The present study describes aspects of the epidemiology of malaria in a migrant population living in a hypoendemic area in Brazil using an open cohort study design. Rural settlement residents in Leonislândia, Peixoto de Azevedo, Mato Grosso, Brazil were followed from September 1996 to April 1997. At baseline, an interview and malaria diagnoses were carried out and spleen size was measured. Incident cases were detected through follow-up visits and laboratory records. Cox regression was used to assess risk factors for time to malaria onset. Eighty percent (n = 414) of the study population (n = 521) contributed follow-up data. Overall, malaria prevalence during any study visit ranged from 0.3% to 5.4% and the malaria incidence rate (IR) was 4.49 (95% confidence interval = 3.66, 5.46) per 100 person-months. The 1R of Plasmodium vivax malaria was approximately four times higher than the 1R for P. falciparum malaria during follow-up. Among individuals who had had malaria during his or her lifetime, 14.03% reported hospitalization (median duration = 3 days) and 70.1% reported days of work lost (median duration = 4 days for P. falciparum malaria and 3 days for P. vivax malaria) related to the last malaria episode. No important risk factor was associated with the malaria 1R. The fact that neither work-related factors nor age was associated with the risk of malaria indicates that indoor/peri-domiciliary transmission by the local vector is more important or as important as workplace-related transmission.

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hospitalization economics spleen size open study Caesalpinia ciliata follow up human middle aged Cohort Studies rural population Malaria Aged disease carrier epidemiological data Humans workplace Adolescent male preschool child female Infant risk factor Risk Factors Child, Preschool cost of illness prevalence Protozoa Incidence Article disease transmission Plasmodium vivax absenteeism primaquine migration adult major clinical study infection risk Plasmodium falciparum cohort analysis Brazil Transients and Migrants mefloquine chloroquine Child