RESUMO
Neurocysticercosis is a parasitic disease of major public health importance. Definitive diagnosis requires neuroimaging, which is typically unavailable in rural impoverished regions of endemicity. Screening immunoassays can support diagnosis in this setting by identifying individuals most likely to have severe forms of disease for referral to imaging. Urine sampling is convenient, painless, and generally well accepted. We developed a rapid point-of-care (POC) assay to detect urinary antigens and assessed concordance with a standard antigen ELISA (Ag-ELISA), both using monoclonal antibodies TsW8/TsW5. From 28,145 stored community samples with Ag-ELISA results, we selected 843 for comparison, 281 each from nonreactive (ratio <1), reactive-below-cutoff (ratio 1:3), and positive (ratio ≥3) samples. Overall agreement was 73.6%, with strong agreement observed in the nonreactive (280/281, 99.6%) and positive (255/281, 90.8%) groups. This affordable noninvasive POC test can be applied to identify individuals in the community most at risk of developing severe disease.
Assuntos
Antígenos de Helmintos , Ensaio de Imunoadsorção Enzimática , Sistemas Automatizados de Assistência Junto ao Leito , Humanos , Ensaio de Imunoadsorção Enzimática/métodos , Antígenos de Helmintos/urina , Animais , Cisticercose/diagnóstico , Cisticercose/urina , Sensibilidade e Especificidade , Neurocisticercose/diagnóstico , Neurocisticercose/urina , Taenia solium/imunologia , Feminino , Masculino , Adulto , CriançaRESUMO
BACKGROUND: The long-term effects of schistosomiasis on the glomerulus may contribute to the development of chronic kidney disease. This study aimed to investigate baseline Schistosoma mansoni-Circulating Anodic Antigen (CAA) levels and their association with kidney biomarkers related to podocyte injury and inflammation in long-term follow-up after praziquantel (PZQ) treatment. METHODS: Schistosoma infection was diagnosed by detecting CAA in urine using a quantitative assay based on lateral flow using luminescent up-converting phosphor reporter particles. A cutoff threshold of 0.1 pg/mL CAA was used to diagnose Schistosoma infection (baseline) in a low-prevalence area in Ceará, Northeast, Brazil. Two groups were included: CAA-positive and CAA-negative individuals, both of which received a single dose of PZQ at baseline. Urinary samples from 55 individuals were evaluated before (baseline) and at 1, 2, and 3 years after PZQ treatment. At all time points, kidney biomarkers were quantified in urine and adjusted for urinary creatinine levels. RESULTS: CAA-positive patients had increased baseline albuminuria and proteinuria and showed greater associations between kidney biomarkers. CAA levels correlated only with Vascular Endothelial Growth Factor (VEGF) (podocyte injury) levels. Increasing trends were observed for malondialdehyde (oxidative stress), monocyte chemoattractant protein-1 (inflammation marker), and VEGF. In the follow-up analysis, no relevant differences were observed in kidney biomarkers between the groups and different periods. CONCLUSIONS: S. mansoni-infected individuals presented subclinical signs of glomerular damage that may reflect podocyte injury. However, no causal effect on long-term renal function was observed after PZQ treatment.
Assuntos
Podócitos , Esquistossomose mansoni , Animais , Humanos , Schistosoma mansoni , Fator A de Crescimento do Endotélio Vascular/uso terapêutico , Podócitos/química , Brasil/epidemiologia , Antígenos de Helmintos/urina , Praziquantel/uso terapêutico , Inflamação/tratamento farmacológico , Prevalência , Esquistossomose mansoni/complicações , Esquistossomose mansoni/diagnóstico , Esquistossomose mansoni/tratamento farmacológicoRESUMO
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.
Assuntos
Esquistossomose mansoni , Animais , Humanos , Esquistossomose mansoni/diagnóstico , Esquistossomose mansoni/epidemiologia , Schistosoma mansoni , Brasil/epidemiologia , Sistemas Automatizados de Assistência Junto ao Leito , Sensibilidade e Especificidade , Antígenos de Helmintos/urina , Prevalência , FezesRESUMO
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.
Assuntos
COVID-19 , Esquistossomose mansoni , Animais , Antígenos de Helmintos/urina , Brasil/epidemiologia , Fezes , Humanos , Pandemias , Sistemas Automatizados de Assistência Junto ao Leito , Prevalência , Reprodutibilidade dos Testes , SARS-CoV-2 , Schistosoma mansoni , Esquistossomose mansoni/diagnóstico , Esquistossomose mansoni/epidemiologia , Sensibilidade e EspecificidadeRESUMO
Acute schistosomiasis (AS) manifests with a broad spectrum of clinical features in pediatric populations. Diagnosis may be difficult in the absence of detectable numbers of eggs. As a result, new approaches may be required to achieve an accurate diagnosis. Optimal praziquantel (PZQ) treatment regimen for young children is debatable. Also, the post-treatment response is still poorly evaluated due to the lack of reliable markers. A group of 6 children (a toddler and 5 pre-school children) and one pre-adolescent were investigated for AS clinical manifestations and followed-up for two years after treatment. Ova detection was performed by Kato-Katz (KK) and presence of Schistosoma mansoni DNA was assessed by real-time PCR (rt-PCR) in stool samples. IgG and IgE anti-Schistosoma levels and urinary antigen were detected by ELISA and point-of-care circulating cathodic antigen (POC-CCA) testing in serum and urine, respectively. AS clinical symptoms were present in 5/7 (71.4%) of the infected children, and hypereosinophilia was detected in all of them. Ova detection and serology were positive in only 3/7 (44.9%) and 4/7 (57.1%), respectively. However, real-time PCR (rt-PCR) showed the presence of Schistosoma DNA in 6/7 (85.7%) of the cases, and urinary antigen was detected in all infected children. The long-term follow-up after treatment with three doses of PZQ (80mg/kg/dose), showed high cure rates (CR) as demonstrated by the DNA-based assay as well as reduced levels of side effects. CR based on urinary antigen detection ranged from 28.6 to 100%, being the highest CR due to double testing the 2-year post-treatment samples. The results suggest that high dose and repeated treatment with PZQ might be effective for AS in young children. Also, new laboratory markers should be considered to diagnosis and monitor the drug response.
Assuntos
Anti-Helmínticos/uso terapêutico , Parasitologia , Praziquantel/uso terapêutico , Schistosoma mansoni/efeitos dos fármacos , Esquistossomose mansoni/diagnóstico , Esquistossomose mansoni/tratamento farmacológico , Adolescente , Animais , Anticorpos Anti-Helmínticos/sangue , Antígenos de Helmintos/urina , Biomarcadores/sangue , Biomarcadores/urina , Pré-Escolar , DNA de Helmintos/genética , Ensaio de Imunoadsorção Enzimática , Fezes/parasitologia , Feminino , Glicoproteínas/urina , Proteínas de Helminto/urina , Humanos , Imunoglobulina E/sangue , Imunoglobulina G/sangue , Lactente , Masculino , Contagem de Ovos de Parasitas , Testes Imediatos , Valor Preditivo dos Testes , Reação em Cadeia da Polimerase em Tempo Real , Schistosoma mansoni/genética , Schistosoma mansoni/imunologia , Esquistossomose mansoni/parasitologia , Testes Sorológicos , Resultado do TratamentoRESUMO
Subarachnoid neurocysticercosis (SANCC) is a severe and progressive brain infection with Taenia solium. We performed a pilot study of noninvasive screening for SANCC in two endemic villages in northern Peru using a urine antigen screen followed by brain magnetic resonance imaging for participants with elevated levels of antigen. Among the 978 participants screened, we identified eight individuals with SANCC, many of whom were asymptomatic. This represents a minimum prevalence of 0.8% of SANCC, a level higher than expected based on prior studies, and a positive predictive value of 62% for our novel urine screening test. Future studies should confirm whether early detection and management improve clinical outcomes.
Assuntos
Antígenos de Helmintos/urina , Neurocisticercose/diagnóstico por imagem , Espaço Subaracnóideo/imunologia , Taenia solium/imunologia , Teníase/diagnóstico por imagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Doenças Assintomáticas , Encéfalo/diagnóstico por imagem , Encéfalo/parasitologia , Criança , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neurocisticercose/epidemiologia , Neurocisticercose/parasitologia , Peru/epidemiologia , Projetos Piloto , Teníase/epidemiologia , Teníase/parasitologia , Adulto JovemRESUMO
The Kato-Katz (KK) technique is the mainstay mapping tool for the diagnosis of Schistosoma mansoni infection, despite showing poor sensitivity in cases of low-intensity infections. As an alternative, a rapid point-of-care circulating cathodic antigen diagnostic test (POC-CCA) has been commercially developed that involves a simple urine assay to detect S. mansoni, rather than a stool-based parasitological examination. Although POC-CCA has proven to be a more sensitive test than KK, it is not yet clear how to interpret discordant results between the two tests, particularly for situations in which the KK result is positive and the POC-CCA result is negative. Thus, the objective of this study was to evaluate the degree of diagnostic variability between different POC-CCA batches with respect to results obtained with KK. For this purpose, we collected urine and stool samples of school-aged children from areas of low and moderate endemicity in Brazil, and compared different POC-CCA batches results with those of KK-positive individuals. We found a statistically significant difference between the results obtained from various POC-CCA batches using the same urine samples, regardless of the degree of endemicity and the intensity of infection in positive KK samples. In addition, there was poor agreement between the KK and POC-CCA results in some batches of the rapid test, resulting in false negatives. These findings raise concerns around quality control checks of POC-CCA, especially in light of the high cost and increasing reliance on this new diagnostic method as control programs move towards a goal of elimination.
Assuntos
Antígenos de Helmintos/imunologia , Antígenos de Helmintos/urina , Sistemas Automatizados de Assistência Junto ao Leito , Schistosoma mansoni/imunologia , Schistosoma mansoni/isolamento & purificação , Esquistossomose mansoni/parasitologia , Animais , Brasil , Criança , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Masculino , Esquistossomose mansoni/imunologia , Esquistossomose mansoni/urina , Sensibilidade e EspecificidadeRESUMO
Background: Prior to eliminating schistosomiasis, efforts must address accurate and fast individual diagnosis. Diagnosis is still inaccurate by parasitological and point-of-care circulating cathodic antigen (POC-CCA) in areas of low endemicity. Methods: Our group has optimized POC-CCA with a 30 min urine concentration step with no need for specialized technicians or equipment and with high accuracy. We evaluated this new method, called POC-CCA filter (FLT), in two Brazilian endemic areas with distinct profiles. Results: At baseline, POC-CCA had a poor performance with several false results and undefined trace readings, revealing a prevalence rate of 10% against a rate of 23% for POC-CCA FLT, which was similar to the parasitological rates. Accuracy increased from as low as 0.36 to 0.96 after urine concentration in one area. POC-CCA properly diagnosed only half of the cases at three post-treatment time points, while POC-CCA FLT was able to diagnose 96, 83 and 100%, respectively. Conclusions: The improvement of conventional POC methodology by a fast and simple urine concentration step provided not only an increase in its accuracy before and after praziquantel treatment, but also preserved its applicability in low-prevalence endemic areas, allowing the definition of trace readings as negative cases.
Assuntos
Antígenos de Helmintos/urina , Sistemas Automatizados de Assistência Junto ao Leito , Schistosoma mansoni/imunologia , Esquistossomose mansoni/diagnóstico , Esquistossomose mansoni/urina , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Anti-Helmínticos/uso terapêutico , Brasil/epidemiologia , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Praziquantel/uso terapêutico , Estudos Prospectivos , Reprodutibilidade dos Testes , Esquistossomose mansoni/tratamento farmacológico , Esquistossomose mansoni/epidemiologia , Sensibilidade e Especificidade , Adulto JovemRESUMO
BACKGROUND: In some tropical countries, such as Brazil, schistosomiasis control programs have led to a significant reduction in the prevalence and parasite burden of endemic populations. In this setting, the Kato-Katz technique, as the standard diagnostic method for the diagnosis of Schistosoma mansoni infections, which involves the analysis of two slides from one fecal sample, loses its sensitivity. As a result, a significant number of infected individuals are not detected. The objective of this study was to perform extensive parasitological testing of up to three fecal samples and include a rapid urine test (POC-CCA) in a moderate prevalence area in Northern Minas Gerais, Brazil, and evaluate the performance of each test separately and in combination. METHODS AND FINDINGS: A total of 254 individuals were examined with variants of the standard Kato-Katz technique (up to18 Kato-Katz slides prepared from three fecal samples), a modified Helmintex (30 g of feces), the saline gradient (500 mg of feces), and the POC-CCA methods. We established a reference standard taking into consideration all the positive results in any of the parasitological exams. Evaluation of the parasite burden by two Kato-Katz slides confirmed that most of the individuals harbored a light infection. When additional slides and different parasitological methods were included, the estimated prevalence rose 2.3 times, from 20.4% to 45.9%. The best sensitivity was obtained with the Helmintex method (84%). All parasitological methods readily detected a high or moderate intensity of infection; however, all lost their high sensitivity in the case of low or very low intensity infections. The overall sensitivity of POC-CCA (64.9%) was similar to the six Kato-Katz slides from three fecal samples. However, POC-CCA showed low concordance (κ = 0.34) when compared with the reference standard. CONCLUSIONS: The recommended Kato-Katz method largely underestimated the prevalence of S. mansoni infection. Because the best performance was achieved with a modified Helmintex method, this technique might serve as a more precise reference standard. An extended number of Kato-Katz slides in combination with other parasitological methods or with POC-CCA was able to detect more than 80% of egg-positive individuals; however, the rapid urine test (POC-CCA) produced a considerable percentage of false positive results.
Assuntos
Técnicas de Laboratório Clínico/métodos , Fezes/parasitologia , Doenças Negligenciadas/diagnóstico , Carga Parasitária , Schistosoma mansoni/isolamento & purificação , Esquistossomose mansoni/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Antígenos de Helmintos/urina , Brasil , Criança , Pré-Escolar , Feminino , Humanos , Renda , Masculino , Pessoa de Meia-Idade , Doenças Negligenciadas/epidemiologia , Contagem de Ovos de Parasitas , Sistemas Automatizados de Assistência Junto ao Leito , Prevalência , Esquistossomose/diagnóstico , Esquistossomose mansoni/epidemiologia , Esquistossomose mansoni/urina , Sensibilidade e Especificidade , Fatores Socioeconômicos , Abastecimento de Água , Adulto JovemRESUMO
Taenia solium cysticercosis is difficult to eliminate without interventions or societal development. Atahualpa is a rural Ecuadorian village with documented low migration rate, where domestic pig raising is common and human cysticercosis is endemic. To assess neurocysticercosis (NCC) prevalence, 1,273 villagers aged ≥ 20 years underwent neuroimaging studies, which showed calcified lesions in 121 (9.5%) individuals, but no active disease. Likewise, positive reactions, apparently nonspecific, were found in only 3/200 subjects by the use of a monoclonal antibody-based enzyme-linked immunosorbent assay to detect T. solium antigens in urine. Only 2/418 pigs reacted to three antibody bands on serum western blot and none to more than three bands. This is the first time that spontaneously arrested T. solium transmission is documented in a known endemic village. Understanding why active transmission stopped could provide insights on potential targets for control interventions. Atahualpa could provide an optimal scenario for longitudinal studies on the consequences of calcified NCC.
Assuntos
Doenças Endêmicas/prevenção & controle , Neurocisticercose/prevenção & controle , Neurocisticercose/transmissão , Doenças dos Suínos/prevenção & controle , Doenças dos Suínos/transmissão , Adulto , Criação de Animais Domésticos , Animais , Anticorpos Anti-Helmínticos/sangue , Antígenos de Helmintos/urina , Equador/epidemiologia , Fezes/parasitologia , Feminino , Humanos , Masculino , Neurocisticercose/diagnóstico por imagem , Neurocisticercose/epidemiologia , Neuroimagem/métodos , Prevalência , População Rural , Suínos , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/parasitologia , Taenia solium/fisiologiaRESUMO
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.
Assuntos
Humanos , Animais , Masculino , Feminino , Schistosoma mansoni/isolamento & purificação , Esplenopatias/epidemiologia , Esquistossomose mansoni/epidemiologia , Hepatopatias Parasitárias/epidemiologia , Esplenopatias/parasitologia , Esplenopatias/diagnóstico por imagem , Esquistossomose mansoni/diagnóstico , Prevalência , Estudos Transversais , Morbidade , Escolaridade , Fezes/parasitologia , Hepatopatias Parasitárias/parasitologia , Hepatopatias Parasitárias/diagnóstico por imagem , Antígenos de Helmintos/urinaRESUMO
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.
Assuntos
Antígenos de Helmintos/urina , Schistosoma mansoni/imunologia , Esquistossomose mansoni/diagnóstico , Adolescente , Adulto , Idoso , Animais , Brasil , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sistemas Automatizados de Assistência Junto ao Leito , Reprodutibilidade dos Testes , População Rural , Esquistossomose mansoni/complicações , Sensibilidade e Especificidade , Adulto JovemRESUMO
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.
Assuntos
Humanos , Animais , Masculino , Feminino , Criança , Adolescente , Adulto , Idoso , Adulto Jovem , Schistosoma mansoni/imunologia , Esquistossomose mansoni/diagnóstico , Antígenos de Helmintos/urina , População Rural , Esquistossomose mansoni/complicações , Brasil , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Sistemas Automatizados de Assistência Junto ao Leito , Pessoa de Meia-IdadeRESUMO
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.
Assuntos
Hepatopatias Parasitárias/epidemiologia , Schistosoma mansoni/isolamento & purificação , Esquistossomose mansoni/epidemiologia , Esplenopatias/epidemiologia , Animais , Antígenos de Helmintos/urina , Estudos Transversais , Escolaridade , Fezes/parasitologia , Feminino , Humanos , Hepatopatias Parasitárias/diagnóstico por imagem , Hepatopatias Parasitárias/parasitologia , Masculino , Morbidade , Prevalência , Esquistossomose mansoni/diagnóstico , Esplenopatias/diagnóstico por imagem , Esplenopatias/parasitologiaRESUMO
INTRODUCTION: Schistosomiasis, caused by Schistosoma mansoni, is a public health concern in Brazil. However, the most popular diagnostic method, the Kato-Katz technique, exhibits low sensitivity in low-endemicity areas. We aimed to compare the performance of an immunological assay, the point-of-care circulating cathodic antigen (POC-CCA®) test, with that of two parasitological techniques in a low-endemicity population. METHODS: Our study included 141 individuals living in Estreito de Miralta, Minas Gerais, Brazil. Fecal samples were obtained from all participants and analyzed for schistosomiasis using two parasitological techniques: the Kato-Katz technique and the saline gradient technique. Additionally, POC-CCA® strips were utilized for testing urine samples. The results obtained by the different techniques were compared. RESULTS: Analysis of two or 24 slides using the Kato-Katz technique resulted in a positivity rate of 10.6% (15/141) or 19.1% (27/141), respectively. The saline gradient technique yielded a positivity rate of 17.0% (24/141). The prevalence according to both parasitological techniques was 24.1% (34/141). The POC-CCA® test yielded a positivity rate of 22.7% (32/141); however, the positivity rate was merely 2.1% if trace results were considered negative. The agreements observed between POC-CCA® and the parasitological techniques were good (Kappa indexes > 0.64). The POC-CCA® test was more sensitive than the two-slide Kato-Katz technique (p < 0.05) in detecting cases of S. mansoni infection when trace results were considered positive. CONCLUSIONS: These findings reinforce the importance of using multiple diagnostic techniques in low-endemicity areas for effective control of disease.
Assuntos
Antígenos de Helmintos/urina , Fezes/parasitologia , Schistosoma mansoni/imunologia , Schistosoma mansoni/isolamento & purificação , Esquistossomose mansoni/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Contagem de Ovos de Parasitas , Sistemas Automatizados de Assistência Junto ao Leito , Sensibilidade e Especificidade , Adulto JovemRESUMO
BACKGROUND: Accurate diagnostic techniques for schistosomiasis are essential for prevalence determination and identification of positive patients. A point-of-care test for detecting schistosome circulating cathodic antigen (POC-CCA) has been evaluated for its accuracy in different endemic regions. This reagent strip/dipstick based assay has showed high sensitivity for individuals with high or moderate worm burden, but the interpretation of light infections is less clear, especially for trace readings. METHODOLOGY/PRINCIPAL FINDINGS: We introduced a urine lyophilization step to the POC-CCA assay to improve its sensitivity and clarify the interpretation of traces. We evaluated POC-CCA sensitivity and specificity within individuals with low parasite burdens in a Brazilian endemic area where a high number of traces were detected. Patients that were positive for other helminths were also evaluated for cross reactions. In all cases, a combined parasitological diagnosis using Kato-Katz (24 slides) and Saline Gradient (1 g of feces) were used as reference. At baseline, diagnosis by POC-CCA (1-2 cassettes) showed 6% sensitivity, inaccurately predicting a low prevalence of Schistosoma mansoni infections (2 POC-CCA positives/32 egg positives). After urine lyophilization, the sensitivity was increased significantly (p < 0.05). Prevalence rates changed from 2% to 32% (27 POC-CCA positives/32 egg positives), equivalent to parasitological techniques. Most of the trace readings changed to positive after lyophilization while some negatives turned into traces. Cross reaction analysis confirmed the specificity of POC-CCA. CONCLUSIONS/SIGNIFICANCE: Trace readings cannot be primarily defined as positive or negative cases. It is critical to verify case-by-case by concentrating urine 10 fold by lyophilization for the diagnosis. Following lyophilization, persistent trace readings should be read as negatives. No trained technician is needed and cost is restricted to the cost of a lyophilizer and the electricity to run it.
Assuntos
Antígenos de Helmintos/urina , Liofilização/métodos , Glicoproteínas/urina , Proteínas de Helminto/urina , Testes Imediatos , Schistosoma mansoni/fisiologia , Esquistossomose mansoni/diagnóstico , Esquistossomose mansoni/urina , Albendazol/administração & dosagem , Albendazol/uso terapêutico , Animais , Anti-Helmínticos , Fezes/parasitologia , Humanos , Contagem de Ovos de Parasitas , Parasitologia/métodos , Praziquantel/administração & dosagem , Praziquantel/uso terapêutico , Esquistossomose mansoni/tratamento farmacológico , Sensibilidade e EspecificidadeRESUMO
Abstract: INTRODUCTION: Schistosomiasis, caused by Schistosoma mansoni, is a public health concern in Brazil. However, the most popular diagnostic method, the Kato-Katz technique, exhibits low sensitivity in low-endemicity areas. We aimed to compare the performance of an immunological assay, the point-of-care circulating cathodic antigen (POC-CCA®) test, with that of two parasitological techniques in a low-endemicity population. METHODS: Our study included 141 individuals living in Estreito de Miralta, Minas Gerais, Brazil. Fecal samples were obtained from all participants and analyzed for schistosomiasis using two parasitological techniques: the Kato-Katz technique and the saline gradient technique. Additionally, POC-CCA® strips were utilized for testing urine samples. The results obtained by the different techniques were compared. RESULTS: Analysis of two or 24 slides using the Kato-Katz technique resulted in a positivity rate of 10.6% (15/141) or 19.1% (27/141), respectively. The saline gradient technique yielded a positivity rate of 17.0% (24/141). The prevalence according to both parasitological techniques was 24.1% (34/141). The POC-CCA® test yielded a positivity rate of 22.7% (32/141); however, the positivity rate was merely 2.1% if trace results were considered negative. The agreements observed between POC-CCA® and the parasitological techniques were good (Kappa indexes > 0.64). The POC-CCA® test was more sensitive than the two-slide Kato-Katz technique (p < 0.05) in detecting cases of S. mansoni infection when trace results were considered positive. CONCLUSIONS: These findings reinforce the importance of using multiple diagnostic techniques in low-endemicity areas for effective control of disease.
Assuntos
Humanos , Animais , Masculino , Feminino , Lactente , Pré-Escolar , Criança , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Adulto Jovem , Schistosoma mansoni/isolamento & purificação , Schistosoma mansoni/imunologia , Esquistossomose mansoni/diagnóstico , Fezes/parasitologia , Antígenos de Helmintos/urina , Contagem de Ovos de Parasitas , Sensibilidade e Especificidade , Sistemas Automatizados de Assistência Junto ao Leito , Pessoa de Meia-IdadeRESUMO
Neurocysticercosis (NCC), an infection of the brain by Taenia solium (Ts) cysts, is the most common cause of adult-onset epilepsy in developing countries. Serological testing consists primarily of varying methods to detect antibodies in body fluids and more recently antigen (Ag) detection assays to identify individuals or animals with viable parasites. Antigen assays currently in use employ monoclonal antibodies (mAbs) raised against T. saginata, which have known cross reactivity to animal cestodes but are highly specific in human samples. We produced, characterized and tested 21 mAbs raised against T. solium whole cyst antigens, vesicular fluid or excretory secretory products. Reactivity of the TsmAbs against specific cyst structures was determined using immunofluorescence and immunohistochemistry on histological sections of Ts muscle cysts. Four TsmAbs reacted to vesicular space alone, 9 to the neck and cyst wall, one to the neck and vesicular space and 7 to the neck, cyst wall and vesicular space. An in-house ELISA assay to detect circulating Ts antigen, using the TsmAbs as capture antibodies and a rabbit polyclonal anti-Ts whole cyst antibody as a detector antibody demonstrated that eight of the 21 TsmAbs detected antigens in known NCC-positive human sera and three of these also in urine samples. Reactivity was expressed as normalized ratios of optical densities (OD positive control/OD negative control). Three TsmAbs had ratios >10 and five between 2 and 10. The TsmAbs have potential utility for the diagnosis and post-treatment monitoring of patients with viable NCC infections.
Assuntos
Anticorpos Monoclonais/imunologia , Antígenos de Helmintos/análise , Neurocisticercose/diagnóstico , Taenia solium/imunologia , Animais , Anticorpos Anti-Helmínticos/imunologia , Anticorpos Monoclonais/metabolismo , Especificidade de Anticorpos , Antígenos de Helmintos/sangue , Antígenos de Helmintos/urina , Bile/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Imunofluorescência , Hibridomas/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Neurocisticercose/imunologia , Coelhos , Especificidade da Espécie , SuínosRESUMO
(Neuro)cysticercosis is an important zoonotic disease caused by infection with Taenia solium metacestode larvae. Existing immunodiagnostic techniques detect antibodies and circulating antigens (Ag) in serum and cerebrospinal fluid (CSF). Blood/CSF collection is an invasive procedure associated with blood-borne infections and is often not well accepted by communities. Detection of circulating Ag in urine has been suggested as an alternative, however this has been evaluated in clinical settings only. The aim of the present study was to evaluate the performance of a urine Ag-ELISA under field conditions. Paired serum and urine samples were obtained from participants in endemic areas of Ecuador (n=748) and Zambia (n=690) and were subjected to a monoclonal antibody-based Ag-ELISA. Calculation of positive and negative agreement indices (AI) showed better agreement in the negative direction both for Ecuadorian and Zambian samples (AI of 93.1 and 86.8, respectively). Using a Bayesian approach to determine the test characteristics, similar sensitivities were obtained for serum and urine Ag detection, whereas a decreased specificity was determined for the urine Ag-ELISA with a lower specificity (78.6%) for Zambian samples than for Ecuadorian samples (88.4%). This study indicates a higher specificity for the serum test under field conditions and promotes further research to improve the urine test.
Assuntos
Antígenos de Helmintos/urina , Cisticercose/urina , Taenia solium/isolamento & purificação , Animais , Teorema de Bayes , Cisticercose/diagnóstico , Cisticercose/epidemiologia , Equador/epidemiologia , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Masculino , Sensibilidade e Especificidade , Zâmbia/epidemiologiaRESUMO
Neurocysticercosis (NCC) is a major cause of seizures and epilepsy. Diagnosis is based on brain imaging, supported by immunodiagnosis in serum or cerebrospinal fluid (CSF). Lumbar puncture is invasive and painful. Blood sampling is slightly painful and poorly accepted. Urine antigen detection has been used for other parasites and tried in NCC with suboptimal performance. We used a monoclonal antibody-based ELISA to detect Taenia solium antigens in urine from 87 Peruvian neurocysticercosis patients (viable cysts, N = 34; subarachnoid cysticercosis, N = 10; degenerating parasites, N = 7; calcified lesions, N = 36) and 32 volunteers from a non-endemic area of Peru. Overall sensitivity of urine antigen detection for viable parasites was 92%, which decreased to 62.5% in patients with a single cyst. Most patients (30/36, 83%) with only calcified cysticercosis were urine antigen negative. Antigen levels in paired serum/urine samples (evaluated in 19 patients) were strongly correlated. Non-invasive urine testing for T. solium antigens provides a useful alternative for NCC diagnosis.