#Assessment of #influenza virus and #coronavirus #tropism, #replication competence and disease severity in ex vivo and in vitro cultures of the #human respiratory tract

ABSTRACT

The emergence of animal influenza viruses circulating in poultry and human populations poses a significant public health threat, yet current risk assessment tools that connect surveillance data to human transmission risk and disease severity are lacking. To address this, we employed a semi-quantitative approach to analyze virus tropism and replication competence, conducting risk assessments of influenza and coronavirus adaptation to human transmission in an ex vivo model, and evaluating virus-induced impairment of alveolar fluid clearance (AFC) in vitro as a correlation of disease severity. Our results showed that seasonal influenza A H1N1, H3N2, influenza B, MERS-CoV, and SARS-CoV exhibited productive viral replication and tissue infection in bronchial tissues, whereas wild bird surveillance isolates such as H5N3 and H7N1 showed minimal replication when compared to pandemic H1N1 and highly pathogenic avian influenza (HPAI) H5N1. Notably, differential lung viral replication and tissue tropism were detected for H5N6 and H9N2. HPAI H5N1, H7N9, MERS-CoV, and SARS-CoV caused more severe AFC impairment than seasonal H1N1, H3N2, and influenza B viruses, correlating with their clinical severity. Overall, these findings revealed an important association between viral tropism and human transmissibility in ex vivo explants, as well as the impairment of AFC in vitro, which aligns with the clinical manifestations of disease severity across different viral strains.

Source: 

Link: https://www.microbiologyresearch.org/content/journal/jgv/10.1099/jgv.0.002281

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#Ebola disease caused by #Bundibugyo virus, #DRC & #Uganda (WHO D.O.N., July 3 '26): 1460 cases and 452 deaths in DRC

 

Situation at a glance

    The Bundibugyo virus disease (BVD) outbreak in the Democratic Republic of the Congo continues to evolve rapidly, with sustained transmission and increasing numbers of reported cases. 

    As of 1 July, a cumulative of 1460 confirmed cases, including 452 deaths, have been reported from the Democratic Republic of the Congo. 

    As of 2 July, Uganda has reported 20 confirmed cases including two deaths, as well as one probable case who has died. 

    In addition, on 24 June 2026, French authorities notified WHO of a laboratory-confirmed case of Ebola disease caused by Bundibugyo virus in a medical doctor returning from the Democratic Republic of the Congo. 

    In Uganda, the outbreak remains epidemiologically linked to transmission originating in the Democratic Republic of the Congo, with evidence of both imported infections and secondary transmission among contacts and healthcare workers. 

    Uganda has not reported any new cases since 21 June 2026. 

    National authorities in the two affected countries, in collaboration with WHO and partners, are implementing an extensive set of response measures. 

    A regional preparedness and prioritization framework continues to guide readiness activities across the African Region.

Description of the situation

    Since the last Disease Outbreak News was published on 19 June 2026, the number of confirmed cases and deaths have increased rapidly in the Democratic Republic of the Congo. 

    In total, 1481 confirmed cases; 1460 from the Democratic Republic of the Congo, 20 from Uganda and one from France (linked to DRC); and 454 deaths including two from Uganda, have been reported.  

    At least 229 patients have recovered from the disease; 213 patients from the Democratic Republic of the Congo and 16 patients from Uganda.

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(...)

Democratic Republic of the Congo

    Since 19 June when the last Disease Outbreak News was published, an additional 564 confirmed cases, including 220 confirmed deaths, have been reported from the Democratic Republic of the Congo. 

    The increase is in part due to the scale up of surveillance activities, testing and diagnostic capacities.

    As of 1 July 2026, a total of 1460 confirmed cases including 452 deaths (crude case fatality ratio [CFR] 30.9%) have been reported from the Democratic Republic of Congo. 

    So far, 213 patients have recovered. 

    Cases have been reported from 36 health zones (HZ) from Ituri (24/36 HZ), North Kivu (11/35 HZ) and South Kivu provinces (1/34 HZ).[1] 

    To date, 102 confirmed cases including 25 deaths have been reported among health and care workers.

    Of the 36 affected health zones, the outbreak remains active in 21 health zones from where cases have been reported in the past 21 days. The remaining health zones have not reported any new cases during this period. In the past 21 days, 838 confirmed cases, including 314 confirmed deaths, have been reported.

    Ituri Province remains the most affected, accounting for 91.3% (1333/1460) of all confirmed cases and 84% (380/452) of all reported deaths nationwide. Within the province, the highest number of confirmed cases have been reported from Bunia (416 cases), Rwampara (308 cases), Mongbwalu (270 cases), Nyankunde (95 cases), and Nizi (65 cases) health zones. 

    As of 1 July, the outbreak has spread to three additional health zones in the province. Following epidemiological investigations, three confirmed cases with travel history from Nia Nia health zone in Ituri province have been reported on 30 June in Wamba health zone in Haut Uele Province and Kisangani in Tshopo province. These cases have been reported under Nia Nia health zone. Response activities, including contact tracing and follow-up, are ongoing in both provinces. Of the total confirmed cases, 17 are yet to be assigned to a specific health zone.

    As of 1 July, 10 821 contacts have been identified and are under follow-up across Ituri (8376), and North Kivu (2445). Of these, 8954 contacts have been followed up, corresponding to follow-up rates of 83.2% in Ituri, and 81% in North Kivu. Previously listed contacts from South Kivu province have completed 21 days of follow up.  

    In addition, 107 contacts of the case reported in France have been listed and are under follow up in Kinshasa.

    The outbreak is unfolding in a complex humanitarian and conflict-affected environment, characterized by highly mobile and often displaced populations, often lacking access to basic services, including food, clean water, shelter, healthcare and protection which poses an increased risk of transmission to the populations living in overcrowded internally displaced camps. These dynamics, combined with increasing security-related incidents affecting health facilities, have posed additional operational challenges in affected provinces, such as constrained access for response teams, disrupted surveillance and response activities, and heightened risk of undetected transmission. These conditions underscore the need for response efforts to be led by local leaders and anchored in communities.

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Figure 2: Number of confirmed cases (n = 1460), in the Democratic Republic of the Congo, by date of reporting, as of 1 July 2026  Confirmed cases in DRC

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Figure 3: Number of deaths among confirmed cases (n = 452), in the Democratic Republic of the Congo, by date of reporting, as of 1 July 2026. Deaths in DRC

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NB: Newly reported confirmed cases/deaths may be part of the backlog of samples and therefore not necessarily newly acquired infections. 

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Uganda

    The last confirmed case was reported to be identified on 21 June 2026.  

    As of 2 July 2026, a cumulative of 20 confirmed cases including two deaths in imported cases (reported on 15 May and 5 June), and one probable case who has died, have been reported. 

    Of the confirmed cases, 15 are imported cases, while five are secondary cases among contacts and health workers with links to imported cases from the Democratic Republic of the Congo. 

    The cases have been reported in two districts, Kampala and Wakiso, both part of the Kampala Metropolitan Area. 

    To date, there has been no documented community transmission in Uganda. 

    Exposure risks are associated with healthcare settings and cross-border movements. 

    Following case reclassification, the number of affected healthcare workers was revised from five to four. In total, 16 recoveries have been reported to date.

    Of the 831 contacts listed as of 28 June, 821 contacts have completed their 21-day follow-up period as of 2 July.

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Figure 4: Number of confirmed cases (n = 20), in Uganda by date of reporting, as of 2 July 2026 

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France:

    On 24 June 2026, French authorities notified WHO of a laboratory-confirmed case of Ebola disease caused by Bundibugyo virus in a middle-aged male medical doctor returning from the Democratic Republic of the Congo. 

    The patient had been deployed for five weeks in Ituri Province, where he was involved in the care of patients with BVD. 

    Upon arrival at Charles de Gaulle Airport on 23 June 2026, the patient self-reported symptoms to airport health authorities, prompting immediate isolation and referral to a designated high-containment healthcare facility.

    At the time of reporting, the patient was clinically stable and had no fever, with no reported vomiting, diarrhoea, or haemorrhagic manifestations during travel. PCR testing detected Bundibugyo virus. Comprehensive contact tracing has been initiated in the Democratic Republic of the Congo and in France.

Epidemiology

    Bundibugyo virus disease (BVD) is a severe Ebola disease caused by the Bundibugyo virus, one of the Orthoebolavirus species. It is a zoonotic disease, with fruit bats suspected to be the natural reservoir. Human infection is thought to occur through close contact with the blood or secretions of infected wildlife, such as bats or non-human primates, and it subsequently spreads from person to person through direct contact with the blood, secretions, organs, or other bodily fluids of infected individuals or contaminated surfaces or items. Transmission is particularly amplified in health-care settings when infection prevention and control (IPC) measures are inadequate, and during unsafe burial practices involving direct contact with the deceased.

    The incubation period for BVD ranges from two to 21 days, and individuals are not infectious until symptom onset. Early symptoms such as fever, fatigue, muscle pain, headache, and sore throat, are non-specific, which complicates clinical diagnosis and can delay detection. These symptoms then progress to gastrointestinal symptoms, organ dysfunction, and in some cases haemorrhagic manifestations. CFRs in the past two BVD outbreaks, reported in Uganda and in the Democratic Republic of the Congo in 2007 and 2012 were 30% and 50%, respectively.

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

Public health response

    Health authorities in the Democratic Republic of the Congo and Uganda, in collaboration with WHO and partners, are implementing extensive public health measures including implementing the continental response plan, engaging donors and mobilizing additional resources to address critical funding gaps and sustain response operations across affected and at-risk areas.

(...)

WHO risk assessment

    On 6 June 2026, WHO reassessed the risk of the outbreak of BVD to incorporate newly available information and align with the WHO Temporary Recommendations. 

    The risk for countries sharing land borders with countries with documented Bundibugyo virus (BVDV) detection, currently the Democratic Republic of the Congo and Uganda, has been separated out from the risk for other countries in the African Region.

    The risk in the Democratic Republic of the Congo remains assessed as very high due to ongoing transmission and the continued expansion of the outbreak into new health zones, increasing the potential for further national and regional spread.

    The risk in Uganda is assessed as high due to confirmed cross-border spread through imported cases and ongoing epidemiological links along the eastern Democratic Republic of the Congo–western Uganda corridor, historically affected by Ebola outbreaks, including Bundibugyo and Sudan virus disease outbreaks.

    The risk for countries with land borders adjoining countries with documented BDBV detection is assessed as high due to sustained population mobility linked to cross-border trade and mining activities, variation in capacities and experience of BVD response, and variable levels of readiness.

    The risk for the rest of the Africa region and at the global level is assessed as low.

(...)

WHO advice

    WHO advises against any restriction of travel to, or trade with, the Democratic Republic of the Congo or Uganda based on the currently available information. WHO continues to closely monitor and, where necessary, verify travel and trade measures in relation to this event.

    For further information on the considerations for implementing border health and international travel-related temporary recommendations, please see the relevant technical note issued on 26 May 2026.

    The Temporary Recommendations issued to State Parties on 22 May 2026 underscore the importance of coordinated outbreak control, enhanced cross‑border collaboration, and sustained surveillance and preparedness to prevent further regional spread and ensure an effective public health response.

    WHO has convened several technical advisory groups, including the Strategic Advisory Group of Experts on Immunization (SAGE) to assess candidate vaccines and therapeutics for BVD. Key recommendations made are available in the news release published on 28 May 2026.

(...)

Citable reference: World Health Organization (3 July 2026). Disease Outbreak News; Bundibugyo Virus Disease, Democratic Republic of the Congo and Uganda. Available at https://www/who.int/emergencies/disease-outbreak/news/item/2026-DON612

 [1] #Data source: Centre des opérations d'urgences de sante publique (COUSP-DRC) 

Source: 

Link: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON612

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#Influenza at the #human - #animal #interface - Summary and #risk #assessment, from 9 May to 12 June 2026 (WHO, July 3 '26): 4 new human #H9N2 cases in #China

 

Influenza at the human-animal interface -  Summary and risk assessment, from 9 May to 12 June 2026 {1} 

    • New human cases {2}: 

        ° From 9 May to 12 June 2026, based on reporting date, detections of influenza A(H9N2) in four humans were reported officially. 

    • Circulation of influenza viruses with zoonotic potential in animals: 

        ° High pathogenicity avian influenza (HPAI) events in poultry and non-poultry animal species continue to be reported to the World Organisation for Animal Health (WOAH).{3} 

        ° The Food and Agriculture Organization of the United Nations (FAO) also provides a global update on avian influenza viruses with pandemic potential.{4} 

    ° Additionally, low pathogenicity avian influenza viruses as well as swine influenza viruses continue to circulate in animal populations. 

    • Risk assessment {5}: 

        ° Sustained human to human transmission has not been reported associated with the above-mentioned human infection events. 

        ° Based on information available at the time of this risk assessment update, the overall public health risk from currently known influenza A viruses detected at the human-animal interface has not changed and remains low. 

        ° At present, these viruses are not thought to be capable of sustained human-to-human transmission, although this could change as they evolve.  

        ° Although human infections with viruses of animal origin are infrequent, they are not unexpected at the human-animal interface.  

    • IHR compliance {6}: 

        ° This includes any influenza A virus that has demonstrated the capacity to infect a human and its haemagglutinin (HA) gene (or protein) is not a mutated form of those, i.e. A(H1) or A(H3), circulating widely in the human population. 

        ° Information from these notifications is critical to inform risk assessments for influenza at the human-animal interface.  

Avian influenza viruses in humans 

A(H9N2), China  

    ° Between 13 May and 11 June 2026, China notified WHO of four laboratory-confirmed cases of A(H9N2) virus infection detected through influenza-like illness surveillance. 

    ° All cases recovered from illness. 

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    ° The child with onset in April was admitted to hospital with pneumonia. 

    ° The adult case had comorbidities and was hospitalized. 

    ° All the cases had exposure to live bird markets or household poultry. 

    ° Samples from environments associated with the likely area of exposure of all but one of these cases tested positive for A(H9) viruses. 

    ° No further cases were detected among contacts of these cases.   

Risk assessment for avian influenza A(H9N2):  

1. What is the global public health risk of additional human cases of infection with avian influenza A(H9N2) viruses?  
• Most human cases follow exposure to the A(H9N2) virus through contact with infected poultry or contaminated environments. 
• Most human infections of A(H9N2) to date have resulted in mild clinical illness. 
• Since the virus is endemic in poultry in multiple countries in Africa and Asia, additional human cases associated with exposure to infected poultry or contaminated environments are expected but remain unusual. 
• The impact to public health if additional sporadic cases are detected is minimal. 
• The overall global public health risk is low.  
2. What is the likelihood of sustained human-to-human transmission of avian influenza A(H9N2) viruses related to these events?  
• At the present time, no sustained human-to-human transmission has been identified associated with the recently reported human infections with A(H9N2) viruses. 
• Current evidence suggests that A(H9N2) viruses from these cases did not acquire the ability of sustained transmission among humans.  
3. What is the likelihood of international spread of avian influenza A(H9N2) virus by travellers?  
• Should infected individuals from affected areas travel internationally, their infection may be detected in another country during travel or after arrival. 
• If this were to occur, further community level spread is considered unlikely as current evidence suggests the A(H9N2) virus subtype has not acquired the ability to transmit easily among humans.  

Overall risk management recommendations: 

    

    ° Surveillance and investigations 

    

        • Due to the constantly evolving nature of influenza viruses, WHO continues to stress the importance of global strategic surveillance in animals and humans to detect virologic, epidemiologic and clinical changes associated with circulating influenza viruses that may affect human (or animal) health. 

        

            Continued vigilance is needed within affected and neighbouring areas to detect infections in animals and humans. 

        

            Close collaboration with the animal health and environment sectors is essential to understand the extent of the risk of human exposure and to prevent and control the spread of animal influenza. 

    

            WHO has published guidance on surveillance for human infections with avian influenza A(H5) viruses. 

        • As the extent of influenza virus circulation in animals is not clear, epidemiologic and virologic surveillance and the follow-up of suspected human cases should continue systematically. 

            

            Guidance on investigation of non-seasonal influenza and other emerging acute respiratory diseases has been published on the WHO website. 

            Countries should: 

            

                - increase avian influenza surveillance in domestic and wild birds, enhance surveillance for early detection in cattle populations in countries where HPAI is known to be circulating, include HPAI as a differential diagnosis in non-avian species, including cattle and other livestock populations, with high risk of exposure to HPAI viruses; 

                

                - monitor and investigate cases in non-avian species, including livestock, report cases of HPAI in all animal species, including unusual hosts, to WOAH and other international organizations, 

                - share genetic sequences of avian influenza viruses in publicly available databases, 

                - implement preventive and early response measures to break the HPAI transmission cycle among animals through movement restrictions of infected livestock holdings and strict biosecurity measures in all holdings, 

                - employ good production and hygiene practices when handing animal products, and 

                - protect persons in contact with suspected/infected animals.{7} 

            More guidance can be found from WOAH and FAO. 

        • When there has been human exposure to a known outbreak of an influenza A virus in domestic poultry, wild birds or other animals – or when there has been an identified human case of infection with such a virus – enhanced surveillance in potentially exposed human populations becomes necessary. 

            - Enhanced surveillance should consider the health care seeking behaviour of the population, and could include a range of active and passive health care and/or communitybased approaches, including: enhanced surveillance in local influenza-like illness (ILI)/SARI systems, active screening in hospitals and of groups that may be at higher occupational risk of exposure, and inclusion of other sources such as traditional healers, private practitioners and private diagnostic laboratories. 

        • Vigilance for the emergence of novel influenza viruses with pandemic potential should be maintained at all times including during a non-influenza emergency. In the context of the cocirculation of SARS-CoV-2 and influenza viruses, WHO has updated and published practical guidance for integrated surveillance. 

    ° Notifying WHO 

        • All human infections caused by a new subtype of influenza virus are notifiable under the International Health Regulations (IHR, 2005).{8,9} State Parties to the IHR (2005) are required to immediately notify WHO of any laboratory-confirmed {10} case of a recent human infection caused by an influenza A virus with the potential to cause a pandemic {11}. Evidence of illness is not required for this report. Evidence of illness is not required for this report. 

        • WHO published the case definition for human infections with avian influenza A(H5) virus requiring notification under IHR (2005): https://www.who.int/teams/global-influenzaprogramme/avian-influenza/case-definitions. 

    ° Virus sharing and risk assessment 

        • It is critical that these influenza viruses from animals or from humans are fully characterized in appropriate animal or human health influenza reference laboratories. Under WHO’s Pandemic Influenza Preparedness (PIP) Framework, Member States are expected to share influenza viruses with pandemic potential on a timely basis {12} with a WHO Collaborating Centre for influenza of GISRS. The viruses are used by the public health laboratories to assess the risk of pandemic influenza and to develop candidate vaccine viruses.  

        • The Tool for Influenza Pandemic Risk Assessment (TIPRA) provides an in-depth assessment of risk associated with some zoonotic influenza viruses – notably the likelihood of the virus gaining human-to-human transmissibility, and the impact should the virus gain such transmissibility. TIPRA maps relative risk amongst viruses assessed using multiple risk elements. The results of TIPRA complement those of the risk assessment provided here, and those of prior TIPRA risk assessments are published at http://www.who.int/teams/global-influenza-programme/avianinfluenza/tool-for-influenza-pandemic-risk-assessment-(tipra).  

    ° Risk reduction 

        • Given the observed extent and frequency of avian influenza in poultry, wild birds and some wild and domestic mammals, the public should avoid contact with animals that are sick or dead from unknown causes, including wild animals, and should report dead birds and mammals or request their removal by contacting local wildlife or veterinary authorities.  

        • Eggs, poultry meat and other poultry food products should be properly cooked and properly handled during food preparation. Due to the potential health risks to consumers, raw milk should be avoided. WHO advises consuming pasteurized milk. If pasteurized milk isn’t available, heating raw milk until it boils makes it safer for consumption. 

        • WHO has published practical interim guidance to reduce the risk of infection in people exposed to avian influenza viruses. 

    ° Trade and travellers 

        • WHO advises that travellers to countries with known outbreaks of animal influenza should avoid farms, contact with animals in live animal markets, entering areas where animals may be slaughtered, or contact with any surfaces that appear to be contaminated with animal excreta. Travelers should also wash their hands often with soap and water. All individuals should follow good food safety and hygiene practices.  

        • WHO does not advise special traveller screening at points of entry or restrictions with regards to the current situation of influenza viruses at the human-animal interface. For recommendations on safe trade in animals and related products from countries affected by these influenza viruses, refer to WOAH guidance.  

Links:  

    WHO Human-Animal Interface web page https://www.who.int/teams/global-influenza-programme/avian-influenza 

    WHO Influenza (Avian and other zoonotic) fact sheet https://www.who.int/news-room/fact-sheets/detail/influenza-(avian-and-other-zoonotic) 

    WHO Protocol to investigate non-seasonal influenza and other emerging acute respiratory diseases https://www.who.int/publications/i/item/WHO-WHE-IHM-GIP-2018.2 

    WHO Public health resource pack for countries experiencing outbreaks of influenza in animals:  https://www.who.int/publications/i/item/9789240076884 

    Cumulative Number of Confirmed Human Cases of Avian Influenza A(H5N1) Reported to WHO  https://www.who.int/teams/global-influenza-programme/avian-influenza/avian-a-h5n1-virus 

    Avian Influenza A(H7N9) Information https://www.who.int/teams/global-influenza-programme/avian-influenza/avian-influenza-a-(h7n9)virus 

    World Organisation of Animal Health (WOAH) web page: Avian Influenza  https://www.woah.org/en/home/ 

    Food and Agriculture Organization of the United Nations (FAO) webpage: Avian Influenza https://www.fao.org/animal-health/avian-flu-qa/en/ 

    WOAH/FAO Network of Expertise on Animal Influenza (OFFLU) http://www.offlu.org/

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{1} This summary and assessment covers information confirmed during this period and may include information received outside of this period. 

{2} For epidemiological and virological features of human infections with animal influenza viruses not reported in this assessment, see the reports on human cases of influenza at the human-animal interface published in the Weekly Epidemiological Record here.  

{3} World Organisation for Animal Health (WOAH). Avian influenza. Global situation. Available at: https://www.woah.org/en/disease/avian-influenza/#ui-id-2. 

{4} Food and Agriculture Organization of the United Nations (FAO). Global Avian Influenza Viruses with Zoonotic Potential situation update. Available at: https://www.fao.org/animal-health/situation-updates/global-aiv-withzoonotic-potential. 

{5} World Health Organization (2012). Rapid risk assessment of acute public health events. World Health Organization. Available at: https://iris.who.int/handle/10665/70810. 

{6} World Health Organization. Case definitions for the four diseases requiring notification in all circumstances under the International Health Regulations (2005). Available at: https://www.who.int/publications/m/item/case-definitions-for-the-four-diseases-requiring-notification-towho-in-all-circumstances-under-the-ihr-(2005).  

{7} World Organisation for Animal Health. Statement on High Pathogenicity Avian Influenza in Cattle, 6 December 2024 (https://www.woah.org/en/high-pathogenicity-avian-influenza-hpai-in-cattle/). 

{8} World Health Organization. International Health Regulations (2005), as amended through resolutions WHA67.13 (2014), WHA75.12 (2022), and WHA77.17 (2024) (https://apps.who.int/gb/bd/pdf_files/IHR_20142022-2024-en.pdf). 

{9} World Health Organization. Case definitions for the four diseases requiring notification in all circumstances under the International Health Regulations (2005) (https://www.who.int/publications/m/item/casedefinitions-for-the-four-diseases-requiring-notification-to-who-in-all-circumstances-under-the-ihr-(2005)). 

{10} World Health Organization. Manual for the laboratory diagnosis and virological surveillance of influenza (2011) (https://apps.who.int/iris/handle/10665/44518). 

{11} World Health Organization. Pandemic influenza preparedness framework for the sharing of influenza viruses and access to vaccines and other benefits, 2nd edition (https://iris.who.int/handle/10665/341850). 

{12} World Health Organization. Operational guidance on sharing influenza viruses with human pandemic potential (IVPP) under the Pandemic Influenza Preparedness (PIP) Framework (2017) (https://apps.who.int/iris/handle/10665/259402). 

Source: 

Link: https://www.who.int/publications/m/item/influenza-at-the-human-animal-interface-summary-and-assessment--12-june-2026

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#Genomic #Surveillance Uncovers the Silent #Spread of Avian #Influenza Virus #H5N1 2.3.4.4b Among Wild #Birds and #Mammals Along #Brazil’s Southern Coast

 

Abstract

Avian influenza viruses (AIVs) are widely distributed and have a wide range of hosts. Recently, the number of cases of infection associated with the circulation of highly pathogenic avian influenza H5N1 2.3.4.4b has raised concerns about its high transmission capacity in birds and mammals. This study analyzed swabs from bird and mammal species from the coast of Paraná and the northwest region of São Paulo, Brazil, for the presence of AIV in animals that did not present clinical or histopathological lesions of infection that indicated the need for molecular characterization during monitoring. Of the 661 animals analyzed, three tested positive, two of which were birds (Sula leucogaster and Thalasseus acuflavidus) while one was a mammal (Otaria flavescens) (0.45%, CI 95%: 0.16–1.33). A complete genome sequence of H5N1 AIV was obtained from a brown booby (Sula leucogaster) from the Paraná coast (GISAID accession number: EPI_ISL_1897537). Our study reinforces the importance of continuous genomic surveillance, especially in AIV hosts that do not show signs of infection, to enhance the One-Health assessment approach.

Source: Viruses, https://www.mdpi.com/journal/viruses

Link: https://www.mdpi.com/1999-4915/18/7/738

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#Vaccine #strategies and #development before and during the 1968 #H3N2 #influenza #pandemic

 

Abstract

Nearly 60 years ago, in 1968, the global population was confronted with the emerging pandemic influenza A virus (IAV) subtype H3N2 (1968 H3N2pdm). An estimate of up to two million fatalities have been linked to 1968 H3N2pdm, and the H3N2 subtype continues to circulate as seasonal IAV among humans until today. The last IAV pandemic dates back to the year 2009 but concerns about a new IAV pandemic in the near future are increasing. The global spread of H5N1 highly pathogenic avian influenza virus and its spill-over into new mammalian hosts, discovery of novel influenza A virus with zoonotic or even pandemic potential, as well as seasonal influenza viruses undergoing antigenic changes necessitate constant vigilance. Here, we highlight the proactive actions, precautionary measures and vaccination strategies used during the 1968 H3N2 IAV pandemic. Our review highlights the emergence and spread of 1968 H3N2pdm over the course of the pandemic, alongside a delineation of vaccine development before, during and after the 1968 pandemic. Updating these strategies in the context of new findings combined with our experiences during the coronavirus disease 2019 (COVID-19) pandemic is necessary to improve preparedness for the next pandemic. Influenza viruses with zoonotic potential will remain a constant threat to public health, and improving countermeasures and communication to the public is key to limit the pandemic ramifications.

Source: 

Link: https://www.sciencedirect.com/science/article/abs/pii/S0264410X26006869?via%3Dihub

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Mapping #SARS-CoV-2 #immunity after an #XBB.1.5 #booster by antigenic cartography of merged #human and hamster sera

 

Abstract

The ongoing evolution of SARS-CoV-2, particularly the emergence and rapid spread of new immune-evasive variants, continues to challenge the durability of vaccine-induced protection. Understanding how repeated variant exposures shape neutralizing antibody breadth is therefore essential for optimizing booster design. Here, we investigated polyclonal neutralizing antibody responses in individuals who received a bivalent (ancestral + BA.4/5) boost followed by an additional monovalent XBB.1.5 boost, with and without breakthrough infection, against a diverse panel of SARS-CoV-2 variants. To visualize human multi-exposure immunity in antigenic space via antibody landscapes, we extended our existing human sera-based antigenic map with hamster sera infected with more recent variants. The hamster sera allowed us to map BA.2.86 and JN.1 variants, which largely escape human single exposure sera. Our analysis of human multi-exposure sera revealed that the number and type of exposures significantly shaped antibody landscapes. The XBB.1.5 booster immunization notably increased neutralizing antibody titers across variants, elevating the height of the antibody landscape. However, titers against more recent Omicron variants, such as JN.1, were low despite booster administration. These findings highlight the dynamic nature of SARS-CoV-2 immunity and emphasize the need for continuous monitoring and adaptation of vaccine strategies to maintain effective protection against emerging variants.

Source: npj Vaccine, https://www.nature.com/npjvaccines/

Link: https://www.nature.com/articles/s41541-026-01516-7

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#Hantavirus #outbreak linked to cruise #ship travel, Multi-locations (WHO, July 3 '26): End of the Event

 

Situation at a glance

    This is the fifth Disease Outbreak News posting on the Andes hantavirus (ANDV) outbreak linked to the cruise ship M/V Hondius. 

    The outbreak identification followed the notification to the World Health Organization (WHO) on 2 May 2026 of severe acute respiratory illness cases onboard. 

    Since the previous Disease Outbreak News was published on 28 May 2026, one of the probable cases from Tristan da Cunha, an Overseas Territory of the United Kingdom of Great Britain and Northern Ireland (hereafter referred to as the United Kingdom), was laboratory confirmed. 

    As of 2 July, a total of 13 cases, including three deaths, have been notified (case fatality ratio 23%). 

    Twelve cases have been laboratory-confirmed for ANDV infection, and one is a probable case. 

    All confirmed cases are among individuals who travelled onboard the M/V Hondius. 

    Among the ten cases admitted to hospitals, eight have recovered and have been discharged, while two are still undergoing medical treatment. 

    All identified contacts have completed the 42 day follow-up period by local health authorities in line with WHO guidance. 

    The completion of the contact follow up without detection of additional secondary cases demonstrates effective interruption of transmission and confirms outbreak containment. 

    This outbreak no longer poses a public health risk and no further related transmission is expected.

Description of the situation

    On 2 May 2026, in accordance with the International Health Regulations (2005) (IHR), WHO received a notification from the National IHR Focal Point (NFP) of the United Kingdom of a cluster of severe acute respiratory illness aboard the Netherlands-flagged cruise ship M/V Hondius, with further details rapidly notified authorities in the Netherlands and South Africa.

    As of 2 July, a total of 13 cases (12 confirmed and one probable case), including three deaths (two confirmed and one probable), have been reported globally linked to the cruise ship. 

    The case fatality ratio for this outbreak to date is 23%. 

    Since the last Disease Outbreak News was published on 28 May 2026, ANDV infection was laboratory confirmed in a probable case in Tristan da Cunha who developed signs and symptoms after disembarkation from the cruise ship. 

    The early detection and isolation of the case prevented further transmission of the virus, but the limited diagnostic capacities on the island delayed the confirmation of the case until a sample was shipped and tested in the United Kingdom. 

    The patient has recovered and has been discharged.

    Among the confirmed cases admitted to hospital, eight have recovered and been discharged, while two, one in South Africa and one in France, continue to be hospitalized. 

    All 13 cases are among people who travelled on board the M/V Hondius.

(...)

    Nine of the reported cases were males, and four were females. The median age was 65-years-old (IQR 56-70), similar to the median age of the passengers onboard the ship (...). The ages of the three deceased cases were 69, 70 and 79-years-old.

(...)

    Currently available information suggests that infection of initial cases was likely acquired on land prior to embarkation, although the exact source and route of exposure remain undetermined, with subsequent human-to-human transmission occurring aboard the vessel. 

    Investigations remain underway to establish the circumstances and source of the outbreak, including genomic sequencing of ANDV samples from surveillance cases in Chile and Argentina, and will be published as soon as these are available.

    This outbreak was managed through a coordinated international response, which included comprehensive epidemiological investigations, case isolation and clinical management, medical evacuations, laboratory testing, repatriation of passengers and crew from the ship and international contact tracing, as well as quarantine and monitoring measures.

    Contact identification and follow-up of contacts of hantavirus cases linked to the cruise ship has been conducted in 33 countries and overseas territories. 

    This included passengers and crew onboard the ship, contacts of the case on Tristan da Cunha, contacts from two different international flights, healthcare workers and airport crew who assisted cases before the detection of the outbreak. 

    As of 2 July 2026, 317 high-risk contacts have completed quarantine and monitoring by local health authorities in the countries and territories where they were repatriated, evacuated or identified. 

    Some 336 low-risk contacts completed self-monitoring in line with the updated guidance on management of contacts of Andes virus (ANDV) cases from the MV Hondius cruise ship published on 17 May 2026. 

Epidemiology

    Hantavirus disease is a zoonotic viral disease caused by hantaviruses of the genus Orthohantavirus, family Hantaviridae, order Elliovirales, class Bunyaviricetes. More than 20 viral species have been identified within this genus. 

    Human hantavirus infection is primarily acquired through contact with the urine, faeces, or saliva of certain species of (specific) infected rodents, or by touching contaminated surfaces. 

    Exposure typically occurs during activities such as cleaning buildings with rodent infestations, though it may also occur during routine activities in heavily infested areas. 

    Human cases are most commonly reported in rural settings, such as forests, fields, and farms, where rodents are present and opportunities for exposure are greater.

    Limited human-to-human transmission has currently only been reported for hantavirus pulmonary syndrome (HPS) associated with ANDV virus infection. 

    ANDV is endemic in South America, with confirmed circulation and human infections reported primarily in Argentina and Chile, and additional cases and related strains identified in Uruguay, southern Brazil, and Paraguay.

Andes virus transmission between humans

    Based on the available information and the existing observations of the current outbreak, limited human-to-human transmission of ANDV is known to occur. 

    However, no large-scale human-to-human outbreaks have been observed historically.[1] 

    ANDV circulates in specific species of rodents in the Americas, and there have been many sporadic cases reported in Argentina and Chile that have not led to onward transmission.[2]  

    Clusters of human cases have been reported in multiple past outbreaks and have been typically associated with close and prolonged interactions, often in shared indoor environments such as households.  

    The largest reported outbreak of ANDV was reported in Argentina in 2018-2019,2 where high viral titres in combination with attendance at large social gatherings or extensive contacts among people were associated with higher transmission.  

    While the available evidence suggests that there are multiple modes of transmission that occur with ANDV, the probability of onward transmission between humans remains low.

    Initial epidemiological investigation and the genomics analysis[3] of the identified cases show that in this outbreak of ANDV infection, human-to-human transmission has occurred on the ship. 

    While detailed information on the interaction between cases or with a contaminated environment aboard the ship is currently not available, these exact modes of transmission might be elucidated by upcoming results from an in-depth epidemiological investigation, as well as publication of the environmental sampling performed after the disembarkation.  

Response activities operated under the assumption that ANDV transmission:

    ° may have included contact with an infected individual or contaminated surfaces;

    ° and/or through-the-air transmission (via direct deposition of infectious respiratory particles onto exposed facial mucosal surfaces—mouth, nose, or eyes);

    ° and/or airborne transmission (via inhalation of infectious respiratory particles).

    Given the attack rate among the ship passengers, as well as the absence of secondary cases among contacts off the ship, the virus did not exhibit transmission dynamics consistent with highly transmissible airborne pathogens (such as measles).

Public health response

    Authorities from States Parties managing cases and/or contacts, WHO, and partners such as the European Centre for Disease Prevention and Control have coordinated response measures, including:

        ° Ongoing engagement between WHO and the NFPs of countries managing cases and/or contacts ensured timely information sharing and coordination of response actions.

        ° International contact tracing and follow-up of contacts was conducted by local health authorities in line with national arrangements.

        ° WHO requested regular information sharing and periodic updates from States Parties through IHR channels regarding the follow-up of contacts and their health status.

        ° Ongoing epidemiological investigations to define epidemiological links between cases and exposure factors on the ship, as well as to try to understand the potential source of exposure.

    A prospective natural history study designed to improve understanding of Andes virus (ANDV) transmission dynamics, incubation periods, immune responses, viral kinetics, and the determinants of severe disease through harmonised longitudinal follow-up of exposed individuals. The study uses a standardised prospective protocol implemented across 21 participating countries.[4]

    WHO developed and published specific technical guidance documents to support response to the event, including:

        ° Technical guidance on the management of hantavirus onboard ships was shared with States Parties through IHR channels

        ° Technical note for the disembarkation and onward management of passengers and crew in the context of an ANDV-associated cluster;

        ° Management of contacts of Andes Virus (ANDV) cases from the MV Hondius cruise ship

        ° Laboratory testing of Andes virus (Orthohantavirus andesense) infection: Interim guidance

    The NFPs of countries managing cases and/or contacts have been exchanging passenger- and crew-related information.

    WHO provided risk communication coordination and support, ensured timely evidence-based information sharing, activated the coordination mechanisms across the three organizational levels, and supported national authorities in implementing public health measures, including in accordance with IHR provisions.

    WHO convened regular Member State briefings, expert discussions covering key technical, laboratory, clinical care and infection prevention and control (IPC) topics, and global webinars via the EPI-WIN knowledge platform to facilitate experience sharing and coordinate support.

    WHO supported the development of research protocols with national and international partners and planned a hantavirus consultation on medical countermeasures.

    WHO coordinated the distribution of the laboratory testing and reference materials made available by Chile and Argentina, as well as diagnostic protocols and information on available test kits and their performance.

WHO risk assessment

    The ANDV outbreak associated with the MV Hondius cruise ship no longer poses a public health risk and no further related transmission is expected.  

    ANDV remains endemic in South America, and it is associated with hantavirus pulmonary syndrome with substantial case fatality, its transmissibility remains limited, typically requiring close and prolonged exposure, and tends to result in temporally and spatially restricted clusters.

    While the confined maritime environment of this event likely facilitated transmission during the voyage, epidemiological and genomic evidence supports a point source outbreak, originating either from contact with an infected animal or infected person, followed by limited chains of human-to-human secondary transmission, without evidence of sustained transmission.

    The completion of the 42-day follow-up period for all identified contacts without further detection of additional secondary cases demonstrates effective interruption of transmission and confirms outbreak containment. 

    Additionally, IPC measures continue to be applied for the management of the two cases still hospitalized.

WHO advice

    WHO advises all countries to sustain strong engagement and collaboration to document and learn from this outbreak response, including both successes and operational challenges, and to apply the lessons identified to strengthen preparedness, surveillance including international tracing and follow up of contacts, clinical care, IPC, risk communication, and response capacities for future public health emergencies.

    WHO further encourages the continuation of epidemiological, clinical, laboratory, and ecological studies to better understand the outbreak, its transmission dynamics, risk factors, and determinants of disease severity.

    In areas where hantavirus is endemic, WHO recommends strengthening measures to prevent and control transmission through enhanced surveillance, public awareness, environmental management, reduction of exposure to rodent reservoirs and contaminated environments, and early detection, implementation of IPC measures and management of cases.

    WHO also encourages continued investment in research and development to advance the availability of effective diagnostics, therapeutics, and vaccines, and to improve preparedness and response capabilities for future hantavirus outbreaks.

Further information

    ° World Health Organization. Management of contacts of Andes virus (ANDV) cases from the MV Hondius cruise ship. https://www.who.int/publications/m/item/management-of-contacts-of-andes-virus-(andv)-cases-fromthe-mv-hondius-cruise-ship

    ° World Health Organization. WHO Technical note for the disembarkation and onward management of passengers and crew in the context of an Andes virus-associated cluster MV Hondius cruise ship. https://www.who.int/publications/m/item/who-technical-note-for-the-disembarkation-and-onward-management-of-passengers-and-crew-in-the-context-of-an-andes-virus-associated-cluster-mv-hondius-cruise-ship

    ° World Health Organization. Hantavirus fact sheet. https://www.who.int/news-room/fact-sheets/detail/hantavirus 

    ° World Health Organization. WHO’s response to hantavirus cases linked to a cruise ship. https://www.who.int/news/item/07-05-2026-who-s-response-to-hantavirus-cases-linked-to-a-cruise-ship

    ° World Health Organization. Handbook for management of public health events on board ships. https://www.who.int/publications/i/item/9789241549462

    ° World Health Organization. Guide to Ship Sanitation, 3rd edition https://www.who.int/publications/i/item/9789241546690

    ° World Health Organization. Handbook for management of public health events in air transport, https://www.who.int/publications/i/item/9789241510165

    ° World Health Organization. Guide to hygiene and sanitation in aviation, 3rd edition, https://www.who.int/publications/i/item/9789241547772

    ° Preliminary analysis of Orthohantavirus andesense virus sequences from a cruise-ship related cluster, May 2026. https://virological.org/t/preliminary-analysis-of-orthohantavirus-andesense-virus-sequences-from-a-cruise-ship-related-cluster-may-2026/1029

    ° World Health Organization. Standard precautions for the prevention and control of infections: aide-memoire. https://www.who.int/publications/i/item/WHO-UHL-IHS-IPC-2022.1

    ° World Health Organization. Transmission-based precautions for the prevention and control of infections: aide-memoire. https://www.who.int/publications/i/item/WHO-UHL-IHS-IPC-2022.2

    ° World Health Organization. Hantavirus outbreak toolbox. https://www.who.int/emergencies/outbreak-toolkit/disease-outbreak-toolboxes/hantavirus-outbreak-toolbox

    ° World Health Organization (8 May 2026). Disease Outbreak News. Hantavirus cluster linked to cruise ship travel, Multi-country. Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON600

    ° World Health Organization (4 May 2026). Disease Outbreak News. Hantavirus cluster linked to cruise ship travel- Multi-country. Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON599

    ° World Health Organization. A decision framework for effective, equitable and context-specific public health and social measures during public health emergencies: decision navigator: https://iris.who.int/server/api/core/bitstreams/ceaf4aa7-00c8-4681-9c35-965e231a3706/content

    ° World Health Organization Health Emergencies EPI-WIN webinar: Hantavirus in Focus I: what we know and what it means. https://www.who.int/news-room/events/detail/2026/05/20/default-calendar/hantavirus-in-focus-i-what-we-know-and-what-it-means

    ° World Health Organization Health Emergencies EPI-WIN webinar: Hantavirus in Focus II: hantavirus natural history, infection control and clinical management of patients in hospital. https://www.who.int/news-room/events/detail/2026/05/22/default-calendar/who-health-emergencies-epi-win-webinar-hantavirus-in-focus-ii-hantavirus-in-an-international-maritime-setting-natural-history-infection-control-and-clinical-management-of-patients-in-hospital

    ° World Health Organization Health Emergencies EPI-WIN webinar: Hantavirus in focus III: reflections from the IHR Border Health and Points of Entry perspective. https://www.who.int/news-room/events/detail/2026/06/04/default-calendar/who-health-emergencies-epi-win-webinar--hantavirus-in-focus-iiireflections-from-a-border-health-and-point-of-entry-perspective

    ° World Health Organization Health Emergencies EPI-WIN webinar: Hantavirus in focus IV: Infection prevention and control: from isolation to safe discharge and quarantine. https://www.who.int/news-room/events/detail/2026/06/16/default-calendar/who-health-emergencies-epi-win-webinar-hantavirus-in-focus-iv-infection-prevention-and-control-from-isolation-to-safe-discharge-and-quarantine

    ° Pan American Health Organization / World Health Organization. Infection prevention and control of hantavirus infection, including Andes virus disease. Interim regional guidance for suspected or confirmed cases. https://iris.paho.org/items/bc5a7b5a-5a0a-4407-829e-663c762ad615

    ° Pan American Health Organization / World Health Organization. Clinical management of hantavirus infection, including Andes virus disease: Interim regional guidance for suspected or confirmed cases. https://iris.paho.org/items/0fa0dcb1-4395-467d-a431-5408b4eff337    

    ° Pan American Health Organization / World Health Organization. PAHO supports the international response to hantavirus pulmonary syndrome cases linked to a cruise ship in the Atlantic. https://www.paho.org/en/news/7-5-2026-paho-supports-international-response-hantavirus-pulmonary-syndrome-cases-linked

    ° Epidemiological Alert Hantavirus Pulmonary Syndrome. https://www.paho.org/en/documents/epidemiological-alert-hantavirus-pulmonary-syndrome-americas-region-19-december-2025  

    ° Hantavirus in the Americas: Guidelines for diagnosis, treatment, prevention and control. Available at: https://iris.paho.org/handle/10665.2/40176

    ° Hantavirus Prevention, CDC: https://www.cdc.gov/hantavirus/prevention/?CDC_AAref_Val=https://www.cdc.gov/hantavirus/hps/prevention.html

    ° Martínez Valeria, Paola N, et al. (2020). “Super-Spreaders” and Person-to-Person Transmission of Andes Virus in Argentina. New England Journal of Medicine. 383. 2230-2241. 10.1056/NEJMoa2009040.

    ° US CDC. How to Clean Up After Rodents: https://www.cdc.gov/healthy-pets/rodent-control/clean-up.html

    ° Hantavirus, Washington State Department of Heath, https://doh.wa.gov/sites/default/files/2025-08/420-056-Guideline-Hantavirus.pdf

    ° Hantavirus Infection, MDS Manual, professional version: https://www.msdmanuals.com/professional/infectious-diseases/arboviruses-arenaviridae-and-filoviridae/hantavirus-infection

    ° Hantavirus pulmonary syndrome, https://www.mayoclinic.org/diseases-conditions/hantavirus-pulmonary-syndrome/symptoms-causes/syc-20351838

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    [1] “Super-Spreaders” and Person-to-Person Transmission of Andes Virus in Argentina | New England Journal of Medicine. https://www.nejm.org/doi/full/10.1056/NEJMoa2009040

    [2] Padula PJ, Edelstein A, Miguel SD, López NM, Rossi CM, Rabinovich RD. Hantavirus pulmonary syndrome outbreak in Argentina: molecular evidence for person-to-person transmission of Andes virus. Virology. 1998 Feb 15;241(2):323-30. doi: 10.1006/viro.1997.8976. PMID: 9499807.  https://pubmed.ncbi.nlm.nih.gov/9499807/

    [3] Preliminary analysis of Orthohantavirus andesense virus sequences from a cruise-ship related cluster, May 2026. https://virological.org/t/preliminary-analysis-of-orthohantavirus-andesense-virus-sequences-from-a-cruise-ship-related-cluster-may-2026/1029

    [4] Twenty-one countries launch coordinated Andes virus research initiative following hantavirus outbreak. https://www.who.int/news/item/12-06-2026-twenty-one-countries-launch-coordinated-andes-virus-research-initiative-following-hantavirus-outbreak  

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Citable reference: World Health Organization (2 July 2026). Disease Outbreak News. Hantavirus outbreak linked to cruise ship travel, Multi-locations. Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON611

Source: 

Link: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON611

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