Please use this identifier to cite or link to this item: https://www.arca.fiocruz.br/handle/icict/33996
Title: Cross-sectional Study Defines Difference in Malaria Morbidity in Two Yanomami Communities on Amazonian Boundary between Brazil and Venezuela
Authors: Marcano, Teodardo José
Morgado, Anastácio
Tosta, Carlos Eduardo
Coura, José Rodrigues
Affilliation: Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Medicina Tropical. Rio de Janeiro, RJ. Brasil.
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Medicina Tropical. Rio de Janeiro, RJ. Brasil.
Universidade de Brasília. Faculdade de Ciências da Saúde. Departamento de Patologia. Brasília, DF, Brasil.
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Medicina Tropical. Rio de Janeiro, RJ. Brasil.
Abstract: It is well established that immunity to malaria is short-lived and is maintained by the continuous contact with the parasite. We now show that the stable transmission of malaria in Yanomami Amerindian communities maintains a degree of immunity in the exposed population capable to reduce prevalence and morbidity of malaria. We examined 508 Yanomami Amerindians living along Orinoco (407) and Mucajaí (101) rivers, on the Venezuelan and Brazilian Amazon region, respectively. At Orinoco villages, malaria was hyperendemic and presented stable transmission, while at Mucajaí villages it was mesoendemic and showed unstable transmission. The frequency of Plasmodium vivax and P. falciparum was roughly comparable in Venezuelan and Brazilian communities. Malaria presented different profiles at Orinoco and Mucajaí villages. In the former communities, malaria showed a lower prevalence (16% x 40.6%), particularly among those over 10 years old (5.2% x 34.8%), a higher frequency of asymptomatic cases (38.5% x 4.9%), and a lower frequency of cases of severe malaria (9.2% x 36.5%). Orinoco villagers also showed a higher reactivity of the immune system, measured by the frequency of splenomegaly (72.4% x 29.7%) and by the splenic index (71.4% over level 1 x 28.6), and higher prevalence (91.1% x 72.1%) and mean titer (1243 x 62) of antiplasmodial IgG antibodies, as well as a higher prevalence (77.4% x 24.7%) and mean titer (120 x 35) of antiplasmodial IgM antibodies. Our findings show that in isolated Yanomami communities the stability of malaria transmission, and the consequent continuous activation of the immune system of the exposed population, leads to the reduction of malaria prevalence and morbidity.
Keywords: Malaria
Morbidity
Immunity
Yanomami Amerindians
Amazon region
Brazil
keywords: Malária
Ameríndios Yanomami
Imunidade
Morbilidade
Região Amazônica
Issue Date: 2004
Publisher: Fundação Oswaldo Cruz. Instituto Oswaldo Cruz
Citation: MARCANO, Teodardo José et al. Cross-sectional Study Defines Difference in Malaria Morbidity in Two Yanomami Communities on Amazonian Boundary between Brazil and Venezuela. Mem'órias do Instituto Oswaldo Cruz, Rio de Janeiro, v. 99, n. 4, p. 369-376, June 2004.
DOI: 10.1590/S0074-02762004000400005
ISSN: 0074-0276
Copyright: open access
Appears in Collections:IOC - Artigos de Periódicos

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