ABSTRACT
BACKGROUND Loa loa is a filarial species found exclusively in West and Central Africa. Microscopy is the traditional diagnosis method for human loiasis. Several molecular methods have developed as an alternative approach for identification of L. loa filarial parasites. OBJECTIVES The aim of this study was to evaluate a Loa-Loop-mediated isothermal amplification (LAMP) assay to diagnose loiasis disease on dried blood spots (DBS) samples, compared to microscopy, filaria-real time-polymerase chain reaction (PCR) and nested-Loa PCR. METHODS A total of 100 DBS samples and 100 blood smears were used for this study. DNA was extracted using saponin/Chelex method. DNA isolated was assayed by a Loa-LAMP assay in parallel to microscopy, filaria-real time PCR and nested-Loa PCR. The sensitivities and specificities of Loa-LAMP assay was computed comparing to each one of the reference methods. FINDINGS Loa-LAMP's sensitivity was more than 90% and specificity was nearly 100% when compared to molecular methods. On the other hand, sensitivity was decreased a bit when Loa-LAMP faced microscopy, but keeping the other statistical values high. MAIN CONCLUSIONS Loa-LAMP is an appropriate method for loiasis diagnosis in endemic areas. Though, it has disadvantages like the reagents' high price at the moment and not to be able to detect more filarial species at once.
ABSTRACT
Introduction: This study aimed to determine the prevalence of intestinal helminths; risk factors and haematocrit values among primary schoolchildren. Methodology: Across-sectional study was conducted in 12 primary schools in March 2011. Stool samples were randomly selected from 778 children and were microscopically examined using Kato-Katz and formal-ether concentration methods. Haematocrit values were measured using heparinized capillary tubes. Results: The overall prevalence of intestinal helminths was 51.5 (rural = 68.3; urban = 36.2). Hookworm spp.; Schistosoma mansoni and Schistosoma stercoralis were more prevalent in rural schools; whereas Hymenolepis nana was higher in urban schools (p = 0.0001). With regard to haematocrit; 34 of rural and 21.7 of urban schoolchildren had haematocrit values below the median (40.5) (p=0.001). Hookworm spp. and S. mansoni infected children had lower haematocrit values than non-infected children (p = 0.001). Lack of footwear was positively associated with intestinal helminths infection in rural schools [OR = 2.5 (95 CI: 1.5-4.1)]; and having dirty fingernails and untrimmed fingernails were positively associated with the prevalence of intestinal helminths in urban samples [OR = 1.58 (95 CI: 1.03-2.5)]. Conclusion: The prevalence of soil-transmitted helminths and S. mansoni differs by geographical area of the schools and social determinants. Primary school de-worming and health education on proper hygiene are recommended