Comparative evaluation of Strongyloides ratti and S. stercoralis larval antigen for diagnosis of strongyloidiasis in an endemic area of opisthorchiasis

Abstract

The use of Strongyloides ratti as heterologous antigen for serodiagnosis of strongyloidiasis is preferable to Strongyloides from humans due to the ease and safety of antigen preparation. In Southeast Asia where Opisthorchis viverrini coexists with Strongyloides stercoralis, there has been no report in using S. ratti for serodiagnosis of S. stercoralis. In this study, performance of an enzyme-linked immunosorbent assay (ELISA) based on S. ratti was compared with that based on S. stercoralis for diagnosis of strongyloidiasis in areas where O. viverrini is co-endemic in Thailand. Of the 107 individuals, 50 (46.7 %) were positive for S. stercoralis by agar culture method and by ELISA; 82 (76.6 %) and 81 (75.7 %) were seropositive using S. ratti and S. stercoralis antigens, respectively. The levels of parasite-specific IgG to S. ratti and S. stercoralis antigen were significantly proportionally correlated (P < 0.001). Mixed infections with O. viverrini have little effect on diagnosis of strongyloidiasis. Of 42 subjects who were infected with other parasites, there were no cross-reaction with Angiostrongylus cantonensis, Taenia spp., hookworms, Paragonimus spp., Clonorchis sinensis, Ascaris lumbricoides except for Fasciola spp. (1 of 5), and Opisthorchis viverrini (5 of 20). In spite of cross-reactivities, the results suggest that the S. ratti antigen provides an useful option for diagnosis of strongyloidiasis in an endemic area of opisthorchiasis with high sensitivity comparable to the S. stercoralis antigen and provide a basis for effective control strategies for strongyloidiasis.

Strongyloides stercoralis diagnostic polypeptides for human strongyloidiasis and their proteomic analysis

“…Strongyloidiasis is primarily diagnosed by detecting larvae in stool samples using method such as direct fecal smear examination, Baermann concentration, formalinethyl acetate concentration, Harada-Mori filter paper culture, and agar plate cultures (Olsen et al 2009). The development of reliable immunological assays is an important alternative approach for strongyloidiasis diagnosis (Levenhagen and Costa-Cruz 2014;Eamudomkarn et al 2015). Immunoblot analysis has been reported as a method for detection of the specific antibody against various antigenic polypeptide bands (Sato et al 1990;Northern and Grove 1990;Conway et al 1993Conway et al , 1994Atkins et al 1999;Sudre et al 2007).…”

Strongyloides stercoralis: spatial distribution of a highly prevalent and ubiquitous soil-transmitted helminth in Cambodia

“…Previously to this national survey, prevalence was 397 found to increase with age and reach a plateau in adulthood in North Cambodia, while no 398 cases were found in individuals aged less than 15 years in Yunnan, China [9,45,46]. Yet, no 425 other STH [20,21]. However, validation of the method in different settings should be carried 426 out.…”

“…While this last 98 aspect would be an issue for cure assessment, it would not affect prevalence estimates in a 99 population naïve to treatment against the investigated parasite. A serological test using an 100 antigen from S. ratti to detect antibodies in urine was recently developed in Thailand [20,21].…”

“…A serological test using an 100 antigen from S. ratti to detect antibodies in urine was recently developed in Thailand [20,21].…”

“…This technique has several strengths. While collecting urine samples is much easier than fecal 102 samples, this test has a high sensitivity for S. stercoralis detection and does not cross-react 103 with other soil-transmitted helminth (STH) species [20,21]. 104 Geostatistical models have been increasingly used in the past decade to delineate risk 105 zones for helminthic infections at small and large scale and help targeting control efforts in 106 areas of highest need [22][23][24][25][26][27][28][29].…”