#Bundibugyo Virus Disease #Outbreak in #DRC, #Uganda & #France - #Situation Report 09, Data as of 12 July 2026 (WHO AFRO, edited): 1963 cases & 719 deaths in DRC

 

Key Figures at a Glance (Democratic Republic of the Congo) 

{Click on Image to Enlarge}

___

Summary

{Click on Image to Enlarge}

___

Event description

    ° The Bundibugyo virus disease outbreak in the Democratic Republic of the Congo intensified during the past week, with epidemiological indicators suggesting sustained and increasing transmission. 

    ° The outbreak was characterized by a rising incidence of reported cases, increasing mortality and continued geographic expansion into additional provinces and health zones, indicating ongoing propagation across affected areas. 

    ° Outside the Democratic Republic of the Congo, the epidemiological situation remained unchanged, with no new cases reported in Uganda or France and no evidence of secondary transmission. 

    ° Nevertheless, continued geographic expansion and increasing transmission intensity within the Democratic Republic of the Congo elevate the likelihood of cross-border spread and reinforce the need for sustained regional surveillance, preparedness and response measures. 

Democratic Republic of the Congo

    ° Since the last update of 5 July 2026 (Situation Report #8), the epidemiological situation in the Democratic Republic of the Congo has further deteriorated with sustained transmission and continued geographic expansion. 

    ° An additional 339 confirmed cases and 198 confirmed deaths have been reported, representing increases of 20.9% and 38.0% in cumulative confirmed cases and deaths, respectively. 

    ° The crude case fatality ratio (CFR) among confirmed cases increased from 32.1% to 36.6%, likely reflecting delayed case detection, late presentation for care, and the persistently high proportion of deaths occurring in the community, rather than increased disease severity. 

    ° Geographic spread also continued during the reporting period, with the outbreak expanding from three to five affected provinces following the confirmation of cases in Haut-Uélé and Tshopo provinces. 

    ° The number of affected health zones increased from 36 to 42, with Wamba (Haut-Uélé Province), Ariwara and Boga (Ituri Province), and Lubunga, Makiso-Kisangani, and Mangobo (Tshopo Province) reporting their first confirmed cases.  

    ° Daily reported confirmed cases have continued to increase over the course of the outbreak, although substantial day-to-day variability is observed. 

    ° A log-linear model fitted to the daily incidence data estimates an average daily growth rate of 2.3% (95% CI 2.0% - 2.5%), indicating that the outbreak continues to expand and transmission remains above the threshold required for sustained epidemic expansion.  

Figure 1. Epidemic curve showing daily confirmed case incidence and estimated epidemic growth, Democratic Republic of the Congo, 11 May–12 July 2026 

{Click on Image to Enlarge}

___

(...)

    ° Despite this continued geographic expansion, recent transmission remains concentrated in a subset of affected areas. 

    

    ° Of the 42 affected health zones, 33 have reported at least one confirmed case within the past 21 days. 

    ° During this period, 869 confirmed cases and 441 confirmed deaths were reported. 

    ° Ituri Province continues to bear the overwhelming burden of the outbreak, accounting for 775 cases (89.2%) and 382 deaths (86.6%), while the remaining four affected provinces together reported 94 cases (10.8%) and 59 deaths (13.4%). 

    ° In contrast, nine previously affected health zones have now surpassed 21 consecutive days without reporting a confirmed case, suggesting an absence of recent transmission while enhanced surveillance remains in place. 

    ° These include Miti-Murhesa (53 days) in South Kivu Province; Aru (38 days), Aungba (23 days), and Gety (52 days) in Ituri Province; and Goma (48 days), Kalunguta (49 days), Mabalako (29 days), Oicha (26 days), and Vuhovi (31 days) in North Kivu Province. 

    ° The highest levels of recent transmission were recorded in Bunia (207 cases), Rwampara (159), Mongbwalu (92), and Nizi (80) in Ituri Province, reaffirming the Bunia–Rwampara–Mongbwalu transmission corridor while highlighting Nizi as an increasingly important hotspot. 

    ° Transmission also intensified in Mangala (36 cases) and Nia-Nia (33), the latter serving as the epidemiological source of the newly affected provinces of Haut-Uélé and Tshopo. 

    ° In North Kivu Province, Katwa (39 cases) remained the principal hotspot, followed by Butembo (16) and Beni (10). 

    ° Collectively, these health zones accounted for 77.3% of all confirmed cases reported during the past 21 days. 

    ° A similar pattern was observed for mortality. Bunia reported the highest number of confirmed deaths (108), followed by Mongbwalu (71), Rwampara (52), Nizi (30), Katwa (28), Mangala (23), Nyankunde (14), Lita (13), Nia-Nia (11), Beni (8), and Butembo (7). 

    

    ° Together, these health zones accounted for 365 (82.8%) of the 441 confirmed deaths reported during the same period. 

    ° The confirmation of cases in Haut-Uélé and Tshopo provinces marks a significant geographic expansion of the outbreak beyond its original focus in Ituri and North Kivu. 

    ° Although relatively few cases have been reported in these newly affected provinces, the detection of cases in three health zones in Tshopo, including Makiso-Kisangani in the provincial capital, raises concern because of its large urban population and its role as a major transport hub connecting northeastern DRC with other parts of the country. 

    ° Epidemiological investigations indicate that the cases in Tshopo and Haut-Uélé are linked to transmission originating in Nia-Nia Health Zone in Ituri, suggesting geographic extension of an existing transmission chain rather than the emergence of independent outbreak foci. 

    ° The recent confirmation of the first case in Ariwara Health Zone represents a further northward expansion of the outbreak towards the borders with South Sudan and Uganda, increasing the potential for cross-border spread through frequent population movement and trade.  

    ° The expanding geographic footprint of the outbreak has also continued to pose risks beyond affected communities. 

    ° During the reporting period, a United States humanitarian worker infected with Bundibugyo virus disease while working in the Democratic Republic of the Congo was medically evacuated to a specialized high-level isolation unit at Frankfurt University Hospital, Germany. 

    ° The patient, a logistics staff member with a humanitarian organization supporting the Ebola response in Bunia, Ituri Province, was reported to be in stable condition following early diagnosis and treatment. 

    ° The case highlights the continued occupational risk faced by frontline humanitarian personnel responding to the outbreak. 

(...)

    ° Since the beginning of the outbreak, the Democratic Republic of the Congo has reported 1963 confirmed cases, including 719 confirmed deaths (CFR 36.6%). 

    ° Ituri Province remains the epicentre of the outbreak, accounting for 90.3% (1,772) of all confirmed cases and 84.6% (608) of all reported deaths nationwide. 

    ° The most affected health zones continue to be Bunia (503 cases, 156 deaths), Rwampara (384 cases, 89 deaths), Mongbwalu (329 cases, 171 deaths), Nizi (110 cases, 36 deaths), Nyankunde (97 cases, 23 deaths), Mangala (50 cases, 29 deaths), and Lita (45 cases, 19 deaths), all located in Ituri Province, together with Katwa (71 cases, 47 deaths), Butembo (44 cases, 20 deaths), and Beni (30 cases, 20 deaths) in North Kivu Province. Collectively, these health zones account for approximately 84.7% of all confirmed cases and 84.8% of all confirmed deaths reported nationally. 

(...)

    ° Close contacts, including 7,830 (79.4%) successfully seen during the reporting period. In North Kivu, 2,152 of 2,377 contacts (90.5%) were successfully followed up, while all contacts in South Kivu had completed the required 21-day monitoring period. 

    

    ° Contact follow-up data for the newly affected provinces of Haut-Uélé and Tshopo were not reported. 

    ° The overall follow-up rate remains below the operational target for effective contact tracing. 

    ° The marked disparity between provinces is of particular concern. While North Kivu achieved a follow-up rate exceeding 90%, Ituri, the epicentre of the outbreak and home to more than 80% of contacts under follow-up, reached only 79.4%. This leaves a substantial number of contacts in the highest transmission setting unreached each day, increasing the risk of undetected infections and sustained community transmission. 

(...)

Uganda

    ° No new confirmed case has been reported in Uganda since the previous update. The most recent confirmed case, reported on 21 June 2026, was identified in a truck driver travelling along the Democratic Republic of the CongoUganda international route. 

    ° Since then, no additional imported or locally acquired cases have been detected and there is no evidence of ongoing transmission.  

    ° As of 12 July 2026, the outbreak remained limited to 21 cases (20 confirmed and one probable), including three deaths (two confirmed and one probable). 

    ° Seventeen patients have recovered and been discharged from care, leaving one confirmed patient currently admitted to a treatment facility. 

    ° Since the onset of the outbreak, 836 contacts were identified. All contacts have successfully completed the required 21-day follow-up period with 6 secondary cases detected, indicating that known transmission chains have been effectively contained. 

{Click on Image to Enlarge}

___

France

    ° No additional Bundibugyo virus disease (BVD) cases have been reported in France since the previous update. No secondary transmission has been identified among the five flight contacts who were placed under precautionary quarantine following exposure to the imported case reported on 24 June 2026.

    ° Their formal release from follow-up had not been officially announced at the time of reporting. 

Risk Assessment 

    ° The overall public health risk in the Democratic Republic of the Congo remains very high, driven by sustained transmission, increasing mortality, and continued geographic expansion from three to five affected provinces. 

    ° Although transmission remains concentrated in Ituri Province, the emergence of new affected health zones in HautUélé and Tshopo highlights the continued potential for spread to previously unaffected areas. 

    ° The increasing crude CFR and the high proportion of community deaths continue to indicate delays in case detection, isolation, and access to clinical care. 

    ° Contact tracing remains below the operational target, particularly in Ituri Province, where follow-up performance is substantially lower than in North Kivu despite accounting for the majority of ongoing transmission. 

    ° Uganda remains at high risk of re-introduction because of the ongoing outbreak in the neighbouring Democratic Republic of the Congo despite reporting no new cases during the reporting period. 

    ° The absence of secondary transmission following the imported case in France demonstrates the effectiveness of rapid public health measures but also underscores the continued risk of international spread through travel. 

(...)

Source: 

Link: https://www.afro.who.int/countries/democratic-republic-of-congo/publication/ebola-bundibugyo-virus-disease-outbreak-2

____

Avian #Influenza #Report: July 5 – 11 '26 (Wk 28) (HK CHP, July 14, 2026)

{Excerpt}

(...)

Avian influenza A(H5N1) 

    

    ° Phnom Penh {Cambodia}: 

        

        - The case involved a 9-month-old girl.

        - She has been isolated in the hospital and is receiving intensive medical care. 

        - The source of infection has not yet confirmed and the investigation is ongoing. 

(...)

Source: 

Link: https://www.chp.gov.hk/files/pdf/2026_avian_influenza_report_vol22_wk28.pdf

____

#Taiwan, As #COVID19 #epidemic wave continues to escalate, public is urged to get vaccinated (CDC, July 14 '26)

 

    The Centers for Disease Control (CDC) stated today (July 14th) that the domestic COVID-19 epidemic continues to escalate. 

    To protect their own health and the health of others, the CDC urges the public to take self-prevention measures and get vaccinated against COVID-19 this season. 

    It is recommended to wear masks when entering and exiting medical care facilities and in crowded places where proper social distancing cannot be maintained or ventilation is poor. 

    If fever or respiratory symptoms occur, it is recommended to stay home and avoid unnecessary outings. 

    Individuals with severe risk factors should seek medical attention as soon as possible if they experience suspected symptoms. 

    A doctor can assess and conduct a rapid test, or they can use a commercially available home rapid test. 

    A doctor can also assess and prescribe antiviral drugs for those with severe risk factors who test positive for COVID-19, reducing the risk of serious complications or death after infection.

    The CDC stated that the domestic COVID-19 epidemic continues to rise. 

    In the 27th week (July 5th-July 11th), there were 2,811 outpatient and emergency room visits for COVID-19, an increase of 34.4% compared to the previous week. 

    Last week (July 7th-July 13th), there were 17 new local cases of severe COVID-19 complications, with no new local deaths. 

    Since October 2025, a total of 136 local cases of severe COVID-19 complications have been reported, with 18 deaths. 

    The majority of severe cases were among those aged 65 and above (72.1%) and those with a history of chronic diseases (83.8%). 

    94.9% of these cases were not vaccinated this season. 

    Globally, the COVID-19 positivity rate has recently increased, showing an upward trend in all regions except the Eastern Mediterranean region. 

    Neighboring countries/regions such as China, Hong Kong, Japan, South Korea, and Singapore are also experiencing rising cases. 

    Currently, the predominant circulating strain globally is NB.1.8.1, followed by JN.1 and XFG.

    The Centers for Disease Control (CDC) indicates that as of July 12, 2026, approximately 1.732 million COVID-19 vaccinations have been administered this season. 

    The vaccination rates among those aged 65 and above are 20.97% for the first dose and 0.51% for the second dose. 

    International research has found that receiving the current season's COVID-19 vaccine provides additional protection on top of existing immunity. 

    Vaccination with the current season's COVID-19 vaccine can reduce the risk of visiting the emergency room or emergency outpatient clinic due to COVID-19 by approximately 48%–50%, and reduce the risk of hospitalization by approximately 53%–55%. This demonstrates that COVID-19 vaccination effectively reduces the severity of the disease and the medical burden caused by COVID-19, and has a significant protective effect in preventing severe illness and hospitalization.

    The Taiwan Centers for Disease Control (CDC) urges that, as the majority of severe local COVID-19 cases in Taiwan are still among the elderly aged 65 and above and those with a history of chronic diseases, and most of them have not yet received the current season's COVID-19 vaccine, the CDC urges high-risk individuals, such as those aged 65 and above, who have not yet been vaccinated or have received their first dose at least 6 months ago, to get vaccinated as soon as possible to enhance their immune protection and reduce the risk of severe illness and hospitalization. 

    Furthermore, with the summer travel season in full swing, the risk of virus transmission is increased. 

    The nationwide rollout of publicly funded COVID-19 vaccines to those who have been vaccinated for 6 months (180 days) or more will continue until July 31, 2026. 

    Approximately 456,000 doses of vaccine remain in stock (including 450,000 doses of Moderna single-dose vaccine and 6,000 doses of Novavax vaccine). The public is encouraged to seize this opportunity to get vaccinated as soon as possible to enhance their immune protection.

    The Centers for Disease Control (CDC) emphasizes that there are currently sufficient reserves of antiviral drugs in Taiwan, including 155,000 doses of Remdesivir, 113,000 doses of Belavavir, and 18,000 doses of Xocova. 

    Local government health bureaus in various counties and cities will continue to monitor the usage at distribution points and manage the supply in a timely manner. 

    The public can also purchase home rapid testing kits at convenience stores or pharmacies that sell them for self-testing to facilitate subsequent medical diagnosis. 

    For information regarding vaccination sites, contracted sites for publicly funded oral antiviral drugs, and the latest epidemic prevention policies, please visit the Taiwan Centers for Disease Control and Prevention (CDC) website (https://www.cdc.gov.tw) or call the toll-free epidemic prevention hotline 1922 (or 0800-001922).

Source: 

Link: https://www.cdc.gov.tw/Bulletin/Detail/AAQZdiS2u2nFoJxcIj-DNA?typeid=9

____

Rapid #Expansion of Highly Pathogenic Avian #Influenza #H5N1 Clade 2.3.4.4b Genotype #D1.1 Virus across #Flyway Regions, North #America, Fall 2024

 

Abstract

Highly pathogenic avian influenza clade 2.3.4.4b virus continues to circulate in North America and has caused severe human disease. That clade includes genotype D1.1, which became dominant in birds in late 2024. Recent phylodynamic reconstructions place D1.1 emergence in mid-2024 but differ on its inferred origin and early dissemination pathways. We combined targeted surveillance of wild birds in Arizona with publicly available US clade 2.3.4.4b hemagglutinin sequences to estimate when D1.1 genotype emerged and to infer its diffusion among the 4 major US flyways. Phylodynamic analyses showed transitions concentrated among adjacent flyways regions, consistent with stepwise dissemination during fall 2024 and limited support for long-distance Pacific–Atlantic exchange. The Pacific Flyway showed patterns consistent with an early source and the Central Flyway with a secondary hub linked to onward spread. Our findings support coordinated genomic surveillance across adjacent flyways to reduce detection delays and improve situational awareness during rapid viral expansion.

Source: 

Link: https://wwwnc.cdc.gov/eid/article/32/8/26-0205_article

____

Highly Pathogenic Avian #Influenza #H5N1 in South #America, 2022–2025: Spread, Affected Species, and Southward Expansion into the #Antarctic Region

 

Abstract

The H5N1 highly pathogenic avian influenza (HPAI) virus has caused severe global losses, reaching South America in 2022 and Antarctica in 2024. Here, we synthesize outbreak reports submitted to the World Organization for Animal Health by South American countries and overseas territories in this continent, and document the virus’s unprecedented expansion into Antarctica, affecting wild birds, wild mammals, and domestic poultry. Phylogenetic and time-calibrated Bayesian analyses were performed on available genomic sequences. Over 6 million domestic birds were lost, mostly from commercial operations. Of the 11 South American countries and overseas territories that reported H5N1 to WOAH, 10 reported infections in wild birds, spanning 104 species, 59.62% of which are migratory and predominantly non-trans-equatorial. Marine mammal outbreaks followed wild bird detections, with the South American sea lion (Otaria flavescens) being the most reported species. Several Antarctic bird species with migratory behavior were also reported in South America. Genomic analyses revealed multiple introduction events, regional viral diversification, and patterns consistent with repeated cross-species spillover events. These findings highlight H5N1’s extensive ecological reach in the Southern Hemisphere and underscore the urgent need for a One Health approach that strengthens wildlife and backyard-poultry surveillance, alongside coordinated regional action to control and prevent further HPAI spread.

Source: 

Link: https://www.mdpi.com/1999-4915/18/7/764

____

The Pillar of Fire, Tintoretto (1577 - 1578)

 

{Click on Image to Enlarge}

__

Public Domain.

Source: 

Link: https://www.wikiart.org/en/tintoretto/the-pillar-of-fire-1578

____

#MHC-II acts as a #fusion-triggering #receptor for #bat #influenza virus

 

Abstract

Influenza A virus hemagglutinin is a prototypical class I viral fusion protein that binds sialylated glycans and is activated by low pH in endosomes. In contrast, bat-derived IAV subtypes H17N10 and H18N11 use major histocompatibility complex class II (MHC-II) as an entry receptor, but how this receptor contributes to membrane fusion remains unknown. We find that MHC-II-dependent hemagglutinin subtypes H17, H18, and H19 possess an increased negative net charge relative to canonical HAs. Using cryo-electron tomography, we demonstrate that H18N11 morphology remains stable and H18 is in prefusion conformation at strongly acidic pH. Remarkably, H18 undergoes fusion-relevant conformational changes only when both MHC-II binding and low pH are present. By reconstitution of H18N11 fusion with liposomes and purified MHC-II, we show that receptor engagement is required to trigger the fusion activity of H18. These findings identify MHC-II as a receptor that directly triggers membrane fusion and reveal a previously unrecognized receptor-dependent mechanism of influenza virus entry.

Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

Deutsche Forschungsgemeinschaft, https://ror.org/018mejw64, 240245660 – P19, 537227910

European Research Council, 882631—Bat Flu

Excellence Initiative of the German Research Foundation, GSC-4, Spemann Graduate School

Hans A. Krebs Medical Scientist Programme

Source: 

Link: https://www.biorxiv.org/content/10.64898/2026.07.08.737388v1

____

Lactylation of #Influenza Virus #Polymerase Acidic Protein Promotes Viral #Replication and #Pathogenicity

 

Abstract

Influenza virus poses a potential risk of triggering the next global pandemic. In-depth investigation into the mechanisms underlying influenza virus replication and pathogenicity will provide robust support for controlling influenza virus infection. Although post-translational modifications are known to regulate viral infection, the role of lactylation in influenza virus replication remains elusive. In this study, influenza virus ribonucleoprotein complex subunits are found to be lactylated. Specifically, ATAT1 promotes viral polymerase acidic protein (PA) lactylation and enhances viral replication. In contrast, SIRT1 mediates de-lactylation of PA and exerts an inhibitory effect on viral replication. Further investigations reveal lactylation of PA at residues K605 and K609 is essential for viral replication and pathogenicity. Mechanistically, PA K605/609 residues are localized at the interaction interface of the ANP32-mediated polymerase asymmetric dimer; mutation at these residues inhibits polymerase asymmetric dimerization, thereby impairing RNA production during viral genome replication. Collectively, this study uncovers a novel mechanism by which influenza virus hijacks host enzymes to mediate PA lactylation, and expands the molecular regulatory network of influenza virus infection.

Competing Interest Statement

The authors have declared no competing interest.

Source: 

Link: https://www.biorxiv.org/content/10.64898/2026.07.10.737663v1

____

Long-Term #Monitoring of #Influenza A Viruses in Wild #Waterfowl: Evidence from the Lake #Baikal Basin (2018–2024)

 

Abstract

Wild waterfowl constitute the primary natural reservoir of influenza A viruses, and wetlands at the convergence of major migratory flyways serve as critical hubs for viral genetic exchange. Baikal Siberia, situated at the intersection of the East African–West Asian, Central Asian, and East Asian–Australasian flyways, represents a unique yet understudied region in this context. Here we report the results of long-term virological surveillance of wild birds in the Lake Baikal basin conducted between 2018 and 2024. A total of 1036 cloacal swab samples from 28 bird species were screened, yielding 42 influenza A virus isolates belonging to 12 HA/NA subtype combinations: H1N1, H3N1, H3N2, H3N5, H3N6, H3N8, H4N6, H6N1, H6N2, H6N3, H6N8, and H12N5. Among the detected subtypes, H6 viruses—identified with four distinct neuraminidase combinations (N1, N2, N3, N8)—are of particular public health relevance owing to their documented capacity for dual-receptor binding and potential for zoonotic transmission to mammals, including humans. Full-genome sequencing followed by cluster analysis of internal gene segments identified 16 distinct segment constellations, indicating extensive reassortment. BLAST searches against the GISAID database revealed closest genetic relatives in Mongolia, South Korea, Japan, China, and Western Siberia, with more distant links to Bangladesh, Europe, and a possible intercontinental connection via the Pacific flyway. Maximum-likelihood phylogenetic analysis of the HA and NA segments confirmed that all isolates belong to the Eurasian genetic lineage, yet they are distributed across multiple clades rather than forming a single monophyletic group, reflecting the role of Buryatia as a mixing zone for genetically diverse viral populations. These findings substantially expand the understanding of influenza A virus ecology in the Lake Baikal basin and underscore the importance of continued surveillance at this key migratory crossroads in Northern Asia.

Source: 

Link: https://www.mdpi.com/1999-4915/18/7/761

____

Preparing for the Next #Pandemic: Learning From #COVID19 to Build What Comes Next

 

Abstract

WHO's efforts to strengthen pandemic preparedness—grounded in what the world learned during COVID-19 and what today's outbreaks of avian influenza, Hantavirus and Ebola are teaching us.

Source: 

Link: https://academic.oup.com/ofid/article/13/7/ofag348/8728458

____

History of Mass Transportation: A Vagónka Studénka Class 810 Diesel Raibus of the Czech Railways

 {Click on Image to Enlarge}

__

By Kryštof W - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=93583276

Source: 

Link: https://en.wikipedia.org/wiki/List_of_Czech_locomotive_classes#/media/File:Motorov%C3%BD_v%C5%AFz_811_(2020).jpg

____

#Bundibugyo Virus Disease #Outbreak, #DRC & #Uganda & #France - External #Situation Report 08, as of 05 July 2026 (WHO AFRO, edited): 1624 cases and 521 deaths in DRC

 

{Excerpts}

Key Figures at a Glance 

    ° 3 Countries Affected 

    ° 1 645 Confirmed Cases 

    ° 523 Confirmed Deaths 

    ° 31.8% CFR Confirmed 

    ° 12 417 Contacts to follow 

Summary 

{Click on Image to Enlarge}

__

Event description

    ° The Bundibugyo virus disease (BVD) outbreak in the Democratic Republic of the Congo continues to intensify, driven by sustained transmission in hotspot health zones of Ituri and North Kivu provinces. 

    ° The outbreak is marked by growing numbers of community deaths, and the continued spread of infection into previously unaffected health zones. 

    ° While Uganda has not reported any new confirmed cases during the past week, and the imported case reported in France has fully recovered without evidence of secondary transmission among identified contacts, the ongoing epidemic in eastern Democratic Republic of the Congo continues to pose a significant regional and global public health threat.  

Democratic Republic of the Congo

    ° Compared with the previous update issued on 28 June 2026 (Situation Report #7), the epidemiological situation in the Democratic Republic of the Congo has deteriorated further. 

    ° An additional 317 confirmed cases and 144 confirmed deaths have been reported, representing increases of 24.3% and 38.2%, in cumulative cases and deaths respectively. 

    ° The crude case fatality ratio (CFR) rose from 28.8% to 32.1%. 

    ° Geographic spread continues as the first confirmed case was detected in Lolwa health zone in Ituri Province, increasing the total number of affected health zones to 36. 

Figure 1.  Weekly trends of confirmed cases of Bundibugyo virus disease in the Democratic Republic of the Congo by epidemiological week of report, epidemiological weeks 18 – 27, 2026 

{Click on Image to Enlarge}

__

    ° Mabalako and Vuhovi health zones have now completed 21 consecutive days, without reporting a confirmed case and have been added to the list of areas with no recent transmission. 

    ° However, Rimba Health Zone, which had previously gone 25 days without reporting a case, has now reported a new confirmed case. 

    ° This brings the total number of previously affected health zones that have surpassed the 21-day threshold to eight. 

    ° These include MitiMurhesa in South Kivu Province (46 days); Gety (45 days), Mambasa (33 days), and Aru (31 days) in Ituri Province; and Kalunguta (42 days), Goma (41 days), Vuhovi (24 days), and Mabalako (22 days) in North Kivu Province.   

    ° The outbreak remains active in 28 health zones across Ituri and North Kivu provinces that have reported confirmed cases within the past 21 days. 

    ° During this period, 787 confirmed cases and 325 confirmed deaths were reported. 

    ° Ituri Province continues to bear the overwhelming burden of the outbreak, accounting for 710 cases (90.2%) and 282 deaths (86.8%) across 21 active health zones. 

    ° The remaining seven active health zones in North Kivu reported 77 cases (9.8%) and 43 deaths (13.2%). 

    ° The highest transmission was recorded in Bunia (237 cases), Rwampara (190 cases), Mongbwalu (103 cases), Nizi (62 cases), Nyankunde (51 cases), and Lita (24 cases) in Ituri Province. 

    ° In North Kivu Province, Katwa (27 cases) and Butembo (21 cases) remained the main areas of transmission. 

    ° Collectively, these health zones accounted for 90.9% of all confirmed cases reported during the past 21 days. 

    ° A similar pattern was observed for mortality. Bunia reported the highest number of deaths (101), followed by Mongbwalu (66), Rwampara (45), Katwa (22), Nizi (18), Nyankunde (15), Lita (12), Mangala (11), and Butembo (11). 

    ° Together, these health zones accounted for 92.6% of all confirmed deaths reported during the same period.  

    ° The crude CFR of the outbreak also increased over recent weeks. In Ituri Province, the CFR rose from 20.5% on 15 June to 29.7% on 05 July 2026, while North Kivu continued to record the highest provincial CFR, remaining above 56% throughout the reporting period. 

    ° The largest increase in CFR was observed in Lita Health Zone (+36.4 percentage points), followed by Komanda (+22.1 percentage points), Nizi (+18.1 percentage points), and Bunia (+17.6 percentage points). 

    ° These elevated CFRs likely reflect continued delays in case detection and healthcare-seeking behaviour, compounded by the persistently high proportion of deaths occurring in the community. 

(...)

    ° Since the beginning of the outbreak, the Democratic Republic of the Congo has reported 1624 confirmed cases, including 521 confirmed deaths (CFR 32.1%]. 

    ° Ituri Province remains the epicentre of the outbreak, accounting for 90.9% (1477) of all confirmed cases and 84.3% (439) of all reported deaths nationwide. 

    ° The most affected health zones are Bunia (452 cases, 121 deaths), Rwampara (349 cases, 72 deaths), Mongbwalu (288 cases, 149 deaths), Nyankunde (96 cases, 19 deaths), Nizi (78 cases, 19 deaths), Lita (33 cases, 12 deaths), and Mangala (33 cases, 14 deaths), all located in Ituri Province, as well as Katwa (52 cases, 38 deaths), Butembo (40 cases, 18 deaths), and Beni (29 cases, 17 deaths) in North Kivu Province. Together, these health zones account for nearly 89.3% of all confirmed cases and 91.9% of confirmed deaths reported nationally. 

(...)

    ° Investigation of 430 confirmed deaths as of 05 July 2026, showed that 397 (92.3%) occurred in the community or before admission to a treatment facility, highlighting persistent delays in case detection, referral, isolation, and access to clinical care. 

    ° Only 33 deaths (7.7%) occurred after patients had been admitted to treatment centres or healthcare facilities.  

    As of 05 July 2026, a total of 12412 contacts were under follow-up of whom 9624 (77.5%) were successfully seen within the previous 24 hours. 

    ° Ituri Province accounted for the majority of contacts under follow-up, with 9757 contacts, including 7574 (77.6%) seen during the reporting period. 

    ° In North Kivu, 2050 out of 2655 contacts (77.2%) were followed up, while all contacts in South Kivu had completed the required 21-day monitoring period.  

    ° Although contact tracing performance has improved overall, follow-up remains below optimal levels, leaving a significant proportion of contacts unreached and increasing the likelihood of undetected infections and continued transmission.  

    ° The proportion of new confirmed cases identified among registered contacts increased steadily as the outbreak progressed, exceeding 40% by late June 2026. 

    ° Overall, 32.4% of confirmed cases were detected through contact follow-up. However, a substantial number of infections continued to occur outside known contact lists, indicating ongoing gaps in surveillance. These gaps are likely driven by insecurity in affected areas, population displacement and mobility, delayed case detection, community resistance, incomplete epidemiological investigations, and the movement of suspected cases and deceased individuals across affected areas. 

(...)

Uganda  

    ° Uganda has not reported any new cases during the past two weeks. 

    ° The latest confirmed case was reported on 21 June 2026 and involved a truck driver travelling along the Democratic Republic of the Congo–Uganda international route. 

    ° The case became symptomatic on 15 June 2026, crossed into Uganda on 19 June, and was admitted to the treatment unit for isolation on 20 June 2026.  

    ° As of 5 July 2026, the outbreak had resulted in a total of 21 cases (20 confirmed and one probable). 

    ° Three deaths, including two confirmed and one probable, had been reported, while 16 patients had recovered and been discharged from care. 

    ° Two patients remained hospitalised. 

    ° Since the onset of the outbreak, health authorities had identified 831 contacts. 

    ° All contacts placed under follow-up have now completed the required 21-day monitoring period without any new linked cases being detected.  

Figure 5.  Weekly trends of confirmed cases of Bundibugyo virus disease in Uganda by epidemiological week of report, epidemiological weeks 18 – 27, 2026 

{Click on Image to Enlarge}

__

France

    ° The imported laboratory-confirmed case of BVD, notified to WHO by the French authorities on 24 June 2026, has recovered and was discharged from hospital on 4 July after obtaining two consecutive negative laboratory test results. 

    ° The patient, a middle-aged male physician, had recently returned from a five-week deployment in Ituri Province, Democratic Republic of the Congo, where he provided clinical care to patients with BVD. 

    ° Upon arrival at Charles de Gaulle Airport in Paris on 23 June 2026, he voluntarily reported experiencing symptoms to airport health officials, prompting his immediate isolation and transfer to a designated high-containment treatment facility.  

    ° Contact tracing identified five passengers who had travelled on the same flight as the patient. These individuals were placed under quarantine in France and continue to be monitored. 

    ° None had become symptomatic as of 5 July 2026.   

Risk Assessment  

    ° The overall public health risk in the Democratic Republic of the Congo remains very high, driven by sustained and widespread transmission that continues to outpace the current response capacity. 

    ° The outbreak remains concentrated in the Bunia–Rwampara–Mongbwalu corridor, although transmission persists across multiple affected health zones. 

    ° The persistently elevated case fatality ratio in North Kivu suggests ongoing delays in case detection, diagnosis, and access to clinical care, while treatment capacity in Ituri Province is becoming increasingly strained. 

    ° Although contact follow-up and alert investigation have improved, performance remains insufficient to rapidly interrupt transmission.   

    ° In addition, reports of threatened strike action among frontline response workers have emerged in affected areas, reportedly linked to delays in payment and other operational constraints. 

    ° If not rapidly addressed by health authorities and partners, these challenges could further disrupt critical response activities and undermine ongoing outbreak control efforts.  

    ° Uganda continues to face a high risk of importation due to frequent population movement from eastern Democratic Republic of the Congo, including commercial trucking routes and possible informal cross-border crossings linked to border closures.  

    ° The imported case reported in France further demonstrates the continued risk of international spread and highlights the need to sustain enhanced surveillance, strengthen traveller awareness, and reinforce cross-border coordination and preparedness measures.

(...)

Source: 

Link: https://www.afro.who.int/countries/democratic-republic-of-congo/publication/ebola-bundibugyo-virus-disease-outbreak-1

____

History of Mass Transportation: A Romanian Broad Gauge Class 84 Diesel-Hydraulic Shunter

 

{Click on Image to Enlarge}

__

By Stefan Puscasu - [1]., Public Domain, https://commons.wikimedia.org/w/index.php?curid=8459414

Source: 

Link: https://en.wikipedia.org/wiki/Rolling_stock_of_the_Romanian_Railways#/media/File:Locomotiva_CFR_clasa_84.jpg

____

#Coronavirus Disease Research #References (AMEDEO, July 11 '26)

 

Am J Respir Crit Care Med

1. JERRETT M, Nau CL, Young DR, Butler RK, et al
   Association Between Air Pollution and Post Acute Sequelae of SARS-CoV-2 (PASC).
   Am J Respir Crit Care Med. 2026 Jul 3:aamag341. doi: 10.1093.
   PubMed        
   
   

   
   Ann Intern Med

2. DARNALL BD, Perez L, Kao MC, Lorig K, et al
   Patient-Centered Prescription Opioid Tapering Methods : A Randomized Clinical Trial.
   Ann Intern Med. 2026 Jul 7. doi: 10.7326/ANNALS-25-04784.
   PubMed         Abstract available
   
   

   
   BMJ

3. HAQ ZU
   Ebola control is weakened by mistrust and cultural insensitivity.
   BMJ. 2026;394:e100190.
   PubMed        
   
   

   
   Clin Infect Dis

4. ROSTER KIO, White PJ, Grad YH
   Why Are Gonorrhea Case Rates Declining in the United States? A Research Agenda.
   Clin Infect Dis. 2026;82:1082-1090.
   PubMed         Abstract available
   
   

   
   Int J Infect Dis

5. MIYAKAWA K, Sano K, Seki Y, Sato R, et al
   Cross-neutralization of SARS-CoV-2 BA.3.2.2 lineage by JN.1 mRNA vaccine-induced immunity.
   Int J Infect Dis. 2026 Jul 4:108954. doi: 10.1016/j.ijid.2026.108954.
   PubMed         Abstract available
   
   
6. JO Y, Hu Z, Joo H, Jung J, et al
   Time to Recovery from Long COVID: A Longitudinal Analysis of Symptom Duration and Risk Factors Using Accelerated Failure Time Models.
   Int J Infect Dis. 2026 Jul 5:108963. doi: 10.1016/j.ijid.2026.108963.
   PubMed         Abstract available
   
   
7. CHUI CSL, Lau JC, Fan M, Chan BP, et al
   Concurrent comparison of severity of influenza and COVID-19 among hospitalized patients in Hong Kong: a target trial emulation on observational healthcare data.
   Int J Infect Dis. 2026 Jul 7:108958. doi: 10.1016/j.ijid.2026.108958.
   PubMed         Abstract available
   
   
8. JABER F, Rawas SE, Faraj S, Zoghby LA, et al
   Value of the Pitt bacteremia score in predicting the outcome of non-bacteremic patients with infections caused by multidrug-resistant organisms.
   Int J Infect Dis. 2026 Jul 7:108960. doi: 10.1016/j.ijid.2026.108960.
   PubMed         Abstract available
   
   
9. ACANFORA D, Nolano M, Acanfora C, Colella C, et al
   Vagal cholinergic denervation of the gastric mucosa in Long-COVID-19: in vivo evidence of structural autonomic dysfunction.
   Int J Infect Dis. 2026 Jul 9:108973. doi: 10.1016/j.ijid.2026.108973.
   PubMed         Abstract available
   
   

   
   J Infect

10. VINK E, Murphy ME, Gunson R, MacConnachie A, et al
    Respiratory viral detection in adult severe acute respiratory infection post-COVID-19 pandemic: implications for antimicrobial stewardship.
    J Infect. 2026;93:106805.
    PubMed         Abstract available
    
    

    
    J Med Virol

11. BUMBERGER AM, Kastner MT, Gawish R, Rusing L, et al
    Torque Teno Virus Dynamics in Plasma and BAL of COVID-19 ARDS Patients With and Without ECMO.
    J Med Virol. 2026;98:e71047.
    PubMed         Abstract available
    
    
12. WENINGER J, Zedginidze A, Katsounas A, Pohl M, et al
    Assessment of Residual-Serum SARS-CoV-2-N-Antigen Testing for Hospital Surveillance in Germany.
    J Med Virol. 2026;98:e71055.
    PubMed         Abstract available
    
    
13. GORIS M, Valdez M, Lamont L, Yang W, et al
    Tracking COVID-19 Severity and Progression Through Amines and Lipid Mediators.
    J Med Virol. 2026;98:e71030.
    PubMed         Abstract available
    
    
14. TUNER B, Agca H
    Molecular Types of Rhinovirus Among Cases of Acute Respiratory Infections in a University Hospital.
    J Med Virol. 2026;98:e71058.
    PubMed         Abstract available
    
    

    
    J Virol

15. LIANG Y-F, Li X, Zhu G-x, Song Y, et al
    Magnolol inhibits porcine epidemic diarrhea virus infection by suppressing cathepsin L expression in vitro and in vivo.
    J Virol. 2026 Jun 25:e0013726. doi: 10.1128/jvi.00137.
    PubMed         Abstract available
    
    
16. ZHAO Y, Zhao J, Li Y, Duan L, et al
    Disruption of the S1/S2 multibasic cleavage site attenuates infectious bronchitis virus, while S2' partially restores viral virulence and expands tissue tropism.
    J Virol. 2026 Jul 6:e0061426. doi: 10.1128/jvi.00614.
    PubMed         Abstract available
    
    
17. STEFANOS B, Green NRB, Nadig I, Lapierre LA, et al
    Coronavirus membrane protein with a fluorescent protein tag enables particle tracking for the study of virus assembly and egress in live cells.
    J Virol. 2026 Jul 6:e0222825. doi: 10.1128/jvi.02228.
    PubMed         Abstract available
    
    
18. ZHOU R, Yue M, Shen Q, Liu N, et al
    Glucagon-like peptide-1 receptor agonist prevents pulmonary fibrosis following acute COVID-19 infection associated with type 2 diabetes.
    J Virol. 2026 Jul 9:e0040126. doi: 10.1128/jvi.00401.
    PubMed         Abstract available
    
    

    
    Lancet

19. DEZZA FC, Pulido LB, Borreguero IB, Perez FD, et al
    Temocillin versus carbapenems for bacteraemia due to third-generation cephalosporin-resistant Enterobacterales in Spain (ASTARTE): a multicentre, phase 3, open-label, non-inferiority, randomised clinical trial.
    Lancet. 2026 Jul 9:S0140-6736(26)00760-9. doi: 10.1016/S0140-6736(26)00760.
    PubMed         Abstract available
    
    

    
    Lancet Infect Dis

20. 
    Efficacy and safety of rivaroxaban, colchicine, and famotidine-loratadine with specialist supportive clinical care for fatigue in patients with post-COVID-19 condition in the UK: a multisite, open-label, randomised controlled trial.
    Lancet Infect Dis. 2026 Jul 8:S1473-3099(26)00242.
    PubMed         Abstract available
    
    

    
    MMWR Morb Mortal Wkly Rep

21. PATRICK R, Lee K, Kuan M, Chan M, et al
    Norovirus, COVID-19, and Influenza Outbreaks Among Residents and Staff Members at the Eaton Wildfire Evacuation Shelter - Pasadena, California, January-February 2025.
    MMWR Morb Mortal Wkly Rep. 2026;75:337-342.
    PubMed         Abstract available

#Influenza and Other Respiratory Viruses Research #References (AMEDEO, July 11 '26)

 

BMC Pediatr

1. HEIBA D, Salem N, Antonios M, Shoman W, et al
   Comparative study of post- COVID-19 Kawasaki disease and multisystem inflammatory syndrome cases at Alexandria University Children's Hospital.
   BMC Pediatr. 2026;26:644.
   PubMed         Abstract available
   
   
2. LIN C, Zhu Z, Li Y, Wei J, et al
   Diagnostic value of cytokine detection in children with Mycoplasma pneumoniae pneumonia complicated by bacterial or viral co-infections.
   BMC Pediatr. 2026;26:629.
   PubMed         Abstract available
   
   

   
   Epidemiol Infect

3. DAVOODI Z, Laurie C, Tingley K, Skidmore B, et al
   Risk-of-bias assessment of vaccine effectiveness studies: a scoping review of systematic reviews.
   Epidemiol Infect. 2026;154:e95.
   PubMed         Abstract available
   
   
4. ROSCA EC, Oke J, Jefferson T, Brassey J, et al
   Serial cycle threshold to assess the infectious potential of SARS-CoV-2: A systematic review.
   Epidemiol Infect. 2026;154:e89.
   PubMed         Abstract available
   
   

   
   J Clin Microbiol

5. MCTAGGART LR, Eshaghi A, Cronin K, Patel SN, et al
   Post-pandemic surge of Mycoplasma pneumoniae in Ontario, 2024: molecular surveillance and resistance trends relative to 2018-2023.
   J Clin Microbiol. 2026;64:e0018826.
   PubMed         Abstract available
   
   

   
   J Infect

6. LI Y, Zhang T, Gao J
   Home-Based Rapid Testing and Early Antiviral Treatment as a Potential Strategy to Blunt Pediatric Influenza Peak.
   J Infect. 2026 Jul 7:106807. doi: 10.1016/j.jinf.2026.106807.
   PubMed        
   
   

   
   J Infect Dis

7. SKELLINGTON CN, Schmidt K, Schofield C, Ganesan A, et al
   The Effect of Prevaccination Analgesics on Influenza Vaccine Immunogenicity and Effectiveness.
   J Infect Dis. 2026 Jul 10:jiag334. doi: 10.1093.
   PubMed         Abstract available
   
   

   
   J Virol

8. JIA H, Lin C, Guo Y, Cai W, et al
   A neuraminidase-targeted nanobody confers broad protection against influenza B virus.
   J Virol. 2026 Jul 10:e0076226. doi: 10.1128/jvi.00762.
   PubMed         Abstract available
   
   
9. BARRON-CASTILLO U, Berube N, Swan CL, Javed MA, et al
   Receptor profiling and growth assessment of influenza A virus in porcine mammary and non-mammary tissues and derived cells.
   J Virol. 2026 Jul 6:e0061526. doi: 10.1128/jvi.00615.
   PubMed         Abstract available
   
   

   
   MMWR Morb Mortal Wkly Rep

10. PATRICK R, Lee K, Kuan M, Chan M, et al
    Norovirus, COVID-19, and Influenza Outbreaks Among Residents and Staff Members at the Eaton Wildfire Evacuation Shelter - Pasadena, California, January-February 2025.
    MMWR Morb Mortal Wkly Rep. 2026;75:337-342.
    PubMed         Abstract available
    
    

    
    Pediatrics

11. LEONARD JS, Reinhart K, Lu PJ, Santibanez TA, et al
    Influenza Vaccine Effectiveness Against Pediatric Death in the United States: 2016-2025.
    Pediatrics. 2026 Jul 6:e2026076453. doi: 10.1542/peds.2026-076453.
    PubMed         Abstract available
    
    
12. HAHN C, Sardi A, Ratner AJ
    Averting the Unthinkable: Immunization to Prevent Childhood Deaths From Influenza.
    Pediatrics. 2026 Jul 6:e2026076867. doi: 10.1542/peds.2026-076867.
    PubMed        
    
    

    
    PLoS Comput Biol

13. WANG B, Valdano E
    Redefining and estimating the early-phase reproduction ratio for epidemic outbreaks in spatially structured populations.
    PLoS Comput Biol. 2026;22:e1014425.
    PubMed         Abstract available
    
    

    
    PLoS One

14. LI W, Tan HL, Zhuang CY, Li JY, et al
    Parental knowledge, vaccine hesitancy, and practices regarding seasonal influenza vaccination for preschool-aged children in Shenzhen, China: Insights from a cross-sectional survey.
    PLoS One. 2026;21:e0353478.
    PubMed         Abstract available
    
    
15. SANOGO IN, Puryear WB, Simulynas AF, DiGiovanni R, et al
    Serological evidence of SARS-CoV-2 exposure in marine mammals in the United States between 2020 and 2025.
    PLoS One. 2026;21:e0351734.
    PubMed         Abstract available
    
    
16. HIRATA K, Chiba T, Takaku R, Meilai C, et al
    Beyond the freedom to refuse patient: A retrospective comparative study of emergency transportation during the COVID-19 pandemic in Japan.
    PLoS One. 2026;21:e0331535.
    PubMed         Abstract available
    
    
17. HAKKI S, Nevin S, Conibear E, Madon KJ, et al
    Full blood count dynamics in immunologically naive individuals with mild COVID-19: A prospective community cohort study.
    PLoS One. 2026;21:e0353142.
    PubMed         Abstract available
    
    
18. BURCHARDI JM, Brunger M, Freitag H, Brock A, et al
    Improving the care of people affected by post-COVID syndrome (LCovB):study protocol of a mixed-methods study.
    PLoS One. 2026;21:e0353270.
    PubMed         Abstract available
    
    
19. AL-AGHBARI N
    Serum albumin and blood urea as independent predictors of in-hospital mortality in hospitalized COVID-19 patients: A retrospective cohort study.
    PLoS One. 2026;21:e0353456.
    PubMed         Abstract available
    
    
20. JEWELL M, Marye A, Barbeau B, Oakeson K, et al
    Beyond traditional outbreak investigation: Using genomic data for enhanced detection of COVID-19 disease clusters in Utah.
    PLoS One. 2026;21:e0342637.
    PubMed         Abstract available
    
    
21. IIDA K, Mori H, Remez D, Krokva D, et al
    Epidemiological characteristics of amebiasis in Japan from 2001 to 2022.
    PLoS One. 2026;21:e0318901.
    PubMed         Abstract available
    
    
22. FREDERIKSEN L, Subedi S, Choong K, Anderson J, et al
    Respiratory and bloodstream coinfections and antimicrobial use in hospitalised patients with moderate to severe COVID-19: An Australian retrospective cohort study.
    PLoS One. 2026;21:e0352344.
    PubMed         Abstract available
    
    
23. FUKUDA T, Haruyama R, Tanaka Y, Natori S, et al
    Development of a COVID-19 Vaccination Anxiety Scale to measure COVID-19 vaccine anxiety in Japanese adults.
    PLoS One. 2026;21:e0330146.
    PubMed         Abstract available
    
    
24. MICHALAKI E, Van Zanten A, Najjar J, Byagathvalli G, et al
    A piezoelectric electroporator (Piezopen) for enhanced "naked" RNA vaccine delivery.
    PLoS One. 2026;21:e0353214.
    PubMed         Abstract available
    
    
25. GACH D, van Osch FHM, van den Bergh JP, Posthuma R, et al
    Long-term multidimensional health status of individuals with and without post COVID-19 condition: A cross-sectional study.
    PLoS One. 2026;21:e0352332.
    PubMed         Abstract available
    
    
26. CONGDON C, Malik F, Jina R, Kumar D, et al
    A multi-country qualitative evaluation of rapid mortality surveillance during the COVID-19 pandemic.
    PLoS One. 2026;21:e0333157.
    PubMed         Abstract available
    
    

    
    Vaccine

27. ZHANG L, Lin T, Wang M, Ma X, et al
    Retraction notice to "Effectiveness of prescription-based influenza vaccination services among older adults in Binzhou, China: A cluster-randomized controlled trial" [Vaccine 82 (2026) 128588].
    Vaccine. 2026 Jul 6:128885. doi: 10.1016/j.vaccine.2026.128885.
    PubMed        

Isolation and characterization of a clade 2.3.4.4b genotype #D1.1 #H5N1 virus from dairy #cattle in #Wisconsin

 

ABSTRACT

Highly pathogenic avian influenza A(H5N1) (HPAI H5N1) viruses of clade 2.3.4.4b have recently been detected in U.S. dairy cattle following multiple spillover events from avian reservoirs. In December 2025, HPAI H5N1 virus was identified in a dairy herd in Wisconsin through the National Milk Testing Strategy. Here, we report the isolation of a clade 2.3.4.4b, genotype D1.1 H5N1 virus, A/dairy cow/Wisconsin/25G05743-001/2025 (WI5743-H5N1), from bulk milk associated with the affected herd, describe its phylogenetic relationships, and assess its pathogenicity in mice. Infectious virus was recovered following blind passage in embryonated chicken eggs. Phylogenetic analysis demonstrated that WI5743-H5N1 is distinct from previously reported D1.1 viruses detected in dairy cattle in Nevada and Arizona, supporting an independent introduction into cattle, and indicating a likely local avian source. Compared with closely related avian viruses, WI5743-H5N1 encoded the mammalian-adapting substitution PB2-E627K and additional amino acid differences in HA, PB1-F2, and NS1. In mice, WI5743-H5N1 replicated efficiently in respiratory tissues and was detectable in the brain but exhibited lower lethality relative to other recent clade 2.3.4.4b, genotype B3.13 viruses. Together, these findings highlight the genetic and phenotypic diversity of HPAI H5N1 viruses infecting dairy cattle and underscore the importance of continued surveillance and functional characterization of emerging strains.

IMPORTANCE

Highly pathogenic avian influenza A(H5N1) viruses have recently entered U.S. dairy cattle through multiple spillover events from avian reservoirs, creating new opportunities for viral adaptation in mammals. Here, we describe the isolation and characterization of a clade 2.3.4.4b, genotype D1.1 H5N1 virus from bulk milk collected during a spillover event in Wisconsin in December 2025. Phylogenetic analyses demonstrated that this virus represents an independent introduction into dairy cattle distinct from previously reported D1.1 viruses identified in Nevada and Arizona. Although the virus encoded the mammalian-adapting PB2-E627K substitution, it exhibited comparatively low lethality in mice, highlighting the complexity of mammalian adaptation and pathogenicity in H5N1 viruses. These findings expand current understanding of the genetic and phenotypic diversity of H5N1 viruses infecting dairy cattle and emphasize the importance of continued surveillance and functional characterization of emerging strains.

Source: 

Link: https://journals.asm.org/doi/10.1128/jvi.00761-26

____