ETIDIOH - NEW

Abstract We analyzed 15 cases of highly pathogenic avian influenza (HPAI) clade 2.3.4.4b virus infections detected in wild birds in South Korea during September 2023–March 2024. We isolated and sequenced 8 H5N1 and 7 H5N6 viruses . We investigated spatiotemporal transmission dynamics by using a Bayesian discrete trait phylodynamic model that incorporated geographic and host species information. Our source–sink dynamics support introductions of H5N1 viruses from northern Japan to South Korea and subsequent spread through multiple regions in South Korea. The H5N6 viruses were most likely introduced into southwestern South Korea and spread northeastward. Wild waterfowl, especially wild ducks , played a key role in transmission of both H5N1 and H5N6 viruses. Our data showed multiple introductions and extensive spread of HPAI clade 2.3.4.4b viruses and bidirectional transmission between Japan and South Korea. Our results highlight the value of enhanced active surveillance for monitoring HPA...

ABSTRACT Betacoronaviruses, which have caused three human outbreaks within the last two decades, are thought to originate from bats , raising the concern that bat coronaviruses could cause a novel human outbreak in the future. To determine whether the bat merbecovirus EjCoV-3 strain , previously detected in Eptesicus japonensis in Japan , has the potential to infect humans, we analyzed its cellular entry mechanism. Cellular entry of EjCoV-3 via the spike protein requires protease treatment and is mediated by an unknown receptor, other than DPP4 or ACE2 . We generated cultivable recombinant EjCoV-3 using bacterial artificial chromosome-based reverse genetics and found that it efficiently replicated in human respiratory and intestinal cell cultures as well as nasal ciliated epithelium in hamsters. These findings suggest that bat merbecovirus with ACE2- and DPP4-independent cell entry has the potential to cause human infections , highlighting the importance of extensive bat surveillance f...

 Sea Otters in Hokkaido Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6551 ____

 A wild Peregrine falcon in Kagoshima Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6545 ____

Abstract During the 2022–23 winter season, >1,500 endangered cranes , including hooded crane (Grus monacha) and white-naped crane (Grus vipio), were found debilitated or dead in the Izumi Plain, Japan . Most of the cranes, particularly those collected in November, were infected with highly pathogenic avian influenza (HPAI) H5N1 viruses; virus shedding was higher from the trachea than from the cloaca . The isolation rate from the cranes’ roost water was not markedly higher than that of previous seasons, suggesting that the viruses might be more effectively transmitted among cranes via the respiratory route than through feces. Most wild bird–derived H5N1 isolates were phylogenetically distinct from viruses isolated on nearby chicken farms , indicating limited relationship between the wild bird and chicken isolates. Serologic analyses suggested that herd immunity had little effect on outbreak subsidence. This study deepens our understanding of the circumstances surrounding the unexpect...

 <Outbreaks 1-3> In early April, Livestock Hygiene Service Centres (LHSCs) in Kumamoto Prefecture received notifications from farmers with animals presenting clinical signs and collected samples. On 8 April, the LHSCs confirmed positive for Equine Influenza by RT-PCR. Genotyping is currently underway. Source: WOAH,  https://wahis.woah.org/#/in-review/6420 ____

Abstract Influenza A(H1N1)pdm09 virus carrying an I38N substitution was detected in an untreated teenager in Japan . The I38N mutant virus exhibited reduced susceptibility to baloxavir but remained susceptible to neuraminidase inhibitors and showed reduced growth capability . Monitoring antiviral drug susceptibility of influenza viruses is necessary to aid public health planning and clinical recommendations. Source: US Centers for Disease Control and Prevention,  https://wwwnc.cdc.gov/eid/article/31/5/24-1123_article ____

 Three wild Hooded Cranes in Izumi Region, Kagoshima city. Source: WOAH,  https://wahis.woah.org/#/in-review/6239 _____

Abstract In recent years, infection cases of H5 subtype highly pathogenic avian influenza viruses (HPAIVs) in wild mammals have increased globally. To obtain recent epidemiological information regarding influenza A virus (IAV) infection in raccoons (Procyon lotor), the prevalence of anti-IAV antibodies in sera was analyzed among raccoons captured in Tokachi District, Hokkaido, Japan , from 2019 to 2023. Screening of serum samples using enzyme-linked immunosorbent assay and agar gel precipitation test detected anti-IAV antibodies in 5 of 114 (4.4 %) raccoons. All positive sera were from raccoons captured from 2022 to 2023. The hemagglutination inhibition test revealed that all five serum samples contained anti-H5 subtype HPAIV antibodies, and one also contained anti-H1 subtype antibodies . The neuraminidase inhibition test revealed that all five sera contained anti-N1 subtype antibodies, and one also contained anti-N8 subtype antibodies . In the virus neutralization test, these five ser...

Abstract Migratory water birds are considered to be carriers of high pathogenicity avian influenza viruses (HPAIVs). In Japan , mallards are often observed during winter, and HPAIV-infected mallards often shed viruses asymptomatically. In this study, we focused on mallards as potential carriers of HPAIVs and investigated whether individual wild mallards are repeatedly infected with HPAIVs and act as HPAIV carriers multiple times within a season. Mallards were experimentally infected with H5N1 and H5N8 HPAIVs that were isolated recently in Japan and phylogenetically belong to different hemagglutinin groups ( G2a, G2b, and G2d ). All of these strains are more infectious to mallards than to chickens, and the infected mallards shed enough virus to infect others, regardless of whether they exhibited clinical signs. Serum antibodies to the homologous antigen, induced by a single infection with a low virus dose (10 times the 50% mallard infectious dose), were maintained at detectable levels f...

Abstract Only 2 cases of human adenovirus type 14 (HAdV-14) have been reported in Japan since 1980. We report a 7-year-old girl with acute encephalopathy associated with HAdV-14 infection genetically similar to strains from the United States . The patient had not had contact with international travelers. HAdV-14 surveillance should be strengthened in Japan. Source: Emerging Infectious Diseases Journal,  https://wwwnc.cdc.gov/eid/article/31/2/24-1168_article _____

Abstract During the 2023–2024 winter, 11 high pathogenicity avian influenza (HPAI) outbreaks caused by clade 2.3.4.4b H5N1 and H5N6 HPAI viruses were confirmed in Japanese domestic poultry among 10 prefectures (n = 10 and 1, respectively). In this study, we aimed to genetically and pathologically characterize these viruses. Phylogenetic analysis revealed that H5N1 viruses were classified into the G2d-0 genotype , whereas the H5N6 virus was a novel genotype in Japan, designated as G2c-12. The G2c-12 virus shared PB2, PB1, PA, HA, and M genes with previous G2c viruses , but had NP and NS genes originating from avian influenza viruses in wild birds abroad. The N6 NA gene was derived from an H5N6 HPAI virus that was different from the viruses responsible for the outbreaks in Japan in 2016–2017 and 2017–2018. Experimental infections in chickens infected with H5N1(G2d-0) and H5N6(G2c-12) HPAI viruses showed no significant differences in the 50% chicken lethal dose, mean death time, or virus ...