Epidemiology of Plasmodium falciparum in a rice field and a savanna area in Burkina Faso: seasonal fluctuations of gametocytaemia and malarial infectivity
| Autor: | Pierre Ambroise-Thomas, M. F. Bosseno, Christian Boudin, J. Lyannaz, Pierre Carnevale |
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| Rok vydání: | 1991 |
| Předmět: |
Adult
Male Rural Population Veterinary medicine medicine.medical_specialty Time Factors Adolescent 030231 tropical medicine Native population Biology law.invention 03 medical and health sciences 0302 clinical medicine law 030225 pediatrics parasitic diseases Epidemiology Anopheles Burkina Faso Gametocyte medicine Animals Humans Longitudinal Studies Malaria Falciparum Child Disease Reservoirs Infectivity Age Factors Infant Plasmodium falciparum medicine.disease biology.organism_classification Virology Insect Vectors Infectious Diseases Transmission (mechanics) Child Preschool Paddy field Parasitology Female Seasons Malaria |
| Zdroj: | Annals of tropical medicine and parasitology. 85(4) |
| ISSN: | 0003-4983 |
| Popis: | For a better understanding of the epidemiology of Plasmodium falciparum in an African savanna area, the authors have: (a) defined the real gametocyte reservoir in the native population; (b) followed the fluctuations of gametocytaemia throughout the transmission period; and (c) measured the infectiousness of malarious individuals to mosquitoes. The transversal surveys, in different villages of this endemic area, have shown that gametocyte carrier rates decreased with age and malaria experience; 10.9% of the whole population were potentially infectious to mosquitoes, and of these 73% were children and only 27% were adults. The longitudinal studies have shown that the P. falciparum gametocyte rate depends on the equilibrium between the gametocyte conversion rates and the density of the asexual forms. When there are large numbers of children who become carriers of the sexual stage of the parasite and at the same time a small number who lose their gametocyte infection, the gametocyte rate increases in the population; and vice versa. The circumstances under which gametocytes are produced are not well-known. Two factors seem to be important: the level of the parasite density and immune mechanisms. The infectiousness of malarious individuals was estimated by the 'mosquito infection probability'. The percentage of mosquitoes infected after feeding on gametocyte carriers (which may partly reflect the infectiousness of a human population to mosquitoes) was multiplied by the percentage of gametocyte carriers in the population. This indicated that, in this endemic area, 4% of biting mosquitoes would become infected; but this theoretical mosquito infection probability is over-estimated.(ABSTRACT TRUNCATED AT 250 WORDS) |
| Databáze: | OpenAIRE |
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