Transboundary and Emerging Diseases最新文献

Understanding timing and distribution of virus spread is critical to global commercial and wildlife biosecurity management. A highly pathogenic avian influenza virus (HPAIv) global panzootic, affecting ~600 bird and mammal species globally and over 83 million birds across North America (December 2023), poses a serious global threat to animals and public health. We combined a large, long-term waterfowl GPS tracking dataset (16 species) with on-ground disease surveillance data (county-level HPAIv detections) to create a novel empirical model that evaluated spatiotemporal exposure and predicted future spread and potential arrival of HPAIv via GPS tracked migratory waterfowl through 2022. Our model was effective for wild waterfowl, but predictions lagged HPAIv detections in poultry facilities and among some highly impacted nonmigratory species. Our results offer critical advance warning for applied biosecurity management and planning and demonstrate the importance and utility of extensive multispecies tracking to highlight potential high-risk disease spread locations and more effectively manage outbreaks.

Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most impactful viruses in swine production worldwide. Early detection of PRRSV outbreaks is the first step in rapid disease response. A syndromic surveillance system can be implemented to detect early signs of PRRSV activity in breeding herds. This study aimed to integrate multiple data sources and test univariate and multivariate statistical process control charts to identify early indicators associated with PRRSV outbreaks in sow farms. From March 2022 until May 2023, 16 breed-to-wean swine farms were enrolled in the study. The following key clinical and productivity indicators associated with PRRSV outbreaks were investigated: number of abortions, number of dead sows, number of off-feed events, preweaning mortality rate (PWM), and percentage of neonatal losses. The PRRSV status for the herd was determined by reverse transcriptase polymerase chain reaction testing using processing fluid samples, and it was considered as the reference to calculate the performance of the surveillance system. The exponentially weighted moving average (EWMA), cumulative sum (CUSUM), multivariate exponentially weighted moving average (MEWMA), and multivariate cumulative sum (MCUSUM) were the methods used to detect significant changes in the aforementioned parameters following the PRRSV outbreaks. Using the EWMA model, the indicators with the highest early detection rates were PWM followed by the abortions (71% and 64%, respectively), with the models raising alarms 4 weeks earlier on average than the processing fluids, respectively. For the CUSUM model, the weekly number of PWM, followed by abortions, were the indicators with the highest early detection rates (71% and 64%, respectively), with the models raising alarms 4 weeks earlier on average than the processing fluids for both indicators. Concerning the multivariate models, the MEWMA model with higher early detection used the PWM and neonatal losses (86%), with the models raising alarms 4 weeks earlier on average than the processing fluids, with the models raising alarms 3.5 weeks earlier on average than the processing fluids. For the MCUSUM, the model with higher early detection used PWM and neonatal losses (86%), with the models raising alarms 4.3 weeks earlier on average than the processing fluids. The models with the earliest time to detect signs associated with a PRRSV outbreak and with the lowest false negative and false positive were the multivariate models, MEWMA and the MCUSUM, using the combination of PWM and neonatal losses. Thus, monitoring multiple indicators outperformed the univariate models. With that, using multivariate models is the best option for disease surveillance using indicators, and it allows the decision-makers to investigate potential outbreaks earlier.

Bovine coronavirus (BCoV) is a causative agent of enteric and respiratory disease in cattle. BCoV has been reported to cause a variety of animal diseases and is closely related to human coronaviruses; moreover, it has attracted extensive attention from both cattle farmers and researchers. With the rise of BCoV, a vaccine that is prophylactic and immunotherapeutic has to be utilized for a preemptive and adroit therapeutic approach. The aim of this study was to develop a novel multiepitope-based BCoV vaccine that can induce an immune response using a silicon reverse vaccinology approach. In this study, an immunoinformatics approach was employed to identify potential vaccine targets against BCoV, and four candidate antigen proteins were selected to predict B-cell and T-cell epitopes. To identify dominant epitopes, we employed a variety of bioinformatics techniques, including antigenicity prediction, immunogenicity assessment, allergenicity analysis, conservative analysis, and toxicity assessment. Finally, six multiepitope vaccines were developed using dominant epitopes, suitable adjuvants, Pan HLADR—binding epitope (PADRE), and linkers. Then based on the antigenicity score, solubility analysis, allergenicity evaluation, physicochemical property assessment, and tertiary structure verification score, construct 6 was selected as the best candidate vaccine; it was named CY. Molecular modeling and structural validation ensured the high-quality 3D structure of construct CY. The immunogenicity and complex stability of the vaccine were evaluated by molecular docking and kinetic simulation. In silicon clones, the BCoV vaccine had high levels of gene expression in the insect expression system. These results may contribute to the development of experimental BCoV vaccines with higher potency and safety.

Pseudorabies virus (PRV) is widely spread, characterized by high contagiousness, high viral load, and strong infectivity, and poses severe threats to the global pig farming industry. Apart from pigs, PRV can also infect several other mammals, including mice, cattle, cats, dogs, and wolves, with diverse clinical symptoms. Notably, approximately more than 20 cases of human PRV infection have been reported in recent years, with fever, seizures, human encephalitis, intraocular inflammation, and severe central nervous system symptoms. However, whether PRV can infect humans or belongs to a zoonotic virus is still controversial. In this study, human neuronal cells were infected with PRV and blindly passaged to obtain human cell-adapted PRV, followed by comparing the characteristics of human cell-adapted PRV and pig-derived PRV in vitro and in vivo, to determine whether PRV has the potential to infect humans. The results showed that PRV could be stably passaged in human cells and produced progeny viruses similar to the parental virus, including morphology, infectivity, and pathogenicity. The human cell-adapted PRV can also cross-transmit to cells from other origins, including humans, mice, pigs, and monkeys, causing different cytopathic effects. Moreover, multiple tissue damage can be detected in mice infected with human cell-adapted PRV. These results demonstrate that PRV is a potential zoonotic virus, and it is necessary to pay close attention to the spread and variation of the virus in animals and humans.

The porcine epidemic diarrhea virus (PEDV) has caused severe economic losses in the pig industry. Since its discovery, the virus has spread in pig herds for more than 50 years. Many new features have been found in the PEDV spike genes. In this study, 123 representative S genes were used to analyze their characteristics across strains. Phylogenetic analysis revealed that PEDV can be divided into nine groups: G1a, G1b, G1c, G1d, G2a, G2b, G2c, G2d, and G3. In addition, 21 different lengths of the S gene were found. Analysis of the amino acid insertion and deletion sites revealed that most deletions and insertions occurred in the loops of the spike quaternary structure, primarily in the D0 and N-terminal domains (NTDs). According to the above results, PEDV has undergone considerable evolution, possibly under the immune pressure of vaccination. These results are highly important for understanding the current epidemic situation of PEDV.

Movement restrictions are a critical component of response plans for an African swine fever (ASF) outbreak in the United States. These restrictions are likely to include requiring permits to move animals and products within, into, and out of 5-km control areas (CAs) established around confirmed positive farms. For quarantined finishing farms located within a CA, diagnostic testing is an expected criterion for receival of a permit to move pigs to a harvest facility or removal of quarantine. A stochastic disease transmission and active surveillance model were used to evaluate premovement active surveillance protocols varying by the number of samples and timing of sample collection before movement. Surveillance protocol scenarios were evaluated for several different sampling prioritization schemes; virus strains of medium or high virulence; barn sizes of 1,200, 2,400, and 4,800 pigs; and farms with average to high mortality and morbidity during routine production. Surveillance protocols that included prioritization schemes targeting dead pigs and pigs with clinical signs resulted in the highest probabilities of detection and the lowest numbers of infectious pigs at the time of movement in barns that went undetected. There was some evidence that targeting sick pigs prior to dead pigs may be more effective for moderately virulent strains. However, in most scenarios, including all highly virulent strain scenarios and moderately virulent strain scenarios in barn sizes of 1,200 with average farm performance, prioritization of dead versus sick pigs first did not have a large impact on the predicted outcomes. Increasing sample sizes improved outcomes, though only marginal gains were achieved once the available dead and sick were sampled. Predicted outcomes may be further improved by sampling the available dead and sick pigs in a barn across multiple days, though the associated increase in the probability of detection was minor.

Streptococcus suis is a significant bacterial pathogen in the swine industry and represents a zoonotic threat to human health. This study aimed to investigate the prevalence, serotype distribution, and pathotypic characteristics of S. suis isolates obtained from nasopharyngeal swabs of slaughtered pigs in the high-density swine farming region of Thailand. Among 322 swab samples, 194 samples (60.25%) were found to harbor S. suis. The most prevalent serotype was serotype 8 (7.98%), followed by 19 (7.56%), 29 (6.72%), 3 (5.88%), and 2 (5.04%), with 39.92% of isolates classified as non-typeable. Molecular characterization revealed the presence of various clonal complexes (CCs), with CC221/234 being the most prevalent (19.15%). Human-associated clades (HAC) were identified in 29.79% of isolates, including serotypes 2 (two isolates), 1/2 (two isolates), and 4 (four isolates) in CC233/379. Additionally, several isolates exhibited a high potential for zoonotic transmission, particularly within the CC233/379 clade, which emerged exclusively in Thailand. Molecular pathotyping uncovered challenges in differentiating pathogenic and commensal S. suis strains in healthy pigs. Despite this, surveillance and monitoring of S. suis populations are essential to track dynamics and mitigate the risk of human infections.

Subclade 2.3.4.4b H5Nx highly pathogenic avian influenza (HPAI) viruses, emerged in 2013 with multiple subtypes of H5N8, H5N1, and H5N6, had unprecedently caused a global epizootic by H5N1 since 2021, which had devasted multiple species of wild birds, poultry, and wild mammals (terrestrial and marine) with a high mortality, causing severe ecological damage. The infected wild mammals may become new “mixers” for influenza viruses, posing the potential transmission to human. Frequent outbreaks of subclade 2.3.4.4b H5Nx viruses among wild birds and poultry had exposed major gaps in our knowledge on their evolution, spatiotemporal diffusion, and species-crossing transmission. Here, we integrated the phylogenetic and epidemiological data of subclade 2.3.4.4b H5Nx viruses in public database and used Bayesian phylodynamic analysis to reveal the pattern of the global large-scale transmission. Phylogenic analysis demonstrated that the HA gene of these viruses diverged into two dominant clusters around 2015 and 2016. The Bayesian phylodynamic analysis illustrated that the viruses presented spatiotemporally complex transmission network with geographical and host relative expansion and recombination with different subtypes of NA segment. Spatially, the Russian Federation (Siberia) was identified as the primary hub for virus transmission, which was further facilitated by the establishment of strong epidemiological linkages between West Europe and broader regions, such as North America. As for hosts, wild Anseriformes were the primary species for the virus spillover, contributing to the spatial expansion and rapid diffusion globally of subclade 2.3.4.4b viruses. We investigated the phylogeny of subclade 2.3.4.4b H5Nx viruses and the spatiotemporal pattern of transmission with initial location and the primary host, which could provide comprehensive insights for subclade 2.3.4.4b H5Nx viruses. Due to the wild birds involved the widespread of subclade 2.3.4.4b H5Nx viruses, the epizootics in poultry are inevitable, so we highly recommend to apply the policy of culling plus with vaccination to protect the poultry industry and potentially protect the public health.

Lumpy skin disease (LSD) is a viral disease caused by lumpy skin disease virus (LSDV), which mainly infects cattle and can cause huge economic losses. In May 2023, yaks, cattle-yaks, and cattle in Tibet (Xizang), China, developed fever, skin nodules, and severe discharges and were suspected to be cases of LSD. Samples from these animals were analyzed using molecular biology and serological methods. The RPO30, P32, and GPCR genes were amplified by PCR and sequenced, and the whole genome of the virus was determined using viral metagenomics technology. Sequencing results showed that it was indeed an LSDV infection, and enzyme-linked immunosorbent assay results confirmed the presence of LSDV antibodies. The whole genome phylogenetic tree shows that LSDV/CHINA/Tibet/2023 is different from the previous epidemic strains in China, but clusters with India 2022 strain. This is the first report of LSD in yaks, cattle-yaks, and cattle on the highest altitude plateau in the world.

Rotavirus A (RVA) is a prevalent cause of enteric diarrhea in infants, bovine, pigs, and sheep globally. Currently, the G6P[1]-type rotaviruses are prevalent in sheep or goat in Bangladesh, Turkey, and Uganda. However, this genotype has not been reported in Chinese sheep or goat. Therefore, 12 anal swabs were collected from diarrheal sheep in Gansu Province, China, in 2023 and tested for rotavirus using reverse transcription-polymerase chain reaction (RT-PCR). Pathological sections and immunohistochemistry were used to observe pathological changes and rotavirus antigens in the duodenum, respectively. The sheep rotavirus was isolated in MA-104 cells and characterized through indirect immunofluorescence and transmission electron microscopy. The genes of the strain were obtained using the next-generation sequencing technology and analyzed phylogenetically. One sheep was positive for rotavirus by RT-PCR, and immunohistochemistry revealed numerous rotavirus antigens in the apical portion of the duodenal villi. Transmission electron microscopy revealed that the strain was characterized by virus particles that were “wheel-shaped” and measured 70–80 nm in size. The gene constellations of this strain is G6-P[1]-I2-R2-C2-M2-A11-N2-T6-E2-H3. BLASTn and phylogenetic tree analyses suggest that this strain is likely a recombinant of human rotavirus, goat rotavirus, and bovine rotavirus. The comparison of amino acid similarities revealed three differences in the key antigenic epitopes of the VP7 and VP4 proteins between the GO34 strain and this study strain despite the identical gene constellations of the two strains. To date, this is the first report of this constellation of RVA being found in sheep.