Dear Editor,Since 2024,the clade 2.3.4.4b highly pathogenic avian influenza(HPAI)H5N1 viruses have been identified in dairy cattle in the United States,raising global concerns about public health(Neumann and Kawaoka,2...Dear Editor,Since 2024,the clade 2.3.4.4b highly pathogenic avian influenza(HPAI)H5N1 viruses have been identified in dairy cattle in the United States,raising global concerns about public health(Neumann and Kawaoka,2024).As of December 18,2024,the U.S.Centers for Disease Control and Prevention(CDC)has reported over 61 confirmed cases of H5N1 infection in humans,predominantly associated with exposure to infected poultry or dairy cattle(U.S.Centers for Disease Control and Prevention,2024).Notably,the circulating 2.3.4.4b H5N1 clade has demonstrated continuous evolution in both wild and domestic birds globally,with expanding mammalian host tropism that now includes swine,cats,red foxes,harbor seals,and skunks(Peacock et al.,2024).These viruses have not only incurred substantial economic impacts but also posed dual threats to human health and ecological stability particularly during co-infections with other viruses(Abolnik,2024;Wang and Wang,2023).展开更多
Highly pathogenic avian influenza(HPAI)H5 viruses have caused widespread mortality in wild birds and poultry,with increasing spillover risk into mammals.The recently dominant clade 2.3.4.4b has produced multiple epide...Highly pathogenic avian influenza(HPAI)H5 viruses have caused widespread mortality in wild birds and poultry,with increasing spillover risk into mammals.The recently dominant clade 2.3.4.4b has produced multiple epidemic waves,first driven by H5N8 and more recently by H5N1,which has spread more rapidly,infected a broader host range,and caused higher mortality.While earlier studies identified consistent roles of waterbird community composition in shaping HPAI outbreaks,it remains unclear whether these factors also apply to the currently circulating H5N1.We analyzed HPAI H5N1 outbreaks in European wild birds during the 2021/22epidemic,examining the influence of waterbird communities and environmental variables,and compared these patterns with earlier epidemics,including H5N1 in 2005/06 and H5N8 in 2016/17 and 2020/21.Our results showed that waterbird abundance,species richness,and the abundance of key species were positively associated with disease occurrence,whereas phylogenetic diversity was negatively associated,suggesting greater interspecific transmission among closely related hosts.Models trained on earlier epidemics accurately predicted the H5N1 occurrence in 2021/22.These findings demonstrate consistent effects of waterbird community composition across multiple epidemics and highlight their values as predictors of HPAI risk.Integrating community metrics into surveillance and early-warning systems can strengthen our capacity to anticipate future outbreaks across clades and subtypes.展开更多
Influenza A(H5N1),particularly the clade 2.3.4.4b,caused a panzootic outbreak starting in 2022,resulting in 40 human infections from January 2022 to September 2024.Among these cases,15 have been confirmed to be of the...Influenza A(H5N1),particularly the clade 2.3.4.4b,caused a panzootic outbreak starting in 2022,resulting in 40 human infections from January 2022 to September 2024.Among these cases,15 have been confirmed to be of the clade 2.3.4.4b.Despite the availability of three FDA-approved A(H5N1)vaccines,these vaccines,based on earlier strains of other clades,have shown reduced hemagglutination inhibition(HAI)titers against clade 2.3.4.4b due to antigenic drift.1 In 2023,the EMAapproved a vaccine containing an A(H5N8)strain of clade 2.3.4.4b.However,a recent study reported a decrease in HAI titers of serum induced by this strain against recent 2.3.4.4b strains.1 These findings highlight the urgent need for developing an effective vaccine.展开更多
What is known about this topic?Global human cases of zoonotic influenza A(H5N6)have increased significantly in recent years,primarily due to widespread circulation of clade 2.3.4.4b virus since 2020.Concurrent with th...What is known about this topic?Global human cases of zoonotic influenza A(H5N6)have increased significantly in recent years,primarily due to widespread circulation of clade 2.3.4.4b virus since 2020.Concurrent with this trend,sporadic human infections with clade 2.3.4.4h H5N6 avian influenza virus continue to occur.The high mortality rate associated with H5N6 virus infections has emerged as a critical public health concern.What is added by this report?Through comprehensive field epidemiological investigations and laboratory analyses,we identified the infection sources for these cases and conclusively ruled out human-to-human transmission.Genetic analyses revealed that while the virus maintains its avian host tropism,it has acquired mutations that may enhance human receptor binding affinity,viral replication capacity,pathogenicity,and neuraminidase inhibitor resistance.What are the implications for public health practice?The ongoing viral mutations increase the potential for H5 subtype avian influenza viruses to overcome species barriers and cause human epidemics.Enhanced surveillance strategies incorporating advanced technologies,such as metagenomic sequencing,are essential for early risk detection and management.Special attention should be directed toward cancer patients and immunocompromised individuals,who demonstrate increased susceptibility to avian influenza virus infections and require targeted prevention and control measures.展开更多
文摘Dear Editor,Since 2024,the clade 2.3.4.4b highly pathogenic avian influenza(HPAI)H5N1 viruses have been identified in dairy cattle in the United States,raising global concerns about public health(Neumann and Kawaoka,2024).As of December 18,2024,the U.S.Centers for Disease Control and Prevention(CDC)has reported over 61 confirmed cases of H5N1 infection in humans,predominantly associated with exposure to infected poultry or dairy cattle(U.S.Centers for Disease Control and Prevention,2024).Notably,the circulating 2.3.4.4b H5N1 clade has demonstrated continuous evolution in both wild and domestic birds globally,with expanding mammalian host tropism that now includes swine,cats,red foxes,harbor seals,and skunks(Peacock et al.,2024).These viruses have not only incurred substantial economic impacts but also posed dual threats to human health and ecological stability particularly during co-infections with other viruses(Abolnik,2024;Wang and Wang,2023).
基金supported by the National Natural Science Foundation of China(32271605)。
文摘Highly pathogenic avian influenza(HPAI)H5 viruses have caused widespread mortality in wild birds and poultry,with increasing spillover risk into mammals.The recently dominant clade 2.3.4.4b has produced multiple epidemic waves,first driven by H5N8 and more recently by H5N1,which has spread more rapidly,infected a broader host range,and caused higher mortality.While earlier studies identified consistent roles of waterbird community composition in shaping HPAI outbreaks,it remains unclear whether these factors also apply to the currently circulating H5N1.We analyzed HPAI H5N1 outbreaks in European wild birds during the 2021/22epidemic,examining the influence of waterbird communities and environmental variables,and compared these patterns with earlier epidemics,including H5N1 in 2005/06 and H5N8 in 2016/17 and 2020/21.Our results showed that waterbird abundance,species richness,and the abundance of key species were positively associated with disease occurrence,whereas phylogenetic diversity was negatively associated,suggesting greater interspecific transmission among closely related hosts.Models trained on earlier epidemics accurately predicted the H5N1 occurrence in 2021/22.These findings demonstrate consistent effects of waterbird community composition across multiple epidemics and highlight their values as predictors of HPAI risk.Integrating community metrics into surveillance and early-warning systems can strengthen our capacity to anticipate future outbreaks across clades and subtypes.
基金the support from the Major Program(92369201)of the National Natural Science Foundation of China.This research was also supported by the National Key Research and Development Program of China(2021YFA0910700)the Health and Medical Research Fund(COVID1903010 and T-11-709/21-N)of the Food and Health Bureau,Hong Kong Special Administrative Region(HKSAR)+5 种基金the L&T Charitable Foundationthe Program for Guangdong Introducing Innovative and Entrepreneurial Teams(2019BT02Y198)the Shenzhen Key Laboratory for Cancer Metastasis and Personalized Therapy(ZDSYS20210623091811035)to J.-D.H.supported by the National Natural Science Foundation of China-Excellent Young Scientists Fund(Hong Kong and Macao)(32122001)the Health and Medical Research Fund(CID-HKU1-5)of the Food and Health Bureau,the Collaborative Research Fund(C7103-22G)the Research Grants Council of the HKSAR to H.C.
文摘Influenza A(H5N1),particularly the clade 2.3.4.4b,caused a panzootic outbreak starting in 2022,resulting in 40 human infections from January 2022 to September 2024.Among these cases,15 have been confirmed to be of the clade 2.3.4.4b.Despite the availability of three FDA-approved A(H5N1)vaccines,these vaccines,based on earlier strains of other clades,have shown reduced hemagglutination inhibition(HAI)titers against clade 2.3.4.4b due to antigenic drift.1 In 2023,the EMAapproved a vaccine containing an A(H5N8)strain of clade 2.3.4.4b.However,a recent study reported a decrease in HAI titers of serum induced by this strain against recent 2.3.4.4b strains.1 These findings highlight the urgent need for developing an effective vaccine.
基金Supported by the Fujian Natural Science Foundation(2021J01351)the Major Scientific Research Program for Young and Middle-aged Health Professionals of Fujian Province,China(Grant No.2021ZQNZD006).
文摘What is known about this topic?Global human cases of zoonotic influenza A(H5N6)have increased significantly in recent years,primarily due to widespread circulation of clade 2.3.4.4b virus since 2020.Concurrent with this trend,sporadic human infections with clade 2.3.4.4h H5N6 avian influenza virus continue to occur.The high mortality rate associated with H5N6 virus infections has emerged as a critical public health concern.What is added by this report?Through comprehensive field epidemiological investigations and laboratory analyses,we identified the infection sources for these cases and conclusively ruled out human-to-human transmission.Genetic analyses revealed that while the virus maintains its avian host tropism,it has acquired mutations that may enhance human receptor binding affinity,viral replication capacity,pathogenicity,and neuraminidase inhibitor resistance.What are the implications for public health practice?The ongoing viral mutations increase the potential for H5 subtype avian influenza viruses to overcome species barriers and cause human epidemics.Enhanced surveillance strategies incorporating advanced technologies,such as metagenomic sequencing,are essential for early risk detection and management.Special attention should be directed toward cancer patients and immunocompromised individuals,who demonstrate increased susceptibility to avian influenza virus infections and require targeted prevention and control measures.
