Impact of Repeated Anthelmintic Treatment on the Risk of Malaria in Kenyan School Children
Status:
Completed
Trial end date:
2015-01-01
Target enrollment:
Participant gender:
Summary
Many school children in Kenya are infected with plasmodia and helminth species and are at
risk of coinfection. It has been suggested that the immune response evoked by helminth
infections may modify immune responses to plasmodia species and consequently alter infection
and disease risks. However, studies conducted to date have been typically cross-sectional and
produced conflicting results, and there is a need for longitudinal studies to better
understand the clinical consequences for individuals harbouring coinfection. This study aims
to investigate the impact of intensive (once every 3 months) anthelminthic treatment versus
annual treatment on the risk of clinical malaria and on immune responses among school
children aged 5-14 years in Western Province. Specifically, this study aims to investigate
the impact of intensive anthelminthic treatment on (i) the incidence of clinical malaria in
school children, assessed using active case detection; (ii) the prevalence and density of
Plasmodium spp. infection, using repeat cross-sectional surveys; and (iii) malaria and
helminth specific immune responses. The study hypothesis is that intensive anthelminthic
treatment among children infected with either Ascaris lumbricoides or hookworm modifies human
host immune responses to plasmodia and helminth infections, and therefore alters the risk of
Plasmodium infection and clinical disease.
This individually randomised trial will recruit 1,450 children aged 5-14 years found to be
infected with either Ascaris lumbricoides or hookworm species. Recruited children will be
randomized to receive albendazole treatment either every three months or annually and
monitored through periodic surveillance for clinical malaria episodes over 18 months. In
addition, blood samples will be collected from sub-sample of children and screened for
malaria specific immunoglobulin (Ig)G1 and IgG3 and helminth specific IgE, IgG2, IgG4 and
IgM. Cell culture supernatants will be assayed for interferon (IFN)-γ, tumor necrosis factor
(TNF)-α, interleukin (IL)-10, IL-5, IL-4 and IL-2.