinfection completed thoroughly. 

    ° Trace-back investigation was immediately initiated, and the source poultry farm was placed under movement restriction; subsequent diagnostic testing yielded negative results for avian influenza nucleic acid. 

    ° There are no poultry farms within 3 kilometers of the slaughterhouse.

Source: 

Link: https://wahis.woah.org/#/in-review/7778

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Operational #epidemiology of the early phase of the 2026 #Bundibugyo virus disease #outbreak in the #DRC and #Uganda

 

Abstract

The 2026 Bundibugyo virus disease outbreak in the Democratic Republic of the Congo (DRC) and Uganda occurred in a fragile cross-border setting marked by delayed recognition, diagnostic uncertainty, insecurity, population mobility, community mistrust, and healthcare-worker exposure. We conducted a retrospective operational epidemiology study using official situation reports, public health declarations, ministry statements, WHO and Africa CDC updates, cross-border communiqués, and selected partner statements. This analysis reflects publicly available data from the early outbreak period, with the primary DRC data lock on 27 May 2026 and Uganda and regional triangulation through 29 May 2026. We reconstructed the early timeline, described epidemiological and geographic progression, quantified response indicators, and applied a transparent health-zone prioritization framework. The earliest documented symptom onset was 24 April 2026. The Institut National de Recherche Biomédicale (INRB) detected non-Zaire ebolavirus in eight of 13 samples on 14 May, giving a 20-day symptom-onset-to-first-laboratory-detection interval; species-level Bundibugyo virus confirmation and official declaration followed on 15 May. By the DRC data lock on 27 May, 125 confirmed cases and 17 confirmed deaths had been reported, giving a confirmed case fatality ratio of 13.6%. DRC also reported 906 suspected cases and 223 suspected deaths, giving a suspected fatality proportion of 24.6%. Confirmed cases expanded from three to 13 health zones across three provinces within 12 days. Ituri province accounted for 110 confirmed cases (88.0%); Bunia, Rwampara, and Mongbwalu health zones together contributed 90 cases (72.0%). Uganda reported nine confirmed cases and one death by 29 May. Operational pressure included 2,635 listed contacts in DRC, 436 contacts under follow-up in Uganda, and 126 of 774 collected samples (16.3%) pending testing in DRC. Healthcare workers represented 16 of 125 DRC confirmed cases (12.8%) and at least three of nine Uganda cases (33.3%). Applying the health-zone prioritization framework, Rwampara, Mongbwalu, and Bunia were classified as higher priority health zones. Excluding confirmed burden did not change any health-zone tier; data classification confidence was high for 10 zones and moderate for three. Within this early operational snapshot, outbreak visibility reflected both transmission and operational factors, particularly detection delay, laboratory backlog, cross-border movement, healthcare-linked exposure, and community trust or security incidents. The framework provides a transparent basis for rapid decision support during an outbreak’s early phase by directing surveillance, laboratory, case-management, infection prevention and control, contact-tracing, and community-engagement resources toward health zones where multiple operational risks converge.

Source: 

Link:https://journals.plos.org/globalpublichealth/article?id=10.1371/journal.pgph.0006680

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Pre-existing systemic and #nasal #antibodies against avian #H5 #influenza A viruses vary according to childhood #imprinting

 

ABSTRACT

Avian influenza A viruses (IAVs) pose a constant pandemic threat, with the recent 2.3.4.4b clade of the H5 subtype causing high pathogenicity and spreading across animal species and geographic locations. Understanding human pre-existing immunity to avian H5 IAV can inform on population susceptibility, a critical aspect of pandemic preparedness. To that end, we analyzed the IAV HA-specific antibodies across individuals born between 1928 and 1999 with different early life exposures to IAV subtypes. Individuals born prior to 1957 had the highest pre-existing serum antibodies to group 1 HA antigens, including the 2.3.4.4b H5 and a group 1 HA stem antigen. These birth year-specific patterns were not reflected in the limited pre-existing serum neutralizing antibodies detectable against a 2.3.4.4b H5 IAV or in H5-specific memory B cell populations. They were, however, evident in pre-existing nasal IgG and IgA titers to H5, which were greater in individuals born prior to 1957. Our findings demonstrate that the immunological biases afforded by early life exposure extend to antibodies detected in the nasal mucosa, the site of IAV replication.

Source: 

Link: https://journals.asm.org/doi/10.1128/mbio.01892-26

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West African Clade C #MERS-CoV Strains BF785 and Mor213 Induce More Robust #Interferon and Inflammatory Signaling Compared to Clade A in #Human Respiratory Cells

 

Abstract

Clade A Middle East respiratory syndrome coronavirus (MERS-CoV) spilled over from camels into humans in Saudi Arabia in 2012 and caused pneumonia and severe respiratory disease, with a 37% case fatality rate. While clade A and B viruses are closely related phylogenetically, clade B MERS-CoV strains have since outcompeted clade A strains and continue to circulate in camels and humans in the Middle East and cause outbreaks in humans. Clade C strains circulate in camels across the African continent but have not been reported to cause disease in humans. We have shown that a number of East African clade C isolates are less able to utilize the TMPRSS2-mediated pathway for viral entry in both cell lines and primary nasal epithelial cultures, which may underlie the reduced replication of East African clade C strains in humans. However, the reduced replicative capacity of West African strains in human cells appears to be independent of viral entry, suggesting an alternative basis for their attenuation. Here, we report that West African clade C MERS-CoV isolates with deletions in ORF4b encoding a key accessory protein, NS4b, induced significantly more robust interferon and inflammatory responses than clade A MERS in human respiratory cell lines and primary bronchial air–liquid interface cultures. The replication deficit for the West African strain BF785, which has a complete deletion of ORF4b, was partially rescued when RNASEL was knocked out in A549 cells. These findings demonstrate that complete loss of NS4b results in stronger innate immune activation than partial truncation and suggests that differential selection on NS4b may contribute to the varying phenotypes of clade C MERS-CoV strains circulating in African camels.

Source: 

Link: https://www.mdpi.com/1999-4915/18/9/935

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#Italy, #WNV & #Usutu Virus #Human Cases Weekly #Surveillance Report (ISS, August 27 '26): 432 cases so far this season, of which 223 #WNND

 

{Excerpt}

(...)

Highlights

    ° Since the beginning of surveillance season and as of August 26 '26, 432  human cases of infection with West Nile Virus have been confirmed in Italy. They were 312 last week. 

    ° Of these: 

        § 223 were WNND (of these, three were imported: 1 from Maldives, 1 from France and 1 from Belgium), 

        § 63 were asymptomatic cases in blood donors, 

        § 144 were West Nile Fever cases, 

    ° Among confirmed cases, 17 were fatal. 

    ° Case Fatality Rate (CFR) is so far at 7.2% (last year it was 13.9%) for severe neuroinvasive cases.

    ° So far this season, 10 human cases of infection with Usutu virus have been confirmed.

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Source:

Link: https://www.epicentro.iss.it/westnile/bollettino/Bollettino_WND_2026_5.pdf

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A cross-sectional #study of avian #influenza virus in #poultry #markets of #Guangdong #China, 2025

 

Abstract

Background: 

Guangdong, China is a critical epicenter for avian influenza virus (AIV) emergence, where H5N1 and highly pathogenic H7N9 were first identified. Monitoring AIV genotype distribution and genetic diversity in this region is essential for providing early warnings and mitigating the risk of human infections.

Methods: 

In May 2025, a cross-sectional study was conducted across 4 representative cities in Guangdong. We collected 500 environmental swabs and 45 wastewater samples from 23 live poultry markets (LPMs). Samples were screened for influenza A virus (IAV) and subtyped for H5, H7, and H9. Next generation sequencing (NGS) and phylogenetic analyses were employed to characterize viral diversity and zoonotic potential.

Results: 

AIV was detected in 49.2% (246/500) of environmental samples. H9 was the dominant subtype (38.2%), followed by H5 (3.2%) and H7 (0.8%); 2.4% of positive samples showed multi-subtype co-occurrence. “Non-restricted zone” markets (80.0%) and “waste storage areas” (68.4%) were identified as primary contamination hotspots. Phylogenetic analysis revealed that H5 and H9 viruses are accumulating mutations linked to enhanced human-type receptor affinity. Notably, H5 and H6 sequences exhibited long internal branches and clustered with isolates from other Asian countries rather than domestic strains, highlighting a significant gap in current domestic molecular surveillance and a lack of continuous evolutionary data for these genotypes.

Conclusions: 

Widespread AIV contamination persists in Guangdong LPMs, dominated by H9 with low-level circulation of highly pathogenic subtypes. The identified surveillance gaps for H5/H6 and the presence of multi-subtype environments underscore the urgent need for strengthened, integrated molecular monitoring and stricter market regulation to mitigate public health risks.

Source: 

Link: https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2026.1914072/full

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#Bundibugyo virus #glycoprotein seroreactivity following recombinant VSV–Zaire #Ebola virus glycoprotein #vaccination in outbreak-affected populations of #DRC: a longitudinal cohort study

 

Summary

Background

There are currently no licensed vaccines for disease caused by Bundibugyo virus (BDBV). The recombinant vesicular stomatitis virus–Zaire Ebola virus glycoprotein (rVSVΔG-ZEBOV-GP) vaccine has been widely deployed during Ebola virus disease outbreaks caused by Ebola virus (EBOV). Human studies have shown cross-reactive BDBV antibody responses following licensed Ebola virus disease vaccine administration, but the durability and longitudinal kinetics of these responses in populations vaccinated during outbreaks remain unknown. We aimed to evaluate BDBV glycoprotein seroreactivity following rVSVΔG-ZEBOV-GP vaccination in two longitudinal cohorts from regions of the Democratic Republic of the Congo affected by Ebola virus disease outbreaks.

Methods

This longitudinal cohort study was done in Mbandaka, Equateur Province, and Beni, North Kivu Province. Individuals aged 1 year and older who received the rVSVΔG-ZEBOV-GP vaccine under the WHO ring-vaccination protocol were eligible for enrolment. These populations were defined as: people with confirmed Ebola virus disease, contacts of people with Ebola virus disease or contacts-of-contacts, and health-care or front-line workers in areas affected by Ebola virus disease. Participants were enrolled from June 2 to July 3, 2018, in Mbandaka and from Aug 15 to 29, 2018, in Beni. Serum samples were collected from vaccine recipients and antibody reactivity was assessed using a multiplex pan-filovirus immunoassay. Both cohorts were followed up over 5 years, with seven data collection periods in each province. We evaluated longitudinal trends in EBOV and BDBV glycoprotein seroreactivity using a pan-filovirus multiplex immunoassay across follow-up visits.

Findings

We analysed 5849 serum samples from 1081 participants. 715 (66%) of 1081 participants were male and 366 (34%) were female. BDBV glycoprotein seroreactivity differed substantially between study sites. At baseline, 16 (3%) of 482 participants in Mbandaka and 62 (10%) of 599 in Beni were seroreactive to BDBV glycoprotein. In Mbandaka, BDBV glycoprotein antibody reactivity remained stable through to 6 months after initial vaccination before increasing from a mean median fluorescent intensity (MFI) of 1238 (SD 1599) at 2·5 years, with 16 (5%) of 355 seroreactive, to 4845 (5881) at 3·5 years and 116 (35%) of 329 seroreactive (p<0·0001), followed by waning at later visits. In Beni, BDBV glycoprotein antibody reactivity increased rapidly after the initial vaccination, with seroreactivity peaking at 21 days to a mean MFI of 6678 (SD 6997) with 283 (52%) of 541 participants seroreactive and at 6 months to an MFI of 6852 (6560) with 270 (54%) of 501 seroreactive. Although antibody levels decreased after 6 months, EBOV glycoprotein and BDBV glycoprotein antibody reactivity remained above baseline through to 5 years after vaccination.

Interpretation

The differing patterns of BDBV glycoprotein seroreactivity observed between Beni and Mbandaka warrant further investigation into the epidemiological and immunological factors associated with this seroreactivity, including the epidemiological significance of baseline seroreactivity observed before vaccination. To our knowledge, these findings provide the first longitudinal human data describing BDBV glycoprotein seroreactivity following licensed Ebola virus disease vaccination in populations living in regions now affected by the current outbreak of disease caused by BDBV. They add to the growing body of human evidence describing cross-reactive antibody responses following licensed Ebola virus disease vaccination and support rigorous clinical evaluation of rVSVΔG-ZEBOV-GP during the ongoing outbreak while BDBV-specific vaccines continue to be developed.

Funding

The US Food and Drug Administration, the Gates Foundation, and the US Defense Advanced Research Projects Agency.

Source: 

Link: https://www.sciencedirect.com/science/article/pii/S0140673626016089?dgcid=rss_sd_all

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Highly persistent #antibody levels but limited population #immunity in #gannets after #HPAI #outbreak

 

Abstract

The recent large-scale circulation of High Pathogenicity Avian Influenza (HP AI) viruses H5Nx of clade 2.3.4.4b has been responsible for massive die-offs in wild species, notably in long-lived seabirds, with unknown implications for the immunity of surviving individuals. In the North Atlantic, northern gannet colonies were heavily affected in 2022, with more than 40% mortality observed among breeding adults and some surviving individuals developing dark irises. Using samples collected in 2023 and 2024 on Rouzic colony (France), we report persistent individual anti-AI antibody levels and seroneutralisation titres, with most of the immune individuals showing dark irises. A modelling approach further stressed the importance of long-lasting immunity in such species by showing that the proportion of individuals which kept their immunity between years strongly limited decreases in population size in case of repeated outbreaks. Overall, our results highlight the existence and importance of long-lasting immunity in long-lived species for population persistence.

Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

CNRS Ecology Evolution SEE-Life program for long term monitoring

Ceva Wildlife Research Fund, CWR1

Agence Nationale de la Recherche, https://ror.org/00rbzpz17, ECOPATHS (ANR-21-CE35-0016), WILDFLU (ANR-25-CE35-0691)

Ailes Marines

Observatoire de Recherche Montpelliérain de l'Environnement OREME, https://ror.org/00cesps27, SO ECOPOP

Source: 

Link: https://www.biorxiv.org/content/10.64898/2026.08.25.745523v1

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Person died from a #WNV #infection acquired in the #Netherlands (RIVM, August 26 '26)

 

    In the province of Utrecht, someone has died from West Nile fever. 

    The person contracted the West Nile virus in the Netherlands and died in a hospital. Due to privacy and out of respect for the relatives, RIVM will not make any further statements about this person. 

    So far in 2026, there have been three cases of West Nile virus infections reported that were probably contracted in the Netherlands. 

    It is still very unlikely for people to contract West Nile fever in the Netherlands.

West Nile fever

    The West Nile virus occurs in birds. The common house mosquito can contract the virus when feeding on the blood of an infected bird. An infected mosquito can then pass the virus on to other birds, to mammals such as horses, and to humans. Humans and horses can fall ill with the West Nile virus, but they cannot pass the virus on to others. The disease caused by the West Nile virus is called West Nile fever.

    About 80% of people who contract the West Nile virus do not show any symptoms. Around 19% experience flu-like symptoms, and 1 per cent may develop neurological symptoms. People over 50 and people with weakened immune systems due to illness or medication have a higher risk of becoming very ill from West Nile fever. A small proportion of people who have a severe form of West Nile fever may die.

Alert on West Nile virus

    Experts from various organisations are closely keeping an eye on how often West Nile virus occurs in the Netherlands among humans, horses, birds, and mosquitoes. 

    So far this year, West Nile virus has been found in the provinces of Utrecht, North Brabant, and South Holland. It is possible that the virus is also present in other parts of the Netherlands. That is why RIVM has asked doctors across the country to be alert if they see people with symptoms that match West Nile fever.

What can you do to prevent West Nile fever?

    The West Nile virus is spread by common house mosquitoes that feed on the blood of an infected bird. Mosquitoes are mostly active at dusk. 

    To avoid mosquito bites as much as possible, you can, for example:

        ° wear clothing that covers the skin (long sleeves, long trousers)

        ° keep mosquitoes out (insect screens for windows/doors)

        ° use mosquito repellents on exposed skin

        ° sleep under a mosquito net

Source: 

Link: https://www.rivm.nl/en/news/person-died-from-west-nile-virus-infection-acquired-in-netherlands

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Evaluating the #impact of #antiviral post-exposure #prophylaxis for health-care workers during #orthoebolavirus outbreaks: a modelling study

 

Summary

Background

Orthoebolavirus outbreaks place health-care workers (HCWs) at substantial risk, and HCW illness or death can weaken response capacity. The 2026 Bundibugyo virus outbreak in DR Congo highlights the need for deployable countermeasures when species-specific vaccines are unavailable. With candidate antivirals under evaluation, we aimed to estimate the impact of HCW-targeted antiviral post-exposure prophylaxis (PEP) across different readiness, disruption, and allocation scenarios.

Methods

We adapted a previously published stochastic branching-process model of orthoebolavirus transmission, representing health care, community, and funeral transmission; time-varying non-pharmaceutical interventions; and HCW-targeted PEP. The model was calibrated to two historical outbreaks using sequential approximate Bayesian computation: the 2013–16 west Africa epidemic, to define a high-burden, reasonable worst-case scenario archetype (west Africa-like archetype); and the 2018–20 North Kivu and Ituri outbreak in eastern DR Congo, to define an archetype with longer transmission under conflict-related response disruption (DR Congo-like archetype). The primary outcome was HCW deaths averted. For both archetypes, we simulated three antiviral deployment readiness scenarios (scenario 1: 100% coverage on day 0; scenario 2: scaled up to 80% coverage over 180 days; and scenario 3: scaled up to 50% coverage over 1 year) and compared their impact on HCW deaths with a scenario of no antiviral. For the DR Congo-like archetype only, we simulated four disruption scenarios: no antiviral PEP, ideal delivery (100% coverage and no dosing delay), delayed dosing with coverage preserved, and delayed dosing with delayed coverage. As a secondary outcome, we assessed number of PEP doses required per HCW death averted under different allocation scenarios.

Findings

At baseline (no antiviral PEP), cumulative HCW deaths reached a median of 553 (IQR 208–983) in the west Africa-like archetype by week 60, compared with 61 (19–125) in the DR Congo-like archetype by week 80. Assuming 80% efficacy and 80% coverage with antiviral PEP in the same timeframe in a central analysis, cumulative HCW deaths fell to 200 (68–349; equivalent reduction of 64% [63–66] relative to baseline) in the west Africa-like archetype and 22 (10–44; equivalent reduction of 64% [60–68]) in the DR Congo-like archetype. Under different scenarios of deployment readiness at 80% antiviral efficacy, the median reduction in HCW deaths compared with no PEP was 80% (95% CrI 79–81) in the west Africa-like archetype and 80% (76–84) in the DR Congo-like archetype for scenario 1; 60% (57–62) and 52% (41–58), respectively, for scenario 2; and 19% (16–22) and 22% (7–29), respectively, for scenario 3. In the DR Congo-like operational disruption analyses, an ideal scenario (PEP delivered at 100% coverage without a delay after exposure) averted 83% (79–87) of HCW deaths compared with no antiviral; maintaining 100% coverage but introducing delayed dosing (1–5 days post-exposure) reduced this finding to 50% (40–55) compared with no antiviral. Delayed coverage and dosing resulted in only 35% (25–47) of the ideal scenario impact. At 80% antiviral efficacy with same-day dosing, targeted allocation of recognised high-risk exposures (such as personal protective equipment breaches or direct body-fluid contact) required 44 doses (95% Crl 43–44) per HCW death averted versus 109 doses (85–161) with broad allocation.

Interpretation

HCW-targeted antiviral PEP could substantially reduce HCW deaths during orthoebolavirus outbreaks if efficacious antivirals can be delivered rapidly and high operational coverage is maintained. Comparisons of antiviral use cases and alternative response investments are needed to determine how resources can best support outbreak response.

Funding

Gilead Sciences, UK National Institute for Health and Care Research, Oxford Martin School, Miller Institute, EU Global Health EDCTP3, and Coalition for Epidemic Preparedness Innovations.

Translations

For the French and Swahili translations of the abstract see Supplementary Materials section.

Source: 

Link: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(26)00437-8/fulltext?rss=yes

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