Detection of Highly Pathogenic Avian #Influenza #H5N1 Virus in #Cat and #Rats during #Outbreak in Backyard #Poultry, #USA, 2025

 

Abstract

In 2025, highly pathogenic avian influenza A(H5N1) virus was detected in a poultry flock in Illinois, USA. Quantitative reverse transcription PCR, sequencing, and histopathology on cat and rat samples from the farm showed multiple positive tissues and high sequence identity to an avian isolate. Small mammals might contribute to H5N1 transmission.

Source: 

Link: https://doi.org/10.3201/eid3210.260418

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#Habitat-Mediated #Spillover #Risk of #Andes #Hantavirus in Oligoryzomys longicaudatus: A Mechanistic Eco-Epidemiological Model

 

Abstract

Andes hantavirus (ANDV) is a rodent-borne orthohantavirus associated with hantavirus cardiopulmonary syndrome in southern South America. Its maintenance and spillover risk depend on the ecology of its principal reservoir, Oligoryzomys longicaudatus, and on environmental changes that alter habitat availability, host abundance, and human–rodent interfaces. We developed a mechanistic eco-epidemiological model that couples effective habitat cover to an SIR framework for ANDV transmission in O. longicaudatus. Habitat degradation and compensatory restoration modify rodent carrying capacity, natality, and the force of infection, which depends on infected host load relative to instantaneous ecological capacity. We derived the habitat equilibrium, the basic reproduction number ℛ0, and the time-dependent effective reproduction number ℛ𝑒(𝑡) and evaluated infection-burden and threshold indicators across degradation-restoration scenarios. The  analysis shows that ℛ0 is independent of equilibrium habitat cover because susceptible abundance scales with carrying capacity at the disease-free  equilibrium. In contrast, ℛ𝑒(𝑡), cumulative incidence, and infected load depend on transient habitat-mediated crowding. Restoration increases reservoir abundance and absolute infection burden, whereas degradation can reduce abundance while increasing crowding-driven transmission pressure and prolonging supercritical windows. These results identify ecological conditions under which habitat change may intensify reservoir infection pressure and guide One Health surveillance at human–rodent interfaces.

Source: 

Link: https://www.mdpi.com/1999-4915/18/9/1024

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Increasing spatial scale of #analysis weakens and can mask the #dilution effect for #hantaviruses

 

Abstract

Despite its major implications for biodiversity conservation and public health, the generality of a protective effect of biodiversity on zoonotic pathogen transmission (i.e., the dilution effect) remains strongly debated. This controversy may partly arise from the diversity of analytical approaches used, but also from the spatial scales at which studies are conducted. Here, we explicitly test whether increasing the spatial scale of analysis affects the detection of the relationship between hantavirus infection prevalence and rodent species richness, using a global dataset spanning multiple regions. Although the association between species richness and infection prevalence remains negative across all spatial scales, we show that the magnitude of the dilution effect progressively weakens as spatial aggregation increases and can become statistically non-significant at coarse spatial resolutions. These results, which are consistent across world regions, indicate that the dilution effect is likely a general feature of hantavirus–rodent systems, but that its empirical detection is highly sensitive to the spatial scale of analysis. Our findings highlight how large-scale spatial aggregation can mask underlying ecological processes and emphasize the need to carefully match spatial scale to the biological mechanisms under investigation when testing biodiversity–disease relationships. Finally, we discuss the ecological and methodological mechanisms that may obscure dilution effects and outline why scale-explicit approaches are essential for robust inference in biodiversity-disease research.

Source: 

Link: https://journals.plos.org/globalpublichealth/article?id=10.1371/journal.pgph.0007045

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The #Coinfection of #Bartonella spp. and #Hantavirus in Wild #Rodent and #Shrew Species in Eastern #China

 

Abstract

Background:

Bartonella spp. are Gram-negative bacteria that cause diseases including endocarditis, lymphadenopathy, and neuroretinitis. Hantavirus (HV), belonging to the family Hantaviridae, induces illnesses such as hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome. Both pathogens exhibit host specificity—defined as a preference or restriction to specific host species or ranges. Rodents and shrews are primary hosts for these pathogens, and their high coinfection rates often indicate elevated risk of human exposure. To our knowledge, however, data on Bartonella spp.–HV coinfection in rodents and shrews from Eastern China remain limited.

Materials and Methods:

Between 2020 and 2023, rodents (n = 311) and shrews (n = 16) were investigated for coinfection with Bartonella spp. and HV in Qingdao, eastern China. Nested Polymerase Chain Reaction (PCR) was used for the detection of RNA-dependent RNA polymerase (RdRp) gene of HV and the Internal Transcribed Spacer, citrate synthase (gltA) and RNA polymerase beta subunit (rpoB) genes of Bartonella spp.

Results:

The overall infection rates of Bartonella spp., HV, and coinfection were 21.4%, 6.7%, and 4.0%, respectively. The highest rates were observed in Apodemus agrarius (53.8%, 21.3%, and 15.0%). Coinfection rates differed significantly by species (p < 0.05), with A. agrarius exhibiting the highest rate (15.0%). Notably, the coinfection rate was significantly higher in male (28.9%) than female A. agrarius (7.1%) (p < 0.05).

Conclusions:

This study confirms the coinfection of Bartonella spp. and HV in rodents in the eastern region of China. Enhanced monitoring of rodent and shrew densities, as well as their carried pathogens, is essential. Additionally, timely screening, diagnosis, and treatment should be conducted for high-risk populations in the region to reduce the incidence of related zoonoses.

Source: 

Link: https://journals.sagepub.com/doi/10.1177/15303667261448824

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#Genomic Analysis of #SinNombre Virus #Sequences, Northwestern #USA, 2023

 

Abstract

We report Sin Nombre virus (SNV) genome sequences in the northwestern United States, including SNV sequences recovered from montane voles. Analysis of samples collected from 189 individual rodents revealed high SNV prevalence in the region and evidence of virus reassortment or coinfection, highlighting ongoing virus diversification in rodents.

Source: 

Link: https://pubmed.ncbi.nlm.nih.gov/42116630/

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Identification and #genetic characterization of a distinct #genotype of #Puumala #orthohantavirus in #Hebei Province, #China

 

Abstract

Orthohantavirus infections pose a significant threat to human health, while numerous orthohantaviruses have been identified, suspected viral infections remain undiagnosed in the world, which highlights the need for further identification and characterization of viruses circulating in humans and host animals. In this study, viral metagenomics was utilized to investigate orthohantaviruses present in tissue samples collected from rodents trapped at the Bashang Grassland of Hebei Province, China. A total of 145 wild rodents belonging to six species were captured in the study area, and 725 tissue samples (lung, liver, kidney, spleen, gut) were collected in 2024. A Puumala orthohantavirus (PUUV), named Guyuan strain, was identified in Myodes rufocanus, with a positive rate of 0.69%. The complete genomic sequences of the L, M, and S segments were obtained and confirmed by Sanger sequencing. Phylogenetic analysis of these genomic sequences with those of other orthohantavirus species showed that the L, M, and S segments clustered with PUUV genomic sequences, while sharing a nucleotide sequence similarity of 81.2%, 80.2%, and 84.3% with previously characterized reference viral strains Kitahiyama128L, Tobetsu_04, and Baltic/205 Cg, respectively. Amino acid homology analysis demonstrated that the sequences exhibited the highest identity to PUUV Hokkaido strain at a level of 95.4%, 94.6%, and 97.0% respectively. Viral particles were observed in lung and kidney tissues using transmission electron microscopy, and viral protein antigen was detected in viral RNA-positive lung, liver, and kidney tissues through immunofluorescence assay with antibodies against the PUUV nucleocapsid protein, thereby confirming the virus’s multiorgan tropism. The results demonstrated that a distinct genotype of PUUV was circulating in rodents in the study areas, which may have implications for zoonotic transmission surveillance and public health management in Hebei Province.

Source: 

Link: https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014250

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Evidence of #Juquitiba and #Jaborá #Orthohantavirus Co-Circulation in #Rodent Communities of #Argentina

 

Abstract

Hantaviruses infect a wide range of vertebrate hosts. In the Americas, Orthohantavirus species pose a major public health concern due to their ability to cause Hantavirus Cardiopulmonary Syndrome (HCPS). Given the lack of approved vaccines and specific treatments for HCPS, identifying circulating orthohantavirus genotypes and their hosts, along with estimating prevalence, is essential for designing effective preventive strategies. The objectives of this study were: (1) to identify the orthohantavirus hosts, (2) to determine the circulating orthohantavirus genotypes, (3) to assess the population structure and dynamics of Akodon montensis, (4) to characterize the rodent communities, and (5) to evaluate associations between A. montensis abundance and environmental variables in two protected natural areas of Misiones Province, Argentina. A total of 12 rodent trapping sessions were conducted from April 2021 to February 2023 in Urugua-í and Cruce Caballero Provincial Parks. Orthohantavirus antibodies were detected in four A. montensis and three Oligoryzomys nigripes from both Provincial Parks. Molecular analyses provided evidence of the co-circulation of Jaborá and Juquitiba orthohantavirus genotypes. Both areas exhibited similar rodent community compositions, with A. montensis as the numerically dominant species and O. nigripes occurring at low abundance. In Urugua-í, A. montensis abundance varied in relation to precipitation and vegetation productivity, whereas no such associations were observed in Cruce Caballero. Further studies are needed to effectively monitor these communities and to gain a better understanding of potential fluctuations in seroprevalence, changes in genotype pathogenicity, and the possible detection of unknown genotypes.

Source: 

Link: https://link.springer.com/article/10.1007/s10393-026-01803-8

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#Evidence of #SARS-CoV-2 #Exposure in #Rodents from Rural Localities in the #Yucatan Peninsula, #Mexico

 

Abstract

Zoonotic diseases involve pathogen transmission between humans and animals, with most research focused on animal-to-human spillover. However, reverse zoonosis—the transmission of pathogens from humans to animals—remains understudied despite its potential ecological and epidemiological consequences. The SARS-CoV-2 pandemic highlights this risk, as human-associated viruses may sporadically infect wildlife species and generate novel exposure pathways. To assess evidence of SARS-CoV-2 exposure in wildlife, we analyzed serum and rectal swab samples from rodents collected in rural localities of the Yucatan Peninsula, Mexico, between 2021 and 2022. An indirect ELISA detected antibodies against SARS-CoV-2 in 23.1% of sampled rodents. Molecular analysis detected one positive sample with a pan-coronavirus RT-PCR, though all were negative for SARS-CoV-2–specific assays. This study provides serological evidence of SARS-CoV-2 exposure in rodent communities from rural areas of Mexico and is consistent with sporadic wildlife spillback events rather than sustained transmission. The observed exposure patterns may be influenced by human activities and frequent human–wildlife interactions in heterogeneous rural landscapes. Our results underscore the need for integrated serological and genomic surveillance to better understand the ecological context of reverse zoonosis and its implications for public health.

Source: 

Link: https://www.mdpi.com/1999-4915/18/4/435

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Discovery of a Novel #Parahenipavirus, Parahenipavirus_GH, in #Shrews in South #Korea, 2022

Abstract

Highly pathogenic henipaviruses (Nipah and Hendra viruses) and parahenipaviruses (Langya virus) have demonstrated significant zoonotic potential. We aimed to identify Henipavirus or Parahenipavirus species in rodents and shrews in South Korea to underline the potential zoonotic transmission risk. Kidney and lung tissues from 285 rodents and shrews were screened for Henipavirus and Parahenipavirus using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) targeting the Gamak virus and Daeryong virus (DARV) sequences. Based on the qRT-PCR results, 75 out of the 285 individuals tested positive, with the highest viral loads in the kidneys of Apodemus agrarius, Crocidura lasiura, and Crocidura shantungensis. A kidney sample from C. shantungensis that exhibited the lowest Ct value was further analyzed using PCR, Sanger sequencing, and metagenomic analysis, yielding a near-complete genome of a novel Parahenipavirus, designated Parahenipavirus_GH (PHNV-GH), which is phylogenetically related to DARV and Jingmen virus but exhibits distinct genomic features. Ixodes granulatus ticks were also identified on the host shrew. The identification of PHNV-GH in southern South Korea expands the known geographical distribution range of parahenipaviruses and highlights the ongoing risk of zoonotic transmission. Given the uncertain transmission dynamics and pathogenic potential of parahenipaviruses, comprehensive environmental surveillance and characterization of emerging parahenipaviruses are essential for preventing future outbreaks.

Source: Viruses, https://www.mdpi.com/1999-4915/17/6/867

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