A new rapid diagnostic test for detection of anti-Schistosoma mansoni and anti-Schistosoma haematobium antibodies

Background: parasitological methods are widely used for the diagnosis of schistosomiasis. however,they are insensitive,particularly in areas of low endemicity,and labour-intensive. immunoassays based on detection of anti-schistosome antibodies have the merit of high sensitivity and recently a rapid diagnostic test (rdt),incorporating schistosoma mansoni cercarial transformation fluid (smctf) for detection of anti-schistosome antibodies in blood has been developed. here,we assessed the diagnostic performance of the smctf-rdt for s. mansoni and s. haematobium infections by comparing it with microscopy for egg detection. methods. a cross-sectional survey was carried out in azaguié,south côte d'ivoire. 118 pre-school-aged children submitted two stool and two urine samples,which were subjected to the kato-katz and urine filtration methods for the detection of s. mansoni and s. haematobium eggs,respectively. urine was also subjected to a commercially available cassette test for s. mansoni,which detects circulating cathodic antigen. a finger-prick blood sample was used for the smctf-rdt for detection of anti-s. mansoni and anti-s. haematobium antibodies. results: the prevalence of both anti-s. mansoni and anti-s. haematobium antibodies was more than three times higher than the prevalence of infection estimated by egg detection under a microscope. using quadruplicate kato-katz as the reference standard for the diagnosis of s. mansoni infection,the sensitivity,negative predictive value (npv),and positive predictive value (ppv) of the smctf-rdt was 75.0%,84.2% and 22.5%,respectively. when two urine filtrations were considered as the reference standard for the diagnosis of s. haematobium infection,the sensitivity,npv and ppv of smctf-rdt was 66.7%,94.9% and 5.1%,respectively. the specificity of smctf-rdt,when using egg-detection as the reference standard,was estimated to be 34.4%. this low specificity may be a reflection of the relative insensitivity of the direct diagnostic approaches using microscopy. conclusions: the smctf-rdt is at least as sensitive as duplicate kato-katz and a single urine filtration for detection of s. mansoni and s. haematobium,respectively. further investigations into the specificity of the test for anti-schistosome antibodies are necessary,but our results suggest that it may be a useful tool for mapping the prevalence of anti-schistosome antibodies in a given population pending intervention. © 2013 coulibaly et al; licensee biomed central ltd.