[Development and assessment of Schistosoma japonicum antibody test kit (IHA)].

OBJECTIVE: To develop a Schistosoma japonicum antibody test kit (IHA). METHODS: According to the requirement of Good Manufacturing Practice (GMP) and Quality Control (QC) of drugs, the components of kit as well as its preparation method and procedure were studied, and the test kit was assembled and its diagnostic effect was assessed. RESULTS: The sensitivity and specificity were up to 94.49% and 97.14% when testing the serum samples of chronic schistosomiasis patients and normal serum samples by the kit, respectively. The Youden Index of the Kit was 0.92. The cross reaction rates with paragonimus and trichina were 15.00% and 10.00%, respectively. Compared with ELISA and another IHA kit produced by An'Ji company which were used to test schistosome antibody in residents of endemic areas at the same time, the coincident rates of the developed kit were 93.06% and 92.25%, respectively. CONCLUSION: The IHA kit for Schistosomajaponicum antibody has a high sensitivity and specificity, and has the value of application and popularization in the field.

[Diagnostic efficiency of Indirect Hemagglutination Assay Kit for antibody detection of schistosomiasis japonica].

OBJECTIVE: To evaluate the clinical diagnostic efficiency of Indirect Hemagglutination Assay Kit (IHA kit) for antibody detection of schistosomiasis japonica. METHODS: Schistosomiasis examinations by parasitological method were conducted in the schistosomiasis endemic areas in Jiangxi, Anhui and Hubei provinces, respectively. A total of 371 serum samples of schistosomiasis patients and 761 serum samples of non-patients without history of schistosome infection and infested water contact were collected. All the sera were detected by using IHA Kit. The diagnostic efficiency indicators of the kit, including sensitivity, specificity, positive predicted value, negative predicted value etc. were calculated. RESULTS: The sensitivity and specificity of the kit were 95.1% (95% confidence interval was between 92.9% and 97.3%) and 97.8% (95% confidence interval was between 96.8% and 98.8%), respectively; the positive and negative predicted values were 95.4% and 97.6%, respectively. No statistically significant difference was found in the prevalence of IHA positive detecting by the kit among the groups with different EPG levels (< or = 40, 41-100, > 100). Also, no significant difference was observed in sensitivity and specificity among the different age groups. CONCLUSIONS: The IHA kit shows a relative high efficiency for diagnosis and can be used for mass screening of schistosomiasis in field sites.

[Effectiveness of routinely used assays for the diagnosis of schistosomiasis japonica in the field].

OBJECTIVE: To evaluate the effectiveness of routinely used assays for schistosomiasis diagnosis in the field. METHODS: From late November to early December 2005, 6-65 years old inhabitants from 3 endemic villages were examined by Kato-Katz technique (3 thick smears) and nylon bag sedimentation/hatching method. At the same time, dipstick dye immunoassay(DDIA), fast enzyme linked immunosorbent assay (F-ELISA), indirect haemagglutination test A (IHA-A) and B ( IHA-B) were carried out in parallel RESULTS: 1864 people were examined by stool examination with an average positive rate of 9.7%. The missing rate of DDIA was relatively stable in medium and heavily endemic areas of schistosomiasis. The missing rate of nylon bag sedimentation/hatching method was 25% and relatively stable when the number of eggs per gram of feces(EPG) was larger than 100. The average positive rate of DDIA, F-ELISA, IHA-A and IHA-B was 47.8%, 50.0%, 66.3% and 40.1% respectively. Using stool examination as the gold standard, the sensitivity of DDIA, F-ELISA, IHA-A and IHA-B was 75.3%, 65.8%, 85.6% and 76.0%; and the specificity was 55.1%, 51.7%, 35.7% and 63.6%, respectively. Among the four sero-diagnostics, the specificity, Youden index, positive likelihood rate and coincidence of IHA-B were the highest. CONCLUSION: Kato-Katz method is more stable and effective than nylon bag sedimentation/hatching method in medium and heavily endemic areas of schistosomiasis japonica. The sensitivity and specificity of these four diagnosis kits are lower than 90%.

[A case-control study on risk factors for advanced schistosomiasis japonica].

OBJECTIVE: To investigate risk factors for the development of advanced schistosomiasis. METHODS: The case-control study was designed with a match of 1:1 and 1:2. Healthy persons and chronic schistosomiasis patients were used as control. Each group was composed of 213 cases. Items investigated included: history of schistosomiasis and treatment, exposure to the contaminated water, social-economical condition and nutritional status, other concomitant diseases. Cellular and humoral immunity, HBVMs and ABO blood groups were also detected. Statistical analysis was performed by 1:1 and 1:2 matched single and stepwise conditional logistic regression analysis with SAS software. RESULTS: By stepwise conditional logistic regression analysis, it was revealed that number of schistosomiasis examination (OR = 1.168-1.311), interval from first infection to last treatment(OR = 1.142), interval from first infection to this investigation (OR = 1.089), HBsAg+ (OR = 4.683-10.759), HBcAb+ (OR = 2.873), HBsAg+ + HBeAb+ + HBcAb+ (OR = 7.64) were risk factors of developing advanced schistosomiasis. The average living space and cellular immunity were lower in advanced schistosomiasis patients than others. No association was found between advanced schistosomiasis and ABO blood groups. CONCLUSION: The development of advanced schistosomiasis is associated with repeated infections, and delayed or incomplete treatment. Combined infection with hepatitis B, poor socio-economic conditions and impaired cellular immunity may increase the pathogenetic risk of schistosomiasis.