Publications by authors named "Naftale Katz"

Background: The prevalence of intestinal parasites is known to be high among Amerindian populations; further, there are serious problems in the healthcare of these populations in Brazil. The Maxakali, located in the northeastern region of Minas Gerais, Brazil, is an indigenous group that still preserves many of its cultural aspects. This study aimed to compare the positivity rate of schistosomiasis and soil-transmitted helminths in this ethnic group in epidemiological surveys conducted in 1972 and 2014.

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The World Health Organization (WHO) recognizes schistosomiasis as one of the Neglected Tropical Diseases targeted for global elimination in the 2030 Agenda of the Sustainable Development Goals. In Brazil, schistosomiasis mansoni is considered a public health problem, particularly prevalent among vulnerable populations living in areas with poor environmental and sanitary conditions. In 2022, the WHO published a Guideline encompassing recommendations to assist national programs in endemic countries in achieving morbidity control, eliminating schistosomiasis as a public health problem, and advancing towards interrupting transmission.

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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.

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Article Synopsis
  • Praziquantel (PZQ) is the only current drug used to control schistosomiasis, but researchers are evaluating a synthetic curcumin analog called EF24 for its effectiveness against Schistosoma mansoni.
  • EF24 showed significant schistosomicidal activity, being more potent than PZQ against certain worm isolates, particularly in inducing harmful changes in the parasites at low concentrations.
  • The compound was found to increase oxidative stress in the worms while being less toxic to mammalian cells, suggesting it may be a promising candidate for further development in treating schistosomiasis.
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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.

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Rapid diagnostics provide actionable information for patient care at the time and site of an encounter with the health care system. The mainstay of infectious diseases care is early detection (case finding) and treatment completion, but for many, it is hard to identify positive individuals, as is the case of infection with low burden in schistosomiasis, a parasitic disease common in the tropics and subtropics. We developed a new, accurate, and fast Dot blot methodology (iDot) to indirectly detect Schistosoma mansoni in individuals with very low parasite burden using urine samples.

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A point-of-care test for detecting schistosome circulating cathodic antigen in urine (POCCCA) has been proposed for mapping infection and defining prevalence thresholds for mass drug administration (MDA). However, there is increasing evidence that POCCCA may yield false-positive results, which requires rigorous specificity evaluation in non-endemic areas. POCCCA was applied in an area known to be free from infection and devoid of any condition for schistosomiasis transmission as part of a multicentre study to evaluate the performance of POCCCA in Brazil's low or potentially endemic settings.

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A prospective cohort study with rigorous searching for schistosomiasis cases was conducted among residents of Pedra Preta, Montes Claros, Minas Gerais State, Brazil, seven years after an intervention. Kato-Katz (KK), Saline Gradient, Miracidia Hatch and Polymerase Chain Reaction (PCR) were used as the diagnostic methods in 2008. In the period of 2013-2016, 175 patients remaining in the area were examined using the diagnostic methods Kato-Katz (24 slides, 1 g of feces) and Saline Gradient (2 procedures, 1 g of feces).

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Background: Point of care tests would be valuable for field diagnosis. However, high sensitivity will likely be required in low endemicity sets where individuals with low schistosome burden are hard to diagnose.

Methods: Commercially available POC tests (POC-CCA® and Urine CCA (Schisto) ECO Teste®) were evaluated to evidence their potential in low endemicity areas.

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Schistosomiasis is still a public health problem in Brazil. The Kato-Katz test is the most frequently used diagnostic method for Schistosoma mansoni infection. However, it lacks sensitivity in areas of low prevalence.

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Article Synopsis
  • Accurate and rapid diagnosis is crucial for controlling schistosomiasis, as existing methods like POC-CCA perform poorly in low-endemicity areas.* -
  • A new method called POC-CCA filter (FLT) was developed, incorporating a quick urine concentration step that significantly improved diagnostic accuracy in Brazilian endemic areas.* -
  • Results showed that POC-CCA FLT had a much higher accuracy rate (up to 100%) compared to the traditional POC-CCA, enhancing its effectiveness in diagnosing cases both before and after treatment.*
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Schistosomiasis, one of the 17 neglected tropical diseases listed by the World Health Organization, presents a substantial public health and economic burden. Of the 261 million people requiring preventive chemotherapy for schistosomiasis in 2013, 92% of them lived in sub-Saharan Africa and only 12.7% received preventive chemotherapy.

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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.

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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.

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Mice infected with Schistosoma mansoni were treated with oxamniquine, praziquantel, artesunate at the pre-patent phase, aiming at observing schistogram alterations. Half of the animals were perfused five days post-treatment for counting and classification of immature worms, based on pre-established morphological criteria (schistogram); the remaining animals were evaluated 42 or 100 days after infection and perfusion of the portal-system was performed for collection and counting of adult worms and oogram. It was observed that oxamniquine and artesunate treatment administered at the pre-postural phase causes significant reduction in the number of immature and adult worms.

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Imatinib, a drug used for treatment of human chronic myeloid leukaemia, due to its activity against protein kinases, has been also evaluated in vitro against Schistosoma mansoni showing high schistosomicidal activity. In the present experiments imatinib activity in vitro was confirmed at the doses of 25 µM, 50 µM and 100 µM. The first drug activity observed with the lower dose was interruption of egg-laying and with the higher dosages was the death of the worms.

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Current schistosomiasis control strategies are largely based on chemotherapeutic agents and a limited number of drugs are available today. Praziquantel (PZQ) is the only drug currently used in schistosomiasis control programs. Unfortunately, this drug shows poor efficacy in patients during the earliest infection phases.

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To elucidate the mechanisms of antischistosoma resistance, drug-resistant Schistosoma mansoni laboratory isolates are essential. We developed a new method for inducing resistance to praziquantel (PZQ) using successive drug treatments of Biomphalaria glabrata snails infected with S. mansoni.

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Background: Various studies showed that chemotherapy can control schistosomiasis morbidity, but association of measures (water supply, sewage disposal and increase of socioeconomic conditions) is necessary for transmission control.

Methodology/principal Findings: A survey dealing with socioeconomic conditions, snail survey, contact with natural waters, and clinical and stool examinations was undertaken at an endemic area in the State of Minas Gerais, Brazil. The methodology used was the same for both evaluations (1981 and 2005).

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The development of novel methods for parasitological diagnosis that are both highly sensitive and low in cost has been strongly recommended by the World Health Organization. In this study, a new technique for diagnosis of schistosomiasis mansoni is proposed based on the differential sedimentation of eggs when subjected to a slow continuous flux of 3% saline solution through a porous plaque. This influx suspends low-density faecal material, effectively cleaning the sample.

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The antischistosomal activity of clonazepam, when administered alone or in association with oxamniquine and praziquantel, was experimentally evaluated in mice infected with Schistosoma mansoni. The animals were treated 45 days post-infection with a single dose, by oral route, according to three treatment schedules: clonazepam 25 mg/kg and sacrificed 15 min, 1h or 4 h after treatment; clonazepam 1.0, 2.

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