Impact of asymptomatic carriers in the epidemiology and control of malaria in the Peruvian Amazon

Objectives

1. To estimate the prevalence and incidence of asymptomatic malaria parasite carriage, by combining microscopic and molecular diagnosis, and to characterize risk factors for clinical disease among parasite carriers in rural Amazonia.

2. To estimate the prevalence, incidence and risk factors for gametocyte carriage in symptomatic and asymptomatic infections.

3. To estimate the average duration of gametocytemia in asymptomatic infections.

4. To compare the ability of symptomatic and asymptomatic carriers of gametocytes to experimentally infect wild-caught Anopheles darlingi.

5. To estimate prospectively the risk of subsequent clinical malaria among asymptomatic parasite carriers and non-infected controls living in the same communities.

6. To determine whether consecutive malaria episodes diagnosed in the population- based cohorts are due to parasite lineages that persist in human populations or to new, genetically unrelated parasites introduced by migration of both symptomatic and asymptomatic carriers.

7. To compare the genetic complexity of parasites recovered from symptomatic and asymptomatic infections, with and without gametocytemia, to test whether intra-host competition of multiple, genetically distinct parasite clones contributes to increased parasite virulence, greater risk of disease, and increased gametocyte production

This study is part of the Amazonian ICEMR´s projects supported by NIH.