Age-Dependent Acquisition of Protective Immunity to Malaria in Riverine Populations of the Amazon Basin of Brazil
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
20/10/2012
20/10/2012
2009
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Resumo |
Five community-based cross-sectional surveys of malaria morbidity and associated risk factors in remote riverine populations in northwestern Brazil showed average parasite rates of 4.2% (thick-smear microscopy) and 14.4% (polymerase chain reaction [PCR]) in the overall population, with a spleen rate of 13.9% among children 2-9 years of age. Plasmodium vivax was 2.8 times more prevalent than P. falciparum, with rare instances of P. malariae and mixed-species infections confirmed by PCR; 9.6% of asymptomatic subjects had parasitemias detected by PCR. Low-grade parasitemia detected by PCR only was a risk factor for anemia, after controlling for age and other covariates. Although clinical and subclinical infections occurred in all age groups, the risk of infection and disease decreased significantly with increasing age, after adjustment for several covariates in multilevel logistic regression models. These findings suggest that the continuous exposure to hypo- or mesoendemic malaria may induce significant anti-parasite and anti-disease immunity in native Amazonians. PAPES IV/Fiocruz Fundação Oswaldo Cruz (Fiocruz) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) CNPq[410398/2006-3] FAPESP Fundacao de Amparo a Pesquisa do Estado de Sao Paulo[05/51988-0] Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Conselho Nacional de Desenvolvimento Cientffico e Technologico (CNPq), Brazil |
Identificador |
AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, v.80, n.3, p.452-459, 2009 0002-9637 |
Idioma(s) |
eng |
Publicador |
AMER SOC TROP MED & HYGIENE |
Relação |
American Journal of Tropical Medicine and Hygiene |
Direitos |
restrictedAccess Copyright AMER SOC TROP MED & HYGIENE |
Palavras-Chave | #POLYMERASE-CHAIN-REACTION #PLASMODIUM-FALCIPARUM #HYPOENDEMIC MALARIA #HIGH PREVALENCE #INFECTIONS #REGION #TRANSMISSION #VIVAX #AREA #Public, Environmental & Occupational Health #Tropical Medicine |
Tipo |
article original article publishedVersion |