Ovalocytosis protects against severe malaria parasitemia in the Malayan aborigines.
Am J Trop Med Hyg
; 47(3): 271-5, 1992 Sep.
Article
em En
| MEDLINE
| ID: mdl-1524139
ABSTRACT
The malaria parasite rates and densities were compared in 79 ovalocytic-normocytic pairs of Malayan Aborigines matched for age, sex, proximity of residence to each other, and use of bed nets when sleeping in their jungle settlement in central Peninsular Malaysia. Malaria infection was determined from thick and thin Giemsa-stained blood films collected monthly for a period of six months. Blood films from ovalocytic individuals were found to be positive for malaria less often than in persons with normal red blood cells (P less than 0.05). Malaria infections per 100 person-months at risk were 9.7 in the ovalocytic group compared with 15.19 in the normocytic group. Among individuals parasitemic at any time, heavy infections (greater than or equal to 10,000 parasites/mm3 of blood) with Plasmodium falciparum, P. vivax, and P. malariae were encountered only in normocytic subjects, which comprised approximately 12.5% of the malaria-positive individuals in this group. In an earlier survey of 629 settlers that identified subjects for the above study, the prevalence of ovalocytosis was found to increase significantly with age. The above field observations support the view that ovalocytic individuals might have a survival advantage in the face of malaria. Consideration of the ovalocytic factor is indicated in future evaluations of malaria control measures in areas where ovalocytosis is prevalent.
ABSTRACT
PIP The malaria parasite rates and densities were compared in 79 ovalocytic-normocytic pairs of Malayan Aborigines matched for age, sex, proximity of residence to each other, and use of bednets when sleeping in their jungle settlement in central Peninsular Malaysia. Malaria infection was detected from thick and thin Giemsa-stained blood films collected monthly for a 6-month period. Blood films from ovalocytic individuals were found to be positive for malaria less often than in those individuals with normal red blood cells (p0.05). Malaria infections/100 person-months at risk were 9.7 in the ovalocytic group as compared with 15.19 in the other group. Among those parasitemic at any time, heavy infections (or= 10,000 parasites/cu.mm of blood) with Plasmodium falciparum, P. vivax, and P. malariae were seen only in normocytic subjects, approximately 12.5% of the malaria-positive persons in this group. In an earlier survey of 629 settlers who identified subjects for the above study, the prevalence of ovalocytosis was found to increase significantly with age. The above field observations support the view that ovalocytic individuals might have a survival advantage in the face of malaria. Consideration of the ovalocytic factor is indicated in future evaluations of malaria control measures in those areas where ovalocytosis is prevalent.
Palavras-chave
Asia; Biology; Cultural Background; Data Analysis; Demographic Factors; Developing Countries; Diseases; Ethnic Groups; Examinations And Diagnoses; Hemic System; Hemoglobin Level--analysis; Incidence; Laboratory Examinations And Diagnoses; Malaria--prevention and control; Malaysia; Measurement; Parasitic Diseases; Physiology; Population; Population Characteristics; Research Methodology; Screening; Southeastern Asia
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Havaiano Nativo ou Outro Ilhéu do Pacífico
/
Eliptocitose Hereditária
/
Malária
Tipo de estudo:
Diagnostic_studies
/
Incidence_studies
/
Prevalence_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Adolescent
/
Adult
/
Child
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Child, preschool
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Female
/
Humans
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Infant
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Male
/
Middle aged
País/Região como assunto:
Asia
Idioma:
En
Revista:
Am J Trop Med Hyg
Ano de publicação:
1992
Tipo de documento:
Article
País de afiliação:
Malásia