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Chieng B, Okoyo C, Simiyu E, Gichuki P, Mwatele C, Kepha S, Njenga S, Mburu D. Comparison of quantitative polymerase chain reaction, Kato-Katz and circulating cathodic antigen rapid test for the diagnosis of Schistosoma mansoni infection: A cross-sectional study in Kirinyaga County, Kenya. Curr Res Parasitol Vector Borne Dis 2022; 1:100029. [PMID: 35284880 PMCID: PMC8906081 DOI: 10.1016/j.crpvbd.2021.100029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/11/2021] [Accepted: 05/14/2021] [Indexed: 01/11/2023]
Abstract
The current standard diagnostic tests for Schistosoma mansoni are the Kato-Katz and circulating cathodic antigen (CCA) techniques. However, these techniques have been documented to have several limitations that have a direct impact on schistosomiasis control programmes. Therefore, there is a need for more sensitive and specific tests for diagnosing schistosomiasis. This study compared the performance of quantitative polymerase chain reaction (qPCR), Kato-Katz, and point-of-care circulating cathodic antigen (POC-CCA) techniques in the diagnosis of S. mansoni infection in the Mwea irrigation scheme, Kirinyaga County in Central Kenya. We carried out a cross-sectional study on 357 individuals residing in four villages in the Mwea irrigation scheme. The participants provided urine and stool samples which were screened for S. mansoni infections using the three techniques. The prevalence of S. mansoni by each technique was calculated and 95% confidence intervals estimated using binomial regression model. Sensitivity and specificity were determined using 2 × 2 contingency tables and compared using the McNemar’s chi-square test. Positive and negative predictive values were also determined using the weighted generalized score chi-square test for paired data. The study showed that the prevalence of S. mansoni was 32.8%, 62.5% and 72.8% using Kato-Katz, POC-CCA and qPCR techniques, respectively. Further, when using Kato-Katz as a gold standard, POC-CCA sensitivity was 78.6% and specificity was 45.4%, while qPCR sensitivity was 97.4% and specificity was 39.2%. When using qPCR as the gold standard, Kato-Katz sensitivity was 43.8% and specificity was 96.9%, while POC-CCA sensitivity was 78.1% and specificity was 79.4%. Finally, when using the averaged results from the three techniques as the gold standard, the sensitivity was 41.6%, 79.4% and 92.5% for Kato-Katz, POC-CCA and qPCR, respectively, with a specificity of 100% for all techniques. Kato-Katz technique showed low sensitivity compared to the POC-CCA and qPCR despite it being the most commonly preferred method of choice to diagnose S. mansoni infections. qPCR showed superior sensitivity followed by POC-CCA, hence it can be used as an alternative or to confirm the results obtained by the Kato-Katz technique. Comparison of the performance of Kato-Katz, POC-CCA and qPCR for diagnosis of S. mansoni in Kirinyaga County, Kenya. A total of 357 urine and stool samples were tested for S. mansoni infection. qPCR estimated the highest prevalence followed by POC-CCA and Kato-Katz. qPCR showed a generally high sensitivity and specificity.
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Affiliation(s)
- Benard Chieng
- Eastern & Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), PO BOX 54840-00200, Nairobi, Kenya.,Department of Microbiology, Biotechnology and Biochemistry, Kenyatta University, Nairobi, Kenya
| | - Collins Okoyo
- Eastern & Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), PO BOX 54840-00200, Nairobi, Kenya
| | - Elses Simiyu
- Eastern & Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), PO BOX 54840-00200, Nairobi, Kenya
| | - Paul Gichuki
- Eastern & Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), PO BOX 54840-00200, Nairobi, Kenya
| | - Cassian Mwatele
- Eastern & Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), PO BOX 54840-00200, Nairobi, Kenya
| | - Stella Kepha
- Eastern & Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), PO BOX 54840-00200, Nairobi, Kenya
| | - Sammy Njenga
- Eastern & Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), PO BOX 54840-00200, Nairobi, Kenya
| | - David Mburu
- Department of Microbiology, Biotechnology and Biochemistry, Kenyatta University, Nairobi, Kenya
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Dacal E, Bermejo-Peláez D, Lin L, Álamo E, Cuadrado D, Martínez Á, Mousa A, Postigo M, Soto A, Sukosd E, Vladimirov A, Mwandawiro C, Gichuki P, Williams NA, Muñoz J, Kepha S, Luengo-Oroz M. Mobile microscopy and telemedicine platform assisted by deep learning for the quantification of Trichuris trichiura infection. PLoS Negl Trop Dis 2021; 15:e0009677. [PMID: 34492039 PMCID: PMC8448303 DOI: 10.1371/journal.pntd.0009677] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 09/17/2021] [Accepted: 07/21/2021] [Indexed: 11/18/2022] Open
Abstract
Soil-transmitted helminths (STH) are the most prevalent pathogens among the group of neglected tropical diseases (NTDs). The Kato-Katz technique is the diagnosis method recommended by the World Health Organization (WHO) although it often presents a decreased sensitivity in low transmission settings and it is labour intensive. Visual reading of Kato-Katz preparations requires the samples to be analyzed in a short period of time since its preparation. Digitizing the samples could provide a solution which allows to store the samples in a digital database and perform remote analysis. Artificial intelligence (AI) methods based on digitized samples can support diagnosis by performing an objective and automatic quantification of disease infection. In this work, we propose an end-to-end pipeline for microscopy image digitization and automatic analysis of digitized images of STH. Our solution includes (a) a digitization system based on a mobile app that digitizes microscope samples using a 3D printed microscope adapter, (b) a telemedicine platform for remote analysis and labelling, and (c) novel deep learning algorithms for automatic assessment and quantification of parasitological infections by STH. The deep learning algorithm has been trained and tested on 51 slides of stool samples containing 949 Trichuris spp. eggs from 6 different subjects. The algorithm evaluation was performed using a cross-validation strategy, obtaining a mean precision of 98.44% and a mean recall of 80.94%. The results also proved the potential of generalization capability of the method at identifying different types of helminth eggs. Additionally, the AI-assisted quantification of STH based on digitized samples has been compared to the one performed using conventional microscopy, showing a good agreement between measurements. In conclusion, this work has presented a comprehensive pipeline using smartphone-assisted microscopy. It is integrated with a telemedicine platform for automatic image analysis and quantification of STH infection using AI models.
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Affiliation(s)
| | | | - Lin Lin
- Spotlab, Madrid, Spain
- Biomedical Image Technologies, ETSI Telecomunicación, Universidad Politécnica de Madrid, Madrid, Spain
| | | | | | | | | | | | | | | | | | - Charles Mwandawiro
- Eastern and Southern Africa Center for International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Paul Gichuki
- Eastern and Southern Africa Center for International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Nana Aba Williams
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - José Muñoz
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Stella Kepha
- Eastern and Southern Africa Center for International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
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Kepha S, Nuwaha F, Nikolay B, Gichuki P, Mwandawiro CS, Mwinzi PN, Odiere MR, Edwards T, Allen E, Brooker SJ. Effect of Repeated Anthelminthic Treatment on Malaria in School Children in Kenya: A Randomized, Open-Label, Equivalence Trial. J Infect Dis 2015; 213:266-75. [PMID: 26170395 PMCID: PMC4690148 DOI: 10.1093/infdis/jiv382] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 07/06/2015] [Indexed: 11/12/2022] Open
Abstract
Background. School children living in the tropics are often concurrently infected with plasmodium and helminth parasites. It has been hypothesized that immune responses evoked by helminths may modify malaria-specific immune responses and increase the risk of malaria. Methods. We performed a randomized, open-label, equivalence trial among 2436 school children in western Kenya. Eligible children were randomized to receive either 4 repeated doses or a single dose of albendazole and were followed up during 13 months to assess the incidence of clinical malaria. Secondary outcomes were Plasmodium prevalence and density, assessed by repeat cross-sectional surveys over 15 months. Analysis was conducted on an intention-to-treat basis with a prespecified equivalence range of 20%. Results. During 13 months of follow-up, the incidence rate of malaria was 0.27 episodes/person-year in the repeated treatment group and 0.26 episodes/person-year in the annual treatment group (incidence difference, 0.01; 95% confidence interval, −.03 to .06). The prevalence and density of malaria parasitemia did not differ by treatment group at any of the cross-sectional surveys. Conclusions. Our findings suggest that repeated deworming does not alter risks of clinical malaria or malaria parasitemia among school children and that school-based deworming in Africa may have no adverse consequences for malaria. Clinical Trials Registration. NCT01658774.
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Affiliation(s)
- Stella Kepha
- School of Public Health, Makerere University College of Health Sciences, Kampala, Uganda
| | - Fred Nuwaha
- School of Public Health, Makerere University College of Health Sciences, Kampala, Uganda
| | - Birgit Nikolay
- London School of Hygiene and Tropical Medicine, United Kingdom
| | - Paul Gichuki
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI)
| | - Charles S Mwandawiro
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI)
| | - Pauline N Mwinzi
- Neglected Tropical Diseases Research Unit, Center for Global Health Research, KEMRI, Kisumu, Kenya
| | - Maurice R Odiere
- Neglected Tropical Diseases Research Unit, Center for Global Health Research, KEMRI, Kisumu, Kenya
| | - Tansy Edwards
- London School of Hygiene and Tropical Medicine, United Kingdom
| | - Elizabeth Allen
- London School of Hygiene and Tropical Medicine, United Kingdom
| | - Simon J Brooker
- London School of Hygiene and Tropical Medicine, United Kingdom KEMRI-Wellcome Trust Research Programme, Nairobi
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Smith C, Barton D, Johnson M, Wendt C, Milligan M, Njoroge P, Gichuki P. Bird communities in sun and shade coffee farms in Kenya. Glob Ecol Conserv 2015. [DOI: 10.1016/j.gecco.2015.09.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Kepha S, Nuwaha F, Nikolay B, Gichuki P, Edwards T, Allen E, Njenga SM, Mwandawiro CS, Brooker SJ. Epidemiology of coinfection with soil transmitted helminths and Plasmodium falciparum among school children in Bumula District in western Kenya. Parasit Vectors 2015; 8:314. [PMID: 26063324 PMCID: PMC4486705 DOI: 10.1186/s13071-015-0891-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [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: 03/30/2015] [Accepted: 05/07/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Many school children living in Africa are infected with plasmodia and helminth species and are consequently at risk of coinfection. However, the epidemiology of such coinfection and the implications of coinfection for children's health remain poorly understood. This study describes the epidemiology of Ascaris lumbricoides-Plasmodium and hookworm-Plasmodium coinfection among school children living in western Kenya and investigates the associated risk factors. METHODS As part of a randomized trial, a baseline cross-sectional survey was conducted among school children aged 5-18 years in 23 schools in Bumula District. Single stool samples were collected to screen for helminth infections using the Kato-Katz technique and malaria parasitaemia was determined from a finger prick blood sample. Demographic and anthropometric data were also collected. RESULTS Overall, 46.4% of the children were infected with Plasmodium falciparum while 27.6% of the children were infected with at least one soil transmitted helminth (STH) species, with hookworm being the most common (16.8%) followed by A. lumbricoides (15.3%). Overall 14.3% of the children had STH-Plasmodium coinfection, with hookworm-Plasmodium (9.0%) coinfection being the most common. Geographical variation in the prevalence of coinfection occurred between schools. In multivariable logistic regression analysis, hookworm was positively associated with P. falciparum infection. In stratified analysis, hookworm infection was associated with increased odds of P. falciparum infection among both boys (P < 0.001) and girls (P = 0.01), whereas there was no association between A. lumbricoides and P. falciparum. CONCLUSION These findings demonstrate STH infections are still prevalent, despite the ongoing national deworming programme in Kenya, and that malaria parasitaemia is widespread, such that coinfection occurs among a proportion of children. A subsequent trial will allow us to investigate the implications of coinfection for the risk of clinical malaria.
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Affiliation(s)
- Stella Kepha
- College of Health Sciences, Makerere University, Kampala, Uganda. .,Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya.
| | - Fred Nuwaha
- College of Health Sciences, Makerere University, Kampala, Uganda.
| | - Birgit Nikolay
- London School of Hygiene & Tropical Medicine, London, UK.
| | - Paul Gichuki
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya.
| | - Tansy Edwards
- London School of Hygiene & Tropical Medicine, London, UK.
| | | | - Sammy M Njenga
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya.
| | - Charles S Mwandawiro
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya.
| | - Simon J Brooker
- London School of Hygiene & Tropical Medicine, London, UK. .,KEMRI-Wellcome Trust Research Programme, Nairobi, Kenya.
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