Performances of Mini Parasep SF stool concentrator kit , Kato-Katz and formalin-ethyl acetate concentration methods for diagnosis of opisthorchiasis among residents in an endemic community in northeast Thailand

Abstract

Background Control and elimination of the liver fluke (Opisthorchis viverrini) is a primary preventive strategy against cholangiocarcinoma in Southeast Asia. A sensitive parasitological diagnostic method is required to facilitate such a surveillance and control program. In this study, we evaluated the performance of Mini Parasep SF stool concentrator kit (stool kit) in comparison with Kato-Katz (KK) and the quantitative formalin-ethyl acetate concentration technique (FECT) for detection of O. viverrini and coexisted parasitic infections. Methods A cross-sectional survey of parasitic infection of residents age <15 years old in a community in Kalasin province, northeast Thailand was conducted in 2018. Fecal samples were collected and screened by KK method and a subset of samples was examined by the stool kit and FECT methods. The results were analyzed for prevalence of parasitic infections and diagnostic performances of methods for qualitative and quantitative detection of helminthiasis. Results The initial survey of parasitic infection determined by the KK method (n=567) showed the prevalence of O. viverrini was 32.63%, followed by Taenia 2.65%, echinostomes 1.76%, hookworms 1.41%, Trichuris trichiura 0.53%, and Strongyloides stercoralis 0.53%. Within a subset of samples tested with multiple diagnostics (n=150), the detection rates of O. viverrini by the stool kit, FECT, and KK methods were 27.3%, 30.7%, and 28.7%, respectively. The diagnostic sensitivity for opisthorchiasis were similar for FECT (75.4%) and KK (70.5%) and was lower for the stool kit (67.2%, p<0.05). For other parasitic infections, FECT and stool kit performed better than KK methods particularly in detecting minute intestinal fluke (MIF), S. stercoralis, and coinfections. The intensity of O. viverrini infection (fecal egg counts) by the stool kit had significant positive correlations with KK as well as FECT (p<0.05). Conclusions As the stool kit is simple to use and showed a comparable performance to FECT, it may serve as an alternative method of fecal examination for screening of helminthiasis including opisthorchiasis.