Search Results (604)

Background/Objectives: Long-term serological studies are essential to understand how repeated antigenic exposure affects the specific humoral immune response. The aim of this study was to investigate the long-term SARS-CoV-2 antibody dynamics in Austrian blood donors, as representatives of healthy adults, over a period of 36 months after the first SARS-CoV-2 infection. Methods: SARS-CoV-2 anti-N antibody levels were determined in more than 146,000 blood donations collected between 2020 and 2025. In addition, SARS-CoV-2 anti-N and anti-S antibody dynamics were examined in 204 individual blood donors at predefined points in time over a period of 36 months. Reinfections were inferred from increases in anti-N levels within an individual. Vaccination history and self-reported infection data were documented. Results: Anti-N seroprevalence was over 90% from the beginning of 2023 and remained at this level until 2025. Among the longitudinally observed participants, 97% had at least one serologically detected reinfection and 50% had two or more. While anti-N levels continued to increase over time, suggesting cumulative antigenic stimulation, anti-S concentrations and in vitro antibody functionality remained consistently high. Self-reported reinfections underestimated the actual incidence by a factor of six. Symptom profiles shifted toward mild respiratory manifestations, with significantly fewer cases of hyposmia or dysgeusia reported compared to the initial infection. Conclusions: After three years of observation, SARS-CoV-2 immunity is characterized by sustained antibody activity. The results show a transition from persistent, but inherently declining, to a repeatedly rebuilding, enhanced humoral immunity, indicating that SARS-CoV-2 has become endemic in Austria. Full article

Headache is a common symptom during SARS-CoV-2 infection and may persist beyond three months. Both tension-type and migraine-like headaches have been described during SARS-CoV-2 infection and after immunization. The main objective was to characterize headache phenotype during SARS-CoV-2 infection and its relationship with headache recurrence following reinfection and COVID-19 vaccination in a cohort of healthcare professionals. Secondary aims included profiling primary headaches and identifying predictors of post-COVID-19 headache persistence. We included 109 participants (86.2% women, mean age 45.3 ± 2.5 years). During infection, 49.5% met ICHD-3 criteria for tension-type headache and 12.8% for migraine. Headache recurred in 62.5% after reinfection and 59.2% after vaccination. A primary-headache history was present in 77.9% of sampled patients (25.9% migraine, 47.1% tension-type). The COVID-19 headache phenotype typically mirrored patients’ previous headache type during reinfection and post-vaccination. Persistent headache beyond three months from SARS-CoV-2 infection occurred in 22.9% and was associated with fibromyalgia and obesity. These findings suggest that COVID-19-related headache often mirrors the patient’s pre-existing primary headache and tends to recur with the same phenotype following reinfection or vaccination. Full article

In 2020, a dairy farm in northwest Germany reported several cows with severe respiratory disease, fever, and reduced milk production. Multiple direct and indirect diagnostic methods were used to identify the cause of the disease. However, the pathogens detected could not be correlated with the severity of the clinical symptoms, so further diagnostic steps were taken. Blood and nasal swab samples were examined using next-generation sequencing (NGS) as part of a metagenomic analysis. For the first time in Germany, Hepacivirus bovis genotype 2 was detected. Real-time RT-PCR assays confirmed the presence of BovHepV genotypes 1 and 2 in the herd between 2020 and 2023. Analyses of complete and partial genome sequences demonstrated the presence of different virus variants in the herd over several years. In addition, the sequence data indicated that cattle can be reinfected with viruses belonging either to different BovHepV subtypes or to the same subtype. Although no direct link could be established between the detection of bovine hepaciviruses and the observed clinical symptoms, the PCR and sequence data obtained provide valuable insights into the epidemiology and pathogenesis of BovHepV infections. Full article

Background: Numerous studies have reported on the epidemiology of hand, foot and mouth disease (HFMD) reinfection and its potential influencing factors; however, findings regarding reinfection rates as well as determinants such as gender, age, residence, and pathogens remain inconsistent. Due to this heterogeneity in reported outcomes, a comprehensive systematic review and meta-analysis are warranted to consolidate existing evidence. Methods: Effect estimates were expressed as reinfection rates, odds ratio (OR)/hazard ratio (HR) and 95% confidence intervals (CI). When necessary, data were converted to ensure consistency across comparison groups. Results: A thorough search was carried out using the predetermined literature retrieval approach across the PubMed, Web of Science, and Embase databases. Finally, 9 articles met the inclusion criteria and were included in this study. The results indicated that the overall reinfection rate for HFMD was 4.1% (95% CI: 2.0–6.2%). Males compared to females (overall effect = 1.256, 95% CI: 1.176–1.341), younger compared to older children (overall effect = 2.972, 95% CI: 1.512–5.843), scattered children compared to students (overall effect: 4.017, 95% CI: 1.560–10.344), and enterovirus 71 (EV71) compared to non-EV71 enteroviruses (overall effect = 0.71, 95% CI: 0.59–0.86) were associated with the HFMD reinfection. Conclusions: The overall HFMD reinfection rate was 4.1% (95% CI: 2.0–6.2%). Male, younger age, kindergarten children, and infection with non-EV71 enteroviruses (compared to EV71), were identified as significant risk factors for recurrent HFMD. Targeted intervention strategies should be developed for these high-risk populations to effectively reduce the incidence of reinfection. Full article

Objective: Sternum osteomyelitis and deep sternal wound infection (DSWI) are often used to describe the same clinical condition interchangeably. The aim of our current study is to investigate the prevalence of osteomyelitis in cardiac surgery patients with DSWI and its consequences in therapy and osteosynthetic reconstruction. Patients and Methods: This is a retrospective single-center observational study. All consecutive patients with DSWI after cardiac surgery between 01/2014 and 12/2019 were included. In all patients, the sternal wound was reopened, sternal closure material was removed, and negative pressure therapy was initiated. Wound swabs were taken for microbiological examination, and a bone biopsy was examined for the presence of osteomyelitis. In the presence of osteomyelitis, long-term antibiotics were administered. Results: A total of 130 patients were identified in whom DSWI occurred after sternotomy. In 102 patients (77%), osteomyelitis could be detected histopathologically. The frequency of transverse sternal fractures was lower (p < 0.05) in the osteomyelitis subgroup (63%) as compared to the non-osteomyelitis subgroup (93%). Pathogens were detected in all patients with osteomyelitis, but less frequently (p < 0.05) in the group with no osteomyelitis (64%). If osteomyelitis was treated with long-term antibiotics, there was no difference in the complication rate (reinfection) after sternal restabilization between the two groups. Conclusions: DSWI and osteomyelitis should not be used interchangeably. If osteomyelitis can be detected histopathologically, long-term antibiotic treatment should be consistently conducted. As DSWI, with or without osteomyelitis, has been suggested to be associated with inadequate or failed sternal osteosynthesis, a key strategy to reduce its risk is to ensure safe and reliable primary sternal fixation. Full article

Background/Objectives: Quantitative computed tomography (CT) metrics are widely used to assess pulmonary involvement and to predict short-term severity in coronavirus disease 2019 (COVID-19). However, it remains unclear whether baseline artificial intelligence (AI)-based quantitative high-resolution computed tomography (HRCT) metrics of pneumonia burden provide incremental prognostic value for in-hospital composite adverse outcomes beyond routine clinical factors, or whether these imaging-derived markers carry any exploratory signal for long-term severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfection among hospitalized patients. Most existing imaging studies have focused on diagnosis and acute-phase prognosis, leaving a specific knowledge gap regarding AI-based quantitative HRCT correlates of early deterioration and subsequent reinfection in this population. To evaluate whether combining deep learning-derived, quantitative, HRCT features and clinical factors improve prediction of in-hospital composite adverse events and to explore their association with long-term reinfection in patients with COVID-19 pneumonia. Methods: In this single-center retrospective study, we analyzed 236 reverse-transcription polymerase chain reaction (RT-PCR)-confirmed COVID-19 patients who underwent baseline HRCT. Median follow-up durations were 7.65 days for in-hospital outcomes and 611 days for long-term outcomes. A pre-trained, adaptive, artificial-intelligence-based, prototype model (Siemens Healthineers) was used for pneumonia analysis. Inflammatory lung lesions were automatically segmented, and multiple quantitative metrics were extracted, including opacity score, volume and percentage of opacities and high-attenuation opacities, and mean Hounsfield units (HU) of the total lung and opacity. Patients were stratified based on receiver operating characteristic (ROC)-derived optimal thresholds, and multivariable Cox regression was used to identify predictors of the composite adverse outcome (intensive care unit [ICU] admission or all-cause death) and SARS-CoV-2 reinfection, defined as a second RT-PCR-confirmed episode of COVID-19 occurring ≥90 days after initial infection. Results: The composite adverse outcome occurred in 38 of 236 patients (16.1%). Higher AI-derived opacity burden was significantly associated with poorer outcomes; for example, opacity score cut-off of 5.5 yielded an area under the ROC curve (AUC) of 0.71 (95% confidence interval [CI] 0.62–0.79), and similar performance was observed for the volume and percentage of opacities and high-attenuation opacities (AUCs up to 0.71; all p < 0.05). After adjustment for age and comorbidities, selected HRCT metrics—including opacity score, percentage of opacities, and mean HU of the total lung (cut-off −662.38 HU; AUC 0.64, 95% CI 0.54–0.74)—remained independently associated with adverse events. Individual predictors demonstrated modest discriminatory ability, with C-indices of 0.59 for age, 0.57 for chronic obstructive pulmonary disease (COPD), 0.62 for opacity score, 0.63 for percentage of opacities, and 0.63 for mean total-lung HU, whereas a combined model integrating clinical and imaging variables improved prediction performance (C-index = 0.68, 95% CI: 0.57–0.80). During long-term follow-up, RT-PCR–confirmed reinfection occurred in 18 of 193 patients (9.3%). Higher baseline CT-derived metrics—particularly opacity score and both volume and percentage of high-attenuation opacities (percentage cut-off = 4.94%, AUC 0.69, 95% CI 0.60–0.79)—showed exploratory associations with SARS-CoV-2 reinfection. However, this analysis was constrained by the very small number of events (n = 18) and wide confidence intervals, indicating substantial statistical uncertainty. In this context, individual predictors again showed only modest C-indices (e.g., 0.62 for procalcitonin [PCT], 0.66 for opacity score, 0.66 for the volume and 0.64 for the percentage of high-attenuation opacities), whereas the combined model achieved an apparent C-index of 0.73 (95% CI 0.64–0.83), suggesting moderate discrimination in this underpowered exploratory reinfection sample that requires confirmation in external cohorts. Conclusions: Fully automated, deep learning-derived, quantitative HRCT parameters provide useful prognostic information for early in-hospital deterioration beyond routine clinical factors and offer preliminary, hypothesis-generating insights into long-term reinfection risk. The reinfection-related findings, however, require external validation and should be interpreted with caution given the small number of events and limited precision. In both settings, combining AI-based imaging and clinical variables yields better risk stratification than either modality alone. Full article

Background: Clostridioides difficile infections (CDIs) are caused by a Gram-positive, spore-forming bacillus and are defined by more than three episodes of watery diarrhoea per day. CDI is a major cause of morbidity and mortality in older adults, particularly over 65 years. Recurrent CDI leads to higher mortality and prolonged, debilitating illness. Case Presentations: This article presents two patients, aged over 80 years old, who developed recurrent CDI causing complicated and prolonged treatment courses. Patient 1 required an extended course of antibiotics for treatment of discitis and a congruent psoas abscess. Patient 2 developed CDI after multiple short courses of antibiotics for urinary tract infections (UTIs) in the context of multiple comorbidities. Both patients experienced three distinct episodes of CDI and were treated in collaboration with microbiology specialists. Following the third episode, both were successfully treated with oral capsule faecal microbiome transplants (FMTs). Their cases highlight the challenge of balancing systemic antibiotic use against CDI risk. Discussions: These cases underscore known risk factors for recurrent CDI, including advanced age and prolonged antibiotic exposure. Recurrence rates in patients over 65 can reach 58%. The British Society of Gastroenterology and Healthcare Infection Society support the use of FMTs in recurrent cases. Environmental decontamination, including terminal cleaning with sporicidal agents, is critical in reducing reinfection in hospital settings. Conclusions: Recurrent CDI in elderly patients reflects a complex interplay between infection control and managing comorbidities. New guidelines suggest that FMTs can significantly reduce morbidity and mortality. These cases emphasise the need for individualised, multidisciplinary care, adherence to guidelines, and further research to improve safe, effective CDI management in older adults. Full article

Background/Objectives: Important goals of endodontic treatment procedures are to effectively eliminate microorganisms from the root canal system and prevent reinfection. Despite advances in techniques, these goals continue to be difficult to achieve due to the complex anatomy of the root canal system and bacterial invasion into the dentinal tubules of the surrounding root dentin. This pilot study aimed to refine a confocal laser scanning microscopy (CLSM) model with LIVE/DEAD staining to quantitatively assess the depth of effective disinfection by endodontic disinfection measures. Methods: Thirty caries-free human teeth underwent standardized chemo-mechanical root canal preparation and were inoculated with Enterococcus faecalis. Following treatment, CLSM-guided imaging with LIVE/DEAD staining allowed for differentiation between vital and dead bacteria and quantification of the depth of effective disinfection. Results: An average depth of bacterial eradication of 450 µm for conventional and 520 µm for sonically activated irrigation (EDDY) could be observed with significant differences (p < 0.05) in the coronal and medial positions. Conclusions: The results indicated that sonically activated irrigation (EDDY) provided a more homogeneous (omnidirectional) irrigation pattern compared to conventional irrigation. The study highlights the importance of effective disinfection strategies in endodontics, emphasizing the need for further research on the depth of effective disinfection of endodontic disinfection measures and the optimization of disinfection protocols. Full article

Background/Objectives: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can naturally infect a broad spectrum of animal species, with cats, minks, and ferrets being highly susceptible. There is a potential risk that infected animals could transmit viruses to humans. Moreover, SARS-CoV-2 continues to evolve via mutation and genetic recombination, resulting in the continuous emergence of new variants that have triggered a wave of reinfection. Therefore, safe and effective corona virus disease 2019 (COVID-19) vaccines for animals are still being sought. Methods: We generated three recombinant Modified vaccinia virus Ankara (MVAs) expressing the prefusion-stabilized S proteins, S6P, DS6P, and BA2S6P, targeting the full-length S protein genes of the ancestral, Delta, and Omicron BA.2 strains of SARS-CoV-2. Subsequently, the safety, immunogenicity, and protective efficacy of these MVA-based oral COVID-19 vaccine candidates were assessed in mice, minks, and cats. Results: These recombinant MVAs are safe in mice, minks, and cats. Oral or intramuscular vaccination with rMVA-S6P induced a robust SARS-CoV-2 neutralizing antibody (NA) response and conferred complete protection against the SARS-CoV-2 challenge in mice. Meanwhile, oral or intramuscular administration of these recombinant MVAs in combination induced a potent and durable NA response against homotypic SARS-CoV-2 pseudovirus in mice, minks, and cats, respectively. Conclusions: These findings suggest that the MVA-vectored vaccines are promising oral COVID-19 vaccine candidates for animals, and that the combined vaccination approach is an effective administration strategy for such vaccines. Full article

Onychomycosis is a common nail disease that manifests with varying severity and frequency in specific patient populations, warranting a personalized treatment approach. Novel topical antifungals, such as efinaconazole 10% approved for use in North America and Japan, offer a safe treatment option for many of these patients, though real-world use requires special considerations. In this scoping review, a literature search was conducted in October 2025 using PubMed, Embase (Ovid), the Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science (Core Collection). In children and adolescents (≥6 years), efinaconazole 10% has shown higher efficacy rates than in adults, possibly attributed to less nail trauma, thinner nail plates, and faster nail growth. In the elderly, a mycological response can precede visual nail improvements, which may require extending treatment beyond the standard 48-week regimen, along with intermittent maintenance therapies. Although antifungal resistance is a concern, dermatophytes—including terbinafine-resistant strains—have generally shown high susceptibility to efinaconazole. In diabetic individuals, onychomycosis should be treated promptly to prevent secondary complications. Efinaconazole 10% showed similar efficacy in this population, regardless of glycemic control. In historically underserved populations, efinaconazole 10% showed no significant difference in efficacy for Latino/Hispanic patients, though further research is needed. Overall, efinaconazole 10% solution was well-tolerated across patient groups, with application-site reactions occurring without systemic sequalae. Healthcare providers are advised to check for concomitant tinea pedis, which increases the risk of relapse or re-infection, and advise patients on nail polish use, which may degrade after topical antifungal application. A shared decision-making framework can help improve treatment compliance and patient satisfaction. Full article

Background: Deep sternal wound infections (DSWIs) remain a serious complication after median sternotomy, often requiring complex wound management strategies. While modern approaches include vacuum-assisted closure (VAC) and plating techniques, the pedicled pectoralis major muscle flap (PMF) continues to play a pivotal role in surgical reconstruction, especially in cases with sternal destruction or osteomyelitis. Methods: In this retrospective single-centre analysis, 166 patients with DSWI following cardiac surgery were reviewed. Clinical data, comorbidities, laboratory parameters, and surgical management were evaluated. Logistic regression was performed to assess predictors for reinfection and need for reoperation. Results: Initial wound revision was most frequently performed using sternal rewiring (60.2%), followed by reconstruction with a pectoralis major flap (33.7%). Despite initial surgical treatment, 27.1% of patients developed post-revision wound healing disturbances, and 24.1% ultimately required a second surgical intervention. Among second-time procedures, VAC therapy (32.5%) and PMF reconstruction (20.0%) were the most common approaches. Reinfection was significantly associated with higher preoperative EuroSCOREs (p = 0.044), while initial rewiring carried a higher risk of treatment failure compared to the pectoralis major flap (p = 0.0024). Conclusions: In the setting of sternal destruction or osteomyelitis, the pectoralis major muscle flap remains a fast, effective, and robust solution. Despite its long-standing use, it continues to offer excellent vascularized coverage and infection control in complex DSWI cases. Full article

The parasitic disease scuticociliatosis poses significant economic losses to shrimp culture. In this study, an unidentified species of ciliates was discovered in Litopenaeus vannamei. Morphological and molecular analyses were conducted to identify the parasite species, while a reinfection experiment was performed to assess its virulence towards L. vannamei. Simultaneously, Chinese herbal medicine was assessed for potential prevention and control of this pathogen. The results revealed that the SSU rDNA (93.87%), LSU rDNA (98.20%), and ITS1-5.8S-ITS2 rDNA (87.10%) genes exhibited high homology with Metanophrys sinensis, suggesting its classification within the genus Metanophry sp. The reinfection experiment demonstrated median lethal dosages of 6638 individuals/mL at 24 h and 4658 individuals/mL at 48 h for this ciliate on the host L.vannamei. In terms of drug control, we conducted a screening of 23 Chinese herbal extracts through in vivo injection trials and observed that Mume fructus extract exhibits potent biocidal activity. Specifically, the M. fructus extract solution with a final concentration of 5 mg/mL (0.5% v/v) eliminated all ciliates within 3 h. In conclusion, this study identified the ciliate parasite as Metanophrys sinensis and demonstrated its virulence to Litopenaeus vannamei. Mume fructus extract was found to effectively control the parasite, offering potential for managing scuticociliatosis in shrimp culture. Full article

This study proposes an SVEIR with a reinfection model of tuberculosis disease spread to examine the impact of saturated infection and imperfect vaccination. Vaccinated individuals are considered vulnerable, as they are still likely to be reinfected. As the recovered individuals still have bacteria in their bodies, they are likely to return to their latent class. The dynamic behavior of the proposed model was analyzed to understand both the local and global stability equilibrium points. To analyze the disease-free and endemic equilibrium stability, the Routh–Hurwitz Criterion and Center Manifold theorems were used, respectively. The local and global stability equilibrium state is entirely dependent on the effective reproduction number. If the effective reproduction number is less than one, the disease-free equilibrium point is locally and globally asymptotically stable, whereas if it is greater than one, the endemic equilibrium point is locally asymptotically stable. Numerical simulations show the time series of the solution of the model, phase-plane trajectory, elasticity indices, bifurcation diagram, partial rank correlation coefficients, and the sensitivity of the infected class to variations in the transmission rate represented both in the peak value and a heatmap. Furthermore, the contour plot illustrates that the disease transmission rate affects the effective reproduction number and the stability of equilibrium points. Full article

Egypt has the highest global prevalence of hepatitis C virus (HCV), with genotype 4 (G4) in over 94% of cases. Direct-acting antivirals (DAAs) yield sustained virologic response (SVR) rates above 95%. Second-generation DAAs are recommended for patients with virological failure, achieving over 90% eradication. This study aimed to classify and evaluate the pattern of HCV resistance-associated substitutions (RASs) in patients who failed DAA treatment in Egypt. A total of 1778 chronically infected HCV patients from Egypt’s Nile Delta were enrolled (2016–2018). Among them, 37 relapsed, and high-quality serum samples from 22 patients were available, including 6 cases with pre- and post-treatment samples. Next-generation sequencing (NGS) was performed for HCV subtyping and RAS identification. Among the 22 analyzed cases, 21 (95.4%) were G4: 11 were classified as subtype G4a, seven G4o, and three G4m. One patient (4.5%) was identified as G1g. One case shifted from G4a pre- to G4o post-treatment, suggesting reinfection. The RAS pattern in rare G4 subtypes (G4m/G4o) differs from the G4a subtype. The combination of L28M/L30S mutations was detected in 8/11 G4a samples; in contrast, RASs in G4o were characterized by T30S or Y93C/H/N/S substitutions. Notably, some substitutions identified as RASs may represent fixed polymorphisms in regional viral populations, such as those in Egypt’s Nile Delta. HCV subtypes significantly influence the RAS pattern, particularly within the NS5A region, after DAA-treatment failure. The RAS pattern differs among G4 subtypes, particularly in rare ones, predisposing patients to resistance and underscoring the importance of NGS in regional populations to optimize treatment strategies. Full article

Treatment for complex pleural empyema often requires thoracoplasty with rib(s) resection to remodel the thoracic cage and obliterate chronic infected pleural cavities. Such procedures are complicated and result in permanent body deformation, which is not acceptable by most adults. Standard decortication often fails as there is residual space for reinfection development, and often necrotizing pneumonia co-exists. Here we describe the surgical management of three complicated adult patients using the modified version of the Sawamura technique which involves debridement and partial decortication followed by ribs stripped of periosteum and surrounding soft tissues, to allow collapse deep into the pleural cavity, thereby obliterating the chronic space in conjunction with partial lung re-expansion. We utilized the serratus muscular flap to repair any bronchial defects due to resected gangrenous parenchyma. No further reoperations were necessary, and no residual effusions were drained. At the 6-month follow-up, these three patients experienced no complications, and their body shapes and functionality were unaltered. This modified Sawamura technique offers an effective single-step treatment while being cosmetically suitable for young adults, and presents an extremely attractive option in countries with limited healthcare resources. Full article