Impact of repeated four-monthly anthelmintic treatment on Plasmodium infection in preschool children: a double-blind placebo-controlled randomized trial

A double-blind placebo-controlled randomised trial was conducted to investigate the impact of anthelmintic treatment on Plasmodium infection in children aged 12-59 months. Children were randomly assigned to receive either albendazole or placebo every four months for 12 months with a follow-up at 14 months.320 children (out of 1228, 26.1%) complied with all the follow-up assessments. Plasmodium prevalence and mean Plasmodium parasite density was significantly higher in the treatment group (44.9% and 2319 ± SE 511) compared to the placebo group (33.3% and 1471 ± 341) at baseline. The odds of having Plasmodium infection increased over time for children in both the placebo and treatment groups, however this increase was significantly slower for children in the treatment group (P = 0.002). By month 14, mean Plasmodium density had increased by 156% in the placebo group and 98% in the treatment group but the rate of change in Plasmodium density was not significantly different between the groups. The change from baseline in haemoglobin had a steeper increase among children in the treatment group when compared to the placebo group but this was not statistically significant.Repeated four-monthly anthelminthic treatments for 14 months resulted in a significantly lower increase in the prevalence of Plasmodium infection in preschool children which coincided with a reduction in both the prevalence and intensity of A. lumbricoides infections.Current controlled trials ISRCTN44215995Infections with multiple parasitic species are common in nature [1]. Synergistic and competitive interactions can occur between parasite species, which can influence the likelihood of their successful transmission to other hosts and increase or decrease their overall pathogenic impact [2]. It is estimated that over a third of the world's population are infected with helminths [3] or one or more of the Plasmodium species [4]. Populations infected with helminths and Plasmodium are mainly confined to the tr