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BIBTEX RIS

Epidemiology and control of frontier malaria in Brazil: lessons from community-based studies in rural Amazonia

2010; Oxford University Press; Volume: 104; Issue: 5 Linguagem: Inglês

10.1016/j.trstmh.2009.12.010

1878-3503

Natal Santos da Silva, Mônica da Silva‐Nunes, Rosely S. Malafronte, Maria José Menezes, Rosane R. D’Arcadia, Natália T. Komatsu, Kézia Katiani Gorza Scopel, Érika Martins Braga, Carlos Eugênio Cavasini, José Antônio Cordeiro, Marcelo U. Ferreira,

Global Maternal and Child Health

We describe the epidemiology of malaria in a frontier agricultural settlement in Brazilian Amazonia. We analysed the incidence of slide-confirmed symptomatic infections diagnosed between 2001 and 2006 in a cohort of 531 individuals (2281.53 person-years of follow-up) and parasite prevalence data derived from four cross-sectional surveys. Overall, the incidence rates of Plasmodium vivax and P. falciparum were 20.6/100 and 6.8/100 person-years at risk, respectively, with a marked decline in the incidence of both species (81.4 and 56.8%, respectively) observed between 2001 and 2006. PCR revealed 5.4-fold more infections than conventional microscopy in population-wide cross-sectional surveys carried out between 2004 and 2006 (average prevalence, 11.3 vs. 2.0%). Only 27.2% of PCR-positive (but 73.3% of slide-positive) individuals had symptoms when enrolled, indicating that asymptomatic carriage of low-grade parasitaemias is a common phenomenon in frontier settlements. A circular cluster comprising 22.3% of the households, all situated in the area of most recent occupation, comprised 69.1% of all malaria infections diagnosed during the follow-up, with malaria incidence decreasing exponentially with distance from the cluster centre. By targeting one-quarter of the households, with selective indoor spraying or other house-protection measures, malaria incidence could be reduced by more than two-thirds in this community.