Tools to support policy decisions related to treatment strategies and surveillance of Schistosomiasis japonica towards elimination.
BACKGROUND
Appropriate diagnostics to monitor disease trends and assess the effectiveness and impact of interventions are essential for guiding treatment strategies at different thresholds of schistosomiasis transmission and for certifying elimination. Field validation of these assays is urgently needed before they can be adopted to support policy decisions of the national programme for control and elimination of schistosomiasis in P.R. China. We compared the efficacy and utility of different immunoassays in guiding control strategies and monitoring the endemic status of S. japonicum infections towards elimination.


RESULTS
A cross-sectional survey was conducted in seven villages with different transmission intensities settings to assess the performance and utility of three immunoassays, e.g., an indirect hemagglutination assay (IHA_JX), an enzyme linked immunosorbent assay (ELISA_SZ), and a dot immunogold filtration assay (DIGFA_SH). 6,248 individuals aged 6-65 years old who gave consent and supplied their stool and blood samples were included for data analysis. Results showed that ELISA_SZ performed significantly higher sensitivity (95.45%, 95%CI: 92.94-97.97%) than IHA_JX (87.59%, 95%CI: 83.51-91.49%) and DIGFA_SH (79.55%, 95%CI: 74.68-84.41%), especially in subgroups with very low infection intensity. The specificity of ELISA_SZ, IHA_JX, DIGFA_SH in 6-9 year olds with occasional exposure was nearly 90%. DIGFA_SH performed the highest screening efficacy for patients among three assays with overall positive predicative value of 13.07% (95%CI: 11.42-14.72%). We found a positive correlation of antibody positive rate of IHA_JX with results of stool examination in age strata (r = 0.70, P<0.001). Seropositivity of IHA_JX in children aged 6-9 years old showed an excellent correlation with prevalence of schistosome infection in the seven communities (r = 0.77, P<0.05).


CONCLUSIONS
Studies suggest that ELISA_SZ could be used to guide selective chemotherapy in moderate or low endemic regions. IHA_JX could be used to as a surveillance tool and for certifying elimination of schistosomiasis through monitoring children as a sentinel population.
National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, People's Republic of China.
Xiao-Nong
XN
Zhou
Jing
J
Xu
Hong-Gen
HG
Chen
Tian-Ping
TP
Wang
Xi-Bao
XB
Huang
Dan-Dan
DD
Lin
Qi-Zhi
QZ
Wang
Li
L
Tang
Jia-Gang
JG
Guo
Xiao-Hua
XH
Wu
Ting
T
Feng
Jia-Xu
JX
Chen
Jian
J
Guo
Shao-Hong
SH
Chen
Hao
H
Li
Zhong-Dao
ZD
Wu
Rosanna W
RW
Peeling
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D002648:Child; D002681:China / Q000453:epidemiology; D019411:Clinical Laboratory Techniques / Q000379:methods*; D003430:Cross-Sectional Studies; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D006291:Health Policy; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D008875:Middle Aged; D012554:Schistosomiasis japonica / Q000175:diagnosis* / Q000188:drug therapy* / Q000453:epidemiology / Q000517:prevention & control; D012680:Sensitivity and Specificity; D055815:Young Adult