Accuracy of the urine point-of-care circulating cathodic antigen assay for diagnosing Schistosomiasis mansoni infection in Brazil: A multicenter study

ABSTRACT Background: The World Health Organization recommends a market-ready, urine-based point-of-care diagnostic test for circulating cathodic antigens (CCA) to determine the prevalence of S. mansoni. This study evaluated the performance of the URINE CCA (SCHISTO) ECO TESTE® (POC-ECO), which is currently available in Brazil. Methods: Residents from eight sites with different prevalence estimates provided one urine sample for POC-ECO and one stool sample for Kato-Katz (KK) and Helmintex® (HTX) testing as an egg-detecting reference for infection status. Results: None of the study sites had significantly higher POC-ECO accuracy than KK. Conclusions: POC-ECO is not currently recommended in Brazilian schistosomiasis elimination programs.

Multiplex loop mediated isothermal amplification (m-LAMP) as a point of care technique for diagnosis of malaria

Diagnosis of malaria is a prominent challenge due to the endemic nature of infection. Malaria poses a great threat to global public health. The disease can be diagnosed by several techniques out of which microscopy is a known gold standard. High sensitivity of molecular techniques is making them more reliable and popular as tools for diagnosis of malaria. However, new methods are required which can fulfill the criteria of being Point of Care Test (POCT) as defined by WHO. Loop-mediated isothermal amplification (LAMP) technique amplifies DNA in an isothermal condition, and surpasses the disadvantages of conventional molecular techniques such as polymerase chain reaction. Multiplex LAMP, a modification of LAMP may emerge as a new POC for malaria diagnosis. This review deals with the use of LAMP and multiplex LAMP in diagnosis of malaria and its prospective use as point of care techniques.

Evaluation of urine L-FABP Point of care kit in the Philippines as predictive marker of clinical severity of COVID-19 (EPOCH COVID study)

Background@#The search for simple clinical and laboratory markers to help predict the clinical severity of patients presenting with COVID-19 has prompted this study to look at the predictive value of urine L-FABP (Liver Type-Fatty Acid Binding Protein) point-of-care test kit at the initial presentation of COVID-19 patients to the hospital.@*Methods@#The validation study prospectively included 109 consecutive patients with mild to moderate COVID-19, mean age of 52.2 years (range 19-84) presenting at the Emergency Rooms of 4 participating Metro-Manila hospitals from February to April 2021, with available data for analysis for 103 patients. Urine L-FABP POC (Point-of-Care) test and other clinical parameters and the level of severity of COVID-19 were determined at Day 0, Day 4 and Day 7. Computations for Sensitivity, Specificity, Positive and Negative Predictive values and Likelihood ratios were performed.@*Results@#Twenty-three patients tested positive for urine L-FABP, out of the 103 patients analyzed, while 80 tested negative. Of the 23 patients who tested positive for urine L-FABP, 6 has progressed in severity, while 17 did not progressed. Of the 80 patients who tested negative for urine L-FABP, 13 progressed, while 67 did not progressed in severity. Giving a Sensitivity of 31.58%, Specificity of 79.76%, Positive predictive value of 26.09%, Negative predictive value of 83.75%. Combining urine L-FABP and initial clinical parameters like SIRS (Systemic Inflammatory Response Syndrome) criteria to predict progression of severity yielded a higher Specificity of 91.67 % and Negative Predictive value of 84.62%.@*Conclusions@#The study shows the utility of initial urine L-FABP POC test as a negative screening test in triaging adult patients presenting to the ER with mild to moderate COVID-19. Patients at the ER with a negative urine L-FABP test, will most likely not progressed to severe COVID-19. Combining clinical parameters like SIRS Criteria with the urine L-FABP result can increase the negative predictive value.

Reliability of point-of-care circulating cathodic antigen assay for diagnosing schistosomiasis mansoni in urine samples from an endemic area of Brazil after one year of storage at -20 degrees Celsius

ABSTRACT Background The World Health Organization recommends reliable point-of-care (POC) diagnostic testing to eliminate schistosomiasis. Lateral flow immunoassay that detects schistosome circulating cathodic antigen (CCA) in urine to establish prevalence thresholds for intervention in endemic areas is recommended. Stored urine may be useful if surveying at-risk populations is delayed or interrupted by unforeseen circumstances, such as the current COVID-19 pandemic. This study evaluated the manufacturer's claim that Schistosoma mansoni infection can be reliably diagnosed in urine samples stored at -20°C for one year. Methods Two-hundred-forty-two subjects from an endemic site in Brazil provided one urine sample each for testing with URINE CCA (SCHISTO) ECO TESTE® (POC-ECO) and one stool sample each for testing with Kato-Katz (KK) and Helmintex® (HTX) as a robust reference standard for infection status. At least 2 ml of urine from each participant was stored at -20°C; after one year, 76 samples were randomly selected for POC-ECO retesting. Results: The POC-ECO agreement between freshly collected and stored urine was inadequate considering trace results as positive (Cohen's kappa coefficient κ = 0.08) and negative (κ = 0.36). POC-ECO accuracy was not significantly greater than that of routine KK (54%; 95% confidence interval: 42.1%-65.5%). Conclusions The precision and accuracy of POC-ECO have to be optimized in both freshly collected and stored urine before it can be recommended for use in control programs in Brazil.

Applications of smartphone-based near-infrared (NIR) imaging, measurement, and spectroscopy technologies to point-of-care (POC) diagnostics / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The role of point-of-care (POC) diagnostics is important in public health. With the support of smartphones, POC diagnostic technologies can be greatly improved. This opportunity has arisen from not only the large number and fast spread of cell-phones across the world but also their improved imaging/diagnostic functions. As a tool, the smartphone is regarded as part of a compact, portable, and low-cost system for real-time POC, even in areas with few resources. By combining near-infrared (NIR) imaging, measurement, and spectroscopy techniques, pathogens can be detected with high sensitivity. The whole process is rapid, accurate, and low-cost, and will set the future trend for POC diagnostics. In this review, the development of smartphone-based NIR fluorescent imaging technology was described, and the quality and potential of POC applications were discussed.

Development and validation of a simple and rapid way to generate low volume of plasma to be used in point-of-care HIV virus load technologies

ABSTRACT A new point-of-care HIV viral load, mPIMA HIV-1/2 VL, Abbott, USA, has been recently developed. This point-of-care viral load requires no skilled person to run and uses a small plasma volume (50 µL). However, obtaining 50 µL of plasma can be a challenge in limited resource settings. We validated a simple and easy method to obtain enough amount of plasma to run a point-of-care viral load. The study utilized 149 specimens from patients failing antiretroviral therapy. At least 250 µL of whole blood was collected in a microtube/EDTA from fingerstick (fs-plasma) and immediately centrifuged. Parallel collection of venous blood to obtain plasma (vp-plasma) was used to compare performance in a point-of-care viral load assay and in methodology used in centralized laboratories Abbott M2000, Abbott, USA. The procedure for plasma collection takes less than 10 min and in 94% of the cases only one fingerstick was sufficient to collect at least 250 µL of blood. The Pearson correlation coefficient value for vp-plasma versus fs-plasma ran on mPIMA was 0.990. The Bland-Altman mean difference (md) for this comparison were virtually zero (md = −0.001) with limits of agreement between −0.225 and 0.223. In addition, the Pearson correlation coefficient value for fs-plasma in mPIMA versus vp-plasma in Abbott M2000 was 0.948 for values above the mPIMA limit of quantification (LoQ; from 800 to 1,000,000 copies/mL). These results validate this simple plasma isolation method capable to be implemented in low resource countries where point-of-care decentralization is deeply needed.

Schistosomiasis: an epidemiological update on Brazils southernmost low endemic area in Esteio

Abstract INTRODUCTION: Brazil's southernmost state, Rio Grande do Sul (RGS), was considered schistosomiasis-free until 1998 when a low endemic focus was identified in Esteio, a city located next to the capital of RGS. In the last two decades, the control interventions applied in the region have been apparently successful, and the absence of new cases indicated the possibility of interrupted schistosomiasis transmission. The objective of this study was to update the clinical and epidemiological data of schistosomiasis in Esteio. METHODS: We reviewed all 28 individuals diagnosed with the infection since 1997 and a survey was applied to a group of 29 school-aged children residing in Vila Pedreira, one of the most affected neighborhoods. RESULTS No eggs were detected in fecal samples using the Helmintex method, and all samples were negative for serum antibodies on examination by the western blot technique using the Schistosoma mansoni microsomal antigen (MAMA- WB). In contrast, 23 individuals (79%) tested positive for the cathodic circulating antigen with the point-of-care immunochromatographic test (POC-CCA) on urine samples. Of the 28 formerly infected individuals, only eight were located, of which four tested positive, and four tested negative for serum antibodies using the MAMA-WB technique. CONCLUSIONS: Current adverse conditions for S. mansoni transmission in Esteio and the absence of a confirmed diagnosis suggests that there is (i) a lack of specificity of the POC-CCA test in low endemic settings, and (ii) a high probability that interruption of schistosomiasis has been achieved in Esteio.

The use of the circulating cathodic antigen (CCA) urine cassette assay for the diagnosis and assessment of cure of Schistosoma mansoni infections in an endemic area of the Amazon region

Abstract INTRODUCTION Schistosomiasis is a poverty-related disease that affects people in 78 countries worldwide. This study aimed to evaluate the point-of-care circulating cathodic antigen (POC-CCA) test performance using sensitive parasitological methods as a reference standard (RS) in individuals before and after treatment. METHODS The RS was established by combining the results of 16 Kato-Katz slides and the Helmintex® method. Positivity rates of the POC-CCA test and Kato-Katz and Helmintex® methods were calculated before treatment and 30 days afterward. Furthermore, the sensitivity, specificity, accuracy, and kappa coefficient before treatment were determined by comparing the methods. The cure rate was defined 30 days after treatment. RESULTS Among the 217 participants, the RS detected a total of 63 (29.0%) positive individuals. The POC-CCA test identified 79 (36.4%) infections. The evaluation of POC-CCA test performance in relation to the RS revealed a sensitivity of 61.9%, specificity of 74.0%, accuracy of 70.5%, and kappa coefficient of 0.33. Out of the 53 remaining participants after treatment, a total of 45 (81.1%) showed egg negative results, and 8 (18.9%) were egg positive according to the RS. A total of 5 (9.4%) egg-positive and 37 (69.8%) egg-negative individuals were positive by the POC-CCA test. CONCLUSIONS Our data show that the POC-CCA test has potential as an auxiliary tool for the diagnosis of Schistosoma mansoni infection, yielding better results than 16 Kato-Katz slides from three different stool samples. However, the immunochromatographic test lacks sufficient specificity and sensitivity for verifying the cure rate after treatment.

Diagnosis of Schistosoma mansoni infections: what are the choices in Brazilian low-endemic areas?

The population of Brazil is currently characterised by many individuals harbouring low-intensity Schistosoma mansoni infections. The Kato-Katz technique is the diagnostic method recommended by the World Health Organization (WHO) to assess these infections, but this method is not sensitive enough in the context of low egg excretion. In this regard, potential alternatives are being employed to overcome the limits of the Kato-Katz technique. In the present review, we evaluated the performance of parasitological and immunological approaches adopted in Brazilian areas. Currently, the diagnostic choices involve a combination of strategies, including the utilisation of antibody methods to screen individuals and then subsequent confirmation of positive cases by intensive parasitological investigations.

A novel carbon nanoparticle probe-based ultrasensitive lateral flow assay for rapid detection of Ebola virus / 生物工程学报

Ebola virus (EBOV) is an extremely contagious pathogen first discovered in Africa associated with severe hemorrhagic disease in humans and nonhuman primates, which has resulted in at least 28 500 suspected cases and 11 300 confirmed deaths in 2014-2016 Ebola epidemic in West Africa. Rapid and sensitive detection of EBOV is the key to increasing the probability of survival and reducing infection rates in pandemic regions. Here, we report an ultrasensitive and instrument-free EBOV detection assay based on colloidal carbon immunochromatography. Carbon nanoparticle-labeled rabbit anti-EBOV-VP40 IgG were concentrated in the conjugate pad, monoclonal antibody (McAb, 4B7F9) against EBOV-VP40 and goat anti-rabbit IgG were immobilized on the nitrocellulose membrane with 2 μL/cm at a concentration of 1 mg/mL as test and control lines, respectively. Then the sample application pad, conjugate release pad, nitrocellulose membrane and absorbent pad were assembled into a lateral flow test strip. The test strip shows strong specificity against related viruses that share similar clinical symptoms and geographic range with EBOV, including marburg virus, influenza virus, yellow fever virus and dengue virus. In addition, 1 500 negative serums were tested with false-positive rate of 1.3‰ which significantly lower than that of ReEBOV™ colloidal gold test kit recommended by World Health Organization (WHO). The sensitivity of this strip was analyzed using inactivated EBOV with detection limit of 100 ng/mL (10⁶ copies/mL) which clearly higher than that of ReEBOV™ dipstick (10⁸ copies/mL). Furthermore, the strip showed excellent thermal stability characteristics in room temperature and could be as a point-of-care (POC), ultra-sensitive and specific promising candidate for EBOV serological screening in rural Africa or entry/exit ports.

Morbidity of schistosomiasis mansoni in a low endemic setting in Ouro Preto, Minas Gerais, Brazil

Abstract INTRODUCTION: Despite the advances of disease control programs, severe forms of schistosomiasis are prevalent. The prevalence of the disease in areas frequented by tourists urges for permanent prevention and control. The aim of this study was to describe the morbidity of schistosomiasis in the district of Antônio Pereira, Ouro Preto, Minas Gerais, Brazil. METHODS: The proportion of positives was defined by Kato-Katz coproscopy and urinary POC-CCA rapid test. Hepatosplenic form was diagnosed using abdominal ultrasound. RESULTS: Out of 180 participants,97 were examined by Kato-Katz, with 4 (4.1%) being positive. Thirty-four (22.1%) out of 154 were positive by POC-CCA. Five (2.8%) of 177 examined by ultrasound had hepatosplenic form. One of them had undergone splenectomy. One (0.6%)participant had myeloradiculopathy. CONCLUSIONS: Severe forms of schistosomiasis are still prevalent in low endemic areas and should be thoroughly investigated.

Sensitivity and specificity of the circulating cathodic antigen rapid urine test in the diagnosis of Schistosomiasis mansoni infection and evaluation of morbidity in a low- endemic area in Brazil

Abstract INTRODUCTION: The Kato-Katz technique is the standard diagnostic test for Schistosoma mansoni infection in rural areas. However, the utility of this method is severely limited by the day-to-day variability in host egg excretion in the stool. In high-transmission areas, the point-of-care circulating cathodic antigen (POC-CCA) urine assay has proven to be a reliable test. However, investigations of the reliability of the POC-CCA assay in low-transmission regions are under way. This study aimed to evaluate the sensitivity and specificity of the POC-CCA assay and the morbidity of schistosomiasis in a low-endemic area in Brazil. METHODS: Pains City is a low-transmission zone for schistosomiasis. A total of 300 subjects aged 7-76 years were randomly selected for the POC-CCA cassette test. For S. mansoni diagnosis, three stool samples on six slides were compared with one urine sample for each subject. The sensitivity and specificity in the absence of a gold standard were calculated using latent class analysis. Clinical examinations and abdominal ultrasounds were performed in 181 volunteers to evaluate morbidity associated with schistosomiasis. RESULTS: The sensitivity and specificity of the Kato-Katz technique were 25.6% and 94.6%, respectively. By contrast, the sensitivity and specificity of the POC-CCA assay were 68.1% and 72.8%, respectively. Hepatosplenic schistosomiasis was diagnosed in two patients (1.1%). CONCLUSIONS: Overall, the POC-CCA urine assay proved to be a useful test for diagnosing S. mansoni in a low-endemic area in Brazil. Severe clinical forms of schistosomiasis can be present even in such low-endemic areas.

Correlación entre criterios clínicos y de laboratorio de casos notificados por sospecha de hantavirosis y el resultado de la técnica de referencia / Correlation between clinical and laboratory criteria of suspected Hantavirus cases and the results of the reference diagnostic technique

Antecedentes: Actualmente en Chile, debido a la elevada sospecha clínica de enfermedad por hantavirus y el alto impacto en salud pública que esto provoca, se hace necesario reforzar al equipo de salud, los criterios de sospecha clínica y epidemiológica de hantavirosis. Objetivo: Analizar la información contenida en las notificaciones de sospecha de infección por hantavirus versus la técnica de referencia para el diagnóstico confirmatorio de casos sospechosos, ELISA IgM de captura anti-hantavirus. Material y Método: Mediante cálculo de precisión diagnóstica se analizó la correlación que existe entre la información entregada en las notificaciones versus el resultado de la confirmación mediante la técnica de referencia. Resultados: De 1.566 pacientes estudiados 3,4% (53 casos) fue confirmado para SCPH. De las notificaciones analizadas 58,6% estaban con datos incompletos. Los porcentajes de positividad de la técnica de referencia asociada a fiebre, mialgia y cefalea, fueron de 80-85%. Destaca que la presencia de inmunoblastos (> 10%), presenta: S: 25%, E: 98%, VPP: 37%, VPN: 97%. Paratrombocitopenia se obtuvo: S: 98%, E: 74%, VPP: 16%, VPN: 100%. Conclusión: Se hace necesario reiterar a nivel del sistema sanitario chileno la importancia de contar con datos completos en los formularios de notificación. La presencia de trombocitopenia e inmunoblastos (> 10%) fue altamente sensible y especifica, respectivamente, en la detección de pacientes con SCPH. Con el fin de optimizar la sospecha de infección por hantavirus, según la definición de caso sospechoso, se plantea la necesidad de desarrollar programas de capacitación para la sospecha clínica y lectura de parámetros de laboratorio, tales como presencia de inmunoblastos en el hemograma, así como incluir un algoritmo con el fin de optimizar la sospecha y el uso adecuado de los recursos sanitarios.

Background: Currently in Chile, due to the frequent clinical suspicion of Hantavirus disease and the high public health impact that this causes, it is necessary to strengthen the criteria for clinical and epidemiological suspicion in the health team. Objective: To analyze the information contained in the reports of suspected Hantavirus infection versus the confirmatory diagnosis with the reference technique, IgM capture ELISA anti-hantavirus. Material andMethods: Correlation between the information provided in notifications versus the result of confirmation was analyzed by calculating diagnostic accuracy. Results: 3.4% of 1,566 patients studied (53 cases) was confirmed as SCPH. 58.6% of the analyzed notifications was incomplete. The percentage of positivity of the reference technique associated with fever, myalgia and headache was 80-85%. The presence of immunoblasts (> 10%) showed 25% sensitivity, 98% specificity, 37% PPV, 97% NPV. Thrombocytopenia exhibited 98% sensitivity, 74% specificity, 16% PPV, 100% NPV. Conclusion: It is necessary to reinforce the importance of comprehensive data reporting at the health system level. The presence of thrombocytopenia and immunoblasts (> 10%) is highly sensitive and specific, respectively, for detecting patients with SCPH. There is a need to develop training programs in order to optimize the suspicion of Hantavirus infection and appropriate use of health resources.

Prevalence of Syphilis and associated factors in homeless people of Sao Paulo, Brazil, using a Rapid Test / Prevalência de Sífilis e fatores associados a população em situação de rua de São Paulo, Brasil, com utilização de Teste Rápido

Introduction: Homeless people are a vulnerable group to sexually transmitted diseases (STD) with high prevalence of syphilis and hepatitis. Objectives: To estimate the prevalence of syphilis infection and its association with risky behaviors for STDs in a sample of homeless people, and to assess the feasibility of the use of rapid syphilis test (RST) in this population. Methods: Cross-sectional study, in a convenience sample of homeless people assisted in social support services of São Paulo, between 2006 and 2007. A structured questionnaire was applied and RST was performed. In addition, a blood sample for syphilis detection was also collected. The sensitivity and specificity of the RST was estimated using conventional laboratory diagnosis (VDRL + TPHA) as reference. Results: 1,405 volunteers were included in the study. The prevalence rate of syphilis was 7.0%, and was associated with homosexual practices (ORadj 4.9; 95%CI 2.6 - 9.4), prior history of STD (ORadj 2.6; 95%CI 1.7 - 4.0) and with self-referred non-white race (ORadj 1.9; 95%CI 1.1 - 3.4). The sensitivity and specificity of the RST for syphilis were, respectively, 81.4 and 92.1%. Conclusion: The high prevalence of syphilis infection among homeless people shows the need for actions for its control and the utilization of RST that can be considered an efficient strategy due to its sensitivity and specificity. Public Health policymakers must strengthen actions for syphilis control, with screening tests for syphilis and early treatment, decreasing morbidity with the improvement of sexual and reproductive health of the population in general and especially the most vulnerable. .

Introdução: Pessoas em situação de rua constituem um grupo com alta vulnerabilidade às doenças sexualmente transmissíveis (DST), com altas prevalências de sífilis e hepatites. Objetivos: Descrever comportamentos, atitudes e práticas de risco para as DST, estimar a prevalência da sífilis, os fatores associados e avaliar a exequibilidade de uso do Teste Rápido (TR) para sífilis em pessoas em situação de rua. Metodologia: Estudo transversal em uma amostra não probabilística de pessoas em situação de rua assistidas em serviços de apoio social da cidade de São Paulo, entre 2006 e 2007. Foi aplicado questionário estruturado e realizado TR, além de coleta de sangue para detecção de sífilis. Estimou-se a sensibilidade e especificidade do TR utilizando como referência o diagnóstico laboratorial convencional (VDRL + TPHA). Resultados: Entre 1.405 voluntários, observou-se prevalência de sífilis de 7,0% que esteve associada à prática homossexual (ORaj 4,9; IC95% 2,6 - 9,4), ao relato de história de DST (ORaj 2,6; IC95% 1,7 - 4,0) e à raça/cor autorreferida não branca (ORaj 1,9; IC95% 1,1 - 3,4). A sensibilidade e especificidade do TR para sífilis foram, respectivamente, de 81,4 e 92,1%. Conclusão: A alta prevalência de sífilis, em pessoas em situação de rua evidencia a necessidade de ações para o seu controle e o uso do TR, devido sua sensibilidade e especificidade, pode ser levado em consideração como uma estratégia eficaz. Políticas públicas de saúde devem priorizar ações para o controle da sífilis, com estratégias de rastreamento, diagnóstico e tratamento precoces, diminuindo a morbidade e com melhoria da saúde sexual e reprodutiva da população ...

Effects of Flunarizine on Contractile Responses of Porcine Brain Arteries to Various Peripheral Vasoactive Agents

Effects of various peripheral vasoconstrictors on isolated porcine basilar and posterior communicating arteries(BA and PCA) were investingated and effected of flunarizine on the contractile responses were compared with those of a vasodilator, nitroglycerin. KCl elicited dose-dependent contractions in BA and PCA. 50mM KCl-induced contraction was not affected by nitroglycerin but dose-dependently inhibited by nimodipin and flunarizine in both rings. Epinephrine produced contractile response of BA and PCA in a dose-dependent fashion, but norepinephrine or phenylephrine did not cause obvious contraction by itself. Norepinephrine and phenylephrine elicited dose-dependent contractions in both rings treated with 10 -6M propranolol and the epinephrine-induced contractions were potentiated by pretreatment with propranolol, 5-hydroxytryptamine and histamine contracted BA and PCA in a dose-dependent manner and the contraction of PCA was more prominent than that of BA. In PCA rings, 10(-6)M 5-hydroxytryptamine and 10 -6M orepinephrine-induced contractions were not changed by nitroglycerin but inhibited by flunarizine in a dose-dependent manner. Small doses of flunarizine inhibited gradually both drug-induced contractions and large doses(3.5 x 10(-6) and 10(-6)M) steeply inhibit ed the contractions. Then the slopes of inhibitory curves in both cases were biphasic. Above results suggest that responsibility of catecholamine in porcine brain artery is more prominent in alpha-adrenoceptors than in beta-adrenoceptors, and inhibitory effect of flunarizine on brain artery results from inhibition of calcium influx through stimulated receptor-operated calcium channel(ROC) and potential-operated calcium channel(POC) .