Microfluidic paper-based analytical devices (μPADs) have been extensively proposed as ideal tools for point-of-care (POC) testing with minimal user training and technical requirements. However, most ...μPADs use dried bioreagents, which complicate production, reduce device reproducibility and stability, and require transport and storage under temperature and humidity-controlled conditions. In this work, we propose a μPAD produced using an affordable craft-cutter and stored at room temperature, which is used to partially automate a single-step colorimetric magneto-immunoassay. As a proof-of-concept, the μPAD has been applied to the quantitative detection of Plasmodium falciparum lactate dehydrogenase (Pf-LDH), a biomarker of malaria infection. In this system, detection is based on a single-step magneto-immunoassay that consists of a single 5-min incubation of the lysed blood sample with immuno-modified magnetic beads (MB), detection antibody, and an enzymatic signal amplifier (Poly-HRP). This mixture is then transferred to a single-piece paper device where, after on-chip MB magnetic concentration and washing, signal generation is achieved by adding a chromogenic enzyme substrate. The colorimetric readout is achieved by the naked eye or using a smartphone camera and free software for image analysis. This μPAD afforded quantitative Pf-LDH detection in <15 min, with a detection limit of 6.25 ng mL−1 when the result was interpreted by the naked eye and 1.4 ng mL−1 when analysed using the smartphone imaging system. Moreover, the study of a battery of clinical samples revealed concentrations of Pf-LDH that correlated with those provided by the reference ELISA and with better sensitivity than a commercial rapid diagnostic test (RDT). These results demonstrate that magneto-immunoassays can be partly automated by employing a μPAD, achieving a level of handling that approaches the requirements of POC testing.
•Time for culture conversion in treated PTB is uncertain and can be delayed.•Patients can have predicatble risk factors associated with late conversion.•Using a simple score could help clinicians to ...make decisions about isolation period.
Patients with pulmonary tuberculosis (PTB) disease and positive sputum cultures are the main source of infection. Culture conversion time is inconsistent and defining the length of respiratory isolation is challenging. The objective of this study is to develop a score to predict the length of isolation period.
A retrospective study was carried out to evaluated risk factors associated with persistent positive sputum cultures after 4 weeks of treatment in 229 patients with PTB. A multivariable logistic regression model was used to determinate predictors for positive culture and a scoring system was created based on the coefficients of the final model.
Sputum culture was persistently positive in 40.6%. Fever at consultation (1.87, 95% CI:1.02–3.41), smoking (2.44, 95% CI:1.36–4.37), >2 affected lung lobes (1.95, 95% CI:1.08–3.54), and neutrophil-to-lymphocyte ratio > 3.5 (2.22, 95% CI:1.24–3.99), were significantly associated with delayed culture conversion. Therefore, we assembled a severity score that achieved an area under the curve of 0.71 (95% CI:0.64–0.78).
In patients with smear positive PTB, a score with clinical, radiological and analytical parameters can be used as a supplemental tool to assist clinical decisions in isolation period.
It is known that the immunoregulatory networks in human Chagas disease play a key role in parasitemia control during the acute phase. However, little is known regarding the control of parasitemia ...during the chronic phase. The aim of the study was to describe the serum cytokine profile of
chronically infected patients and to evaluate its relationship with the presence or absence of parasitemia in peripheral blood. This is a prospective observational study where adult Chagas disease patients were included. Patients previously treated for Chagas disease, pregnant women, and immunosuppressed patients were excluded. Demographic and clinical information was collected, and
real-time polymerase chain reaction (RT-PCR) and serum cytokine profile were determined in peripheral blood. Forty-five patients were included.
RT-PCR in peripheral blood resulted positive in 19 (42.2%) patients. No differences in the serum cytokine profile were found depending on cardiac or digestive involvement. However, patients with positive
RT-PCR had a higher median concentration of IL-10 and IL-1beta and a lower median concentration of IL-8 than those with negative
PCR. These results reinforce the key role that this anti-inflammatory cytokine (IL-10) plays in parasitemia control.
The increasing shortage of organs for transplantation has prompted transplant programs to investigate the use of extended criteria donors, such as those with transmissible infectious diseases. ...Successful cases of organ transplantation (mostly kidney and liver) from
seropositive donors to seronegative recipients have been reported. We present a case of lung transplantation from a donor serologically positive for Chagas disease to a seronegative recipient, and provide a review of the literature. Left single lung transplantation was performed in a 44-year-old Spanish woman presenting with interstitial lung disease in February 2016. The deceased donor was a Colombian immigrant living in Spain who was serologically positive for Chagas disease. Oral administration of 5 mg/kg/day benznidazole divided in three doses for 60 days was given for specific Chagas disease prophylaxis after transplantation. Periodic follow-up with serological reverse transcription polymerase chain reaction to detect
DNA were performed until 6 months after the end of treatment. All results were negative, indicating that transmission of
had not occurred. In a review of the literature, two similar cases were identified in Argentina and the United States. In both cases
infection was detected posttransplant in the recipients, after which they were treated with benznidazole. The course of the patient described herein confirms that lungs from donors with chronic
infection can be used successfully as allografts, and that posttransplant prophylaxis with benznidazole may reduce the probability of transmission of
to the recipient.
Strongyloides stercoralis infection in patients with HTLV-I infection may lead to severe clinical manifestations. The aim of the present study is to determine the seroprevalence of S. stercoralis ...infection among blood donors who tested positive for HTLV-I infection. A cross-sectional study was performed at the Vall d’Hebron University Hospital (Barcelona, Spain) in 2016. Serum samples from HTLV-I positive patients diagnosed from 2008 to 2015 were retrieved from the Blood Bank, and S. stercoralis serology was performed. Thirty six serum samples from HTLV-I positive patients were retrieved from the Blood Bank. The blood samples came from 36 blood donors, and most of them were born in Latin America (75%), being Peru the most frequent country (11 participants). S. stercoralis serology was positive in one patient, corresponding to a prevalence of 2.8% (3.4% if we exclude donors coming from European countries, where the risk of S. stercoralis infection is highly unlikely).
ObjectiveThis study aims to analyse the possible recovery or worsening in retinal microvasculature after 8 months in a previously studied COVID-19 cohort.Methods and analysisA cross-sectional ...case–control study and a prospective longitudinal cohort study. Participants were the subjects of our previous study who re-enrolled for a new examination including a fundus photograph (retinography), an optical coherence tomography (OCT) scan and an OCT angiography. COVID-19 diagnosed patients were divided into three groups: group 1: mild disease, asymptomatic/paucisymptomatic subjects who received outpatient care; group 2: moderate disease and group 3: severe disease, both of which required hospital admission because of pneumonia. Statistical analyses were performed using SPSS software (V.23.0). Cross-sectional intergroup differences were analysed by means of analysis of variance for normally distributed variables and the Kruskal-Wallis test for non-normally distributed ones. In reference to the prospective part of the study (intragroup differences, baseline with 8-month comparison), a paired t-test was used for normally distributed data and Wilcoxon signed ranks sum for non-normally distributed data.ResultsThe fovea-centered superficial and deep vascular densities were significantly diminished in severe cases compared with mild cases (p=0.004; p=0.003, respectively, for superficial and deep) and to controls (p=0.014; p=0.010), also in moderate cases to mild group (p=0.004; p=0.003) and to controls (p=0.012; p=0.024). In the longitudinal study, no significant statistical differences were found between baseline and 8-month follow-up vessel density values.ConclusionWe demonstrated persistent reduction in the central vascular area over time in patients with moderate and severe COVID-19.
is an intestinal protozoan, usually considered nonpathogenic. However, in the last years, there has been an attempt to clarify its possible pathogenic role. We aim to evaluate the clinical and ...epidemiological characteristics of
-infected patients. Adults with
detection in feces who attended the Vall d'Hebron University Hospital (Barcelona, Spain) were evaluated retrospectively from April 2009 to March 2014. We classified the patients in asymptomatic, symptomatic without other causes except infection of
, and symptomatic with another cause. Among symptomatic patients, treatment response was evaluated. One hundred eight patients were included. Sixty-three percent of the patients were immigrants, 29.6% were autochthonous, and 7.4% were travelers. Forty-nine (45.3%) patients presented symptoms, and eosinophilia was observed in 26 (24.1%) patients. Overall, 59 (54.7%) patients were asymptomatic, 15 (13.8%) presented symptoms which were attributable to other causes, and 34 (31.5%) patients presented symptoms with no other causes. In this last group, 29 patients received specific treatment and 65.5% of them presented a complete resolution of the symptoms. The group of symptomatic patients with no other cause had more proportion of women, more proportion of autochthonous people, and were older compared with the group of asymptomatic patients.
infection should be considered as pathogenic when other causes are ruled out.
Chagas disease is a protozoan infection caused by Trypanosoma cruzi. The disease has a chronic course in which 20-30% of the patients would develop progressive damage to the cardiovascular system and ...the gastrointestinal tube. We are still unable to predict who will develop end-organ damage but there are some acquired and genetic risk factors already known.
We reviewed data from 833 patients with serologically confirmed Chagas disease in this retrospective study. Patients were classified as siblings or non-siblings (controls) and the results of pre-treatment blood PCR assay, end-organ damage (cardiac and/or gastrointestinal), and the presence of delayed type hypersensitivity (DTH) skin involvement in patients treated with benznidazole were analyzed. Siblings were grouped by family and we randomly generated groups of 2 or 3 persons with the remaining controls. We classified the results of each variable as concordant or discordant and compared the concordance in these results among the sibling groups with that among control groups. We identified 71 groups of siblings and randomly generated 299 groups of non-related patients. Pre-treatment blood PCR concordance was significantly higher (19%) among siblings compared to controls (P = 0.02), probably due to a higher frequency in pre-treatment positive results. No other statistically significant differences were found.
A significant difference was found in the concordance of pre-treatment blood PCR for T. cruzi among siblings compared to non-related controls.
Background
Chagas disease is a public health problem not only in Latin America, but also in other regions, including Spain, due to migration movements. Conventional serological diagnosis requires an ...invasive sample (plasma or serum) and a well-equipped laboratory. To circumvent those limitations, blood samples dried on filter paper (DBS) or Rapid Diagnostic Test (RDT) could be a practical alternative to reference protocol for serological screening in epidemiological studies. We evaluated the usefulness of dried blood sampling and a rapid diagnostic test (Trypanosoma Detect™) for the detection of antibodies against
T. cruzi
for their use in community-based screening.
Methodology/Principal Findings
A total of 162 stored paired whole-blood and serum samples from Latin American migrants and 25 negative-control blood samples were included. Diagnosis of chronic Chagas disease was performed in serum according to WHO algorithms. Blood samples were retrospectively collected as dried spots and then analyzed using two different serological techniques, enzyme-linked immunosorbent assay (ELISA) and electrochemiluminescence immunoassay (E-CLIA). Whole-blood samples were also used to evaluate a rapid diagnostic test based on immunochromatography. A better correlation with conventional serum was observed in dried blood elutes using E-CLIA than ELISA (97% vs. 77% sensitivity, respectively). Both assays reported 100% specificity. The median cut-off index values of E-CLIA for dried blood were significantly lower than those for serum (138.1 vs. 243.3,
P
<0.05). The Trypanosoma Detect™ test presented a sensitivity and specificity of 89.6% and 100%, respectively.
Conclusions
The detection of antibodies against
T. cruzi
in dried blood samples shows a higher sensitivity when using E-CLIA compared with ELISA. Trypanosoma Detect™ is easier to use but has a lower sensitivity. Hence, we propose a sequential strategy based on performing the rapid test first, and a negative result will be confirmed by DBS-ECLIA for use in community Chagas disease screening programs.
Reactivation of latent imported infections has been periodically reported in migrant patients undergoing immunosuppression. We performed a prospective study at Vall d'Hebron University Hospital ...(Barcelona, Spain). Migrant patients over 16 years with the diagnosis of any oncohematologic disease were included. Patients were tested for soil-transmitted helminths, hepatitis virus, and human immunodeficiency virus, Treponema pallidum, human T-cell lymphotropic virus, latent tuberculosis infection, Toxoplasma spp., Plasmodium infection, Schistosoma spp., Trypanosoma cruzi infection, Leishmania spp., and dimorphic fungi. Patients were treated and followed for 1 year to assess reactivation. A total of 42 patients were included in this study. Median age was 39 (31-51) years. Twenty-five (59.5%) patients were women. More than half of the patients were of Latin American origin. Sixteen patients (38.1%) underwent hematopoietic stem cell transplantation. Of the patients, 71.4% had at least one imported infection. Patients with at least one positive result in the screening did not show any statistically significant association with the studied variables. We did not find any reactivation of the treated latent infections. After specific treatment we did not observe any reactivation. Screening of latent imported infections previous to an immunosuppressive treatment is easy to perform and it may be lifesaving.
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