Impact of repeated mass chemotherapy for filariasis control on soil-transmitted helminth infections in Sri Lanka

Abstract

INTRODUCTION: Under the national lymphatic filariasis elimination programme, five rounds of mass drug administration with diethylcarbarnazine citrate and albendazole were completed in July 2006. Albendazole is also highly effective against soil-transmitted helminths'^ STH). OBJECTIVE: To assess the impact of repeated annual mass chemotherapy with albendazole on STH infections in a co-endemic area. DESIGN, SETTING AND METHODS: Seventeen schools from among the State schools in the Western Province were selected because they were included in a national survey of the health of school children in Grade 5 in 2003. Fecal samples were obtained from one randomly selected class of Grade 5 students in each school in October 2006, and examined using the modified Kato-Katz technique. The prevalence and intensity of ascariasis, trichuriasis and hookworm infections in 2003 and 2006 were compared. RESULTS: Fecal samples from 448 children were examined in 2006, compared with 255 in 2003. Prevalence of ascariasis had declined marginally (18/448, 4.0% in 2006 vs 12/255, 4.7% in 2003), as had hookworm infection (1/448, 0.2%, vs 1/255, 0.4%), whereas the prevalence of trichuriasis had increased (62/448, 13.8% vs 24/255, 9.4%). Mean egg counts for all three infections were marginally higher in 2006 than in 2003. However, all these differences were not statistically significant. Reported compliance with MDA 2006 was 58.6%. Conclusions: The prevalence and intensity of STH infections among schoolchildren in the Western Province have not improved much despite annual mass drug administration with albendazole.