Search Results (477)

Brucellosis remains an underreported zoonotic disease in Ecuador. Its control program in cattle integrates diagnostic testing, vaccination, and eradication incentives, although participation is largely voluntary. Since 2025, vaccination has become compulsory nationwide. Human surveillance remains largely passive, and strain-level data are very limited. This study applied an integrated approach, combining serology (Rose Bengal and SAT-EDTA), microbiological culture, and molecular diagnostics, to assess the presence and diversity of Brucella spp. in cattle and pigs from six slaughterhouses in the northern Andean highlands. A total of 2054 cattle and 1050 pigs from Carchi, Imbabura, and Pichincha were sampled. Among cattle, 133 (6.5%; 95% CI: 5.5–7.6) were seropositive, and viable B. abortus strains were isolated from 17 (12.8%). Genus identification was confirmed by IS711-PCR, while species- and biovar-level differentiation was achieved with AMOS-PCR; additional assays targeting the ery gene and RB51 marker were used to distinguish field from vaccine strains. Biotyping and molecular analysis revealed a predominance of B. abortus biovar 4 (13/17 isolates) over biovar 1, all confirmed as field strains. In pigs, 10 animals (0.95%) tested seropositive, but no isolates were recovered, highlighting limitations of serology in swine. Most livestock, including the positives, originated locally, reinforcing the representativeness of our findings. The successful isolation and molecular characterization of B. abortus demonstrates the value of combining diagnostic strategies beyond serology. These results underscore the utility of active surveillance when supported by traceability systems; this approach may also contribute to guide interventions to reduce infection risk in livestock and humans. Full article

Brucellosis is a significant public health challenge in Kenya, particularly in pastoralist communities where the disease is endemic. Reliable and accurate point-of-care diagnostics are essential for timely case identification and effective disease management. The Febrile Brucella Agglutination Test (FBAT) is commonly used for diagnosis of brucellosis in Kenya, but concerns have been noted about its diagnostic accuracy, prompting an independent evaluation. The aim of this study was to compare the diagnostic performance of five FBAT kits with a commercial Enzyme-Linked Immunosorbent Assay (ELISA) as the reference standard, and to build local laboratory capacity for in-house kit validation for the Kajiado County laboratory staff. A total of 200 serum samples (100 ELISA-confirmed positives and 100 negatives) were tested using the FBAT kits. Each kit was evaluated for its ability to detect antibodies to both B. abortus and B. melitensis antigens. Diagnostic performance indicators, including sensitivity, specificity, and Cohen’s Kappa, were calculated, and McNemar’s test was applied to assess concordance with the ELISA results. Overall, none of the FBAT kits proved to have acceptable sensitivity and specificity compared to ELISA. We conclude that FBAT kits are not sufficient for the diagnosis of brucellosis and that alternative diagnostics should be considered. Full article

Escherichia coli is a significant cause of Neonatal Calf Diarrhoea (NCD). Its extensive antigenic diversity, coupled with the ability to acquire antimicrobial resistance determinants, hampers treatment effectiveness and compromises the control measures. This study investigated the link between the presence of multidrug-resistant (MDR) E. coli and virulence factors (VFs) in NCD from central France (Departments of Cantal, Haute-Loire, Loire, and Puy-de-Dôme), between 2016 and 2022. E. coli was identified at TERANA Laboratories, France, using API 20E (BioMérieux^®) and MALDI-TOF Mass Spectrometry. Virulence factors, namely adhesins, were assessed with the slide agglutination method, and antimicrobial susceptibility testing was conducted across various antimicrobial classes. Out of 2367 E. coli strains isolated from cases of NCD, a high percentage were resistant to aminopenicillins (88.8%), aminoglycosides (89.1%), tetracyclines (79.7%), quinolones (48.4%), and sulphonamides (42.4%). More than half (58.6%) carried VFs, and 84.9% exhibited MDR profile, of which 61.34% (1233/2010) also harboured VFs. The adhesin CS31A-producing E. coli was the most prevalent, followed by the fimbrial adhesins F5 and F17 (60.8%, 20.0%, and 8.3%, respectively), all of which were associated with a high prevalence of MDR strains (79.1–93.9%). The highest occurrence of MDR profiles was observed in E. coli strains carrying CS31A and in those lacking VFs, both groups showing co-resistance to aminopenicillins, aminoglycosides, and tetracyclines or sulphonamides. The calf production sector may act as a reservoir for MDR E. coli strains, regardless of the presence of VFs, posing a major threat to public health and safety. Full article

Human T-cell leukemia virus type 1 (HTLV-1), the first identified human retrovirus, is associated with adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The lack of effective antiviral therapies or vaccines highlights the critical importance of early diagnosis in managing HTLV-1-associated diseases. However, current commercial immunoassays, including enzyme immunoassays, line immunoassays, particle agglutination tests, and Western blots, are often limited by the need for specialized equipment and high costs, which restrict their accessibility in resource-poor regions. To address these challenges, we developed a novel dot-blot immunoassay using HTLV-1 P19 and GP46 synthetic peptides in combination with a precipitating tetramethylbenzidine (TMB) substrate. This innovative approach enables instrument-free visual detection through the formation of distinct blue-brown precipitates. Validation of this immunoassay with 179 clinical serum samples demonstrated 100% specificity and 91% sensitivity. Our assay offers a simple, cost-effective, and field-applicable diagnostic solution for HTLV-1 screening in resource-limited settings, potentially enhancing global surveillance of this neglected pathogen. Full article

Leptospirosis is a zoonotic disease caused by Leptospira spp., with over 250 serovars classified into 24 serogroups. Control measures depend on understanding serovar-specific epidemiology, yet the microscopic agglutination test (MAT) is only serogroup specific, and classification is complicated by cross-reactivity. While MAT is the reference standard for leptospirosis serodiagnosis and seroepidemiological studies, factors influencing serogroup cross-reactivity remain poorly characterized. We investigated the relationship between age, antibody titer, and serogroup diversity among seropositive individuals in a population-based serosurvey in the Dominican Republic. Between June and October 2021, we conducted a multistage national serosurvey, enrolling 6683 participants across 134 clusters. MAT was performed on sera from 2091 participants in two provinces using a 20-serovar panel. MAT positivity was defined as titers ≥ 1:100. Generalized Additive Models were used to assess associations between age, maximum titer, and serogroup diversity. Of 2091 tested samples, 237 (11.3%) were seropositive. Older individuals and those with higher titers reacted to a greater number of serogroups (p = 0.005 and p < 0.0001, respectively). However, mean maximum titer decreased with age, suggesting that broader serogroup reactivity in older individuals reflects cumulative exposure rather than higher titers. Maximum titer was the strongest predictor of serogroup breadth, while gender, study region, and urban/rural setting were not significant. Overall, our findings demonstrate that serogroup cross-reactivity in MAT was significantly influenced by antibody titer and prior exposure, with older individuals displaying broader serogroup reactivity despite lower titers. These findings highlight key considerations for interpreting MAT results in seroepidemiological studies and underscore the limitations of MAT in serogroup-level classification. Full article

Neonatal calf diarrhoea (NCD) is the leading cause of mortality in calves under 30 days old. Although several pathogens are usually involved in outbreaks, most previous research has focused on specific enteropathogens or on the four agents traditionally associated with this syndrome. This study aimed to determine the prevalence of thirteen enteropathogens in 420 diarrhoeic calves under a month of age from north-western Spain and to identify the most frequent co-occurrences. Four diarrhoeagenic pathotypes of Escherichia coli, bovine rotavirus A, coronavirus, norovirus, nebovirus and torovirus were identified using qPCR. Presence of Salmonella spp. was studied using a serum agglutination test. A direct immunofluorescence assay was employed to identify Cryptosporidium and Giardia duodenalis oo/cysts. Eimeria oocysts were found by the floatation technique. Our results confirm the co-occurrence of agents in most cases of NCD. A total of 172 pathogen combinations, involving up to seven agents, were identified. Cases involving one or more viral agents and Cryptosporidium parvum were predominant, maybe because viral immunosuppression facilitates the protozoan life-cycle. The frequent detection of agents typically overlooked in the aetiological diagnosis of NCD suggests that they may play a role in this syndrome and thus should be included in routine diagnostic panels, allowing implementing the most effective control measures. Full article

In order to investigate the occurrence and epidemiology of leptospirosis in the wild boar (Sus scrofa) population of Saxony-Anhalt, Germany, blood samples were collected from 2616 wild boar regularly hunted in 2023 and 2024. The diagnostic investigations were performed using the microscopic agglutination test (MAT) using a panel of fifteen pathogenic and one intermediate serovar of Leptospira spp. Overall, 12.4% (325/2616) (CI 95% 11.2–13.7) of wild boar were seropositive, with Australis being the most prevalent serovar (22.8%), followed by Pomona (13.2%) and Pyrogenes (12.3%). Specific antibodies against the intermediate Leptospira fainei serovar Hurstbridge were also detected in 8% of the positive samples. Based on these results, we conclude that wild boar are regularly infected with different zoonotic Leptospira serovars. As these hunted animals are tested for other notifiable diseases, additional screening for specific antibodies against Leptospira spp. could be easily implemented. This would be an important tool for detecting human and domestic animals’ risk of exposure and may provide insight into which Leptospira serovars might be currently of clinical relevance. Full article

Part-of-speech (POS) tagging in low-resource, morphologically rich languages (LRLs/MRLs) remains challenging due to extensive affixation, high out-of-vocabulary (OOV) rates, and pervasive polysemy. We propose MRL-POS, a unified Transformer-CRF framework that dynamically selects informative affix features and integrates them with deep contextual embeddings via a novel dual-gating co-attention mechanism. First, a Dynamic Affix Selector adaptively adjusts n-gram ranges and frequency thresholds based on word length to ensure high-precision affix segmentation. Second, the Affix–Context Co-Attention Module employs two gating functions that conditionally amplify contextual dimensions with affix cues and vice versa, enabling robust disambiguation of complex and ambiguous forms. Third, Layer-Wise Attention Pooling aggregates multi-layer XLM-RoBERTa representations, emphasizing those most relevant for morphological and syntactic tagging. Evaluations on Uyghur, Kyrgyz, and Uzbek show that MRL-POS achieves an average F₁ of 84.10%, OOV accuracy of 84.24%, and Poly-F₁ of 72.14%, outperforming strong baselines by up to 8 F₁ points. By explicitly modeling the symmetry between morphological affix cues and sentence-level context through a dual-gating co-attention mechanism, MRL-POS achieves a balanced fusion that both preserves local structure and captures global dependencies. Interpretability analyses confirm that 89.1% of the selected affixes align with linguistic expectations. This symmetric design not only enhances robustness in low-resource and agglutinative settings but also offers a general paradigm for symmetry-aware sequence labeling tasks. Full article

Streptococcus pneumoniae has been a PCV10 vaccine-preventable agent in Bulgaria since 2010. Our objective is to determine the phylogenetic structure of 170 invasive and non-invasive pneumococcal isolates, focusing on their serotypes and antimicrobial susceptibility. Serotyping was performed using latex agglutination, capsular swelling reaction, and serotype-specific PCRs. Antibiotic susceptibilities were assessed by broth microdilution. MLST was conducted to define the clonal composition. The non-PCV10 serotypes accounted for 88.2%. The predominant invasive pneumococcal disease (IPD) serotypes were 19A (39.3%), 19F (21.4%), 6C (10.7%), 7F (7.1%), and 3 (7.1%). The prevalent NIPD serotypes were 19A (18.3%), 6C (15.5%), 3 (10.6%), 15A (7.7%), and 6A (6.3%). The overall antimicrobial non-susceptibility rates were: benzylpenicillin (55.2%), ceftriaxone (15.2%), cefuroxime (35.8%), amoxicillin-clavulanic acid (38.8%), erythromycin (60.5%), clindamycin (57.0%), tetracycline (43.5%), trimethoprim-sulfamethoxazole (62.9%), and chloramphenicol (13.5%). The multidrug resistance (MDR) strains were 60.5%. The predominant clone CC320, represented 20.0% MDR 19A and 19F strains linked to Taiwan^19F-14 and GPSC1. CC273/Greece^6B-22 and CC386 accounted for 5.3% 6A and 6C isolates. Most serotype 3 isolates are associated with CC505, associated with Netherlands³-31 and GPSC12. Switching to a conjugate vaccine with broader serotype coverage could reduce the incidence of 19A, 6C, and 15A MDR S. pneumoniae clones in our country. Full article

Background: The accurate evaluation of anti-ABO antibodies is essential for risk stratification in ABO-incompatible (ABOi) transplantation. Historically, hemagglutination-based titration has been the cornerstone of such an assessment; however, different tools are being evaluated in this context. In recent years, several novel methods have been reported. Methods: A narrative review was conducted using PubMed, Scopus, and Google Scholar, focusing on recent studies evaluating anti-ABO antibody measurement techniques in the context of ABOi organ transplantation. Results: In addition to the conventional tube method, techniques such as column agglutination technology, flow cytometry, and enzyme-linked immunosorbent assay are utilized for anti-ABO antibody assessment. However, any particular technique, significant interinstitutional and interoperator variabilities have been reported due to differences in the detailed protocols and the inherently subjective nature of some techniques. Moreover, these assays are based on the antibody binding to ABO antigens expressed on red blood cells, which might not accurately reflect the clinical context of organ transplantation. In recent years, technological advances have enabled the development of novel assays evaluating antibody responses specifically against the ABO antigens expressed on vascular endothelial cells. These include glycan microarrays, which differentiate responses by ABO antigen subtypes, and CD31-based microarrays, wherein recombinant CD31 proteins expressing ABO antigens are immobilized. These approaches are applied to assess clinically relevant anti-ABO antibodies in the context of ABOi organ transplantation. Conclusions: The objective evaluation of antibody titers against ABO antigens on vascular endothelial cells might not only enable a more accurate risk assessment but also facilitate meaningful comparisons between institutions. Full article

Background: Leptospirosis is a potentially fatal infectious disease. Therefore, annual revaccination of dogs is recommended, but this can lead to diagnostic interference due to vaccine-induced antibodies. This study determined the prevalence of Leptospira spp.-specific antibodies in 97 healthy adult dogs revaccinated with a 4-serovar vaccine (Nobivac^® L4). Methods: Antibodies were measured with a microscopic agglutination test against 12 serovars before (week 0) and 2, 4, 12, 26, and 52 weeks after revaccination. Logistic regression analysis was performed to determine the presence of pre-revaccination antibodies. Mixed-effect logistic regression analyses and chi-squared tests were used to compare differences between antibodies against vaccine serovars and between vaccine and non-vaccine serovars at different time points. Results: Overall, 63/97 dogs (64.9%) had antibodies against vaccine serovars before revaccination. During the study period, antibodies against $\ge$1 vaccine serovars were detected in all 97 dogs (100.0%). The highest likelihood of detectable antibodies was present in weeks 2 and 4, but 71/97 dogs (73.2%) had antibodies persisting 52 weeks after revaccination. Of 97 dogs, 75 dogs (78.4%) even had antibodies against $\ge$1 non-vaccine serovars. Among those, 19/75 (25.0%) had a fourfold titre increase. Conclusions: These findings suggest that high levels of antibody titres against Leptospira spp. occur frequently and cross-reactivity against non-vaccine serovars is likely. The detection of vaccine-induced antibodies can therefore complicate the diagnosis of leptospirosis. Full article

At a veterinary hospital in southern Chile, we conducted an epidemiological study involving domestic dogs, cats, and horses to determine the seropositivity for pathogenic Leptospira spp., identify the infecting serogroups, measure antibody titers, and characterize seropositive animals by sex and age. None of the sampled animals showed clinical signs of leptospirosis. The microscopic agglutination test, using a panel of eight serogroups, was used for diagnosis. The seropositivity was 36.5% (95% confidence interval [CI] = 24.5–48.4) in dogs, 12.9% (95% CI = 2.6–23.1) in cats, and 45.2% (95% CI = 30.1–60.2) in horses. Serological reactions were detected for the Tarassovi and Canicola serogroups in dogs, Sejroe, Canicola, Icterohaemorrhagiae, and Grippotyphosa in horses, and Tarassovi in cats. The most frequent antibody titers were 1:200 and 1:400 in dogs, 1:400 in cats, and 1:800 in horses. The distribution of seropositivity varied by sex and age across different animal species. The seropositivity for pathogenic Leptospira in dogs, cats, and horses attending a veterinary hospital underscores the role of domestic animals as sentinels for zoonotic diseases. This finding has implications for epidemiological surveillance systems in increasing awareness of seropositivity and establishing specific prevention measures to mitigate the risk of leptospirosis transmission. Full article

Aeromonas hydrophila (A. hydrophila) is responsible for causing abdominal dropsy, swimming abnormalities, skin ulcerations, and pale gills in fish. Vaccination is an essential strategy for disease prevention in aquaculture. This study evaluated the efficacy of an oral vaccine against A. hydrophila in Ctenopharyngodon idella (C. idella). The vaccine was formulated as feed-based monovalent pellets, incorporating or spraying formalin-killed A. hydrophila on/into commercial feed with 30% crude protein. Mineral and fish oils were used as adjuvants at 10% of the feed. Prior to the trial, the experimental feed groups were subjected to quality and safety tests. Grass carp fingerlings (20 ± 5 g) were divided into seven groups (n = 20 per group): sprayed vaccinated feed with fish oil (SVFF), incorporated vaccinated feed with fish oil (IVFF), sprayed vaccinated feed with mineral oil (SVFM), incorporated vaccinated feed with mineral oil (IVFM), sprayed vaccinated feed (SVF), incorporated vaccinated feed (IVF), and a control group. Feed was provided at 3% of body weight for 60 days. Immunomodulation was investigated through lysozyme activity, antibody titers, and immunoglobulin M (IgM). The IVFF group showed significantly enhanced immunity and growth performance, with an 87% protection rate, 13% mortality, and the highest relative percentage survival (83%) following intraperitoneal A. hydrophila (6.8 × 10⁹ CFU/mL) challenge. Histological analysis indicated minimal pathological changes in the IVFF group compared to controls. Fish oil as an adjuvant enhanced immunity without adverse health effects. Overall, this study demonstrated that feed-based monovalent vaccines effectively improve immune responses and provide protection against A. hydrophila in C. idella. Full article

Background: Brucellosis is a zoonotic bacterial disease primarily controlled through quarantine, culling, and vaccination. Live attenuated vaccines remain the most effective countermeasure, yet their application is limited by residual virulence and diagnostic interference. This study developed three rough-type attenuated Brucella melitensis mutants (G7, G8, G16) and evaluated their potential as DIVA (Differentiating Infected from Vaccinated Animals) vaccine candidates. Methods: Rough phenotypes were characterized through heat agglutination, acridine orange staining, and immunoblotting. Macrophage cytotoxicity was assessed via LDH release assays, while RT-qPCR analyzed macrophage activation capacity. Mouse infection and immunization-challenge experiments, complemented by histopathology, evaluated residual virulence and protective immunity. Antibody profiles were determined by ELISA, and DIVA capability was verified using LPS-coated ELISA. Results: G7 and G8 exhibited complete rough phenotypes, whereas G16 retained partial O-antigen (semi-rough). All rough mutants induced macrophage cytotoxicity and activation. The strains showed attenuated virulence with no viable bacteria recovered from spleens at 4 weeks post-inoculation. Histopathology revealed no liver lesions at 6 weeks post-inoculation. Immunized mice predominantly produced IgG2a-dominated Th1-type responses. The immune protection levels of G7 and G16 matched the reference vaccine M5–90Δ26, while G8 showed slightly lower efficacy. LPS-ELISA effectively differentiated vaccinated from infected animals via concurrent IgM/IgG detection. Conclusions: This study demonstrates that the rough-type B. melitensis mutants G7 and G16 serve as promising DIVA vaccine candidates, offering strong protection with low residual virulence while enabling serological differentiation between vaccinated and infected animals, highlighting their potential as effective vaccines for brucellosis control. Full article

Leptospirosis is a globally significant zoonosis affecting animal health, productivity, and the environment. While typically associated with tropical climates, its persistence in semi-arid regions such as La Laguna, Mexico—characterized by low humidity, high temperatures, and limited water sources—remains poorly understood. Although these adverse environmental conditions theoretically limit the survival of Leptospira, high livestock density and synanthropic reservoirs (e.g., rodents) may compensate, facilitating transmission. In this cross-sectional study, blood sera from 445 dairy cows (28 herds: 12 intensive [MI], 16 semi-intensive [MSI] systems) were analyzed via microscopic agglutination testing (MAT) against 10 pathogenic serovars. Urine samples were cultured for active Leptospira detection. Risk factors were assessed through epidemiological surveys and multivariable analysis. This study revealed an overall apparent seroprevalence of 27.0% (95% CI: 22.8–31.1), with significantly higher rates in MSI (54.1%) versus MI (12.2%) herds (p < 0.001) and an estimated true seroprevalence of 56.3% (95% CI: 50.2–62.1) in MSI and 13.1% (95% CI: 8.5–18.7) in MI herds (p < 0.001). The Sejroe serogroup was isolated from urine in both systems, confirming active circulation. In MI herds, rodent presence (OR: 3.6; 95% CI: 1.6–7.9) was identified as a risk factor for Leptospira seropositivity, while first-trimester abortions (OR:10.1; 95% CI: 4.2–24.2) were significantly associated with infection. In MSI herds, risk factors associated with Leptospira seropositivity included co-occurrence with hens (OR: 2.8; 95% CI: 1.5–5.3) and natural breeding (OR: 2.0; 95% CI: 1.1–3.9), whereas mastitis/agalactiae (OR: 2.8; 95% CI: 1.5–5.2) represented a clinical outcome associated with seropositivity. Despite semi-arid conditions, Leptospira maintains transmission in La Laguna, particularly in semi-intensive systems. The coexistence of adapted (Sejroe) and incidental serogroups underscores the need for targeted interventions, such as rodent control in MI systems and poultry management in MSI systems, to mitigate both zoonotic and economic impacts. Full article