학술논문
The effects of urbanization on global Plasmodium vivax malaria transmission
Document Type
Report
Author
Source
Malaria Journal. December 5, 2012, Vol. 11 Issue 1
Subject
Language
English
ISSN
1475-2875
Abstract
Author(s): Qiuyin Qi[sup.1] , Carlos A Guerra[sup.2] , Catherine L Moyes[sup.2] , Iqbal AR F Elyazar[sup.3] , Peter W Gething[sup.2] , Simon I Hay[sup.2,5] and Andrew J Tatem[sup.1,4,5] Background The [...]
Background Many recent studies have examined the impact of urbanization on Plasmodium falciparum malaria endemicity and found a general trend of reduced transmission in urban areas. However, none has examined the effect of urbanization on Plasmodium vivax malaria, which is the most widely distributed malaria species and can also cause severe clinical syndromes in humans. In this study, a set of 10,003 community-based P. vivax parasite rate (Pv PR) surveys are used to explore the relationships between Pv PR in urban and rural settings. Methods The Pv PR surveys were overlaid onto a map of global urban extents to derive an urban/rural assignment. The differences in Pv PR values between urban and rural areas were then examined. Groups of Pv PR surveys inside individual city extents (urban) and surrounding areas (rural) were identified to examine the local variations in Pv PR values. Finally, the relationships of Pv PR between urban and rural areas within the ranges of 41 dominant Anopheles vectors were examined. Results Significantly higher Pv PR values in rural areas were found globally. The relationship was consistent at continental scales when focusing on Africa and Asia only, but in the Americas, significantly lower values of Pv PR in rural areas were found, though the numbers of surveys were small. Moreover, except for the countries in the Americas, the same trends were found at national scales in African and Asian countries, with significantly lower values of Pv PR in urban areas. However, the patterns at city scales among 20 specific cities where sufficient data were available were less clear, with seven cities having significantly lower Pv PR values in urban areas and two cities showing significantly lower Pv PR in rural areas. The urban-rural Pv PR differences within the ranges of the dominant Anopheles vectors were generally, in agreement with the regional patterns found. Conclusions Except for the Americas, the patterns of significantly lower P. vivax transmission in urban areas have been found globally, regionally, nationally and by dominant vector species here, following trends observed previously for P. falciparum. To further understand these patterns, more epidemiological, entomological and parasitological analyses of the disease at smaller spatial scales are needed. Keywords: Plasmodium vivax, Urbanization, Dominant Anopheles vectors, Mapping
Background Many recent studies have examined the impact of urbanization on Plasmodium falciparum malaria endemicity and found a general trend of reduced transmission in urban areas. However, none has examined the effect of urbanization on Plasmodium vivax malaria, which is the most widely distributed malaria species and can also cause severe clinical syndromes in humans. In this study, a set of 10,003 community-based P. vivax parasite rate (Pv PR) surveys are used to explore the relationships between Pv PR in urban and rural settings. Methods The Pv PR surveys were overlaid onto a map of global urban extents to derive an urban/rural assignment. The differences in Pv PR values between urban and rural areas were then examined. Groups of Pv PR surveys inside individual city extents (urban) and surrounding areas (rural) were identified to examine the local variations in Pv PR values. Finally, the relationships of Pv PR between urban and rural areas within the ranges of 41 dominant Anopheles vectors were examined. Results Significantly higher Pv PR values in rural areas were found globally. The relationship was consistent at continental scales when focusing on Africa and Asia only, but in the Americas, significantly lower values of Pv PR in rural areas were found, though the numbers of surveys were small. Moreover, except for the countries in the Americas, the same trends were found at national scales in African and Asian countries, with significantly lower values of Pv PR in urban areas. However, the patterns at city scales among 20 specific cities where sufficient data were available were less clear, with seven cities having significantly lower Pv PR values in urban areas and two cities showing significantly lower Pv PR in rural areas. The urban-rural Pv PR differences within the ranges of the dominant Anopheles vectors were generally, in agreement with the regional patterns found. Conclusions Except for the Americas, the patterns of significantly lower P. vivax transmission in urban areas have been found globally, regionally, nationally and by dominant vector species here, following trends observed previously for P. falciparum. To further understand these patterns, more epidemiological, entomological and parasitological analyses of the disease at smaller spatial scales are needed. Keywords: Plasmodium vivax, Urbanization, Dominant Anopheles vectors, Mapping