Accuracy of the Kato-Katz method and formalin-ether concentration technique for the diagnosis of Clonorchis sinensis, and implication for assessing drug efficacy.
BACKGROUND
Clonorchiasis is a chronic neglected disease caused by a liver fluke, Clonorchis sinensis. Chemotherapy is the mainstay of control and treatment efficacy is usually determined by microscopic examination of fecal samples. We assessed the diagnostic accuracy of the Kato-Katz method and the formalin-ether concentration technique (FECT) for C. sinensis diagnosis, and studied the effect of diagnostic approach on drug efficacy evaluation.


METHODS
Overall, 74 individuals aged ≥18 years with a parasitological confirmed C. sinensis infection at baseline were re-examined 3 weeks after treatment. Before and after treatment, two stool samples were obtained from each participant and each sample was subjected to triplicate Kato-Katz thick smears and a single FECT examination.


RESULTS
Thirty-eight individuals were still positive for C. sinensis according to our diagnostic 'gold' standard (six Kato-Katz thick smears plus two FECT). Two FECT had a significantly lower sensitivity than six Kato-Katz thick smears (44.7% versus 92.1%; p <0.001). Examination of single Kato-Katz and single FECT considerably overestimated cure rates.


CONCLUSIONS
In settings where molecular diagnostic assays are absent, multiple Kato-Katz thick smears should be examined for an accurate diagnosis of C. sinensis infection and for assessing drug efficacy against this liver fluke infection.
Men-Bao
MB
Qian
Peiling
P
Yap
Yi-Chao
YC
Yang
Hai
H
Liang
Zhi-Hua
ZH
Jiang
Wei
W
Li
Jürg
J
Utzinger
Xiao-Nong
XN
Zhou
University of Basel, Basel, Switzerland. jennifer.keiser@unibas.ch.
Jennifer
J
Keiser
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D019411:Clinical Laboratory Techniques / Q000379:methods*; D003003:Clonorchiasis / Q000175:diagnosis* / Q000188:drug therapy* / Q000469:parasitology; D003004:Clonorchis sinensis / Q000302:isolation & purification*; D016903:Drug Monitoring / Q000379:methods*; D005243:Feces / Q000469:parasitology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010274:Parasitology / Q000379:methods*; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods; D055815:Young Adult
D000871:Anthelmintics