Transboundary and Emerging Diseases最新文献

In October 2019, the first cases of African swine fever (ASF) were confirmed in wild boar in the Republic of Korea (ROK). Since then, ASF has continued to spread throughout the country, particularly among wild boar populations, despite intensive efforts to contain the outbreak. Our objective was to assess the results of current ASF surveillance in wild boars and identify various risk factors related to ASF outbreak in ROK. Between September 2019 and June 2023, a total of 122,078 wild boar samples were submitted, with 3135 tested as positive to ASF infection. Among them, 90.6% (2839/3135) of ASF-positive cases were detected from carcasses. Within the carcass samples, ASF prevalence showed an increase from 5.98% (95% confidence interval [CI] 4.47–7.81) to 37.15% (95% CI 34.12–40.27) through years 2019 and 2023, respectively. Geographically, from the demilitarized zone (DMZ), the region where ASF was first detected in wild boars, the disease has spread toward the east and south direction across the Baekdu mountain range, which is a continuous forest habitat. The movement of the ASF outbreak region between years has been relatively constant for the last 45 months, except for between 2020 and 2021 due to rapid spread during the year 2021. From the ASF-specific antibody assay, only two wild boars were seropositive out of 17,275 serum samples. This is the first study presenting results and patterns of wild boar surveillance and ASF virus prevalence changes in the ROK during 2019–2023. The study showed that output of surveillance and control effort, as well as the epidemiologic course of ASF in ROK is potentially associated with various spatial and anthropogenic factors, with subsets of factors more linked with specific circumstances of ROK. A better understanding regarding the past and current status of the disease will contribute to improving control measures required for preventing further spread of the ASF virus in the Korean peninsula.

Porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis virus (TGEV) are causative agents of acute enteric diseases in pigs and have a high contagion potential. These coronaviruses (CoVs) impose substantial economic losses on global pork production, particularly affecting lactating piglets where coinfections occur. Although traditional vaccines offer partial protection, their efficacy is increasingly challenged by the continuous emergence of mutated strains of PEDV and TGEV. This underscores the demand for novel vaccines with improved protective efficacy and cost-effectiveness. Emerging vaccine technologies, such as nucleic acid vaccines, genetically engineered subunit vaccines, and live vector vaccines, have received widespread attention because of their advantages in terms of safety, stability, targeted delivery, economy, and ease of use. This review summarizes recent advances in PEDV and TGEV vaccine development, highlighting both their potential and limitations. More importantly, we prospect novel techniques that may supplement the status gaps and lead to breakthroughs in blocking the transmission of these CoVs. Notable research priorities encompass mucosal immunity mechanisms, vertical transmission prevention strategies, and computational immunogen design leveraging artificial intelligence (AI). Overall, a deeper understanding of the pathogens coupled with technological advances is expected to accelerate the control of and effective response to pathogenic CoVs, thereby safeguarding the stability of animal husbandry.

Leptospirosis, a globally re-emerging zoonosis caused by pathogenic Leptospira species, poses escalating public health challenges in rapidly urbanizing regions. Canines, as significant reservoir hosts, are increasingly regarded as effective sentinels for human leptospirosis risk. This study assessed the seroprevalence of pathogenic Leptospira in dogs across multiple provinces and regions along the Yangtze River in China. From 2021 to 2023, a total of 1517 canine serum samples were collected from Shanghai, Jiangsu, Anhui, Jiangxi, Hunan, Hubei, Chongqing, Sichuan, and Yunnan. In addition, a tissue sample was obtained from an infected dog, leading to the successful isolation and culture of one Leptospira strain. Microscopic agglutination test (MAT) results indicated an overall seroprevalence of 46.41% (704/1517), predominantly involving L. interrogans serogroups Canicola (72.73%, 512/704) and Icterohaemorrhagiae (28.68%, 202/704), followed by Ballum (18.04%, 127/704) and Australis (17.90%, 126/704). Organ examination and histopathological analysis identified severe pulmonary hemorrhage induced by the isolated strain as the primary cause of canine mortality. Whole-genome sequencing (WGS) and multilocus sequence typing (MLST) based on seven housekeeping genes classified the isolate as L. interrogans serovar Australis, sequence type (ST) ST93. These findings reveal a high seroprevalence of pathogenic Leptospira in dogs within the Yangtze River region, consistent with the distribution of locally prevalent serogroups, and underscore the potential public health risk posed by this zoonotic pathogen in the area.

Sarcoptic mange is a significant welfare and conservation issue in a diverse range of mammalian species, wombats being some of the most impacted. Cases have been observed in bare-nosed (Vombatus ursinus) and southern hairy-nosed (Lasiorhinus latifrons) wombats but not the northern hairy-nosed wombat (Lasiorhinus krefftii). Here, we map the prevalence and model habitat suitability for sarcoptic mange that infests wombats across Australia. Presence-only data was isolated from wombat observation records entered into the citizen science project Wombat Survey and Analysis Tool (WomSAT). Environmental variables were collated from publicly available databases and prepared for analysis in ArcGIS Pro. Maxent modelling software was used to generate the habitat suitability model for wombat sarcoptic mange infestations. Sarcoptic mange contributed to 26.2% of all observations and were most frequent in Victoria (VIC) followed by New South Wales (NSW). The most important factors (percent contribution) in our model were Interim Biogeographic Regionalisation for Australia (IBRA; 25.7%), land use (24.5%), maximum summer temperature (15.1%), rain in summer season (10.7%), Collaborative Australian Protected Areas Database (CAPAD; 7.6%) and the hourly relative humidity at 3 pm (7.3%). All remaining environmental variables had very low to zero effect on the model. Our predictive presence model identified 73 local government areas (LGAs) across NSW (n = 20; 79.27 km²), VIC (n = 27; 265.46 km²) and Tasmania (TAS; n = 26; 21.52 km²) that had ‘highly suitable’ conditions and 79 that had ‘suitable’ conditions (3467.12 km²) for sarcoptic mange occurrence. In Queensland (QLD), only one LGA had ‘suitable’ (0.61 km²) habitat for sarcoptic mange and no areas that were ‘highly suitable’. SA had four LGAs that were ‘moderately suitable’ (74 km²) for sarcoptic mange, while the remaining LGAs were ‘not suitable’. The habitat in the ACT was predominantly ‘not suitable’ for sarcoptic mange. Predictive models, such as this can be used to help plan management strategies and support treatment efforts by carers.

Lumpy skin disease virus (LSDV) causes lumpy skin disease (LSD), a highly contagious cattle disease that leads to substantial economic losses to the global cattle industry. Currently, it is imperative to further elucidate its biological characteristics and analyze the global epidemiological dynamics. In this study, two isolates of LSDV with genetic recombination were identified in Northern and Eastern China, which demonstrated broad host cell entry ability. Through electron microscopy, we further revealed its morphogenetic characteristics across its replication cycle for the first time. Viral particles sequentially formed crescent membranes, nucleoids, and lateral bodies, and ultimately developed into four types of mature virions: intracellular mature virions (IMVs), intracellular enveloped virions (IEVs), cell-associated enveloped virions (CEVs), and extracellular enveloped virions (EEVs). Whole-genome phylogenetic analysis revealed that both isolates belonged to Clade R4. Based on the global reference strains, our integrated analysis for temporal and geographical information revealed that LSDV has progressively expanded its endemic range, particularly in Asia, where recombinant Clade R4 strains have recently emerged as the predominant epidemic strains. Strikingly, recombination analysis detected a limited number of recombination signals between the LSDV isolates and goatpox virus (GTPV) or sheeppox virus (SPPV) strains, suggesting that the possibility of recombination between heterologous vaccines and LSDV cannot be fully excluded. These data may provide important information for prevention and control of LSD global outbreaks.

Antarctica, one of the most isolated and extreme regions on Earth, hosts diverse bird species that share breeding and feeding habitats, facilitating interspecies transmission of pathogens. In this study, we investigated penguin siadenoviruses using cloacal swab samples collected from Antarctic penguins between 2017 and 2023 to explore their genetic diversity and evolutionary relationships. The complete hexon gene was obtained from Adélie penguins, while partial hexon and DNA polymerase sequences were detected in Adélie penguin (AP), chinstrap penguin (CP), and gentoo penguin (GP). Phylogenetic and molecular analysis identified multiple siadenoviruses classified into two distinct lineages, indicating ongoing viral evolution in this region. The hexon genes exhibited considerable genetic diversity caused by recombination and mutation, and predicted hypervariable regions (HVRs)—targets of neutralizing antibodies—showed significant structural differences among penguin siadenoviruses. These findings suggest that penguin siadenoviruses are not restricted to a single host species but may circulate among various penguin populations across the Antarctic region. This implies potential cross-infection between local and surrounding penguin populations. Although the predicted structural models showed limited accuracy due to the use of distant templates, the genetic and structural differences observed provide valuable insights into the adaptive evolution of these viruses. Our findings provide an important foundation for understanding viral transmission and evolution in Antarctic avifauna. Furthermore, findings from this study may guide early detection and risk assessment of emerging viral threats in Antarctica.

African swine fever (ASF) is a lethal hemorrhagic viral disease of pigs with devastating global socioeconomic impacts. Due to the absence of a safe and effective vaccine, early surveillance and precise diagnostics are critical for ASF prevention and control. The ASF virus (ASFV) p30 protein, one of the most immunogenic early-expressed antigens during infection, is a prime target for diagnostic assays and subunit vaccines. Its comprehensive antigenic characterization remains crucial for rational vaccine design. In this study, we generated a panel of 20 monoclonal antibodies (MAbs) against the ASFV p30 protein, classifying them into 11 groups based on epitope specificity. MAbs from six groups (subgroups I-1, I-2, and II-1, as well as groups III, IV, and V, collectively comprising 15 MAbs) recognized six distinct epitopes within the C-terminus of p30 (137–194 aa), while MAb 16-5E7E8 (subgroup II-2) recognized a distinct epitope within residues 154–190. The p30 C-terminus (137–194 aa) demonstrated structural stability under denaturing conditions (SDS–PAGE and western blot [WB]) and was identified as an immunodominant region through its reactivity with ASFV-positive sera. Notably, MAbs targeting this immunodominant region exhibited modest neutralizing activity, whereas those binding to other regions showed no neutralizing activity. Furthermore, MAb Q4-1F10B7 (group VI) recognized a linear epitope “¹¹⁶TSSFETLFEQ¹²⁵,” MAbs Q1-1G4B2 (group VIII) and Q8-4F9F3 (group IX) recognized conformation-dependent epitopes, and MAb 5-1C8B6 (group VII) likely recognized an aberrant or non-native form of the p30 protein. These results expand the epitope landscape of p30 protein and lay a foundation for ASF diagnosis and vaccine research.

Chikungunya virus (CHIKV) is an arthropod-borne virus that has caused several major outbreaks around the world and is becoming increasingly harmful. Although significant progress has been made in understanding the global epidemiology and transmission of CHIKV, a systematic description of the transmission history of its three genotypes is still lacking. To address this gap, this study integrates multiple bioinformatics approaches to explore their origin, evolution, and transmission dynamics. We analyzed publicly available CHIKV genomes from NCBI to elucidate the genetic evolution and transmission potential of these genotypes. Phylogeographic and molecular evolutionary analyses showed that the West African (WA) genotype originated in Nigeria and spread exclusively within Africa; the Eastern/Central/South African (ECSA) genotype originated in Tanzania and spread globally; and the Asian genotype originated in Thailand, spread throughout Asia, Oceania, and the Americas, exhibiting the highest evolutionary rate among the three genotypes. We also identified 15 positively selected sites and 10 nonconservative mutation sites with altered hydrophobicity across CHIKV proteins, all of which need further investigation into their effects on viral protein function. The data from this study are important for understanding the transmission history of the three genotypes of CHIKV, providing new targets for CHIKV antiviral therapy and ideas for developing effective prevention and control measures in the future.

Ethiopia faces significant economic losses from foot-and-mouth disease (FMD). Laboratory diagnostic tools such as antigen detection ELISA (Ag-ELISA), reverse transcription polymerase chain reaction (RT-PCR), and sequencing provide important information that underpin control initiatives. In this study, 411 samples (275 epithelial tissues, 12 oropharyngeal probang cup scrapings and fluids, 122 swab samples, and two whole blood) collected from cattle with clinical signs of FMD were tested to determine serotype diversity of the FMD viruses (FMDVs) present in Ethiopia during a 5-year period (2019–2023). RT-PCR testing showed that most samples, 81.1% (172/212) were positive for FMDV genome while 48.2% (198/411) of the samples were positive for FMDV antigen using ELISA, identifying serotypes O (10.9%), A (7.3%), Southern African Territories (SAT) 1 (1.7%), and SAT 2 (19.5%). Furthermore, evidence for mixed serotype infection was observed for 36 samples using the Ag-ELISA. Viral protein (VP) 1 sequencing for FMDV was performed on 94 samples, confirming the presence of three FMDV serotypes (O, A, and SAT 2). There was no molecular sequence evidence for outbreaks due to SAT 1 during this period, suggesting that the Ag-ELISA results for this serotype may have been false positives. Together with the Ag-ELISA data, the sequences highlighted a dramatic increase in the dominance of serotype SAT 2 viruses during the period of the study, associated with outbreaks due to the emerging SAT2/XIV topotype after a period of absence of more than 30 years. These data highlight Ethiopia’s dynamic FMD landscape, informing national and regional control. These findings are crucial for understanding FMDV in Ethiopia and vaccine selection, although more geographically broad and sequencing-intensive studies may be needed to define a more comprehensive understanding of the national disease epidemiology.

Mastitis is one of the biggest problems and an economic burden facing the dairy industry with a strong negative impact on animal welfare, productivity, and food safety. This study conducted a systematic investigation and analysis of the epidemiological characteristics of mastitis in selected regions of China (significant region for raw milk production). By collecting an extensive number of milk samples from clinical mastitis cases and utilizing methodologies such as bacterial isolation, genomic DNA extraction, and pathogen identification, the research elucidated the distribution patterns and trends of pathogenic bacteria responsible for mastitis across various regions and seasons. A total of 7177 milk samples were analyzed, identifying pathogenic bacteria in 3720 samples, which corresponds to a detection rate of 51.83%. Sixteen species of pathogenic bacteria were identified, with Klebsiella, coagulase-negative staphylococci (CoNS), and Escherichia coli (E. coli) being the predominant pathogens, representing 21.33%, 20.63%, and 18.72%, respectively. The study revealed significant seasonal and regional variations in the prevalence of pathogenic bacteria associated with mastitis. Detection rates of these bacteria were significantly higher in samples collected from May to September compared to other months, with September showing the highest detection rate at 85.94%. Furthermore, the southern region of China demonstrated the highest detection rate of pathogenic bacteria, with a prevalence of 94.98%. This study explored the pathogenicity and antimicrobial resistance profiles of the predominant bacterial strains, and proposed targeted prevention and control strategies based on these insights. The overarching aim is to provide a scientific basis for the effective management of mastitis, thereby alleviating the economic impact on the dairy farming industry.