Featured Malaria Publication - Targeting Asymptomatic Malaria Infections

18 June 2013

Active case detection (ACD) is a recommended intervention in low malaria transmission settings, yet evidence for its effectiveness is sparse. The potential of ACD to impact transmission is hampered by the ability of current field diagnostics to detect very low density infections and continued importation of parasites, as well as the operational challenges of achieving high coverage. The type of ACD employed should be guided by transmission setting and an understanding of risk factors. Standardised monitoring and evaluation of ACD strategies should be an integral component of ACD campaigns.

Targeting Asymptomatic Malaria Infections: Active Surveillance in Control and Elimination

Hugh J. W. Sturrock, Michelle S. Hsiang, Justin M. Cohen, David L. Smith, Bryan Greenhouse, Teun Bousema and Roly Gosling

The scale-up of interventions has reduced malaria burden and transmission across a number of countries. As transmission declines, it often becomes increasingly focal, and programs need to adapt and target the remaining parasite reservoirs, deploying resources with increasing granularity. At very low transmission intensity, elimination of malaria may involve finding and treating individual infections.

At large spatial scales, infections tend to cluster into foci related to environmental, climatic, and ecological suitability for vectors and transmission. At smaller scales within these foci, “hotspots", which consist of a household or groups of households, maintain higher transmission of malaria and a consistent reservoir of parasites throughout the year. Infections are also clustered in certain demographic “hot" populations, or “hotpops", associated with demographic risk factors for transmission. In low transmission or elimination settings, strategies for detecting and targeting these clusters of infection, whether geographic or demographic, become important strategies to reduce the local parasite reservoir and interrupt transmission.

Read the full article in PLOS Medicine