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Greter H, Krauth SJ, Ngandolo BNR, Alfaroukh IO, Zinsstag J, Utzinger J. Validation of a Point-of-Care Circulating Cathodic Antigen Urine Cassette Test for Schistosoma mansoni Diagnosis in the Sahel, and Potential Cross-Reaction in Pregnancy. Am J Trop Med Hyg 2015; 94:361-4. [PMID: 26556831 DOI: 10.4269/ajtmh.15-0577] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Accepted: 09/25/2015] [Indexed: 01/10/2023] Open
Abstract
On the shores of Lake Chad, schistosomiasis among mobile pastoralists was investigated in a field laboratory. Point-of-care circulating cathodic antigen (POC-CCA) cassette test, reagent strip, and filtration were conducted on urine samples. Fresh stool samples were subjected to the Kato-Katz technique, and fixed samples were examined with an ether-concentration method at a reference laboratory. POC-CCA urine cassette tests revealed a Schistosoma mansoni prevalence of 6.9%, compared with only 0.5% by stool microscopy. Three pregnant women with otherwise negative urine and stool testing had positive POC-CCA. This observation raises concern of cross-reactivity in pregnancy. Hence, two pregnant women in Switzerland with no history of schistosomiasis were subjected to POC-CCA and one tested positive. Our data suggest that POC-CCA can be performed under extreme Sahelian conditions (e.g., temperatures > 40°C), and it is more sensitive than stool microscopy for S. mansoni diagnosis. However, potential cross-reactivity in pregnancy needs further investigation.
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Affiliation(s)
- Helena Greter
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire; Institut de Recherche en Elevage pour le Développement, N'Djamena, Chad
| | - Stefanie J Krauth
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire; Institut de Recherche en Elevage pour le Développement, N'Djamena, Chad
| | - Bongo N R Ngandolo
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire; Institut de Recherche en Elevage pour le Développement, N'Djamena, Chad
| | - Idriss O Alfaroukh
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire; Institut de Recherche en Elevage pour le Développement, N'Djamena, Chad
| | - Jakob Zinsstag
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire; Institut de Recherche en Elevage pour le Développement, N'Djamena, Chad
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire; Institut de Recherche en Elevage pour le Développement, N'Djamena, Chad
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Krauth SJ, Greter H, Stete K, Coulibaly JT, Traoré SI, Ngandolo BNR, Achi LY, Zinsstag J, N'Goran EK, Utzinger J. All that is blood is not schistosomiasis: experiences with reagent strip testing for urogenital schistosomiasis with special consideration to very-low prevalence settings. Parasit Vectors 2015; 8:584. [PMID: 26554822 PMCID: PMC4641389 DOI: 10.1186/s13071-015-1165-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/14/2015] [Indexed: 01/02/2023] Open
Abstract
Background Reagent strip testing for microhaematuria has long been used for community diagnosis of Schistosoma haematobium. Sensitivities and specificities are reasonable, and hence, microhaematuria can serve as a proxy for S. haematobium infection. However, assessment of test performance in the context of the underlying S. haematobium prevalence is rare and test parameters other than sensitivity and specificity have been neglected. Methods Data about the association between microhaematuria and urine filtration results from three studies were compared and put into context with findings from a recent Cochrane review. Data were stratified by S. haematobium prevalence to identify prevalence-related differences in test performance. Kappa agreement and regression models were employed to compare data for different S. haematobium prevalence categories. Results We found a “background” prevalence of microhaematuria (13 %, on average) which does not seem to be associated with schistosomiasis in most settings, irrespective of the prevalence of S. haematobium. This background level of microhaematuria might be due to cases missed with urine filtration, or alternative causes apart from S. haematobium. Especially in very-low prevalence settings, positive results for microhaematuria likely give an inaccurate picture of the extent of S. haematobium, whereas negative results are a sound indicator for the absence of infection. Conclusions Reagent strip testing for microhaematuria remains a good proxy for urogenital schistosomiasis, but implications of test results and scope of application differ depending on the setting in which reagent strips are employed. In very-low prevalence settings, microhaematuria is an unstable proxy for urogenital schistosomiasis and treatment decision should not be based on reagent strip test results alone. Our findings underscore the need for highly accurate diagnostic tools for settings targeted for elimination of urogenital schistosomiasis.
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Affiliation(s)
- Stefanie J Krauth
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland. .,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.
| | - Helena Greter
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland. .,Institut de Recherches en Élevage pour le Développement, N'Djamena, Chad.
| | - Katarina Stete
- Center for Infectious Diseases and Travel Medicine, University Hospital Freiburg, Freiburg, Germany.
| | - Jean T Coulibaly
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland. .,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire. .,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire.
| | - Seïdinan I Traoré
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire. .,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire. .,Laboratoire Régional de Korhogo du Laboratoire National d'Appui au Développement Agricole, Korhogo, Côte d'Ivoire.
| | - Bongo N R Ngandolo
- Institut de Recherches en Élevage pour le Développement, N'Djamena, Chad.
| | - Louise Y Achi
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire. .,École de Spécialisation en Élevage de Bingerville, Bingerville, Côte d'Ivoire.
| | - Jakob Zinsstag
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Eliézer K N'Goran
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire. .,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire.
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
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Moser W, Greter H, Schindler C, Allan F, Ngandolo BNR, Moto DD, Utzinger J, Zinsstag J. The spatial and seasonal distribution of Bulinus truncatus, Bulinus forskalii and Biomphalaria pfeifferi, the intermediate host snails of schistosomiasis, in N'Djamena, Chad. Geospat Health 2014; 9:109-118. [PMID: 25545929 DOI: 10.4081/gh.2014.9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
There is a paucity of epidemiological and malacological data pertaining to schistosomiasis in Chad. In view of a recently articulated elimination agenda, a deeper understanding of the spatio-temporal distribution of schistosomiasis intermediate host snails is pivotal. We conducted cross-sectional malacological surveys during the dry season (April/May 2013) and after the short rainy season (October 2013) in N'Djamena, the capital of Chad. Snails were identified at the genus and species level using morphological keys and molecular DNA barcoding approaches. Those belonging to Bulinus and Biomphalaria were examined for cercarial shedding. Snail habitats were characterised and their predictive potential for the presence of schistosomiasis intermediate host snails explored. Seasonal patterns were studied using geographical information system and kriging in order to interpolate snail abundance data to make predictions at non-sampled locations across N'Djamena. Overall, 413 Bulinus truncatus, 369 Bulinus forskalii and 108 Biomphalaria pfeifferi snails were collected and subjected to cercarial shedding. During the dry season, one Bu. truncatus of 119 snails collected shed Schistosoma spp. cercariae (0.84%), while S. mansoni was shed by one of 108 Bi. pfeifferi snails (0.93%). None of the snails collected after the rainy season shed Schistosoma spp. cercariae. The abundance of Bu. truncatus and Bu. forskalii showed an inverse U-shape relationship with the square term of conductivity, i.e. low abundance at the lowest and highest levels of conductivity and high abundance at intermediate levels. Bi. pfeifferi showed a negative, linear association with pH in the dry seasons. It is planned to link these intermediate host snail data to infection data in human populations with the goal to draw a predictive risk map that can be utilised for control and elimination of schistosomiasis in N'Djamena.
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Affiliation(s)
- Wendelin Moser
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Helena Greter
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Christian Schindler
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Fiona Allan
- Department of Life Sciences, Natural History Museum, London, UK
| | - Bongo N R Ngandolo
- Institut de Recherches en Élevage pour le Développement, N'Djamena, Chad
| | - Daugla D Moto
- Centre de Support en Santé International, N'Djamena, Chad
| | - Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Jakob Zinsstag
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
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