Transboundary and Emerging Diseases最新文献

Canine distemper virus (CDV) poses a significant threat to dogs and wildlife worldwide, and this study sought to provide an updated genetic characterization of CDV field strains in Chile during 2022–2023. We collected samples from 52 suspected CDV cases in domestic dogs and detected viral RNA through real-time RT-PCR in 28 dogs (54%). Factors like age and vaccination status were determinants of CDV positivity, with young adult and unvaccinated dogs facing a higher infection risk. We isolated CDV from positive samples in VeroDogSLAM cells. From these isolates and direct samples, we obtained sequences and estimated the phylogeny based on gene H. CDV isolates from nasal and conjunctival swabs exhibited cytopathic effects, and sequence analysis unveiled a substantial genetic diversity among the strains. Chilean CDV strains demonstrated a genetic distance to vaccine strains of approximately 10%, antigenic-change-related amino acid substitutions, and novel putative glycosylation sites. In the phylogeny, Chilean CDV field strains clustered into two lineages, Europe/South America-1 and North/South America-4, indicating the emergence of the North/South America-4 lineage in Chile and underscoring the genetic complexity of CDV in the country. Interestingly, certain Chilean viruses shared a close common ancestor with Brazilian and Peruvian viruses, suggesting viral spreading patterns. Further investigations are warranted to comprehend the potential antigenic implications of these genetically diverse CDV strains.

Since the pandemic in 2019, coronaviruses (CoVs) have been a great concern for public health burden. The fact that CoVs can infect all animals including domestic ones and livestock points to a future pandemic even though interaction between human and wildlife animals is restricted. Moreover, interspecies transmission abilities of CoVs by mutations make them drastically risky not only for humans but also for animal health. Recently, a new CoV outbreak in cats in Cyprus, the so-called FCoV-23, has been realized. In addition to worries over animal health, any possible transmission to humans is now controversial. However, there have been limited characterization studies on FCoV-23. Thus, we aimed to assess the possible transmission of FCoV-23 to humans using in silico prediction tools. Accordingly, we first checked the binding affinities of receptor binding domain (RBD) of FCoV-23 against feline target protein and its human homolog. Next, we randomly and rationally created mutations on the RBD sequence and evaluated the binding affinities using protein docking tools. Our results underlined that multiple mutations at the same time were needed for increased binding affinity towards human target protein, demonstrating that the probability of transmission to humans was extremely low when mutation rates were regarded. Still, further molecular studies are required to comprehensively conclude the possible transmission risk.

Avian influenza is one of the most devastating avian diseases. The current high pathogenicity avian influenza (HPAI) A virus H5N1 clade 2.3.4.4b epizootic began in the 2020–2021 season, and has caused a panzootic, considered one of the worst ever reported. The present panzootic has novel epidemiological features that represent a challenge for its prevention and control. This review examines key epidemiological changes of the disease such as seasonality, geographic spread, and host range. The seasonality of the virus has changed, and contrary to previous avian influenza epizootics, this subclade was able to persist during boreal summer. Its geographic range has expanded, with reports in all continents except Australia. During this epizootic, HPAIV H5N1 has broadened its host range, infecting hundreds of bird species, and causing the death of thousands of wild birds and over 300 million poultry. The number and diversity of mammal species infected by H5N1 2.3.4.4b is unprecedented. Although considered low, this strain’s potential to spillover to humans should not be underestimated, especially considering the current extremely high viral circulation in animals and increasing adaptation to mammals. Overall, HPAI A(H5N1) clade 2.3.4.4b represents an ongoing and growing threat to poultry, wildlife, and human health.

The diagnosis of drug-resistant tuberculosis (TB) by molecular testing of Mycobacterium tuberculosis drug resistance genes is becoming increasingly common clinically. However, M. bovis, as an uncommon pathogen of human TB, may interfere with the test results. A comprehensive understanding of phylogenetically informative mutations in the drug resistance genes of M. bovis is required to distinguish true resistance-conferring mutations. We analyzed 53 drug resistance genes in 165 M. bovis isolated from humans using whole-genome sequencing data and found that 98.2% (162/165) of isolates have pyrazinamide intrinsic genotypic resistance, owing to the H57D mutation in the pncA gene. 12.1% (20/165) of M. bovis isolates were resistant to drugs other than pyrazinamide. Furthermore, we discovered 18 phylogenetically informative mutations that differed between M. bovis and the major lineages 1–4 of M. tuberculosis. Additionally, we reported false-positive ethambutol resistance caused by M. bovis infection due to the phylogenetically informative mutation embB E378A. This study is crucial for gaining insights into the genetic characterization and drug resistance of M. bovis prevalent in humans, as well as contributing to the development of more accurate molecular diagnostic methods and detection tools for drug resistance.

Group A rotaviruses (RVAs) are widespread in humans and many animal species and represent the most epidemiologically important rotavirus group. The aim of the study was the identification of the genotype pattern of human RVA strains circulating in Poland, assessment of their phylogenetic relationships to pig RVAs and identification of reassortant and zoonotic virus strains. Human stool samples which were RVA positive (n = 166) were collected from children and adults at the age of 1 month to 74 years with symptoms of diarrhoea. Identification of the G and P genotypes of human RVAs as well as the complete genotype of reassortant and zoonotic virus strains was performed by the use of an RT-PCR method. The G (G1–G4, G8 or G9) and/or P (P[4], P[6], P[8] or P[9]) genotypes were determined for 148 (89.2%) out of 166 RVA strains present in human stool. G1P[8] RVA strains prevailed, and G4P[8] (20.5%), G9P[8] (15.7%) and G2P[4] (13.3%) human RVA strains were also frequently identified. The full genome analysis of human G4P[6] as well as pig G1P[8] and G5P[6] RVAs revealed the occurrence of porcine–human reassortants and zoonotic RVAs. Detection of G4P[6] in pigs confirms their role as a reservoir of zoonotic RVAs.

African swine fever virus (ASFV) poses serious threats to the global swine industry, food safety, and the economy. Since August 2018, different types of ASFVs have successively emerged in China, making ASF diagnostics more challenging. The highly virulent genotype I recombinant virus has gradually become the prevalent dominant strain and is identified by sequencing several of its genes, which is time-consuming and expensive. Here, we developed a triplex real-time quantitative PCR (qPCR) assay based on the ASFV B646L, X64R, and MGF_360-14L genes to differentiate highly virulent genotype I recombinant viruses from low-virulence genotype I and genotype II viruses in China. This method has high sensitivity and a limit of detection of 10 copies/reaction for standard plasmids, as well as good specificity without cross-reactions with the viral nucleic acids of porcine reproductive and respiratory syndrome virus (PRRSV), classical swine fever virus (CSFV), pseudorabies virus (PRV), porcine circovirus 2 (PCV 2), porcine circovirus 3 (PCV 3), porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), or porcine rotavirus (PoRV). Importantly, triplex qPCR can be used to quickly and accurately evaluate clinical samples and cell cultures infected with highly virulent genotype I virus, low-virulence genotype I virus, or genotype II virus. Thus, triplex qPCR provides an alternative tool for ASF surveillance in China.

The persistent infection caused by foot-and-mouth disease virus (FMDV) still lacks a reliable explanation, as its etiology and maintenance are intricate and potentially involve concurrent infections with multiple pathogens. In this study, we utilized the nanopore platform for direct sequencing of clinical samples obtained from cattle persistently infected with FMDV serotype O and investigated the distribution characteristics of coinfecting pathogens in their pharyngeal region. Briefly, we exploited Oxford Nanopore sequencing technology to generate high-quality and sufficient sequence data for the comprehensive characterization of microbial genomes. Furthermore, we performed sequence comparison, alignment, and phylogenetic tree construction. Our findings revealed a total of 23 viruses in FMDV carrier bovine, with FMDV, bovine orthopneumovirus, and Choristoneura fumiferana granulovirus emerging as the top three identified pathogens. The analysis unexpectedly revealed the presence of porcine circovirus type 2 and pepper mild mottle virus among the viral genes detected in the bovine FMDV carrier. Compared to noncarrier, carrier bovine of FMDV exhibited a greater diversity and abundance of mycoplasma types as well as reads counts. Therefore, we propose that the establishment and perpetuation of persistent FMDV infection may be attributed to the simultaneous presence of other viral agents and mycoplasmas. These findings highlight the significance of investigating multipathogen coinfection in elucidating the etiology of persistent FMD virus infection.

Eimeria stiedae is one of the few eukaryotic pathogens that exclusively infect the liver and serves as a good model to study the host–pathogen interactions in this vital organ. In this study, we show that rabbits infected with E. stiedae develop severe but self-healing cholangitis. RNA-seq analysis of the liver gene expression landscapes over the long course of E. stiedae infection identified 912 differentially expressed genes (DEGs) in the prepatent period (794 up- and 118 downregulated genes), 2889 DEGs in the early oocyst shedding period (1870 up- and 1019 downregulated genes), 2859 DEGs in the peak oocyst shedding period (1923 up- and 936 downregulated genes), and 327 DEGs in the recovery period (164 up- and 163 downregulated genes). Combined with pathological observations, we identified dynamic changes in host–parasite interactions involving multiple pathways. They showed that E. stiedae infection induced full-blown inflammatory, Th1 and Th17 immune responses at all time points. This was associated with the strong innate immune responses during the prepatent period, including increased Toll-like and NOD-like receptor signaling. Despite mounting several damage control and repair responses, such as PI3K-Akt signaling, Ras signaling, and extracellular matrix-receptor interactions, the liver underwent severe metabolic dysfunction, oxidative damage, and coagulopathy after patency and at peak infection, possibly as a result of suppressed peroxisome activities and downregulated PPAR signaling. These responses largely disappeared during late infection, suggesting that the liver self-heals after severe cholangitis. These data provide new insights into host–pathogen interactions during Eimeria infection and improve our understanding of the pathogenesis of parasitic cholangitis.

Avian influenza (AI) is a viral infection that profoundly affects global poultry production. This study aimed to identify the spatial and temporal factors associated with AI in Thailand, using a geographic information system (GIS)–based multi-criteria decision analysis (MCDA) approach. We discovered that high-risk areas for AI were primarily concentrated in the central and lower northern regions of the country, with fewer occurrences in the northeastern and southern regions. Model validation using historical outbreak data showed moderate agreement (AUC = 0.60, 95% CI = 0.58–0.61). This study provides valuable insights for planning national AI surveillance programs and aiding in disease prevention and control efforts. The efficiency and effectiveness of disease surveillance at the national level can be improved using this GIS-based MCDA, in conjunction with temporal risk factor analysis.

Bovine tuberculosis (bTB), caused by Mycobacterium bovis, poses significant zoonotic and economic challenges globally. The current prevention and treatment options are limited and increasingly complicated by the emergence of multidrug-resistant strains. This study employs reverse vaccinology and immunoinformatics to design a multi-epitope subunit vaccine targeting the MPB83, ArfA, DnaK, GrpE, and LpqH proteins of M. bovis. The T-cell and B-cell epitopes of the candidate vaccine were predicted and evaluated for antigenicity, allergenicity, and toxicity. The promising epitopes were then assembled into three vaccine constructs (bTBV1, bTBV2, and bTBV3) using appropriate adjuvants, pan HLA DR-binding epitope (PADRE), and linkers. The constructs were analyzed for physicochemical properties, 3D structure, cytokines induction and stability, followed by molecular docking with bovine CD molecules and toll-like receptor, TLR-9. Among the candidates, bTBV3 was chosen as one of the most promising vaccine candidates due to its high aliphatic index (67.60), lowest instability score (27.26), and a strong binding affinity. Molecular dynamics simulations and the results of interactions between the vaccine–receptor complexes (eigenvalue 2.318704e-06) show that the vaccine construct bTBV3 is stable. In silico immune simulation findings, such as elevated IgM levels and increased Th cell populations, suggest that the designed multi-epitope vaccine candidate bTBV3 elicits robust humoral and cellular immune responses, confirming the vaccine’s potential efficacy. Additionally, codon optimization (CAI: 0.997 and GC: 54.687%) and in silico cloning facilitated efficient expression in E. coli. This study highlights the potential of bioinformatics-driven approaches in developing effective subunit vaccines against bTB, providing a foundation for experimental validation and future applications in combating this pervasive zoonotic disease, bovine tuberculosis.