A cross-sectional study on schistosomiasis and soil-transmitted helminths in Mbita district,western Kenya using different copromicroscopic techniques

Background: identification of populations to be targeted for individual treatment and broad-spectrum therapy in schistosomiasis-endemic areas,assessment of therapy efficacy,morbidity,and evaluation of control strategies need to be based on reliable diagnostic tools. kato-katz is routinely used and remains the standard diagnostic technique for schistosomiasis,despite its many challenges. this study was conducted in nyamanga village,mbita,western kenya,and evaluated the diagnostic performance of kato-katz,mini-parasep and modified mini-flotac techniques in detection of schistosoma mansoni and soil-transmitted helminths (ascaris lumbricoides,trichuris trichiura and hookworm) ova. methods: stool samples from 132 individuals were screened for eggs of s. mansoni by the 3 techniques. mini-parasep® faecal parasite concentrator (apacor ltd,england),a single-use diagnostic device with a built-in filter for faecal concentration of helminth eggs by sedimentation was employed on stool samples fixed in 10 % formalin. a modified mini-flotac (university of naples,italy) was based on floatation of helminths eggs with two different solutions (fs2 and fs7) using a closed system (fill-flotac) with 5 % formalin. kato-katz was performed following who recommendation. prevalence of s. mansoni and sth,sensitivity and degree of agreement among the 3 techniques were determined. results: prevalence of s. mansoni was 47.0 %,34.1 % and 20.5 % by mini-parasep,kato-katz and modified mini-flotac fs7 techniques,respectively. prevalence of any sth infection was 6.1 %,3.0 %,6.1 % and 6.8 % by mini-parasep,kato-katz,modified mini-flotac fs2 and modified mini-flotac fs7 techniques,respectively. considering the pooled results of the three methods (mini-parasep,kato-katz and modified mini-flotac fs7) as diagnostic 'gold' standard,the sensitivity of mini-parasep,kato-katz and modified mini-flotac fs7 for s. mansoni was 77.5 %,56.1 %,and 33.8 %,respectively. mini-parasep and modified mini-flotac fs7 techniques had moderate (κ=0.46) and fairly good (κ=0.25) agreements with kato-katz for s. mansoni,respectively. mini-parasep detected a higher proportion of light intensity s. mansoni infections compared to kato-katz,which detected high proportions of heavy infections. mini-parasep detected a similar mean number of s. mansoni eggs per gram (epg) of stool compared to the standard kato-katz (62.9 vs 97.3; t (131)=-0.49,p=0.6265) and significantly higher epg compared to the modified mini-flotac fs7 (62.9 vs 34.6; t (131)=5.39,p<0.0001). conclusions: the high sensitivity of mini-parasep suggests its promising potential as an alternative tool in enhancing diagnosis and in monitoring schistosomiasis transmission and determining endpoint of intervention programs,especially in low endemicity areas. mini-parasep is also easy to operate,safe and also permits work with fresh stool. © 2016 ng'etich et al.