Transboundary and Emerging Diseases最新文献

African swine fever (ASF), a highly fatal disease often termed the “number one killer” of pigs, presents clinical symptoms indistinguishable from classical swine fever (CSF), such as fever, diarrhea, and vomiting, complicating on-site differential diagnosis. As both ASF and CSF are notifiable diseases under the World Organisation for Animal Health (WOAH), rapid and accurate identification is crucial for effective outbreak management. In this study, we developed a multicolor lateral flow immunoassay (LFIA) based on latex microspheres (LMs) for the simultaneous detection of antibodies against ASF virus (ASFV) and CSF virus (CSFV). The assay enables visual differentiation within 15 min, with red indicating ASFV antibodies and blue indicating CSFV antibodies. After optimization, the LFIA demonstrated a sensitivity of 1:256, equivalent to that of a commercial ASFV ELISA kit and four-fold higher than that for CSFV (1:64). The assay exhibited high specificity, showing no cross-reactivity with other common swine pathogens and bovine viral diarrhea virus (BVDV). When applied to 180 clinical serum samples and compared with commercial ELISA kits, the LFIA achieved Cohen’s kappa values of 0.986 for ASFV and 0.918 for CSFV, indicating excellent agreement. Additionally, intra and interbatch evaluations confirmed its robust repeatability. Overall, the multicolor LM-LFIA offers a rapid, sensitive, specific, and cost-effective tool for point-of-care testing (POCT) of ASFV and CSFV antibodies, holding promise for routine field surveillance and disease control.

Porcine epidemic diarrhea virus (PEDV) causes severe diarrhea in piglets. The ideal route of protection against PEDV for piglets is through passive (lactogenic) immunity, which is not provided by current inactivated and subunit vaccines on the market. In this study, we investigated whether a DNA vaccine encoding the full PEDV spike protein adjuvanted with cyclo-peptide nanotubes (cPNTs) can provide protection against PEDV through active and passive immunity. For the active immunization experiment, piglets were vaccinated, and the immune response was analyzed, followed by a PEDV challenge test. In a separate experiment, to evaluate the passive (lactogenic) immunity elicited by the cPNTs-adjuvanted DNA vaccine, pregnant sows in a local farm were immunized, and the survival of farrowed piglets was examined. The results showed that, in the active immunization experiment, the DNA vaccine elicited IFN-γ and IL-12 production in piglets. IgA antibodies were detected in the serum, and the expansion of CD4⁺ and CD8⁺ T cells was observed. Upon virus challenge, vaccinated piglets remained healthy, gained weight, and showed only mild signs of diarrhea, with minimal virus shedding (Ct value of 33, compared with 16 for the saline-vaccinated control group). For the passive immunity experiment, results show that the DNA vaccine administered orally induced higher levels of IgA in the colostrum of vaccinated sows compared to mock vaccination. The survival rate of the farrowed piglets was higher at 84% for the DNA-oral group compared to that of the mock vaccination group (68%). In conclusion, the cPNTs-adjuvanted DNA vaccine can not only generate protective immunity through direct immunization of piglets but also induce lactogenic immunity in pregnant sows to protect farrowed piglets from PEDV infection.

Viral diseases are a major threat to human and animal health, as illustrated by recent pandemics like COVID-19 and African swine fever (ASF). Timely, accurate detection of viral infections is critical for effective disease control. Among diverse diagnostic techniques, lateral flow immunoassay (LFIA) has become a widely used on-site testing tool, owing to its speed, simplicity, affordability, and portability. The application of LFIA for detecting human and animal viruses is feasible, which highlights its practical utility in veterinary settings. This review summarizes key advances in LFIA for the rapid diagnosis of viral diseases over the past decade, focusing on its technical principles, practical applications, core advantages, existing limitations, and potential effective strategies to provide comprehensive knowledge for virus detection.

Lumpy skin disease (LSD) is a rapidly spreading transboundary viral disease of cattle and water buffalo that poses a significant threat to livestock health and economies of Bangladesh. Calf mortality is steadily increasing over time. This study documented fatal calf mortality with vasculitis-driven multisystemic pathology, which has been rarely reported in Bangladesh. To investigate the rising incidence of calf mortality in Bangladesh, this study conducted a pathological investigation of six deceased calves and molecular analyses of the viruses. Clinically affected calves in north-central Bangladesh exhibited high fever, skin nodules, lymphadenopathy, joint swelling, respiratory distress, ocular and nasal discharge, and edema. Cutaneous nodules often sloughed off, leaving deep ulcerative lesions. Gross pathology of six deceased calves revealed multisystemic lesions, including congestion and edema of the nasal passages, tracheitis, pulmonary consolidation, renal congestion and necrosis, hepatomegaly with multifocal necrosis, splenic atrophy, and lymphadenopathy. Histopathology demonstrated necrotizing inflammation, severe broncho-interstitial pneumonia, hepatic centrilobular necrosis, myocardial infarction, interstitial nephritis with vasculitis, and marked lymphoid depletion. Molecular detection confirmed moderate to high viral loads in the skin and internal organs, consistent with the pathological findings. Whole-genome phylogenetic analysis placed the isolates within cluster 1.2 (classical African/Kenyan sheep and goat pox [KSGP]-like lineage), with one strain clustering closely with isolates from India, Serbia, and Russia, indicating possible cross-border viral movement and genetic evolution. These findings confirm the continued circulation of classical cluster 1.2 LSD virus (LSDV) in Bangladesh, with accumulating genetic variation possibly enhancing virulence in calves. The study underscores the need for sustained genomic surveillance, expanded vaccination, and improved biosecurity to mitigate future LSD outbreaks.

African swine fever (ASF), a high-profile transboundary animal disease caused by ASF virus (ASFV), imposes a devastating impact on the global swine industry. Given that vaccines are still under development, including field evaluations, early detection of ASFV is crucial for effective disease control and mitigation. Although PCR is the primary viral detection method of acute or subacute ASFV infections, antibody detection plays a unique role in detecting low-virulent ASFV infection, identifying recovered animals, and tracking viral transmission. ELISA for ASFV antibody detection is commonly used for initial serological screening. To avoid false positive results, the World Organisation for Animal Health (WOAH) recommends using a second serologic method, such as the indirect immunofluorescence assay (IFA), indirect immunoperoxidase test (IPT), or immunoblot test, to confirm the ELISA-positive cases. This strategy improves specificity but not sensitivity (i.e., false negative cases persist). To address this issue, a novel in-cell ELISA (icELISA) was developed in this study. Receiver operating curve analysis of the icELISA revealed the optimized cutoff value of sample-to-positive ratio (S/P ratio) was at 47% with 99.46% analytical sensitivity and 99.43% analytical specificity. Results of the comparative diagnostic sensitivity analysis showed that positive detections of icELISA (150 samples) surpassed a blocking ELISA-IPT combination (132 samples) by 18 samples. Further investigation revealed that the 18 samples contained ASFV-specific immunoglobulin M (IgM) antibodies instead of immunoglobulin G (IgG). The results suggested the icELISA can detect both ASFV-specific IgG and IgM, which outperforms a blocking ELISA-IPT combination in earlier detection, particularly when only IgM antibody is present in a test sample.

Peste des petits ruminants (PPR) is a highly contagious disease that primarily affects small ruminants such as sheep and goats. Since first emerging in Africa, it has rapidly spread throughout the continent, causing significant mortality and posing a serious threat to livestock production and food security. In this study, we integrated diverse datasets using Geographic Information Systems (GIS) and employed the maximum entropy (MaxEnt) model to identify key drivers influencing the distribution of PPR outbreaks in Africa. Our comprehensive analysis provides critical insights into the spatial and temporal dynamics of PPR transmission, identifying shifting patterns of geographic spread, temporal clusters, and factors contributing to outbreak emergence and persistence over time. Based on existing research data, the results indicate a notable shift in the epidemic’s center of gravity from northwestern to southeastern Africa, offering strategic direction for future surveillance and control efforts. This study to understand and predict the distribution of PPR in Africa will help to develop a targeted surveillance program and analyze the trend of PPRV prevalence in Africa, which is important for the eradication and prevention of PPR.

Porcine reproductive and respiratory syndrome virus (PRRSV) remains a major threat to global swine production. In this study, a novel strain (PRRSV-AH1) was isolated during a respiratory disease outbreak at a commercial swine operation in Anhui Province, China. Viral replication in MARC-145 cells was confirmed by observing cytopathic effects (CPEs) and conducting immunofluorescence assays (IFAs). Whole-genome sequencing revealed a 15,020 bp genome exhibiting 90.0% identity with the NADC30 reference strain, including lineage 1-characteristic nonstructural polyprotein (Nsp)2 deletions. A distinctive L10S substitution in GP2 aligned with conserved residues of PRRSV-1. Recombination analysis identified PRRSV-AH1 as a novel chimera with a NADC30-like backbone incorporating CH-1a-like (lineage 8), JXA1-like (lineage 8), and QYYZ-like (lineage 3) sequences—representing the first reported instance of this specific recombination pattern. Experimental infection of piglets induced characteristic PRRSV pathology, including sustained pyrexia, reduced weight gain, prolonged viremia, and neutralizing antibody seroconversion. Comparative pathogenicity analysis revealed that the PRRSV-AH1 strain elicited febrile responses and peak body temperatures intermediate between classic NADC30-like strains and JXA1 strains. Notably, PRRSV-AH1 demonstrated a PRRSV-N-specific IgG induction capacity comparable to that of highly pathogenic variants. These findings establish PRRSV-AH1 as a multilineage recombinant (NADC30-like, CH-1a, QYYZ, and JXA1 Lineages) resulting from multiple genetic exchanges, underscoring the increasing complexity of PRRSV diversity in China. Accelerated mutation and recombination across lineages complicate disease control efforts, emphasizing the need for enhanced surveillance, mechanistic recombination studies, and the development of novel vaccines to mitigate future outbreaks.

In recent years, particular attention has been paid to the possible connections, similarities, and potential uses of animals, especially pets (dogs and cats), in research on the causes, characteristics, and treatment of cancers occurring in pets and humans. One of the most promising experimental research models used to explore these issues is the avian embryo chorioallantoic membrane (CAM). This review aims to highlight the problem of the occurrence of cancers in domestic animals, placing emphasis on types, incidence, and predispositions of dogs and cats. Methodology and applications in cancer studies of this unique model were presented in detail. Moreover, the advantages and disadvantages of this diagnostic tool, as well as potential and future perspectives, were also described. This review confirms that cancer research can be conducted without the use of animals. Furthermore, the CAM can provide a robust and reliable model for this type of research and provide translational potential as an ethical, cost-effective model bridging laboratory and clinical research.

Glässer’s disease caused by Glaesserella parasuis (GPS) is a severe disease that results in substantial economic losses to the swine industry worldwide. Here we describe a multiepitope vaccine cocktail (MEVC) that was designed using reverse vaccinology and immunoinformatics. The MEVC was comprised of three multiepitope subunits (MESs, designated as TB, 14B, and 24B), which were constructed using 14 B-cell epitopes predicted from six outer membrane antigens of GPS. The MESs exhibited non-allergenicity, high antigenicity, solubility, and stability. Predicted secondary and tertiary structures of the MESs were validated and showed strong binding affinity with the swine leukocyte antigen (SLA) by molecular docking. Immune simulation analysis further confirmed robust induction of both cellular and humoral immune responses. Immunization with MESs plus Gel-01 adjuvant (MEVC) resulted in 80% protection against GPS5 infection in mice, along with significantly increased antigen-specific IgG levels compared to controls. In conclusion, MEVC is a promising vaccine candidate to protect against porcine Glasser’s disease.

Porcine epidemic diarrhea virus (PEDV) is an enteric coronavirus that infects pigs of all ages. Notably, neonatal piglets (≤7 days old) in naïve herds can experience case fatality rates approaching 100%, with hallmark clinical signs of vomiting, diarrhea, and dehydration, thereby representing a major threat to swine herd health. Serum PEDV-specific IgG serves as a key serological marker of vaccine-induced herd immunity. Accordingly, we developed an indirect ELISA (iELISA) using Chinese hamster ovary (CHO) cell-expressed recombinant PEDV spike (S) protein as the coating antigen. Checkerboard titration identified the optimal antigen-coating concentration and serum dilution as 1 μg/mL and 1:300, respectively. Based on sample-to-positive (S/P) ratios from 50 PEDV-negative sera, the diagnostic cutoff was set at 0.796, corresponding to the mean plus 3 standard deviation (SD) of the negative control group (n = 50). The intra- and interassay coefficients of variation (CVs) were both <6.30%, indicating good precision (repeatability) and reproducibility. Specificity testing showed no detectable cross-reactivity with sera positive for five common porcine viruses (porcine deltacoronavirus (PDCoV), transmissible gastroenteritis virus (TGEV), porcine group A rotavirus (PoRVA), porcine reproductive and respiratory syndrome virus (PRRSV), and African swine fever virus (ASFV)). Moreover, PEDV-specific IgG measured by iELISA correlated strongly with virus-neutralizing (VN) antibody titers (r = 0.95), and both metrics were associated with protective outcomes at the herd level. Collectively, this assay provides an effective tool for evaluating protective immunity following PEDV vaccination.