Research Article Lateral Flow Loop-Mediated Isothermal Amplification Test with Stem Primers: Detection of Cryptosporidium Species in Kenyan Children Presenting with Diarrhea Timothy S. Mamba , 1 Cecilia K. Mbae , 2 Johnson Kinyua, 1 Erastus Mulinge, 2 Gitonga Nkanata Mburugu, 3 and Zablon K. Njiru 3,4 1 Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000-0200, Nairobi, Kenya 2 Centre for Microbiology Research, Kenya Medical Research Institute, P.O. Box 19464-00202, Nairobi, Kenya 3 School of Health Sciences, Meru University of Science and Technology, P.O. Box 972-60200, Meru, Kenya 4 School of Health Professions, Murdoch University, Mandurah Campus, Education Drive, Mandurah, WA 6210, Australia Correspondence should be addressed to Timothy S. Mamba; timothysmamba@gmail.com Received 17 November 2017; Accepted 28 January 2018; Published 26 February 2018 Academic Editor: Carlos E. P. Corbett Copyright © 2018 Timothy S. Mamba et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. Cryptosporidium is a protozoan parasite and a major cause of diarrhea in children and immunocompromised patients. Current diagnostic methods for cryptosporidiosis such as microscopy have low sensitivity while techniques such as PCR indicate higher sensitivity levels but are seldom used in developing countries due to their associated cost. A loop-mediated isothermal amplifcation (LAMP) technique, a method with shorter time to result and with equal or higher sensitivity compared to PCR, has been developed and applied in the detection of Cryptosporidium species. Te test has a detection limit of 10 pg/l(∼100 oocysts/ml) indicating a need for more sensitive diagnostic tools. Tis study developed a more sensitive lateral fow dipstick (LFD) LAMP test based on SAM-1 gene and with the addition of a second set of reaction accelerating primers (stem primers). Results. Te stem LFD LAMP test showed analytical sensitivity of 10 oocysts/ml compared to 100 oocysts/ml (10 pg/ul) for each of the SAM-1 LAMP test and nested PCR. Te stem LFD LAMP and nested PCR detected 29/39 and 25/39 positive samples of previously identifed C. parvum and C. hominis DNA, respectively. Te SAM-1 LAMP detected 27/39. On detection of Cryptosporidium DNA in 67 clinical samples, the stem LFD LAMP detected 16 samples and SAM-2 LAMP 14 and nested PCR identifed 11. Preheating the templates increased detection by stem LFD LAMP to 19 samples. Time to results from master mix preparation step took ∼80 minutes. Te test was specifc, and no cross-amplifcation was recorded with nontarget DNA. Conclusion. Te developed stem LFD LAMP test is an appropriate method for the detection of C. hominis, C. parvum, and C. meleagridis DNA in human stool samples. It can be used in algorithm with other diagnostic tests and may ofer promise as an efective diagnostic tool in the control of cryptosporidiosis. 1. Background Cryptosporidiosis is caused by a group of phenotypically, and genotypically diverse Cryptosporidium species [1] and transmission of infection occurs when an individual comes in contact with infective oocyst(s) via contaminated food, water, person-to-person contact [2–4], and contact with animals. Transmission is common in developing countries due to poor sanitation and limited access to safe drinking water. Te disease afects enterocytes of the small intestines and is a major cause of diarrhea, hospitalization, malnutrition in children [5–7] and can be fatal among immune-compromised persons [3, 4]. Te ability of low doses of oocysts to cause infection following exposure and the absence of sensitive and efective diagnostic tools and treatment regime make cryptosporidiosis a major public health concern [5, 8]. In Sub-Saharan Africa and South Asia where most diarrheal disease deaths occur, there is limited data on the burden of Cryptosporidium diarrheal cases [9]. Nevertheless, the prevalence of the infection is thought to range from 10 to 33% among Human Immunodefciency Virus (HIV) infected adult persons [10] and can even be higher in Hindawi Journal of Tropical Medicine Volume 2018, Article ID 7659730, 9 pages https://doi.org/10.1155/2018/7659730