#Ebola disease caused by #Bundibugyo virus - #DRC (WHO D.O.N., September 25 '26): 7,890 cases and 3,799 deaths so far

 

{Extracts}

Situation at a glance

    Since the last Disease Outbreak News was published on 11 September 2026, the Bundibugyo virus outbreak in the Democratic Republic of the Congo has expanded further, with two additional health zones affected. 

    These include Bulu health zone in a new province, Sud Ubangi, located on the north-west part of the country and Dungu health zone in Haut-Uélé province, bordering South Sudan. 

    This brings the total number of affected health zones to 63 across seven provinces out of 26 provinces of the country: Bas-Uélé, Haut-Uélé, Ituri, North Kivu, South Kivu, Sud Ubangi and Tshopo. 

    This latest geographic expansion increases the risk of cross-border transmission. 

    As of 23 September 2026, the Democratic Republic of the Congo has reported 7890 confirmed cases, including 3799 deaths, resulting in a crude case fatality ratio (CFR) of 48.1%. 

    At the national level, the number of new cases reported each day remains high. However, the situation varies across the country, with some provinces and health zones experiencing much higher levels of transmission than others. 

    The continuously high CFR, and especially the continuous high rate of deaths occurring in communities, highlights the seriousness of the disease and the persistent challenges in timely case detection and access to early and adequate patient care. 

    These delays can contribute to preventable illness and deaths among people in affected and newly affected areas, while also allowing transmission to continue within households, communities, and healthcare settings.

Description of the situation

    Since the previous Disease Outbreak News was published on 11 September 2026, an additional 1133 confirmed cases, including 532 confirmed deaths, have been reported in the Democratic Republic of the Congo. 

    The seven-day moving average shows a resurgence in early September followed by a decline over the most recent reporting days. 

    However, the aggregate national trend conceals substantial variation in transmission intensity across affected provinces and health zones. 

    As of 23 September, the Democratic Republic of the Congo has reported a total of 7890 confirmed cases, including 3799 deaths (CFR 48.1%). 

    A total of 1966 patients have recovered to date. 

    Confirmed cases have been reported from 63 health zones across seven provinces, with 48 health zones from six provinces reporting at least one case in the last 21 days. 

    Ituri remains the most affected province, with 28 of its 36 health zones reporting cases, followed by North Kivu (16/34), Tshopo (7/23), Haut-Uélé (7/13), Bas-Uélé (3/11), South Kivu (1/34), and Sud Ubangi (1/16). 

    No new cases have been reported from South Kivu province since 29 May 2026.  

    Dungu Health Zone in Haut-Uélé province and Bulu in Sud Ubangi are the most recently affected areas. 

    As of 23 September, 70 new confirmed cases had been reported in the preceding 24 hours from 26 health zones located in Ituri, North Kivu, Haut-Uélé, Bas Uélé and Tshopo provinces.  

(...)

    Ituri continues to be the epicentre of the outbreak, accounting for 6032 confirmed cases since the start of the outbreak, including 868 new confirmed cases reported in the previous 21 days, as of 23 September. 

    North Kivu is the second most affected province, with a cumulative number of 1480 confirmed cases, including 567 reported in the last 21 days, as of 23 September. 

    North Kivu province continues to report the highest CFR (59.7%) observed in this outbreak; and investigations are ongoing to better understand the factors contributing to this elevated mortality rate. 

    In Ituri, case incidence continues to decline gradually from the peak observed in mid-August, although transmission remains at elevated levels. 

    North Kivu, in contrast, has experienced a substantial increase in incidence, reaching its highest reported level in mid-September, followed by a decline in recent reporting days. 

    Haut-Uélé continues to demonstrate sustained transmission, albeit at levels below the peak recorded in late August, while Tshopo is showing renewed transmission activity following a period of low incidence. 

    In Bas-Uélé, transmission remains sporadic, whereas no recent evidence of transmission has been reported in Sud-Kivu. 

    Sud Ubangi is the seventh province to report a confirmed case of BVD, with one case that was reported on 10 September (Figure 2). 

    The number of individuals requiring follow-up as contact has also risen considerably with the expansion of the outbreak. 

    As of 23 September, 83.4% of identified contacts were successfully monitored during the previous 24 hours with 26 980 contacts seen out of 32 342 requiring follow up. 

    The large volume of contacts under surveillance highlights the extent of potential exposure within affected communities and the substantial demands placed on response operations. 

    The response is being implemented in a challenging humanitarian environment, where conflict, insecurity, displacement, and limited access to basic services continue to affect outbreak control.  These constraints continue to hamper surveillance, case finding, contact tracing, infection prevention and control, and timely access to appropriate care, thereby limiting the overall effectiveness of response activities. 

Figure 2: Number of confirmed Bundibugyo virus disease cases in the Democratic Republic of the Congo, by date of notification, as of 23 September 2026

{Click on Image to Enlarge}

___

Figure 3: Number of deaths among confirmed Bundibugyo virus disease cases in the Democratic Republic of the Congo by date of notification, as of 23 September 2026. 

{Click on Image to Enlarge}

___

(...)

WHO risk assessment

    On 14 August 2026, WHO reassessed the risk of the outbreak of BVD, incorporating newly available information on the evolving situation. 

    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, the risk for countries sharing land borders with the Democratic Republic of the Congo was assessed as high, and the risks 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-DON618

____

#Recommendations announced for #influenza #vaccine composition for the 2027 southern hemisphere influenza season (WHO, extract)

 

{Excerpts}

(...)

    From February to August 2026, influenza A(H1N1)pdm09, A(H3N2) and influenza B viruses circulated in varying proportions across all regions of the world, causing disease. 

    Influenza A viruses were the most common in most regions, except Northern and Western Africa, North America and Eastern Asia, where influenza B viruses dominated.

    WHO recommends that vaccines for use in the 2027 southern hemisphere influenza season contain the following:

Egg-based vaccines

    ° an A/Missouri/11/2025 (H1N1)pdm09-like virus;

    ° an A/Darwin/1454/2025 (H3N2)-like virus; and

    ° a B/Tokyo/EIS13-175/2025 (B/Victoria lineage)-like virus.

Cell culture-, recombinant protein- or nucleic acid-based vaccines

    ° an A/Missouri/11/2025 (H1N1)pdm09-like virus;

    ° an A/Darwin/1415/2025 (H3N2)-like virus; and

    ° a B/Pennsylvania/14/2025 (B/Victoria lineage)-like virus.

    As part of the review, experts also looked at influenza viruses circulating in animals, particularly those that have caused infections in humans. These animal or zoonotic influenza viruses remain a significant concern because of their potential to cause pandemics.

(...)

Source: 

Link: https://www.who.int/news/item/25-09-2026-recommendations-announced-for-influenza-vaccine-composition-for-the-2027-southern-hemisphere-influenza-season

____

Seasonal #surveillance in #humans in 2026 for #WNV - Weekly Report (ECDC, Sept. 25 '26): 1,569 cases so far of which 696 in #Italy

 

{Extracts}

(...)

Week 39, 2026 | Published on 25 September 2026, based on data submitted up until and including 23 September 2026.

Current situation

    Since the beginning of the 2026 transmission season, and as at 23 September, 186 areas affected by West Nile virus (WNV) have been identified in 16 countries across Europe.

    These areas are located in: 

        § Italy (65), 

        § Greece (22), 

        § Romania (22), 

        § France (21), 

        § the Netherlands (13), 

        § Serbia (8), 

        § Spain (6), 

        § Croatia (5), 

        § North Macedonia (5), 

        § Belgium (4), 

        § Hungary (4), 

        § Austria (3), 

        § Germany (3), 

        § Kosovo (3), 

        § Albania (1) and 

        § Cyprus (1).

    This week, six areas are reported as affected for the first time this season. The affected areas identified as at 23 September 2026 are listed in Table 1 and shown in Map 1 below.

    The 16 countries have reported 1 569 locally acquired human cases of WNV infection: 

        § Italy (696 cases), 

        § Greece (355 cases, of which 8 had an unknown place of infection), 

        § Spain (125 cases), 

        § France (102 cases), 

        § Romania (91 cases), 

        § North Macedonia (69 cases), 

        § Serbia (46 cases), 

        § the Netherlands (28 cases), 

        § Croatia (13 cases), 

        § Cyprus (13 cases), 

        § Belgium (9 cases), 

        § Austria (7 cases), 

        § Hungary (5 cases), 

        § Germany (4 cases), 

        § Kosovo (4 cases) and 

        § Albania (2 cases)

(...)

Source: 

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

____

Modelling #assessment of the different #paths of between-farm #transmission of avian #influenza HPAI in Northern #Italy in 2021--2022

 

Abstract

We propose a stochastic epidemic model to describe the spread of avian influenza in a network of poultry farms. We consider three main paths of infection transmission between poultry farms: from nearby farms, mainly through airborne diffusion; from farms belonging to the same company, through shared veterinarians, forage providers and similar; from undetected small farms or wildlife. From the parameter estimation, based on a modified Expectation-Maximization algorithm, we infer that approximately 63% of the farms were infected from nearby ones, with an infection force declining with distance; of these, more than one third belonged to the same company of the estimated infector. About 20% were infected from premises belonging to the same company but farther away than the distance threshold of 2 km; the remaining ones from wildlife or unidentified sources. These estimates have been validated by a comparison with genetic data, available for a subset of the farms: the genetic distance between two farms identified, with high probability, as an infector-infectee pair is much lower than between random pairs. These results may help in the implementation of tailored prevention and control measures for future outbreaks.

Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

Fondazione Caritro (Cassa di Risparmio di Trento e Rovereto), Post-Doc 2024 project ``Modelli matematici di malattie infettive piu` ospiti e popolazioni eterogenee: applicazioni all'influenza aviaria''

Source: 

Link: https://doi.org/10.64898/2026.09.19.752832

____

#Australia, #H5 avian #influenza events in #wildlife (Dept. of Agriculture, Sept. 25 '26)

 

{Extracts}

(...)

Event data

    ° 650 Positive events

    ° 51,361 Hotline reports

    As of 4pm AEST, 24 September 2026, Australia has 650 confirmed events of H5 bird flu in wildlife.

        § 10 in Western Australia (WA)

        § 318 in South Australia (SA)

        § 66 in New South Wales (NSW)

        § 2 in Queensland (QLD)

        § 208 in Victoria (VIC)

        § 45 in Tasmania (TAS)

        § 1 in Other Territories*

{*} Jervis Bay Territory (Commonwealth jurisdiction)

    As H5 bird flu is confirmed in more locations and species in Australia it will not be necessary to continue testing all species in known areas of transmission, or to test every animal involved in an investigation. 

    Reporting will be targeted to provide a clear picture of the national H5 bird flu situation in wildlife in Australia and key developments.

Data disclaimer

    Data reflects information provided by state and territory governments to the Australian Government as at 17:00 AEST daily. The Australian Government publishes this information for national reporting purposes. Responsibility for the accuracy, completeness and currency of the data remains with the relevant state or territory government. Due to differences in reporting timing, information on the national dashboard may differ from information published on state or territory government websites.

{Click on Image to Enlarge}

___

(...)

Source: 

Link: https://www.agriculture.gov.au/campaigns/birdflu/latest-data#h1_bird_flu

____

#Italy, Seasonal #Human Cases #WNV & #Usutu Virus #Surveillance - Weekly Report No. 9 (ISS, Sept. 24 '26): 700 cases with 54 deaths so far

 

{Extract, Summary}

(...)

Summary

    ° Since the beginning of arboviral infection season and as of Sept. 23 '26, 700 confirmed human cases of WNV have been recorded (they were 657 in last week update). 

    ° Of these: 

        § 368 were West Nile Neuroinvasive Disease, of which 5 imported: 1  from Maldives, 1 France, 1 Belgium, 1 Greece and 1 the Netherlands, 

        § 88 were asymptomatic cases among blood donors, 

        § 239 were West Nile Fever cases, 

        § 4 were unspecified cases, 

        § 1 was an asymptomatic case (Table 1).

    ° The number of affected Provinces has risen to 83 in 19 Regions.

    ° Among confirmed cases, 54 deaths have been reported. The Case-Fatality Rate in WNND cases is now 14.6% (in 2025 it was 14.9%).

    ° So far this season, 15 human cases of Usutu virus have been reported (8 in Lombardy, 1 Emilia-Romagna, 1 Marche, 2 Latium, 1 Piedmont, 2 Veneto).

Figure 1. Weekly Confirmed Human Cases of WNV, Italy: 2025 & 2026 Seasons

{Click on Image to Enlarge}

___

(...)

Source: 

Link: https://www.epicentro.iss.it/westnile/bollettino/Bollettino_WND_2026_9.pdf

____

Field #Investigation of #Bundibugyo Virus Disease (BDBV) #Outbreak in Ituri Province, #DRC: ... An Outbreak Investigation Review

 

Abstract

Background: 

The 2026 outbreak of Bundibugyo Ebola virus disease (BDBV) in eastern Democratic Republic of the Congo (DRC), centered in Ituri Province, represents the largest documented outbreak caused by Bundibugyo ebolavirus since its discovery in Uganda in 2007. The outbreak evolved within a complex humanitarian setting characterized by armed conflict, population displacement, mining-related migration, weak health systems, extensive population mobility, and an infodemic environment marked by misinformation and reduced public trust. We conducted a field investigation to assess epidemiological, operational, laboratory, infection prevention and control (IPC), community engagement, risk communication, and infodemic management challenges and identify priority interventions to strengthen outbreak control. 

Methods: 

A rapid field assessment was conducted between 12–15 June 2026 in Bunia, Rwampara Health Zone, and the Ituri Provincial Public Health Laboratory. Data were collected through direct observation, review of surveillance and laboratory reports, health facility assessments, stakeholder interviews, and analysis of outbreak response indicators. Epidemiological trends, surveillance performance, laboratory capacity, clinical care, IPC activities, logistics, risk communication, community engagement, and infodemic management approaches were evaluated. 

Results: 

As of 12 July 2026, the outbreak had resulted in 1926 laboratory-confirmed cases and 702 deaths, corresponding to an overall case fatality rate (CFR) of 36.4% across affected provinces. Ituri Province remained the epicenter, accounting for 90.8% of confirmed cases (1705/1877) and 85.5% of reported deaths (577/675). During the preceding 24 h, 53 new confirmed cases and 30 deaths were reported, including 20 community deaths (66.7%), highlighting persistent delays in detection, referral, and access to care. Surveillance systems identified 766 alerts, of which 678 (88.5%) were investigated, resulting in 235 suspected cases. Contact tracing remained a major challenge, with only 64.4% (4171/6475) of registered contacts successfully followed, below the recommended ≥95% target. Laboratory activities included testing of 137 specimens, with 29 positive results and an overall positivity rate of 21.2%. Decentralized molecular diagnostic platforms improved access to testing; however, data inconsistencies, delayed investigations, and gaps in outcome classification affected response monitoring. Major operational challenges included limited treatment capacity, high occupancy of Ebola treatment centres, shortages of trained personnel and IPC supplies, insecurity affecting response teams, and insufficient preparedness in newly affected areas. Community resistance, attacks on burial teams, detention of frontline responders, misinformation, and rumors contributed to delayed care-seeking, reduced acceptance of public health measures, and incomplete cooperation with contact tracing. Risk communication and community engagement efforts were constrained by limited outreach capacity, language barriers, low trust, and inadequate systems for rumor detection and infodemic response. 

Conclusions: 

The ongoing BDBV outbreak in eastern DRC demonstrates the difficulty of controlling Ebola transmission in conflict-affected and socially complex settings. Sustained transmission, community deaths, geographic expansion, and operational constraints highlight the urgent need to strengthen surveillance, contact tracing, laboratory systems, IPC capacity, clinical care, and integrated risk communication and infodemic management strategies. Building trust through community-centered approaches, proactive misinformation management, and engagement of trusted local actors will be essential to accelerate outbreak containment and strengthen preparedness across the Great Lakes region.

Source: 

Link: https://doi.org/10.3390/idr18050100

____

#Australia, #H5 avian #influenza events in #wildlife (DAFF, September 24 '26)

 

{Extracts}

(...)

Event data

    ° 640 Positive events

    ° 50,755 Hotline reports

    As of 4pm AEST, 23 September 2026, Australia has 640 confirmed events of H5 bird flu in wildlife.

        § 10 in Western Australia (WA)

        § 317 in South Australia (SA)

        § 66 in New South Wales (NSW)

        § 2 in Queensland (QLD)

        § 199 in Victoria (VIC)

        § 45 in Tasmania (TAS)

        § 1 in Other Territories*

{*} Jervis Bay Territory (Commonwealth jurisdiction)

    As H5 bird flu is confirmed in more locations and species in Australia it will not be necessary to continue testing all species in known areas of transmission, or to test every animal involved in an investigation. 

    Reporting will be targeted to provide a clear picture of the national H5 bird flu situation in wildlife in Australia and key developments.

Data disclaimer

    Data reflects information provided by state and territory governments to the Australian Government as at 17:00 AEST daily. The Australian Government publishes this information for national reporting purposes. Responsibility for the accuracy, completeness and currency of the data remains with the relevant state or territory government. Due to differences in reporting timing, information on the national dashboard may differ from information published on state or territory government websites.

{Click on Image to Enlarge}

___

(...)

Source: 

Link: https://www.agriculture.gov.au/campaigns/birdflu/latest-data#h1_bird_flu

____

#Oya Virus in a Patient with Severe #Hepatitis, #Enteritis, and #Coagulopathy

 

Abstract

Oya virus, an orthobunyavirus, was identified in a 54-year-old woman who had sepsis-like symptoms, including leukocytosis, thrombocytopenia, elevated liver-function values, and disseminated intravascular coagulation.

Source: 

Link: https://doi.org/10.1056/NEJMc2602616

____

#Estimation of the #transmission #dynamics of #H5N1 HPAI #outbreak in a dairy #herd using a modeling approach

 

Abstract

The emergence of Highly Pathogenic Avian Influenza (HPAI 2.3.4.4b) in dairy herds in 2024 across 19 states in the United States of America has raised concerns regarding the potential national and global zoonotic impact. All recent modeling efforts implemented homogenous cattle-to-cattle (both intra and inter-herd) transmission models which did not capture the real-world heterogeneity in mixing of animals, individual variations in susceptibility and infectiousness and clinical incidences across pens and lactation groups. The aim of this study was to develop a heterogenous transmission model to estimate the epidemiological parameters for intra-herd HPAI transmission on Californian dairies. We developed a validated stochastic agent-based model to estimate the epidemiological parameters for intra-herd HPAI transmission on California dairies. The hierarchical agent-based model also parameterized stochastic cattle movements within-herd to simulate real dairy management practices. A cow-level SEIR transmission approach was assumed during the outbreak. A novel Bayesian Optimizer with Gaussian Process (BO-GP) was fitted to the agent-based model for validation which converged within 25-40 iterations (out of 100 per farm) with minimal loss over two distinct error metrics, namely, Poisson loss function and temporal distance metric. Our optimized simulations estimated an average R0 was around 10.7-10.8 across all farms within the first 15 days of observed outbreak on four dairy farms with a mean effective transmission rate of 4.5% per contact between susceptible and infectious cows within each pen. Our model demonstrated that the movement of cows between pens ensured localized clusters of outbreaks within the sub-herds (pen population) that prolonged the overall outbreak within farms. We estimated the total duration of infection between 14.5 and 28 days, which is higher than the estimates from the homogenous models. With an integrated hierarchical agent-based model combined with Bayesian approximation, we produced actionable insights on the epidemiology of intra-farm spread of HPAI within cow herds, thereby guiding both future model development and applied disease control strategy.

Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

Animal and Plant Health Inspection Service (USDA-APHIS), AP25VSD&B000C007

Source: 

Link: https://doi.org/10.64898/2026.09.22.753543

____

Comparison of #Baloxavir-Based Combinations and Monotherapies for Treating #Influenza #H5N1 Clade 2.3.4.4b Virus #Infection in Mice

 

Abstract

Highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b virus continues to cause animal outbreaks and sporadic zoonotic infections. In a mouse model of lethal influenza disease, we compared oseltamivir, baloxavir, and molnupiravir monotherapies with 2-drug combinations. Baloxavir-based combinations improved survival, reduced lung viral loads, and prevented extrapulmonary dissemination, supporting H5N1 preparedness strategies.

Source: 

Link: https://doi.org/10.3201/eid3210.260186

____

#Australia, #H5 avian #influenza events in #wildlife (DAFF, September 23 '26)

 

{Extracts}

(...)

Event data

    ° 625 Positive events

    ° 49,864 Hotline reports

    As of 4pm AEST, 22 September 2026, Australia has 625 confirmed events of H5 bird flu in wildlife.

        § 10 in Western Australia (WA)

        § 317 in South Australia (SA)

        § 56 in New South Wales (NSW)

        § 2 in Queensland (QLD)

        § 195 in Victoria (VIC)

        § 44 in Tasmania (TAS)

        § 1 in Other Territories*

{*} Jervis Bay Territory (Commonwealth jurisdiction)

    As H5 bird flu is confirmed in more locations and species in Australia it will not be necessary to continue testing all species in known areas of transmission, or to test every animal involved in an investigation. 

    Reporting will be targeted to provide a clear picture of the national H5 bird flu situation in wildlife in Australia and key developments.

Data disclaimer

    Data reflects information provided by state and territory governments to the Australian Government as at 17:00 AEST daily. The Australian Government publishes this information for national reporting purposes. Responsibility for the accuracy, completeness and currency of the data remains with the relevant state or territory government. Due to differences in reporting timing, information on the national dashboard may differ from information published on state or territory government websites.

{Click on Image to Enlarge}

___

(...)

Source: 

Link: https://www.agriculture.gov.au/campaigns/birdflu/latest-data#h1_bird_flu

____

A single-cycle, recombinant VSV #platform #Nipah #vaccine cross-protects against #Hendra virus in nonhuman #primates

 

Abstract

Nipah virus (NiV) and Hendra virus (HeV) are highly pathogenic paramyxoviruses that produce severe, often fatal disease in humans and animals. Zoonotic spillover of these henipaviruses from the Pteropid bat natural reservoir occurs near-annually in Southeast Asia and Oceania. Outbreaks of NiV disease frequently exceed case fatality rates of 75%, and person-to-person transmission makes controlling outbreaks in low-resource environments challenging. HeV is less transmissible between humans; however, the overall mortality rate is 57%. Approaches to human vaccine development have largely focused on NiV given the larger case burden, and immunogen selection has centered on display of the NiV attachment (G) or fusion (F) surface glycoproteins. However, experimental vaccines displaying these NiV antigens have failed to uniformly cross-protect against HeV disease in preclinical models. The HeV (G) antigen was shown to cross-protect against both HeV and NiV when delivered in a protein subunit form; however, attempts to utilize mRNA or canarypox vectors failed to achieve equivalent protection. We previously developed and evaluated a single-cycle recombinant vesicular stomatitis virus-vectored vaccine displaying the (G) glycoprotein of Nipah virus strain Bangladesh (NiV-B). This experimental vaccine (G*rVSV∆G-NiV-G) demonstrated ideal characteristics of rapid and durable protection against NiV-B challenge in nonhuman primates. In the present work, we show that the G*rVSV∆G-NiV-G vaccine cross-protects against lethal HeV challenge, with the protective response driven by a balance of both cell-mediated and humoral compartments.

Source: 

Link: https://doi.org/10.1371/journal.ppat.1014646

____

Highly Pathogenic Avian #Influenza Virus #H5 in #Cetaceans, #Brazil

 

Abstract

We identified highly pathogenic avian influenza virus subtype H5 in stranded dolphins along the coastline of Brazil during 2023–2025. Infected animals included species classified as vulnerable or endangered. Our results highlight the need for ongoing surveillance of cetaceans susceptible to viral infections, which pose an additional threat to threatened species.

Source: 

Link: https://doi.org/10.3201/eid3210.260051

____

Emergence of short-lived #meningococci causing focal #epidemics can be associated with #gene #transfer from carriage-associated #Neisseria

 

Abstract

In March 2026, an unusually large outbreak of invasive meningococcal disease (IMD) in Kent, UK, was linked to attendance at one nightclub over a single weekend. The outbreak organism was a Neisseria meningitidis variant belonging to the longstanding hyperinvasive genotype, cc41/44. Using genome analysis of six isolates from patients, alongside >48,000 meningococcal genomes, we investigated whether the outbreak variant had acquired traits potentially contributing to the highly invasive phenotype. The six isolates were capsular group B, sequence type (ST-)485, and essentially indistinguishable, consistent with the focal nature of the outbreak. Compared with their closest available relatives, we found changes mediated by phase variation, nucleotide variation, and horizontal gene transfer (HGT) involving adhesins, iron-acquisition systems (including Transferrin and Lactoferrin binding proteins, and FetA), and Type IV pili (Tfp), factors which affect bacteria-bacteria and bacteria-host interactions. These changes occurred in a ST-485 sub-lineage that expressed capsule at high levels and a PorA porin with a truncated surface-exposed epitope, both of which are predicted to reduce immune recognition. Donors for the HGT events were predominantly carriage-associated N. meningitidis and Neisseria cinerea. We show that meningococcal variants responsible for previous focal outbreaks have not been seen subsequently. We propose that focal outbreaks of IMD are caused by meningococcal variants that may have acquired traits from non- or less invasive organisms, but subsequently these variants disappear, as their highly invasive phenotype is inconsistent with sustained transmission. Ongoing disease surveillance alongside carriage studies are therefore essential to inform public health risk and manage epidemic IMD.

Competing Interest Statement

CMT and RME are inventors on patents for meningococcal vaccines. JPD is a co-founder and Director of Immunosig Ltd, a company which offers antigen microarray-based services. JL, RB, SAC and XB perform contract research on behalf of UKHSA for GSK, Pfizer, Sanofi and Serum Institute of India.

Funder Information Declared

Wellcome Trust, https://ror.org/029chgv08, 218205/Z/19/Z, 221924/Z/20/Z

NIH Common Fund, https://ror.org/001d55x84, R01AI127793

Source: 

Link: https://doi.org/10.64898/2026.09.17.752363

____

Avian #influenza #overview June–August 2026 (ECDC/EFSA, September 22 '26, Summary)

 

{Summary}

Abstract

    Between 5 June and 28 August 2026, 110 highly pathogenic avian  influenza (HPAI) A(H5N1) virus detections were reported in domestic (7)  and wild (103) birds in 12 countries in Europe. The number of detections  remained at a seasonal low throughout the summer, continuing the decline  observed since spring. In contrast to previous years, fewer colony-breeding  seabirds were affected, and the geographical range of detections was more  limited. Further sporadic detections of HPAI A(H5) virus were reported in wild  terrestrial carnivores and pinnipeds. Outside Europe, the epidemic continued  in the Americas, where also the HPAI A(H7N3) subtype was detected in Mexico.  Following its first introduction to mainland Australia, HPAI A(H5N1) virus spread within local wild bird populations and spilled over to terrestrial  carnivores and marine mammals. In the US, the number of dairy  cattle farms reportedly affected by HPAI A(H5N1) increased, while detections in  captive American minks were reported for the first time. Between 5 June and  31 August 2026, 15 cases of avian influenza virus infection were publicly  reported in humans (no fatal cases) in three countries and territories:  Bangladesh (one A(H5N1) case), Cambodia (one A(H5N1) case) and China (13 A(H9N2) cases). All human cases reported exposure to poultry or a poultry  environment prior to detection or onset of illness. Human infections with avian  influenza viruses remain rare and no sustained human-to-human transmission has  been documented. The risk posed by avian influenza A(H5N1) clade  2.3.4.4b viruses currently circulating in Europe remains low for the general  public in the European Union/European Economic Area (EU/EEA) and low-to- moderate for those occupationally or otherwise exposed to infected animals or  contaminated environments.

©2026 European Food Safety Authority, European Centre for Disease Prevention  and Control, European Union Reference Laboratory for Avian Influenza. EFSA  Journal published by WileyVCH GmbH on behalf of European Food Safety Authority

(...)

Source: 

Link: https://doi.org/10.2903/j.efsa.2026

____

#Bundibugyo Virus Disease #Outbreak, #DRC - Situation #Report 19, Data as of 20 September 2026 (WHO, summary): 7,733 cases & 3,732 deaths so far

 

{Summary}

{Click on Image to Enlarge}

___

Event description

    The Bundibugyo virus disease (BVD) outbreak in the Democratic Republic of  the Congo has expanded further, with Dungu Health Zone in Haut-Uélé  Province, bordering South Sudan, being the latest affected, bringing the total  number of health zones affected to 63 since the start of the outbreak. 

    This latest geographic expansion heightens concern about further spread  towards international borders, while transmission within the country remains  increasingly heterogeneous across affected provinces and health zones. 

    Since External Situation Report #18, a further 475 confirmed cases and  222 confirmed deaths have been reported, bringing the cumulative total  to 7733 confirmed cases, including 3732 deaths [crude case fatality ratio (CFR 48.3%)], as of 20 September 2026. 

    Ituri remains the principal focus, although its relative contribution  continues to decline, accounting for 76.9% of cumulative confirmed cases, while substantial transmission continues in Nord-Kivu and persists in Haut-Uélé.

    At the national level, daily incidence remains high and fluctuating, with the  seven-day moving average rebounding in early September before declining in the  most recent days. This national pattern masks divergent provincial trajectories. 

    Ituri continues a gradual decline from its late-July peak but remains at a  high level, while Nord-Kivu experienced a marked increase, reaching its highest  incidence in mid-September, followed by an apparent decline in recent days.

    Transmission in Haut-Uélé remains sustained but below its August peak,  while Tshopo shows renewed activity from a low baseline. Bas-Uélé continues to  report sporadic transmission, with no recent transmission evident in Sud-Kivu.

    Overall, the epidemic remains geographically heterogeneous, with  recent declines in the principal transmission areas occurring alongside persistent  low-level transmission and continued geographic expansion to new areas.

Figure 1. Daily national trend in confirmed Bundibugyo virus disease cases, with  seven-day moving average, by date of report, Democratic Republic of the Congo,  as of 20 September 2026

{Click on Image to Enlarge}

___

(...)

    During the most recent 21 days (31 August – 20 September 2026), a total of 1633 confirmed cases were reported nationally. 

    

    Compared with 1719 cases during the preceding 21-day period (10 – 30  August 2026), this represents a decrease of 86 cases (−5.0%). 

    Reported cases declined by 25.8% in Ituri, from 1255 to 931, and by  18.3% in Haut-Uélé, from 109 to 89. 

    

    In contrast, cases increased sharply by 72.7% in Nord-Kivu, from 341 to  589, while Tshopo increased from 10 to 20 cases. 

    Bas-Uélé reported three cases compared with four during the preceding  period, while one case was reported in Sud-Ubangi. 

    Consequently, Ituri’s contribution to newly reported cases fell markedly  from 73.0% to 57.0%, while Nord-Kivu’s contribution increased from 19.8% to  36.1%; Haut-Uélé’s contribution declined from 6.3% to 5.5%. 

    Overall, the modest 5.0% national decline masks a pronounced geographic  redistribution of transmission, with the substantial decline in Ituri  increasingly offset by continued high transmission in Nord-Kivu and geographic  expansion to new areas.

    During the same period, 782 confirmed deaths were reported nationally,  compared with 939 deaths during the preceding 21 days, representing a decrease of 157 deaths (−16.7%). 

    The national decline was driven largely by Ituri, where reported deaths  decreased from 654 to 448 (−31.5%), while deaths also declined in Haut-Uélé,  from 50 to 31 (−38.0%). 

    In contrast, deaths increased substantially in Nord-Kivu, from 228 to  296 (+29.8%). Consequently, Ituri’s contribution to newly reported deaths fell  from 69.6% to 57.3%, while Nord-Kivu’s contribution increased from 24.3% 

to 37.9%; Haut-Uélé’s contribution declined from 5.3% to 4.0%. 

    Tshopo reported five deaths, Bas-Uélé one, and SudUbangi one during the  latest period. 

    Overall, the decline in national mortality was driven predominantly by  the substantial reduction in Ituri and masks the continued concentration of  mortality in Nord-Kivu, which now accounts for more than one-third of newly reported cases and deaths nationally.

(...)

    

    Additionally, during the most recent 21 days (31 August–20 September  2026), 49 of the 63 affected health zones (77.8%) reported at least one new  confirmed case, while 14 (22.2%) reported no new cases. Health zones reporting  no cases were Adja, Aru, Ariwara, Aungba, Boga, Kambala and Mahagi in Ituri;  Goma in Nord-Kivu; Gombari in Haut-Uélé; Lubunga, Tshopo and Wanie-Rukula in  Tshopo; Miti-Murhesa in Sud-Kivu; and Buta in Bas-Uélé.

    Provincial trends continue to mask important differences between health  zones. In Ituri, where cases declined overall between the two consecutive  21-day periods, several health zones showed increasing or sustained transmission.  

    Cases nearly doubled in Komanda, from 36 to 69 (+91.7%), and increased  substantially in Mongbwalu, from 44 to 79 (+79.5%), while remaining broadly  stable in Lita, from 55 to 57 (+3.6%). In contrast, transmission declined  substantially in several major hotspots, including Bunia, from 376 to 265  (−29.5%), Nizi, from 183 to 94 (−48.6%), Rwampara, from 190 to 104 (−45.3%), and Nia-Nia, from 77 to 54 (−29.9%). Mangala also declined from  130 to 91 cases (−30.0%). 

    Nord-Kivu showed the opposite pattern, with continued broad-based  intensification, although trends varied between individual health zones. Cases  more than doubled in Beni, from 62 to 143 (+130.6%), and increased in  Butembo, from 64 to 87 (+35.9%) and Musienene, from 31 to 42 (+35.5%). In  contrast, Katwa remained at a very high level but declined slightly, from 161 to  154 cases (−4.3%). Haut-Uélé declined overall, but this similarly concealed  divergent health-zone trajectories: cases in Pawa more than doubled from 16 to  35 (+118.8%), while declining in Isiro from 50 to 18 (−64.0%) and Wamba from 35 to 25 (−28.6%).

(...)

    Weekly confirmed deaths peaked at 364 during 10 – 16 August, before  declining to 302 and 270 over the following two weeks. Deaths subsequently  increased to 276 during 31 August – 6 September and 284 during 7 – 13  September, before declining to 222 during 14 – 20 September (−21.8%). This  latest decline occurred in both settings, with community deaths decreasing from  193 to 136 (−29.5%) and deaths in treatment facilities declining from 91 to 86  (−5.5%).

    Consequently, the proportion of deaths occurring in the community fell  from 68.0% to 61.3%, continuing the decline from the peak of 75.0% during  31 August – 6 September. Despite this improvement, nearly two-thirds of  confirmed deaths in the latest week continued to occur in the community.

(...)

    The geographic distribution of confirmed BVD community deaths has  shifted substantially over time. Ituri remained the dominant contributor  throughout most of the outbreak, but its share declined markedly in recent weeks  as Nord-Kivu’s contribution increased, reaching near parity during 31 August – 13  September. In the latest week, 14 – 20 September, Ituri’s contribution increased  to 58.8%, while Nord-Kivu’s declined to 33.8%, with Haut-Uélé accounting for  4.4% and only small contributions from other affected provinces. 

    Overall, the  pattern indicates an important geographic redistribution of  community mortality, with Nord-Kivu now contributing a substantially greater  share than during the earlier phase of the outbreak, despite the recent decline.

    Overall, 2,241 community deaths with age and sex information available were analysed. 

    Children aged <5 years accounted for 554 (24.7%) of these deaths,  while 1,157 (51.6%) were male and 1,084 (48.4%) were female. During the most  recent 21 days, 482 community deaths with age and sex information  available were analysed. Of these, children aged <5 years accounted for 146  (30.3%), representing a greater proportional concentration than in the overall distribution. By sex, 251 (52.1%) were male and 231 (47.9%) were  female, broadly consistent with the overall sex distribution. The greater  representation of children under five among recent community deaths suggests  that this age group may be experiencing increasing vulnerability to death before  reaching appropriate care, warranting closer investigation of care-seeking,  detection and referral pathways among young children.

(...)

    Available case investigation information suggests that community deaths may result from multiple barriers along the pathway to appropriate care,  including missed diagnosis at peripheral health facilities, self-medication, care- seeking from traditional healers or religious places, refusal of referral, and no prior  healthcare contact. Although their relative contribution cannot yet be  quantified, these pathways highlight the need to strengthen early case  identification, community detection, and timely referral to appropriate treatment.

Risk Assessment

    The risk of further spread remains very high within the Democratic Republic of the Congo, reflecting sustained transmission, continued geographic  expansion, high mortality, population mobility, insecurity and persistent response 

challenges. 

    A two-week invasion-risk forecast identified 20 previously unaffected  health zones at elevated risk of transmission. Dungu, which was among the health  zones identified as high risk, has since reported confirmed transmission.  The remaining 19 health zones are Rethy, Watsa, Nyarambé, Biringi, Makoro,  Karisimbi, Angumu, Rutshuru, Nyiragongo, Niangara, Linga, Kirotshe,  Bafwagbogbo, Alimbongo, Jiba, Poko, Rwanguba, Kamango and Kibirizi. 

    This development reinforces the value of risk-based preparedness and  readiness measures in health zones identified as being at elevated risk.

    The risk is considered high for neighbouring countries sharing land  borders with the Democratic Republic of the Congo and low elsewhere in Africa and globally. 

    The second IHR Emergency Committee, convened on 18 August 2026, also  reviewed the evolving situation and emphasized that the outbreak remains  far from controlled, and continues to constitute a Public Health Emergency of International Concern.

(...)

Situation interpretation

    The outbreak remains uncontrolled and increasingly geographically dispersed, expanding the operational footprint of the response and placing  additional pressure on already stretched resources. The emergence of  transmission in Dungu, a health zone bordering South Sudan that was previously  identified as being at high risk, further heightens the potential for cross-border  spread and reinforces the need to accelerate readiness in areas where further  spread is anticipated. At the same time, community mortality remains a major  concern, with nearly two-thirds of recent deaths occurring in the community,  indicating persistent delays in detection, referral and access to appropriate care. 

    Children under five are disproportionately represented among  community deaths, suggesting particular vulnerabilities in early recognition of  illness and timely care-seeking and referral for young children. The multiple  pathways leading to community deaths, including missed recognition at health  facilities, self-medication, alternative care-seeking, refusal of referral and no prior  healthcare contact, indicate that reducing mortality will require interventions  across the entire pathway to care.

    Priorities should include stronger community detection, early recognition  at peripheral health facilities, rapid referral and improved community  trust and acceptance, alongside targeted investigation and interventions to  address the specific barriers contributing to community deaths among children under five.

Source: 

Link: https://www.afro.who.int/countries/democratic-republic-of-congo/publication/ebola-bundibugyo-virus-disease-outbreak-4

____