Evidence for an improvement in cognitive function following treatment of Schistosoma japonicum infection in Chinese primary schoolchildren

A double-blind, placebo-controlled, treatment trial was conducted in Sichua n, China to investigate the unique and combined effects on the cognitive fu nction (working memory) of children after treating geohelminth infections w ith albendazole and treating Schistosoma japonicum infection with praziquan tel. One hundred eighty-one children 5-16 years of age participated. At bas eline, the praziquantel and placebo groups were similar in all background c haracteristics. Three months after praziquantel treatment, there was a sign ificant reduction in the prevalence and intensity of S. japonicum infection . There were significant age group by praziquantel treatment interaction ef fects in three of the five cognitive tests, Fluency, Picture Search, and Fr ee Recall, with effects being strongest in the youngest children (5-7 years old). Exploratory analysis within the youngest children showed a significa nt positive main effect of treatment on Fluency (P < 0.001), after controll ing for sex, anthropometric, and parasitic and iron status. There was also a treatment by height-for-age interaction (P = 0.03) and a treatment by iro n status interaction (P = 0.024) on Fluency. There was a treatment by S. ja ponicum intensity interaction (P < 0.001) on Free Recall, but the main effe ct of treatment on Picture Search was not significant (P = 0.058). Younger children and those who are physically the most vulnerable are likely to ben efit the most from the treatment of S. japonicum infection in terms of impr oved performance on tests of working memory.