ETIDIOH - NEW

  Abstract The H5N1 high pathogenicity avian influenza virus (HPAIV) of clade 2.3.4.4b, which spreads globally via wild birds , has become a major public health concern because it can infect a variety of mammals , including humans . In 2024, infection of dairy cattle with H5N1 HPAIV clade 2.3.4.4b was confirmed in the United States , and subsequent human cases were reported. Although these viruses are highly pathogenic in animal models , human infections have generally been mild , revealing a striking discrepancy . Here, we characterized the cattle-derived human H5N1 isolate A/Texas/37/2024 (TX37-H5N1) using three-dimensional human respiratory organoids derived from induced pluripotent stem (iPS) cells. Despite efficient replication , TX37-H5N1 induced minimal interferon and inflammatory cytokine responses . Bulk and single-cell RNA sequencing revealed reduced STAT1-mediated transcriptional activity in TX37-H5N1-infected organoids compared to the historic H5N1 human isolate A/Vietn...

  {Summary} -- During current epidemiological week (from  23 to 29 Oct. 2025) , two new human cases of infection with West Nile Virus have been reported.  -- The cumulative number of confirmed cases this season so far rose to 773 (they were 771 last week), of these:  - 367 were West Nile Neuroinvasive Disease (WNND): 17 in Piedmont, 56 Lombardy, 35 Veneto, 4 Friuli-Venezia Giulia, 1 Liguria, 30 Emilia-Romagna, 11 Tuscany, 1 Marche, 87 Latium, 2 Molise, 83 Campania, 2 Apulia, 2 Basilicata, 5 Calabria, 3 Sicily, 28 Sardinia,  - 56 were asymptomatic cases detected in blood donors ,  - 339 were West Nile Fever cases (of which: 1 imported from Kenya , 1  from Egypt and 1 from Maldives),  - 3 asymptomatic cases ,  - 8 unspecified cases.  -- Among confirmed cases, 72 fatalities have been recorded: 7 in Piedmont, 9 Lombardy, 1 Veneto, 2 Emilia-Romagna, 1 Marche, 19 Latium, 29 Campania, 2 Calabria, 1 Sicily, 1 Sardinia.  - The Case-Fatality ...

  Key Points -- Question :  Have asymptomatic infections with highly pathogenic avian influenza A(H5N1) virus been reported in humans? -- Findings:  This scoping review of published reports through August 25, 2025, identified 10 reports of 18 cases of asymptomatic infection with A( H5N1 ) virus, including 2 cases with molecular and serologic confirmation and 16 cases with molecular confirmation alone. Symptom ascertainment methods varied among reported cases. -- Meaning:   Asymptomatic human avian influenza A(H5N1) virus infections have been infrequently reported , with most lacking serologic confirmation; prospective surveillance studies with serial respiratory and serum sampling and detailed symptom monitoring for persons with high-risk exposures could provide data to inform future public health responses. Abstract Importance    Since 1997, more than 1000 infections with highly pathogenic avian influenza A(H5N1) virus among humans have been reported globa...

  {Excerpt} Risk statement This risk assessment is based on the current epidemiological and epizootic situation of Rift Valley fever (RVF) in Senegal and Mauritania , from 20 September through 8 October 2025. The risk assessment was conducted separately for each country . However, the findings indicate that the level of risk is the same for both countries across all levels, for both human and animal health .   During this period , Senegal reported 119 confirmed human RVF cases , including 16 deaths , resulting in a case fatality rate (CFR) of 13.4% . Cases were recorded across eight health districts in three regions of Senegal, with the majority in Saint-Louis Region with 110 cases (92%) followed by Louga (four cases) and Matam (one case).  The affected districts in Saint-Louis Region : Podor, Richard-Toll, Dagana, and Saint-Louis are located along the northern border with Mauritania along the Senegal River.   The most affected age groups were 15- 35 years ...

  {Excerpts} To the Editor : After a decade of no reported human cases, Cambodia faces a resurgence of highly pathogenic avian influenza (HPAI) A(H5N1) virus infections , with an overall mortality of 38%. Cases have occurred primarily in children and adolescents who were exposed to infected poultry (...). From February 2023 through August 2024, a total of 16 infections were detected through the long-standing national influenza-like illness and severe acute respiratory infection surveillance systems, both of which were strengthened by expanded laboratory-testing capacity that was developed during the coronavirus disease 2019 pandemic. All 16 patients reported exposure to sick or dead poultry , and outbreak investigations identified contemporary, genetically similar viruses in poultry collected in or around case households or from active, longitudinal surveillance of live-bird markets . Genomic sequencing revealed an avian origin for all the human infections , and sequences have been...

  Abstract The H7N9 influenza viruses, which are capable of causing severe respiratory syndrome in humans , were first discovered to infect humans in 2013 and continue to pose a persistent public health threat . Quail has been proposed as a potential intermediate host that may facilitate the emergence of novel reassorted influenza A viruses with the capacity to infect humans across species barriers; however, information on the biological characterization of quail H7N9 remains limited. In this study, we isolated and identified an avian H7N9 influenza virus from quails , designated as A/quail/Hebei/CH06-07/2018 (H7N9) and abbreviated as CH06-07, in Hebei, China . Phylogenetic analyses revealed that both the HA gene and the NA gene of CH06-07 were clustered in the Eurasian lineage . Furthermore, CH06-07 exhibited binding affinity for both α2,3-linked and α2,6-linked sialic acid receptors and demonstrated high pathogenicity in both quails and mice . Notably, transmission studies reveal...

  {Summary} -- New human cases of West Nile Virus infection continue to be reported albeit with reduced intensity.  -- During current epidemiological week (from  9 to 15 October 2025)  26 new confirmed cases have been reported.  -- The total number of cases so far is 767 (they were 740 last week), of these:  - 366 were West Nile Neuroinvasive Disease (WNND): 17 in Piedmont, 56 Lombardy, 34 Veneto, 4 Friuli-Venezia Giulia, 1 Liguria, 32 Emilia-Romagna, 10 Tuscany, 1 Marche, 86 Latium, 2 Molise, 83 Campania, 2 Apulia, 2 Basilicata, 5 Calabria, 3 Sicily, 28 Sardinia,  - 57 were asymptomatic cases among blood donors ,  - 333 were West Nile Fever cases (of which 1 imported from Kenya, 1 from Egypt and 1 from Maldive),  - 3 asymptomatic cases,  - eight unspecified cases.  -- Among confirmed cases, 69 fatalities  have been reported: 7 in Piedmont, 9 Lombardy, 2 Emilia-Romagna, 18 Latium, 29 Campania, 2 Calabria, 1 Sicily, 1 Sardinia....

{Excerpt} This Week : [Date of report - Country - Province / Region District / City - Sex - Age - Condition at time of reporting  - Subtype of virus] 1) .../10/2025 - Cambodia - Takeo Province - F - 14 - Hospitalised - H5N1  2) 16/10/2025 - Cambodia - Kampong Speu Province - F - 3 - Under intensive care - H5N1 (...) [Place of occurrence - No. of cases  (No. of deaths) - Details] -- Bangladesh - 1(0)  - Avian influenza A(H5) :  1) Sylhet Division : A boy with onset on July 27, 2025.  -- Chinese Mainland - 4(0)  - Avian influenza A( H9N2 ):  - Guangdong Province :  1) An individual with onset in February 2025. The case was retrospectively reported.  - Guangxi Zhuang Autonomous Region :  2, 3) Two individuals with onset in February 2025. Both cases were retrospectively reported.   - Tianjin Municipality :  4) An individual with onset in February 2025. The case was retrospectively reported.  -- Mexico - 1(0)  - ...

  {Excerpt} Phnom Penh (ANTARA) - A 3-year-old girl from Kampong Speu Province, western Cambodia, has been confirmed to have contracted H5N1 bird flu , bringing the number of cases to 16 so far this year, the Cambodian Ministry of Health said in a statement on Thursday (16/10) evening local time. Laboratory results from Cambodia's National Institute of Public Health on October 15 showed the girl tested positive for the H5N1 virus, the statement said. The patient had symptoms of fever, diarrhea, cough, and abdominal pain , and is currently undergoing intensive care with a team of doctors, the statement added. The girl is a resident of Chek Village, Basedth District. Investigations found that chickens and ducks had contracted the disease and died at the girl's home and at her neighbor's about a week before she fell ill, the statement said. (...) Source: Antara,  https://www.antaranews.com/berita/5181569/balita-di-kamboja-barat-jadi-korban-flu-burung-ke-16-pada-2025 ____

  Abstract Avian influenza A viruses pose ongoing threats to human and animal health, with H7 subtypes causing outbreaks globally . In Mexico , highly pathogenic H7N3 viruses have circulated in poultry since 2012, causing sporadic human infections . Here we analyzed genetic markers in hemagglutinin sequences from Mexican H7N3 isolates and conducted serological assays on human populations with poultry exposure . Our results show conserved avian-like receptor binding sites , thus limiting human adaptation , alongside antigenic drift and acquisition of glycosylation sites likely driven by vaccination. Serological testing of 1103 individuals revealed no detectable antibodies against H7N3, indicating a naïve population . Phylogenetic analyses revealed multiple virus clades circulating regionally. These findings suggest that while current H7N3 viruses have limited capacity for sustained human transmission, the lack of population immunity underscores the importance of continued surveillan...

  New human cases {1,2}:  -- From 26 August to 29 September 2025 , based on reporting date, the detection of influenza A(H5) in one human , influenza A(H5N1) in one human , influenza A(H9N2) in eight humans and an influenza A(H1N1) variant ((H1N1)v) virus in one human 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}  Risk assessment {5}:  -- Sustained human to human transmission has not been reported from these events.  -- Based on information available at the time of this risk assessment update , the overall public health risk from currently known influenza A viruses d...

  {Excerpt} Influenza A H9N2 -- Hunan Province : - 1) A two-year-old boy with onset on September 28, 2025.  -- Jiangxi Province : - 2) A 70-year-old woman with onset on September 23, 2025.  (...) Source: Centre for Health Protection, Hong Kong PRC SAR,  https://www.chp.gov.hk/files/pdf/2025_avian_influenza_report_vol21_wk41.pdf ____

{Summary} -- During current epidemiological week , a rise in the West Nile Virus human cases has been observed although with reduced intensity compared most recent weeks.  -- Twenty-two new confirmed human cases have been reported during surveillance week from 2 to 8 October 2025.  -- The cumulative number of cases rose to 740  (they were 718 last week), of these:  - 354 were West Nile Neuroinvasive Disease (WNND): 16 in Piedmont, 53 Lombardy, 33 Veneto, 4 Friuli-Venezia Giulia, 1 Liguria, 30 Emilia-Romagna, 11 Tuscany, 1 Marche, 84 Latium, 2 Molise, 81 Campania, 2 Apulia, 2 Basilicata, 5 Calabria, 3 Sicily, 26 Sardinia, - 57 were asymptomatic cases in blood donors ,  - 318 were West Nile Fever cases , of which 1 imported from Kenya , 1 from Egypt and 1 from Maldives ,  - 4 asymptomatic cases,  - 7 unspecified cases.  -- Among confirmed cases there were 68 fatalities : 7 in Piedmont, 9 Lombardy, 2 Emilia-Romagna, 18 Latium, 28 Campania, 2 Cal...

  Significance Since pigs serve as intermediate hosts between humans and the natural reservoir of influenza viruses in wild birds, they play a key role in the emergence of influenza strains with pandemic potential , as demonstrated by the 2009 pandemic. Therefore, influenza pandemic preparedness will benefit from the development of vaccines that broadly protect pigs against diverse influenza A strains. However, progress is limited by our poor molecular understanding of porcine antibody responses to influenza virus. This study isolates and characterizes a panel of broadly neutralizing influenza antibodies from pigs . Our findings not only have significant implications for the development of broadly protective influenza vaccines for pigs, but also reveal the molecular differences in the antibody responses between pigs and humans. Abstract Antibody responses to the influenza virus hemagglutinin (HA) stem, a major target for broadly protective vaccine development , have been extensivel...

  Situation at a glance In 2025, a resurgence of chikungunya virus (CHIKV) disease was noted in a number of countries , including some that had not reported substantial case numbers in recent years.  Between 1 January and 30 September 2025, a total of 445 271 suspected and confirmed CHIKV disease cases and 155 deaths were reported globally from 40 countries , including autochthonous and travel imported cases.  Some WHO Regions are experiencing significant increases in case numbers compared to 2024, although others are currently reporting lower case numbers.  This uneven distribution of cases across regions makes it challenging to characterize the situation as a global rise, however, given the ongoing outbreaks reported globally in 2025, the potential for further spread remains significant .  CHIKV disease can be introduced into new areas by infected travelers and local transmission may be established if there is the presence of Aedes mosquito and a susceptible p...

  {Summary} -- During current epidemiological week (from  25 September to 1rst October 2025),  38 new confirmed human infection with West Nile Virus have been reported.  -- Since the beginning of the epidemic season, 718 confirmed cases have been recorded in Italy (they were 680 in the last bulletin), of these:  - 341 were West Nile Neuroinvasive Disease (WNND): 15 in Piedmont, 51 Lombardy, 30 Veneto, 4 Friuli-Venezia Giulia, 1 Liguria, 27 Emilia-Romagna, 11 Tuscany, 1 Marche, 84 Latium, 2 Molise, 79 Campania, 2 Apulia, 2 Basilicata, 5 Calabria, 2 Sicily, 25 Sardinia,  - 57 were asymptomatic cases in blood donors ,  - 309 were West Nile Fever cases (1 imported from Kenya , 1 Egypt , and one Maldives ),  - 4 asymptomatic cases,  - 7 unspecified cases.  -- Among confirmed cases , there have been 49 fatalities : 7 in Piedmont, 5 Lombardy, 2 Emilia-Romagna, 18 Latium, 14 Campania, 2 Calabria, 1 Sardinia.  - The Case-Fatality Rate in WNN...

  Abstract In China, low pathogenic avian influenza (LPAI) H3N8 virus is widespread among chickens and has recently caused three zoonotic infections , with the last one in 2023 being fatal . Here we evaluated the relative pandemic risk of this 2023 zoonotic H3N8 influenza virus, utilizing our previously published decision tree. Serological analysis indicated that a large proportion of the human population does not have any cross-neutralizing antibodies against this H3N8 strain. LPAI H3N8 displayed a dual affinity for a2-3 and a2-6 sialic acids and replicated efficiently in human bronchial epithelial cells . Furthermore, we observed H3N8 transmission via direct contact but not aerosols to ferrets with pre-existing H3N2 immunity. Although pre-existing H3N2 immunity resulted in a shortened disease course in ferrets, it did not reduce disease severity or replication in the respiratory tract. This study suggests that this zoonotic H3N8 strain has moderate pandemic potential and emphasiz...