Search Results (2,121)

Deer tick virus (DTV) is a Tick-Borne Orthoflavivirus endemic to the United States, transmitted to humans through bites from the deer tick, Ixodes scapularis, which is also the primary vector of Borrelia burgdorferi s.l., the causative agent of Lyme disease. Human infection with DTV can result in acute febrile illness followed by central nervous system complications, such as encephalitis and meningoencephalitis. Currently, there are mouse models established for investigating the pathogenesis and clinical outcomes of DTV that mimic human infections, but the strains of mice utilized are refractory to infection with B. burgdorferi s.l. Here, we describe the pathogenesis and clinical outcomes of DTV infection in C3H/HeJ mice. Neurological clinical signs, mortality, and weight loss were observed in all DTV-infected mice during the investigation. Infected animals demonstrated consistent viral infection in their organs. Additionally, neuropathology of brain sections indicated the presence of meningoencephalitis throughout the brain. This data, along with the clinical outcomes for the mice, indicates successful infection and showcases the neuroinvasive nature of the virus. This is the first study to identify C3H/HeJ mice as an appropriate model for DTV infection. As C3H/HeJ mice are already an established model for B. burgdorferi s.l. infection, this model could serve as an ideal system for investigating disease progression and pathogenesis of co-infections. Full article

Canine visceral leishmaniasis (CVL) is a major zoonosis that poses a growing challenge to public health services, as successful disease management requires sensitive, specific, and rapid diagnostic methods capable of identifying infected animals even at a subclinical level. The objective of this study was to evaluate the performance of the recombinant chimeric protein rMELEISH3 as an antigen in ELISA assays for the robust diagnosis of CVL. The protein was expressed in a bacterial system, purified by affinity chromatography, and evaluated through a series of serological assays using serum samples from dogs infected with Leishmania infantum. ROC curve analysis revealed a diagnostic sensitivity of 96.4%, a specificity of 100%, and an area under the curve of 0.996, indicating excellent discriminatory power. Furthermore, rMELEISH3 was recognized by antibodies present in the serum of dogs with low parasite loads, reinforcing the diagnostic potential of the assay in asymptomatic cases. It is concluded that the use of the recombinant antigen rMELEISH3 could significantly contribute to the improvement of CVL surveillance and control programs in endemic areas of Brazil and other countries, by offering a safe, reproducible and effective alternative to the methods currently recommended for the serological diagnosis of the disease. Full article

Background: Coronavirus disease 2019 (COVID-19) has led to the expansion of the spectrum of invasive fungal infections beyond traditional immunocompromised populations. Although COVID-19-associated pulmonary aspergillosis is increasingly being recognised, COVID-19-associated mucormycosis remains rare, particularly in non-endemic regions. Concurrent COVID-19-associated invasive tracheobronchial aspergillosis and pulmonary mucormycosis with histopathological confirmation is exceedingly uncommon and poses significant diagnostic and therapeutic challenges. Case presentation: We report the case of a 57-year-old female with myelodysplastic syndrome who underwent haploidentical allogeneic haematopoietic stem cell transplantation. During post-transplant recovery, she developed COVID-19 pneumonia, complicated by respiratory deterioration and radiological findings, including a reverse halo sign. Bronchoscopy revealed multiple whitish plaques in the right main bronchus. Despite negative serum and bronchoalveolar lavage fluid galactomannan assay results, cytopathological examination revealed septate hyphae and Aspergillus fumigatus was subsequently identified. Given the patient’s risk factors and clinical features, liposomal amphotericin B therapy was initiated. Subsequent surgical resection and histopathological analysis confirmed the presence of Rhizopus microsporus. Following antifungal therapy and surgical intervention, the patient recovered and was discharged in stable condition. Conclusions: This case highlights the critical need for heightened clinical suspicion of combined invasive fungal infections in severely immunocompromised patients with COVID-19, even in non-endemic regions for mucormycosis. Early tissue-based diagnostic interventions and prompt initiation of optimal antifungal therapy are essential for obtaining ideal outcomes when co-infection is suspected. Full article

Tuberculosis (TB) is an ancient and re-emerging granulomatous infectious disease that continues to challenge public health. Early diagnosis and prompt effective treatment are crucial for preventing disease progression and reducing both morbidity and mortality. These steps play a vital role in infection control and in lowering death rates at both individual and population levels. Although diagnostic methods have improved sufficiently in recent decades, TB can still present with ambiguous laboratory and imaging features. This ambiguity can lead to diagnostic pitfalls and potentially disastrous outcomes due to delayed diagnosis. In this article, we present a case of TB that was difficult to diagnose. The disease had invaded the mediastinum, right atrium, right coronary artery, and inferior vena cava (IVC), resulting in Budd–Chiari syndrome. This rare presentation created clinical, laboratory, and radiological confusion, resulting in a diagnostic dilemma that ultimately led to open cardiac surgery. The patient initially presented with progressive shortness of breath on exertion and fatigue, which suggested possible heart disease. This suspicion was reinforced by computed tomography (CT) imaging, which showed infiltrative mass lesions predominantly in the right side of the heart, invading the right coronary artery and IVC, with imaging features mimicking angiosarcoma. Although laboratory findings revealed an exudative effusion with lymphocyte predominance and elevated adenosine deaminase (ADA), the Gram stain was negative for bacteria, and an acid-fast bacilli (AFB) smear was also negative. These findings contributed to diagnostic uncertainty and delayed the confirmation of TB. Open surgery with excisional biopsy and histopathological analysis ultimately confirmed TB. We conclude that TB should not be ruled out solely based on negative Mycobacterium bacteria in pericardial effusion or AFB smear. TB can mimic aggressive tumors such as angiosarcoma or lymphoma with invasion of the surrounding tissues and blood vessels. Awareness of the clinical presentation, imaging findings, and potential diagnostic pitfalls of TB is essential, especially in endemic regions. Full article

Despite intensive eradication efforts, classical swine fever (CSF) remains endemic across South America, Europe, Asia, and the Caribbean, highlighting the need for more effective surveillance and detection methods. Reverse-transcription real-time polymerase chain reaction (RRT-PCR) is the fastest, and most sensitive assay for detecting CSF virus (CSFV) genomic material. Previously, we demonstrated that spleen swabs outperformed spleen homogenates for the detection of ASFV genomic material by RRT-PCR. In this study, we compared CSFV genome detection in paired spleen homogenates and spleen swabs generated using 49 frozen and 33 fresh spleen samples collected from experimentally inoculated pigs with acute infection. The results show that the CSFV genome detection in spleen swabs is comparable to that in spleen homogenates. The study also demonstrated that the CSFV genomic material can be detected in spleen swabs during early CSFV infections, and the viruses can be successfully isolated from the swabs. The use of spleen swabs instead of spleen tissue homogenates for CSF detection will reduce labor, decrease costs associated with reporting, and increase the diagnostic throughput. Full article

Via a One Health approach, this study concomitantly assessed the susceptibility of humans and dogs to Trypanosoma cruzi infections on three islands and in two mainland seashore areas of southern Brazil. Human serum samples were tested using an enzyme-linked immunosorbent assay (ELISA) to detect anti-T. cruzi antibodies, while dog serum samples were tested using indirect fluorescent antibodies in an immunofluorescence assay (IFA). Seropositive human and dog individuals were also tested using quantitative polymerase chain reaction (qPCR) in corresponding blood samples. Overall, 2/304 (0.6%) human and 1/292 dog samples tested seropositive for T. cruzi by ELISA and IFA, respectively, and these cases were also molecularly positive for T. cruzi by qPCR. Although a relatively low positivity rate was observed herein, these cases were likely autochthonous, and the individuals may have been infected as a consequence of isolated events of disturbance in the natural peridomicile areas nearby. Such a disturbance could come in the form of a fire or deforestation event, which can cause stress and parasitemia in wild reservoirs and, consequently, lead to positive triatomines. In conclusion, T. cruzi monitoring should always be conducted in suspicious areas to ensure a Chagas disease-free status over time. Further studies should also consider entomological and wildlife surveillance to fully capture the transmission and spread of T. cruzi on islands and in seashore mainland areas of Brazil and other endemic countries. Full article

Glanders is a highly contagious and often fatal zoonotic disease of equids caused by Burkholderia mallei, a pathogen of significant concern due to its potential for bioterrorism. In Brazil, glanders remains endemic, particularly among working equids in the Northeast region. Diagnostic confirmation typically involves serology, culture, and polymerase chain reaction (PCR), although false-negative PCR results have been increasingly reported. This study aimed to evaluate the diagnostic performance and analytical sensitivity of four B. mallei-specific PCR primer sets using samples from 30 seropositive equids. Microbiological cultures were obtained from various organs and swabs, followed by PCR targeting four genomic regions: fliP-IS407A(a), fliP-IS407A(b), Burk457, and Bm17. All animals were confirmed positive for B. mallei via culture, but PCR detection rates varied significantly across primer sets. The fliP-IS407A(b) primer set showed the highest sensitivity, detecting 86% of samples, while the WOAH-recommended fliP-IS407A(a) set had the lowest performance (13.4%). Analytical sensitivity assays confirmed that fliP-IS407A(b) and Bm17 primers detected DNA concentrations as low as 0.007 ng, outperforming the others. These findings suggest that certain widely used primer sets may lack sufficient sensitivity for reliable detection of B. mallei, especially in chronically infected animals with low bacterial loads. The study underscores the need for ongoing validation of molecular diagnostics to improve the detection and control of glanders in endemic regions. Full article

Schistosoma mansoni infection is associated with hepatic inflammation and fibrosis, but its systemic metabolic effects remain poorly understood. This study aimed to investigate changes in the serum lipidomic profile associated with S. mansoni infection and parasite load in individuals from an endemic area. This cross-sectional analysis was nested within a longitudinal cohort study conducted in northeastern Brazil. Parasitological diagnosis and quantification were performed using the Kato–Katz technique. A total of 45 individuals were selected and divided into three groups: high parasite load (HL), low parasite load (LL), and uninfected controls (NegE). Serum samples were analyzed using mass-spectrometry-based lipidomics. The most abundant lipid subclasses across all groups were phosphatidylcholines (PC), triacylglycerols (TAG), and phosphatidylethanolamines (PE). However, individuals in the HL group exhibited distinct lipidomic profiles, with increased levels of specific phosphatidylinositols (PI) and reduced levels of certain TAG species compared to the NegE group. These changes may reflect host–parasite interactions and immune–metabolic alterations driven by intense infection. Our findings suggest that S. mansoni infection, particularly at higher parasite burdens, can influence the host’s serum lipid profile and may contribute to metabolic disturbances in endemic populations. Full article

HIV infection and hypertensive disorders of pregnancy (HDP), particularly preeclampsia (PE) with severe features, are leading causes of maternal mortality worldwide. This study investigates the role of asymmetric dimethylarginine (ADMA) and prostacyclin (PGI2) concentrations in endothelial impairment in normotensive pregnant versus PE women within an HIV endemic setting in KwaZulu-Natal Province, South Africa. The study population (n = 84) was grouped according to pregnancy type, i.e., normotensive (n = 42) and PE (n = 42), and further stratified by HIV status. Clinical factors were maternal age, weight, blood pressure (both systolic and diastolic) levels, and gestational age. Plasma concentrations of ADMA and PGI2 were measured using the enzyme-linked immunoassay (ELISA). Differences in outcomes were analyzed using the Mann–Whitney U and Kruskal–Wallis test together with Dunn’s multiple-comparison post hoc test. The non-parametric data were presented as medians and interquartile ranges. Gravidity, gestational age, and systolic and diastolic blood pressures were significantly different across the study groups where p < 0.05 was deemed significant. Furthermore, the concentration of ADMA was significantly elevated in PE HIV-positive vs. PE HIV-negative (p = 0.0174) groups. PGI2 did not show a significant difference in PE compared to normotensive pregnancies (p = 0.8826) but was significantly different across all groups (p = 0.0212). An increase in plasma ADMA levels was observed in the preeclampsia HIV-negative group compared to the normotensive HIV-negative group. This is linked to the role played by ADMA in endothelial impairment, a characteristic of PE development. PGI2 levels were decreased in PE compared to the normotensive group regardless of HIV status. These findings draw attention to the importance of endothelial indicators in pathogenesis and possibly early prediction of PE development. Full article

Background: Anaemia in adolescents can be influenced by parasitic infections, systemic inflammation, and nutritional status. Objective: To determine whether C-reactive protein (CRP), nutritional status, and infection with Ascaris lumbricoides, Giardia lamblia, or Trichuris trichiura are associated with anaemia in adolescent athletes from Tacna compared to non-athletes. Methods: A cross-sectional study was conducted involving 250 male football players aged 13–18 years and 150 age-matched non-athletes. Haemoglobin, haematocrit, ferritin, serum iron, CRP, and parasitic status were measured; mean comparisons and logistic regression were applied. Results: Anaemia was more prevalent among athletes than non-athletes (30% vs. 18%; p < 0.001). Infected athletes showed lower haemoglobin (11.9 ± 1.1 g/dL) and higher CRP (5.0 ± 1.9 mg/L) levels compared to non-infected athletes (13.8 ± 1.0 g/dL and 2.2 ± 1.1 mg/L; p < 0.001). Logistic regression identified CRP as an independent predictor of anaemia (adjusted OR = 1.20; 95% CI: 1.08–1.38; p < 0.001), while parasitic infections showed no direct association after adjustment. Underweight status was associated with a higher prevalence of anaemia (36%). Conclusions: Systemic inflammation emerged as the main factor associated with anaemia in this population, with parasitic infections contributing indirectly by increasing inflammation. Periodic deworming, iron supplementation, and CRP monitoring are recommended to reduce the burden of anaemia in adolescent athletes from endemic regions. Full article

With the increasing detection of artemisinin resistance to front-line antimalarials in Africa and notwithstanding the planned roll-out of RTS’S and R21 in Africa, the search for new vaccines with high efficacy remains an imperative. Towards this endeavour, we performed in silico screening to identify Plasmodium falciparum gametocyte stage genes that could be targets of protection or diagnosis. Through the analysis we identified a gene, Pf3D7_1105800, coding for a Plasmodium falciparum subtilisin-like domain-containing protein (PfSDP) and thus dubbed the gene Pfsdp. Genetic diversity assessment revealed the Pfsdp gene to be relatively conserved across continents with signs of directional selection. Using RT qPCR and Western blots, we observed that Pfsdp is expressed in all developmental stages of the parasite both at the transcript and protein level. Immunofluorescence assays found PfSDP protein co-localizing with PfMSP-1 and partially with Pfs48/45 at the asexual and sexual stages, respectively. Further, we demonstrated that anti-PfSDP peptide-specific antibodies inhibited erythrocyte invasion by 20–60% in a dose-dependent manner, suggesting that PfSDP protein might play a role in merozoite invasion. We also discovered that PfSDP protein is immunogenic in children from different endemic areas with antibody levels increasing from acute infection to day 7 post-treatment, followed by a gradual decay. The limited effect of antibodies on erythrocyte invasion could imply that it might be more involved in other processes in the development of the parasite. Full article

Background: Polyparasitic infections remain widespread in endemic regions, yet its contributing factors and health impact are not well understood. This study aims to estimate the prevalence and associated factors and examines the effect of polyparasitic infection on haemoglobin levels among children. Methods: A cross-sectional study was conducted in Lambaréné, Gabon, among children aged 2–17 years from November 2019 to December 2020. Haemoglobin levels, environmental conditions, and sociodemographic data were collected. Stool, urine, and blood samples were analysed using light microscopy for parasite detection. Factors associated with polyparasitism were explored. Results: Out of 656 participants, 65.4% had at least one infection, with intestinal protozoa species (21.3%), Trichuris trichiura (33%), Ascaris lumbricoides (22%), Schistosoma haematobium (20%), and Plasmodium falciparum (10%) being the most common. Polyparasitic infection was identified in 26% of children, mostly as bi-infections (69.2%), and was negatively associated with haemoglobin levels (β = −0.06). Conclusions: These findings emphasise the burden of polyparasitic infections and adverse health effects in Lambaréné, Gabon. Full article

Simian foamy virus (SFV) is a retrovirus that infects primates. However, epidemiological studies of SFV are often limited to captive populations. The southeastern Brazilian Atlantic Forest is home to both an endemic, endangered species, Leontopithecus rosalia, and an introduced species, Leontopithecus chrysomelas, to which no data on SFV exist. In this study, we assessed the molecular prevalence of SFV, their viral load, and their phylogenetic relationship in these two species of primates. Genomic DNA was extracted from 48 oral swab samples of L. chrysomelas and 102 of L. rosalia. Quantitative PCR (qPCR) was performed to diagnose SFV infection and quantify viral load. SFV prevalence was found to be 23% in L. chrysomelas and 33% in L. rosalia. No age-related differences in prevalence were observed; however, L. rosalia showed a higher mean viral load (3.27 log10/10⁶ cells) compared to L. chrysomelas (3.03 log10/10⁶ cells). The polymerase gene sequence (213 pb) of L. rosalia (SFVlro) was clustered within a distinct SFV lineage found in L. chrysomelas. The estimated origin of SFVlro dated back approximately 0.0836 million years ago. Our study provides the first molecular prevalence data for SFV in free-living Leontopithecus populations while offering insights into the complex evolutionary history of SFV in American primates. Full article

Background: Dyslipidemia and schistosomiasis are major public health challenges, particularly in endemic regions where their coexistence may influence host metabolism and immune responses. This study aimed to evaluate visceral adipose tissue (AT) remodeling in a murine model of acute Schistosoma mansoni infection combined with diet-induced dyslipidemia. Methodology: Female Swiss Webster mice were fed either a standard or high-fat diet (HFD) for 29 weeks and infected with S. mansoni at week 20. Nine weeks after infection, biochemical, morphometric, histopathological, and immunological analyses were performed. Results: The HFD promoted weight gain and dyslipidemia, while S. mansoni infection alone did not alter lipid profiles but partially mitigated the metabolic effects of the HFD. Morphometric analysis revealed adipocyte hypertrophy and reduced cell number in HFD-fed animals. In HFD-fed infected mice, infection partially reversed hypertrophy, suggesting a modulatory effect on AT remodeling. Histopathological examinations showed that while a HFD induced mild inflammation, infection led to intense leukocyte infiltration, hyperemia, and plasma cell degeneration. Peritoneal lavage confirmed a proinflammatory immune profile. Conclusions: These findings indicate that the interaction between a HFD and S. mansoni infection exacerbates adipose tissue inflammation and metabolic alterations, highlighting the complex interplay between parasitic infection, diet, and immune-metabolic regulation. Full article

Background/Objectives: Saliva as a diagnostic medium for COVID-19 requires fewer resources to collect and is more readily adopted across a range of testers. Our study compared an Emergency Use Authorized direct saliva-to-RT-qPCR test against an FDA-authorized nasal swab RT-qPCR assay for participants who reported symptoms of respiratory infection. Methods: We analyzed 737 symptomatic participants who self-selected to test at either a community testing facility or a walk-in clinic due to respiratory symptoms and provided matched saliva and nasal swab samples. Samples were collected between March and September of 2023, both before and after the declared end of the public health emergency. Results: A total of 120 participants tested positive in at least one of the tests. For participants testing in the first 5 days of reported symptoms, the saliva test had a 94.0 positive percent agreement (PPA; 95% C.I. 88.9–99.1%) with the nasal test and a 99.0 negative percent agreement (NPA; 95% C.I. 98.1–99.9%). The viral load decreased beyond day 1 of reported symptoms for saliva testing. Viral load increased up to day 4 for nasal swabs and then decreased. The same number of discordant positive samples (five each) occurred for both tests within 5 days of symptoms onset. Conclusions: In the endemic phase of COVID-19 and for development of new tests, testing methods that are less invasive are more likely to be adopted. The results of saliva-based versus nasal swab PCR measurements relative to days of symptom onset are needed to optimize future testing strategies. Full article