Comparison of three copromicroscopic methods to assess albendazole efficacy against soil-transmitted helminth infections in school-aged children on Pemba Island

The diagnostic accuracy of three faecal egg count techniques (KatoKatz, McMaster and FLOTAC) to assess albendazole efficacy against soil-transmitted helminth (STH) infections was compared. The study is registered with Current Controlled Trials [identifier: ISRCTN90088840]. During SeptemberNovember 2009, 304 school-aged children on Pemba Island, Tanzania, were screened and those infected with Ascaris lumbricoides, hookworm or Trichuris trichiura were treated with a single dose of albendazole (400 mg). Twenty-one days post-treatment, children provided a single stool sample which was examined using the same diagnostic methods. All stool samples were divided into two aliquots and one was fixed in 5 formalin and examined using FLOTAC and McMaster approximately 6 months after collection. Using fresh stool samples, comparable prevalences were demonstrated for the three methods at baseline (9092.2 for T. trichiura, 41.152.8 for hookworm, 32.937.2 for A. lumbricoides); FLOTAC was the most sensitive method at baseline and follow-up. Albendazole showed high cure rate (CR) against A.lumbricoides (9097), moderate CR against hookworm (6372) and very low CR against T.trichiura (69), regardless of the technique used. Egg counts (eggs per gram) at baseline were similar for A. lumbricoides and for hookworm among the three methods, and higher using McMaster and KatoKatz compared with FLOTAC for T. trichiura. All methods were similar for hookworm and A. lumbricoides egg reduction rate (ERR) estimation, but KatoKatz indicated a significantly higher ERR than McMaster and FLOTAC for T. trichiura. Preserved stool samples revealed consistently lower FECs at baseline and follow-up for all STHs. Further development and validation of standard protocols for anthelminthic drug efficacy evaluation must be pursued.