Filter Paper Samples Research Articles

Clinical Significance of Combined Detection of CCL22 and IL-1 as Potential New Bronchial Inflammatory Mediators in Children's Asthma.

Severe asthma is a significant health burden because children with severe asthma are vulnerable to medication-related side effects, life-threatening deterioration, and impaired quality of life. However, there is a lack of data to elucidate the role of inflammatory variables in asthma. This study aimed to compare the levels of inflammatory factors in serum and sputum in children with acute and stable asthma to those in healthy children and the ability to predict clinical response to azithromycin therapy. This study recruited 95 individuals aged 1-3 years old and collected data from January 2018 to 2020. We examined serum and sputum inflammatory factors and constructed the least absolute shrinkage and selection operator (LASSO) model. Predictive models were constructed through multifactor logistic regression and presented in the form of column-line plots. The performance of the column-line diagrams was measured by subject work characteristics (ROC) curves, calibration plots, and decision curve analysis (DCA). Then, filter-paper samples were collected from 45 children with acute asthma who were randomly assigned to receive either azithromycin (10 mg/kg, n = 22) or placebo (n = 23). Pretreatment levels of immune mediators were then analyzed and compared with clinical response to azithromycin therapy. Of the 95 eligible participants, 21 (22.11%) were healthy controls, 29 (30.53%) had stable asthma, and 45 (47.37%) had acute asthma. The levels of interferon-γ (IFN-γ), tumor necrosis factor-a (TNF-α), chemokine CCL22 (CCL22), interleukin 12 (IL-12), chemokine CCL4 (CCL4), chemokine CCL2 (CCL2), and chemokine CCL13 (CCL13）were significantly higher in the acute asthma group than in the stable asthma group. A logistic regression analysis was performed using CCL22 and IL-1 as independent variables. Additionally, IFN-γ, TNF-α, IL-1, IL-13, and CCL22 were identified in the LASSO model. Finally, we found that CCL22 and IL-1 were more responsive in predicting the response to azithromycin treatment. Our results show that CCL22 and IL-1 are both representative markers during asthma symptom exacerbations and an immune mediator that can predict response to azithromycin therapy.

An Investigation into Diatomaceous Earth Stones: A New Tool in Paper Conservation

ABSTRACT This research explores the viability of using diatomaceous earth stone mats, a commercially manufactured, rigid, absorbent board marketed for home use (aka DE stones) as a sustainable tool in paper conservation. Analytical studies, including X-ray fluorescence, Fourier-transform infrared spectroscopy, gravimetry, colorimetry, accelerated aging, pH, solvent reactivity, and absorbency testing, were conducted at the National Archives and Records Administration on the DE stones and on Whatman® filter paper samples. The experiments with samples dried in direct contact with DE stones showed no undesirable transfer to the filter paper. Gravimetric analysis showed the drying rate of samples placed between DE stones was much more rapid than for samples placed between blotter or wool felt. Colorimetry before and after accelerated aging of samples dried in direct contact with DE stones showed no undesirable aging patterns. Successful case studies illustrate high potential for the use of DE stones in paper conservation treatments.

Evaluating the utility of harvester-collected samples for muskox (Ovibos moschatus) pregnancy diagnostics

Monitoring wildlife health in remote and vast regions of the Arctic can be difficult and expensive, but community-based monitoring programs can help alleviate these issues. Reliable bio-monitoring tools, compatible with sample types collected from remote regions, are needed to determine indicators of population health, such as reproductive rates. We sought to establish methods to diagnose pregnancy in muskoxen (Ovibos moschatus) using samples that are commonly collected in harvester-based sampling programs: blood on filter paper and feces. We first evaluated three pregnancy tests, pregnancy-associated glycoproteins (PAG) on filter paper blood samples and fecal progesterone and estrogen metabolites (FPM and FEM), using 12 captive female muskoxen of known pregnancy status. Pregnancy diagnostics using PAG were highly sensitive (100 %) and specific (100 %), with a diagnostic threshold of 19.4 percent positivity (%P) relative to the positive control of the test kit. FPM and FEM diagnostic accuracy differed by hormone and time period. FPM was most accurate in mid-gestation and FEM most accurate in late gestation (sensitivities and specificities of 100 %), but both were overall less accurate than the PAG test during gestation. PAG %P followed a biphasic pattern during gestation, FPM peaked in mid-gestation, and FEM peaked in late-gestation. Following the captive trial, we applied these tests to fecal samples and blood on filter paper samples from 159 adult female muskoxen that were submitted by harvesters through community-based monitoring programs in the Canadian Arctic. The observed patterns of PAG, FPM, and FEM in wild muskoxen throughout gestation were similar to captive muskoxen, though with lower levels of the respective biomarker, requiring different diagnostic thresholds for each test. This work with captive and wild muskoxen provides guidelines for pregnancy diagnostics in muskoxen throughout gestation using samples that can be easily collected by harvesters, allowing for improved monitoring of difficult to access populations through community-based approaches.

Overcoming the limitations of wildlife disease monitoring

Abstract Integrated wildlife monitoring (IWM) combines infection dynamics and the ecology of wildlife populations, including aspects defining the host community network. Developing and implementing IWM is a worldwide priority that faces major constraints and biases that should be considered and addressed when implementing these systems. We identify eleven main limitations in the establishment of IWM, which could be summarized into funding constraints and lack of harmonization and information exchange. The solutions proposed to overcome these limitations and biases comprise: (i) selecting indicator host species through network analysis, (ii) identifying key pathogens to investigate and monitor, potentially including nonspecific health markers, (iii) improve and standardize harmonized methodologies that can be applied worldwide as well as communication among stakeholders across and within countries, and (iv) the integration of new noninvasive technologies (e.g., camera trapping (CT) and environmental nucleic acid detection) and new tools that are under ongoing research (e.g., artificial intelligence to speed-up CT analyses, microfluidic polymerase chain reaction to overcome sample volume constraints, or filter paper samples to facilitate sample transport). Achieving and optimizing IWM is a must that allows identifying the drivers of epidemics and predicting trends and changes in disease and population dynamics before a pathogen crosses the interspecific barriers.

Hydrogels – a desirable alternative to water paper restoring procedures: impacting paper properties

Water immersion is a common practice for treating paper media. However, this treatment could irreversibly damage paper and the information written on it – such procedures are advised if the documents do not contain water-resistant components such as inks or paints and the form is mechanically stable. Thus, polymeric materials are an attractive alternative to water immersion cleaning. Various polymers are used to produce hydrogels, but there is not much information on cleaning effects before and after aging. Due to their highly rigid properties, Kelcogel, TopVision Agarose and PhytagelTM hydrogels could be applied to clean fragile paper media instead of water immersion. The hydrogel could safely clean without any residue or change of paper properties. Selected polymers were analysed for composition, water discharge and acidity according to the corresponding requirements for restoration processes: to establish changes in chemical and physical paper properties after hydrogel cleaning, filter paper samples were analysed with SEM, TGA, FTIR and pH-meter and compared to the benchmarks of filter paper cleaned with distilled water.

ATR-FTIR analysis of filter paper with mass addition of seaweed Ulva Rigida C. Agardh

This paper presents the results obtained from the analysis of some filter paper samples using Fourier Transform Infrared Spectroscopy (FTIR) technique. Based on the FTIR capabilities, using the infrared light to scan the samples and identify their chemical properties, organic, polymeric and inorganic materials can be characterized. The samples analysed were six filter papers with different mass additions of Ulva Rigida C. Agardh seaweed collected from the Black Sea, in Constanta area, SE Romania. The additions used consisted of 0.5%, 1%, 2%, 4% and 8% seaweed material, grounded to a certain grain size.

Termicidal Activity and Chemical Components of Wood Vinegar from Nipah Fruit against Coptotermes curvignathus

The termicidal activity and chemical components of wood vinegar from two sources of biomass, nipah fruit shells (NFS) and a mixture of shells and fiber (MSF), were evaluated against Coptotermes curvignathus. A no-choice test was carried out to evaluate their termicidal activity using filter paper samples treated with 2.5%, 5.0%, 7.5%, 10.0%, and 12.5% NFS or MSF vinegar. Both wood vinegars exhibited antitermitic activity against C. curvignathus. The results show that increased concentrations of NFS and MSF vinegar significantly increased termite mortality. In particular, the NFS vinegar caused complete mortality and the lowest filter paper mass losses at 2.18% when treated with 12.5% wood vinegar. The most abundant chemical compounds of NFS vinegar were cyclopropanecarbonyl chloride, 2,5-dichlorophenol, 2-propanone, acetic acid, propanoic acid, benzenesulfonic acid, 3,7-dimethyl-6-octenal, and trans-geraniol. Meanwhile, the main compounds in the MSF vinegar were 1,2-ethanediol, formic acid, acetic acid, ethanoic acid, 2-furancarboxaldehyde, phenol, 2-methoxy phenol, and 4-methyl phenol.

Utilizing blood filter paper and ear punch samples for the detection of rabbit hemorrhagic disease virus 2 by RT-rtPCR.

Rabbit hemorrhagic disease virus 2 (RHDV2), a virulent and contagious viral pathogen that affects wild and domestic lagomorph populations, was identified in Wyoming, USA in December 2020. A surveillance program was developed involving full-carcass submission and liver analysis, although carcass quality as a result of predation and decomposition impeded analysis. To increase the number of submissions and provide flexibility to field staff, we evaluated 2 sample types: 77 dried blood on filter paper samples, 66 ear punch samples. At initial sampling, test specificity and sensitivity of the RT-rtPCR utilizing dried blood on filter paper and ear punch samples were both 100% compared to liver. Filter paper results were consistent over time; sensitivity stayed >96% through weeks 2, 4, and 6, with a maximum mean difference of 6.0 Ct from baseline liver Ct values (95% CI: 5.0-7.3) at 6 wk. Test sensitivity of the ear punch sample at 1, 3, 5, and 7 wk post-sampling remained at 100%, with a maximum mean difference of 5.6 Ct from baseline liver Ct values (95% CI: 4.3-6.9) at 5 wk. Filter paper and ear punch samples were suitable alternatives to liver for RHDV2 surveillance in wild lagomorph populations. Alternative sampling options provide more flexibility to surveillance programs, increase testable submissions, and decrease exposure of field personnel to zoonotic disease agents.

Methylmalonic acid analysis using urine filter paper samples to screen for metabolic vitamin B12 deficiency in older adults.

Aim: Methylmalonic acid (MMA) analysis in urine represents a noninvasive approach to screening for vitamin B12 deficiency in older adults. A method allowing the analysis of MMA/creatinine in fasting urine collected on filter paper was developed/validated. Method: Dry urine specimens were eluted using a solution containing internal standards, filtrated and analyzed by ultra-performance LC-MS/MS. Results: The method allowed the chromatographic separation of MMA from succinic acid. Dried urine samples were stable for 86days at room temperature. The MMA/creatinine ratios measured in urine collected on filter paper were highly correlated with values derived from the corresponding liquid specimens. Conclusion: This robust filter paper method might greatly improve the accessibility and cost-effectiveness of vitamin B12 deficiency screening in older adults.

Detection of Antibodies Against Toxoplasma gondii in Filter Paper-Dried Blood Dot Spots Compared with Serum in Pigs and Assessment of Variation Associated with Packed Cell Volume.

The aim of this study was to assess the agreement between anti-Toxoplasma gondii IgG antibody detection in serum and filter paper (FP) blood spots using the indirect immunofluorescence antibody assay (IFA) and to evaluate the potential impact of the packed cell volume (PCV) on antibody detection in FPs. A pair of a serum and an FP sample was collected from 96 sows at various farms in Greece, with previously identified high seropositivity and/or risk factors associated with high seropositivity against T. gondii. The PCV value was determined using the microhematocrit method. IFA was used for the detection of antibodies against T. gondii. T. gondii-specific antibodies were detected in 45.8% serum samples and 41.6% FP samples showing almost perfect agreement. Detection in FP samples presented high sensitivity (87.1-92.8%) and excellent specificity (100%) when compared with detection in serum, regardless of the PCV values. The findings of this study support the reliability of FPs for the evaluation of the serological status of swine against T. gondii. FPs could be a good alternative sample type compared with serum for large-scale epidemiological studies.

Molecular profiling of the artemisinin resistance Kelch 13 gene in Plasmodium falciparum from Nigeria.

Accurate assessment and monitoring of the Plasmodium falciparum Kelch 13 (pfk13) gene associated with artemisinin resistance is critical to understand the emergence and spread of drug-resistant parasites in malaria-endemic regions. In this study, we evaluated the genomic profile of the pfk13 gene associated with artemisinin resistance in P. falciparum in Nigerian children by targeted sequencing of the pfk13 gene. Genomic DNA was extracted from 332 dried blood (DBS) spot filter paper samples from three Nigerian States. The pfk13 gene was amplified by nested polymerase chain reaction (PCR), and amplicons were sequenced to detect known and novel polymorphisms across the gene. Consensus sequences of samples were mapped to the reference gene sequence obtained from the National Center for Biotechnology Information (NCBI). Out of the 13 single nucleotide polymorphisms (SNPs) detected in the pfk13 gene, five (F451L, N664I, V487E, V692G and Q661H) have not been reported in other endemic countries to the best of our knowledge. Three of these SNPs (V692G, N664I and Q661H) and a non-novel SNP, C469C, were consistent with late parasitological failure (LPF) in two States (Enugu and Plateau States). There was no validated mutation associated with artemisinin resistance in this study. However, a correlation of our study with in vivo and in vitro phenotypes is needed to establish the functional role of detected mutations as markers of artemisinin resistance in Nigeria. This baseline information will be essential in tracking and monitoring P. falciparum resistance to artemisinin in Nigeria.

Valorification of Ulva rigida Algae in Pulp and Paper Industry for Improved Paper Characteristics and Wastewater Heavy Metal Filtration

This paper presents preliminary results on the possibility of incorporating stranded macroalgae into the papermaking process; analyses of the physical-mechanical properties of filter paper, with the addition of stranded macrophytic marine algae from Ulva rigida species obtained previously; results of SEM–EDX analyses of filter paper samples; and results obtained from the filtration of a wastewater from the metallurgical industry, using the improved filter paper samples. In the filter paper recipe, stranded macrophytic seaweed of the species Ulva rigida was added at different percentages of 0.5%, 1%, 2%, 4% and 8%, and the addition was calculated in relation to the absolute dry material. The physicomechanical properties analyzed are grammage, thickness, density, moisture, ash content, breaking load, breaking length, tear resistance, bursting resistance, folding endurance, porosity, smoothness, water absorption and Cobb60 index. Additional information related to the homogeneity of the distribution of elements in the paper mass was obtained by scanning electron microscopy with energy-dispersive X-ray analysis (SEM–EDX). The addition of macroalgae to the paper mass improved the strength characteristics of the paper, such as breaking load, breaking length, tearing resistance, folding endurance and water absorption. Following industrial wastewater filtration using filter paper with added seaweed, positive results were obtained in terms of reduction of total Cr, Cu, total Fe and Zn concentrations.

High prevalence of Plasmodium malariae and Plasmodium ovale in co-infections with Plasmodium falciparum in asymptomatic malaria parasite carriers in southwestern Nigeria

Asymptomatic malaria parasite carriers do not seek anti-malarial treatment and may constitute a silent infectious reservoir. In order to assess the level of asymptomatic and symptomatic carriage amongst adolescents in a highly endemic area, and to identify the risk factors associated with such carriage, we conducted a cross-sectional survey of 1032 adolescents (ages 10–19 years) from eight schools located in Ibadan, southwestern Nigeria in 2016. Blood films and blood spot filter paper samples were prepared for microscopy and DNA analysis. The prevalence of asymptomatic malaria was determined using microscopy, rapid diagnostic tests and PCR for 658 randomly selected samples. Of these, we found that 80% of asymptomatic schoolchildren were positive for malaria parasites by PCR, compared with 47% and 9%, determined by rapid diagnostic tests and microscopy, respectively. Malaria parasite species typing was performed using PCR targeting the mitochondrial CoxIII gene, and revealed high rates of carriage of Plasmodium malariae (53%) and Plasmodium ovale (24%). Most asymptomatic infections were co-infections of two or more species (62%), with Plasmodium falciparum + P. malariae the most common (35%), followed by P. falciparum + P. malariae + P. ovale (21%) and P. falciparum + P. ovale (6%). Single infections of P. falciparum, P. malariae and P. ovale accounted for 24%, 10% and 4% of all asymptomatic infections, respectively. To compare the species composition of asymptomatic and symptomatic infections, further sample collection was carried out in 2017 at one of the previously sampled schools, and at a nearby hospital. Whilst the species composition of the asymptomatic infections was similar to that observed in 2016, the symptomatic infections were markedly different, with single infections of P. falciparum observed in 91% of patients, P. falciparum + P. malariae in 5% and P. falciparum + P. ovale in 4%.

PREPARATION OF ANTIMICROBIAL PAPER BY MICROWAVE-ASSISTED TWO-POT IN-SITU DEPOSITION OF ZINC OXIDE ON FILTER PAPER

We employed a microwave-assisted two-pot in-situ deposition technique to incorporate zinc oxide particulates in the structure of filter paper to produce antimicrobial paper. The process involved successive immersion of filter paper samples in ZnSO4 (precursor solution) and NaOH (precipitating agent) to form Zn(OH)2, which transformed into ZnO during microwave treatment. Successful deposition of ZnO particles on the filter paper was confirmed via X-ray diffraction and the corresponding morphologies were observed using field emission scanning electron microscopy. The ZnO-deposited papers were tested for antimicrobial activity and were found to be more effective against Staphylococcus aureus (gram-positive) than Escherichia coli (gram-negative). Bacterial populations were reduced by up to 92 ± 2% and 57 ± 4% for S. aureus and E. coli, respectively. Also, it was found that the samples prepared using higher concentrations of ZnSO4 and NaOH exhibited better antimicrobial properties.

Diagnostic performance of a Recombinant Polymerase Amplification Test-Lateral Flow (RPA-LF) for cutaneous leishmaniasis in an endemic setting of Colombia.

Control of cutaneous leishmaniasis by public health systems in the Americas relies on case identification and treatment. Point-of-care diagnostics that can be performed by health workers within or near affected communities could effectively bring the health system to the resource-limited sites providing early diagnosis and treatment, reducing morbidity and the burden of disease. A cross-sectional study was undertaken to evaluate the diagnostic test performance of Isothermal Recombinase Polymerase Amplification (RPA) targeting Leishmania kinetoplast DNA, coupled with a lateral flow (LF) immunochromatographic strip, in a field setting and a laboratory reference center. Minimally invasive swab and FTA filter paper samples were obtained by community health workers and highly trained technicians from ulcerated lesions of > 2 weeks' evolution from 118 patients' ≥ 2 years of age in the municipality of Tumaco, Nariño. Extracted DNA was processed by RPA-LF at a reference center or in a primary health facility in the field. Evaluation was based on a composite "gold standard" that included microscopy, culture, biopsy and real-time polymerase chain reaction detection of Leishmania 18S rDNA. Standard of care routine diagnostic tests were explored as comparators. Sensitivity and specificity of RPA-LF in the reference lab scenario were 87% (95%CI 74-94) and 86% (95%CI 74-97), respectively. In the field scenario, the sensitivity was 75% (95%CI 65-84) and specificity 89% (95%CI 78-99). Positive likelihood ratios in both scenarios were higher than 6 while negative likelihood ratios ranged to 0.2-0.3 supporting the usefulness of RPA-LF to rule-in and potentially to rule-out infection. The low complexity requirements of RPA-LF combined with non-invasive sampling support the feasibility of its utilization by community health workers with the goal of strengthening the diagnostic capacity for cutaneous leishmaniasis in Colombia. ClinicalTrials.gov NCT04500873.

Polymorphisms in Plasmodium falciparum dihydropteroate synthetase and dihydrofolate reductase genes in Nigerian children with uncomplicated malaria using high-resolution melting technique

In 2005, the Nigerian Federal Ministry of Health revised the treatment policy for uncomplicated malaria with the introduction of artemisinin-based combination therapies (ACTs). This policy change discouraged the use of Sulphadoxine-pyrimethamine (SP) as the second-line treatment of uncomplicated falciparum malaria. However, SP is used as an intermittent preventive treatment of malaria in pregnancy (IPTp) and seasonal malaria chemoprevention (SMC) in children aged 3–59 months. There have been increasing reports of SP resistance especially in the non-pregnant population in Nigeria, thus, the need to continually monitor the efficacy of SP as IPTp and SMC by estimating polymorphisms in dihydropteroate synthetase (dhps) and dihydrofolate reductase (dhfr) genes associated with SP resistance. The high resolution-melting (HRM) assay was used to investigate polymorphisms in codons 51, 59, 108 and 164 of the dhfr gene and codons 437, 540, 581 and 613 of the dhps gene. DNA was extracted from 271 dried bloodspot filter paper samples obtained from children (< 5 years old) with uncomplicated malaria. The dhfr triple mutant I51R59N108, dhps double mutant G437G581 and quadruple dhfr I51R59N108 + dhps G437 mutant haplotypes were observed in 80.8%, 13.7% and 52.8% parasites, respectively. Although the quintuple dhfr I51R59N108 + dhps G437E540 and sextuple dhfr I51R59N108 + dhps G437E540G581 mutant haplotypes linked with in-vivo and in-vitro SP resistance were not detected, constant surveillance of these haplotypes should be done in the country to detect any change in prevalence.

Water Repellency of Cellulosic Fibrous Mats Impregnated with Organic Solutions Based on Recycled Polystyrene

Recycled polystyrene in combination with paraffin wax, alkyd resin, and gum rosin were used as components in formulations to investigate their water repellency when applied to cellulosic filter paper substrates. Polystyrene was used in concentration of 5, 10, 15 and 20%, alkyd resin and gum rosin of 5% each and paraffin wax of 0.5%. Totally, twenty four water repellent solutions were prepared. Water repellency was evaluated in terms of water absorption of the cellulosic fibrous mats. The relations between retention of solid substances of the formulations and grammage and water absorption of filter paper samples were also determined. The results showed that all the water repellent formulations exhibited a degree of water repellency. Water absorption decreased by increasing the polystyrene concentration in the solution and polystyrene retention by the impregnated filter paper samples. The incorporation of 0.5% paraffin wax improved the hydrophobicity of treated samples. The best of the three water repellent formulations including paraffin wax was found to be the “polystyrene + gum rosin + paraffin wax” solution followed by the “polystyrene + alkyd resin + paraffin wax” and “polystyrene + paraffin wax” solution. The inclusion of 5% gum rosin in polystyrene solutions compared to that of 0.5% paraffin wax was found more effective in almost all cases.

Long-term follow-up with filter paper samples in patients with propionic acidemia.

BackgroundPropionic acidemia (PA) is an inherited disorder caused by deficiency of propionyl CoA carboxylase. Most patients with this disorder are diagnosed during the neonatal period because of severe metabolic acidosis and hyperammonemia. Patients are required to undergo blood and urine analysis at least 3 to 4 times per year, depending on age and metabolic control.MethodsWe designed a prospective study in which we investigated the results from blood and urinary samples collected monthly in filter paper from 10 PA patients followed in a single metabolic reference center from January 2015 to September 2017. The aim of this study was to evaluate the usefulness of filter paper samples in the follow‐up of the PA patients.ResultsDuring the follow‐up period, 163 dried blood spot (DBS) and 119 urine dried spot samples were analyzed and compared with 160 plasma and 103 liquid urine specimens; 64 specimens of plasma were analyzed for odd‐numbered long‐chain fatty acids (OLCFAs). A total of 40 metabolic crises, 18 of them with hyperammonemia were documented. We observed a strong correlation between the filter paper and the urine/plasma samples for the main PA parameters both in stable metabolic conditions as well as in acute decompensations. Also, there was a strong correlation between OLCFAs measured in plasma and quantification of odd number acylcarnitines in DBS.ConclusionsWe conclude that filter paper blood and urinary samples can be used for the follow‐up of the patients with PA, correctly reflecting their metabolic situation.

Trypanosoma cruzi loop-mediated isothermal amplification (Trypanosoma cruzi Loopamp) kit for detection of congenital, acute and Chagas disease reactivation.

A Trypanosoma cruzi Loopamp kit was recently developed as a ready-to-use diagnostic method requiring minimal laboratory facilities. We evaluated its diagnostic accuracy for detection of acute Chagas disease (CD) in different epidemiological and clinical scenarios. In this retrospective study, a convenience series of clinical samples (venous blood treated with EDTA or different stabilizer agents, heel-prick blood in filter paper or cerebrospinal fluid samples (CSF)) from 30 infants born to seropositive mothers (13 with congenital CD and 17 noninfected), four recipients of organs from CD donors, six orally–infected cases after consumption of contaminated guava juice and six CD patients coinfected with HIV at risk of CD reactivation (N = 46 patients, 46 blood samples and 1 CSF sample) were tested by T. cruzi Loopamp kit (Tc LAMP) and standardized quantitative real-time PCR (qPCR). T. cruzi Loopamp accuracy was estimated using the case definition in the different groups as a reference. Cohen’s kappa coefficient (κ) was applied to measure the agreement between Tc LAMP (index test) and qPCR (reference test). Sensitivity and specificity of T. cruzi Loopamp kit in blood samples from the pooled clinical groups was 93% (95% CI: 77–99) and 100% (95% CI: 80–100) respectively. The agreement between Tc LAMP and qPCR was almost perfect (κ = 0.92, 95% CI: 0.62–1.00). The T. cruzi Loopamp kit was sensitive and specific for detection of T. cruzi infection. It was carried out from DNA extracted from peripheral blood samples (via frozen EDTA blood, guanidine hydrochloride-EDTA blood, DNAgard blood and dried blood spots), as well as in CSF specimens infected with TcI or TcII/V/VI parasite populations. The T. cruzi Loopamp kit appears potentially useful for rapid detection of T. cruzi infection in congenital, acute and CD reactivation due to HIV infection.

PCR performance for the diagnosis of cutaneous leishmaniasis caused by Leishmania viannia complex using biopsy samples, compared with exudate samples from skin lesions on filter paper.

Cutaneous leishmaniasis (CL) is generally diagnosed by molecular methods, including PCR, using biopsy samples, skin scrapings and clinical exudates. In this study, we assessed the PCR performance for diagnosis of CL using skin of biopsy samples vs PCR of skin lesion exudate samples on filter paper and compared the diagnostic concordance of PCR using both sampling methods. We assessed the PCR performance using 80 skin biopsy samples and 80 filter paper samples containing exudates from skin lesions obtained from 74 patients with clinical suspicion of CL in Cusco, Peru. : PCR using skin biopsy samples had superior diagnostic accuracy compared with filter paper PCR (62.5% [50/80] vs 38.7% [31/80], respectively; p˂0.005) and the diagnostic concordance between both sampling methods was 'moderate' (kappa coefficient=0.50, 95% CI 0.98 to 1.0). PCR using biopsy samples remains the standard for diagnosis of CL.