ETIDIOH - NEW

  Abstract The emergence of MERS-CoV, SARS-CoV-1, and SARS-CoV-2 highlights the significant public health and economic threats posed by coronaviruses . In Lao PDR , SARS-CoV-2-related bat coronaviruses capable of binding to human ACE2 receptors have been found in northern regions , but little is known about coronavirus diversity in anthropized environments like temples . This study investigated coronavirus circulation, diversity, and prevalence in bats from caves and temples in Vientiane Province , Lao PDR. A total of 648 guano samples (505 Chaerephon plicatus , 100 Hipposideros spp ., 43 Taphozous spp .) were collected between December 2022 and June 2023 and screened using pan-coronavirus RT-PCR approach . The overall positivity rate was 17.28%, significantly higher in caves (18.8%) than temples (4.41%) (p = 0.003). C. plicatus showed the highest positivity rate (21.38%), followed by Hipposideros spp . 4%, while Taphozous spp . were negative. Phylogenetic analysis revealed diverse...

  Abstract Comparably few lineages of influenza A virus (IAV) have evolved long-term sustained transmission in mammals . The reasons remain largely unknown , and the possibility of avian IAVs evolving sustained mammalian transmission is an ongoing concern . Here we measured the GC content and frequency of GC dinucleotides in 115,520 whole genomes of IAVs using bioinformatic analyses . We found that persistent mammalian lineages showed declining trends in GC-related content and could be reliably separated from IAVs circulating only in birds and those sporadically infecting mammals. Similarly, the earliest viruses of persistent mammalian lineages showed reduced GC-related content , suggesting that this trait might in part contribute to their eventual persistence . Recent highly pathogenic 2.3.4.4b H5 viruses that spread in mink, foxes and humans were also characterized by reduced GC-related content . While not sufficient, reduced GC-related content may be a necessary condition for su...

  Abstract Highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b has expanded rapidly across the Southern Ocean since 2023 , causing extensive mortality in sub-Antarctic wildlife . Yet its penetration into Antarctica and impacts on ice-dependent species remain poorly resolved primarily due to surveillance constraints . We report the first confirmed H5N1 infection in an Antarctic ice-dependent seal (crabeater seal; Lobodon carcinophaga) and document mortality of crabeater seals across the northern Weddell Sea during November-December 2024 . Combining genomic, serological and observational data across nine species, we detected H5N1 RNA in a crabeater seal and a kelp gull (Larus dominicanus), and recovered complete HA, NA and M2 gene sequences from both. Phylogenetic analyses allowed us to identify at least two independent introductions of HPAI H5N1 clade 2.3.4.4b into the northern Antarctic Peninsula region. Serology provided strong evidence of prior exposure in scavenging bir...

  Abstract Avian influenza viruses (AIVs), including H5N1 and H7N9, from the Orthomyxoviridae family present substantial public health concerns . The predominant circulating clade 2.3.4.4b has demonstrated enhanced capacity for mammalian adaptation , raising concerns about potential reassortment with human seasonal influenza viruses . Unlike H7N9 ’s limited host range , H5N1 infects birds, various mammals, and humans . Recent concerns include widespread H5N1 infection of U.S. dairy cattle across 18 states , affecting over 1000 herds with 71 human infections (70 H5N1 and 1 H5N5). Key observations include cow-to-cow transmission, viral presence in milk, and transmission to humans , mainly through occupational exposure . Evidence of mammal-to-mammal transmission has been documented in European and Canadian foxes and South American marine mammals . Standard pasteurization effectively inactivates the virus in milk. The continuing mammalian adaptations , particularly mutations like PB2-E...

  Abstract SARS-CoV, MERS-CoV, and SARS-CoV-2 have posed tremendous threats to human health, highlighting the necessity of monitoring cross-species transmission of animal coronaviruses to humans. Hedgehogs infected with coronaviruses have been reported in several countries across Europe and Asia, raising concerns about the potential transmission of coronaviruses from hedgehogs to humans. In this study, we investigated coronavirus infections in hedgehogs inhabiting greenspaces in metropolitan Beijing and identified a Merbecovirus subgenus coronavirus with a prevalence rate of 30% (95% CI: 25–35%) among 317 hedgehogs . Phylogenetic analysis of 23 complete viral genome sequences revealed a monophyletic origin , showing close relatedness to Erinaceus hedgehog coronavirus HKU31 (Ea-HedCoV HKU31) with genome-wide nucleotide identities of 93.24–96.42%, and evidence of recombination with Tylonycteris bat coronavirus HKU4 . These findings suggest that the increase in wildlife populations as...

  Abstract Highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b has recently emerged as a major threat to wildlife , agriculture, and public health due to its expanding host range and the increasing frequency of spillover into mammals . In July–August 2023, the mass death of over 3500 northern fur seals (Callorhinus ursinus) and at least one Steller sea lion (Eumetopias jubatus) was recorded on Tyuleniy Island in the Sea of Okhotsk, Russia. Two HPAI A( H5N1 ) viruses were isolated from fur seal carcasses and designated A/Northern_fur_seal/Russia_Tyuleniy/74/2023 and A/Northern_fur_seal/Russia_Tyuleniy/75/2023. Both viruses exhibited high pathogenicity in chickens (IVPI 2.7–3.0) and mice (MLD50 1.9–2.5 log10EID50/mL), with distinct differences in disease progression, histopathology, and organ tropism . Experimental infection of mice revealed that strain A/74/2023 induced more severe pulmonary and neurological lesions than A/75/2023. Whole-genome sequencing and phylogeneti...

  Abstract The global spread of highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b viruses has recently extended to include diverse mammalian species , raising new concerns about pandemic risk . In 2023, this clade was first detected in Russian marine mammals during a mass mortality event among northern fur seals in the Far East . Genetic analyses revealed the causative viruses to belong to genotype A3 of European origin , which is known to have circulated in wild birds across the Far East since 2022. Notably, these isolates harbor the mammalian-adaptive substitutions PB2-K482R and NP-N319K—mutations previously linked to enhanced virulence in non-H5 avian influenza viruses , but whose impact on A(H5N1) clade 2.3.4.4b viruses remained to be characterized. The heightened virulence of A3 genotype viruses is confirmed by data obtained via a mouse model . However, despite these adaptive changes, ferret transmission models showed no evidence of airborne transmission of the fur seal...

  Abstract Since 2021, highly pathogenic avian influenza viruses (HPAIV) belonging to H5N1 clade 2.3.4.4b have caused high mortality in North American wild birds and poultry . In 2025 , a new D1.1 genotype caused two human deaths and host-switched to dairy cattle . However, the evolutionary origins and dynamics of D1.1 have not been fully characterized. Here, our phylogenetic analysis of 17,516 H5N1 genome sequences uncovers how D1.1 introduced a major shift in the antigenic diversity and ecology of the H5N1 epizootic in North America. D1.1 is the first major H5N1 genotype to (a) emerge in the Pacific flyway and spread west-to-east faster than any prior genotype; (b) antigenically shift via reassortment with the North American N1 segment, displacing the previously fixed Eurasian N1 ; and (c) transmit to a broader range of host species than any H5N1 genotype to date, introducing mammalian adaptations . Competing Interest Statement The authors have declared no competing interest. Fun...

  Abstract The recent emergence of highly pathogenic H5N1- especially clade 2.3.4.4b has led to widespread mortality in poultry and wild birds and has raised significant concerns for the dairy industry and human health. Migratory waterfowl are considered the main source of infection, and we used publicly available surveillance data and bird observation data from continental North America to show clear seasonal signals correlated with waterfowl movement, both on the continental scale and in three of the four flyways . In early 2024, the virus expanded its host range , and we observed a phase transition with the loss of the seasonal signal coupled with a concomitant increase in the proportion of mammalian cases . We also identified a second harmonic , with a regional east-to-west movement with infections spreading between regional flyways , followed by local viral amplification. We likened this to the movement of balls in a Newton's Cradle with an analogy between potential and viral ...

  Abstract Highly Pathogenic Avian Influenza (HPAI) viruses, particularly IAV (H5N1), continue to pose a major global threat due to their widespread circulation and high mortality rates in birds. Management of HPAI is complicated by challenges in conserving migratory bird populations, sustaining poultry production, and uncertainties in disease dynamics. Structured decision-making frameworks , such as those based on the PrOACT model, are recommended to improve outbreak response and guide critical actions , especially when HPAI virus (HPAIV) detections occur in sensitive areas like wildlife refuges . Surveillance data from late 2024 to early 2025 show persistent HPAI activity , with 743 detections across 22 European countries and beyond, and notable outbreaks in poultry in nations like Hungary, Iceland, and the UK . The proximity of poultry farms to water sources increases environmental contamination risks. Meanwhile, HPAI A(IAV (H5N1)) and other H5Nx viruses have been detected in a ...

  Abstract Identifying animal species that are susceptible to the plethora of existing and emerging viruses is critical for predicting and containing disease outbreaks . Current efforts to assess viral tropism largely rely on experimental infection models , but such experiments are logistically and ethically infeasible for many wildlife species. To tackle this challenge, we developed a panel of airway organoids from ten taxonomically diverse wildlife and livestock species and evaluated their susceptibility to influenza viruses of mammalian (pH1N1) and avian (H5N1) origin . Our analyses revealed large species-specific differences in infection rate and cytopathogenicity that aligned with known in vivo data and field observations. Furthermore, we demonstrated that this organoid panel can serve as a powerful tool to elucidate receptor-binding mechanisms, viral dynamics, and early host adaptation in poorly characterized animal species. In summary, this work provides a robust and ethical...

  Abstract The wildlife reservoir and spillover mechanisms of Ebola virus remain elusive despite extensive research efforts in endemic areas. This study employed a One Health approach to examine the virus’ circulation in wildlife and the associated human exposure risks in the Tshuapa province of the Democratic Republic of the Congo . We screened 1049 samples from 919 animals , predominantly small mammals , collected in 2021, and 380 samples from inhabitants of Inkanamongo village, the site of an Ebola virus disease outbreak in 2014. These samples were screened for evidence of current (RNA) or past (IgG antibodies) Ebola virus infections. We also conducted interviews with 167 individuals in the surrounding districts to assess their interactions with wildlife . While no Ebola virus RNA was detected in the wildlife samples , anti-orthoebolavirus IgG antibodies were found in 13 bats and 38 rodents . Among the human participants , 120 individuals had IgG antibodies against at least 1 or...

  Abstract Highly pathogenic avian influenza A virus (HPAIV) H5N1, clade 2.3.4.4b, has emerged as a significant zoonotic threat . H5N1 is widely circulating in wild birds , and an increasing number of spillover events have been observed in a wide range of mammalian species . These cases are primarily reported in countries on the European and American continents . This review describes the likely transmission routes, lesions, and clinical manifestations of HPAIV H5N1 clade 2.3.4.4b in naturally infected mammals, with a focus on the involvement of the central nervous system (CNS). In the analysis, pathological findings were categorized by organ system and host species , which were further divided into terrestrial mammals, marine mammals, and dairy cattle . The most frequently reported clinical manifestations were neurological and respiratory signs in marine mammals and neurological signs and lethargy in terrestrial mammals . Macroscopic and histological lesions were commonly found in...

  Abstract Influenza A virus (IAV) can infect a wide range of hosts, including wild and domestic pigs . Swine play an important role in influenza evolution and epidemiology due to their ability to get infected with both avian and human influenza viruses, potentially leading to reassorted virus variants . Interactions at the wild-domestic swine interface have been documented on multiple occasions, raising concern about pathogen transmission and the emergence of novel influenza strains. This study investigates the occurrence and subtypes of IAV infecting invasive wild pigs in Alberta, Canada . A total of 267 wild pigs were captured between 2021–2024. Exposure to IAV was initially detected by cELISA , with further confirmation of exposure to the H5Nx virus by hemagglutination inhibition (HI) and virus neutralization (VN) assays. Although no IAV genetic material was detected by qPCR , the seropositive samples by cELISA (4.17%; 5/120) coincided with the 2022–2024 highly pathogenic avian...

  Abstract From 2006 through 2008, 543 synanthropic Rattus norvegicus were sampled from 20 alleys clustered in five high-density human neighborhoods throughout Baltimore, Maryland, USA . Results indicated that rat coronaviruses (RCV) circulated endemically and infected most rats in the region. Collected animals were tested by serology and RT-PCR for evidence of exposure to RCV and the results were used to characterize the epizootiology of natural infection. Serology showed that 71.8% of rats had IgG antibodies to RCV, indicating previous exposure, while only 3.0% showed evidence of recent infection based on positive PCR results. Incidence was estimated at 16% per month . Antibody and PCR results were uniformly distributed throughout the city. Consistent with historical laboratory studies, RCV appeared to be horizontally transmitted and generated an acute infection with a short period of infectiousness . Evidence of past infection increased with rat age but did not differ significan...

Wild Species (unspecified) in Xinjiang Uygur Region. Source:  Link:  https://wahis.woah.org/#/in-review/6978 ____

  Abstract Background Plague, a zoonosis caused by Yersinia pestis, is endemic in Madagascar but knowledge on the epidemiological situation in the northern focus remains unclear . The aim of this study was to investigate the circulation of Y. pestis in terrestrial small mammals in north eastern Madagascar, where suspected plague outbreaks have been reported. Methods Sampling of terrestrial small mammals and their fleas was carried out in 22 trapping sites within 9 localities of the two sectors (1 and 3) of Makira Natural Park (MNP) and surroundings, from 2020 to 2022. Yersinia pestis was investigated in terrestrial small mammal spleen samples and their fleas using bacteriological, serological and molecular methods. Results A total of 614 terrestrial small mammals composed of eight species and 1,754 individual fleas were collected following 4,880 trap-nights. The black rat (Rattus rattus) represented the majority (87.8%) of the small mammal species caught. Flea infestation rate was ...

  Abstract The highly pathogenic H5N1 avian influenza A virus (IAV) clade 2.3.4.4b has spread globally and spilled over into multiple mammalian species , raising concerns about its pandemic potential . In late 2022, clade 2.3.4.4b viruses devastated seabird and marine mammal populations along the Pacific coast of South America . Here, we report the first evidence of H5 IAV infections in wild bats globally, focusing on common vampire bats (Desmodus rotundus) in coastal areas of Peru . Longitudinal serological screening , stable isotope analysis and metabarcoding revealed repeated exposures to H5 IAVs in vampire bats which feed on coastal wildlife species heavily impacted by the 2.3.4.4b epizootic, but no evidence of infection in populations without access to marine prey. We further report bat gene flow between IAV-exposed and IAV-naive populations , and IAV infections in a vampire bat colony that fed on both marine and terrestrial livestock prey, providing insights into how future I...

  Abstract Between 2022 and 2025, high pathogenicity avian influenza (HPAI) H5N1 clade 2.3.4.4b was detected in poultry and wildlife across most countries in Central and South America . The epizootic peaked in 2023, subsided in 2024, and resurged in 2025 . In Central America , outbreaks in wildlife were few and small, and mostly affected pelicans . In contrast, South America experienced unprecedented mass mortality in colonial seabirds and pinnipeds , including endangered and endemic species. Notably, viral adaptation enabled mammal-to-mammal transmission in pinnipeds and rapid viral spread across multiple countries along the Pacific and Atlantic coasts . Subsequent introductions to subantarctic islands and Antarctica stemmed from South American viruses. In February 2025, a novel reassortant virus emerged, recombining HPAI H5N1 B3.2 genotype with South American low pathogenicity avian influenza viruses . In May 2025, HPAI H5N1 viruses re-emerged in Brazil , causing a series of outb...

  Abstract The current panzootic of high pathogenicity avian influenza (HPAI) H5N1 has been catastrophic for wildlife , and following a significant sweep, clade 2.3.4.4b is found in every region aside from Oceania . Herein, we report the results of our third year of targeted surveillance of incoming migratory seabirds and shorebirds into Australia . We did not find evidence of HPAI H5N1 in any of the birds tested , and there were no reports of HPAI H5N1 in wildlife tested through other surveillance schemes in 2024. Unlike previous years, we detected a diversity of low pathogenicity avian influenza (LPAI) viruses in shorebirds. Through phylogenetic analysis we revealed that the H3N7 and H4N7 viruses recovered from Red-necked Stints were complex mosaic viruses, comprising segments of Eurasian, Australian shorebird, and Australian waterfowl segments . A H1N7 virus detected comprised a wholly Eurasian introduction , confirming this route for avian influenza viruses into Australian ecos...