Each child was asked to select a card from the pile and any child who drew a yes card, was selected to participate. Open in a separate window Figure 1 Geographical locations of primary schools sampled in the survey.Circles represent the GPS location of the school. A copy of the information sheet describing the study together with an invitation to meet the study team on a pre-defined date at the school premises were distributed to the caregivers of the selected children who were asked to take them home. a multilevel mixed-effects logistic regression model, simultaneously PF-4191834 adjusting for variations between individuals and school. Results A total of 4140 children, 1897 (46%) boys, were enrolled with mean age of 10.2 years (SD 2.6, range 4C20 years). Microscopy results available for 3640 (87.9%) children showed that 1.9% (69) were positive for infections, most of them (97.1%, 67/69) asymptomatic. The overall seroprevalence was 12.7% (527/4140) with values for the schools ranging from 0.6% to 43.8%. Age (OR 1.12, 95% CI 1.07C1.16,) and parasite carriage (OR 3.36, 95% CI 1.95C5.79) were strongly associated with seropositivity. Conclusion Serological responses to malaria parasites could identify individuals who were or had been infected, and clusters of residual transmission. Field-adapted antibody tests able to guide mass screening and treatment campaigns would PF-4191834 be extremely useful. Introduction In the past decade, there has been a significant but uneven reduction in malaria indicators [1], [2] following the scale up of effective interventions, partly attributed to underlying heterogeneities in malaria transmission [3]. Understanding the dynamics of transmission in places with such heterogeneity could help to explain why similar interventions have differential PF-4191834 impact and support targeted control efforts. An important first step is to determine the tools and Rabbit Polyclonal to FGFR1 (phospho-Tyr766) methods that can efficiently detect these variations in malaria transmission [4]. Classically, malaria endemicity and transmission are described by the parasite prevalence and the entomological inoculation rate (EIR) respectively, and these methods remain useful in many settings. Nevertheless, in low transmission settings, the paucity of infected mosquitoes, the need to collect and analyse large number of samples coupled with declining sensitivities of microscopy, RDTs and EIRs reduce the efficiency of these methods [5]. Estimating the prevalence of antimalarial antibody (seroprevalence) is increasingly recognised as a valuable complement to classic methods for defining transmission intensity [6], [7], determining heterogeneity in outcomes of malaria interventions [8] and for malaria surveillance [9]. Where malaria transmission is stable, children less than 5 years old bear the greatest burden of malaria so the intensity of malaria transmission and the impact of interventions are often established in this age group. However, with decreasing transmission, older children may become increasingly at risk of malaria [1], [10]. Therefore, determining the seroprevalence in this age group may be extremely useful for estimating short-term changes in the burden of infection over a broad location [11], [12]. In this context, school-based serological surveys may be an effective and operationally attractive alternative to population-based surveys for identifying areas with varying transmission [13]. A pilot survey of 32 schools in the Upper River Region; one of the six administrative regions of The Gambia, showed that transmission in the area was quite heterogeneous and identified potential foci of transmission [14]. As part of a number of ongoing studies on the dynamics of transmission in low endemic settings, the methods previously tested in the pilot study were applied in a nationwide schools survey to describe and document the variation in malaria transmission across the whole country. This paper reports on the results and discusses the use of seroprevalence data to describe trends in transmission. Methods In May 2012, at the end of the dry season and before the onset of the rains, a cross-sectional malaria seroprevalence survey was carried out among primary school pupils across The Gambia. The country has a population of about 1.8 M people with 39% less than 15 years old [15]. Summary data on school attendance by district and region was obtained from the Ministry of Education. There are 411.
