Characterizing the effect of temperature fluctuation on the incidence of malaria: an epidemiological study in south-west China using the varying coefficient distributed lag non-linear model

Malaria Journal

Research

Xiao-Hua Zhou¹  Zijian Feng²  Xiaosong Li³  Fei Chen³  Xing Zhao⁴ 

[1] Department of Biostatistics, School of Public Health, University of Washington, NE Pacific Street, 98195, Seattle, USA;HSR&D Center of Excellence, VA Puget Sound Health Care System, 1100 Olive Way Metro Park West Suite 1400, 98101, Seattle, USA;Office for Disease Control and Emergency Response, Chinese Centre for Disease Control and Prevention, NE Pacific Street, 102206, Beijing, China;West China School of Public Health, Sichuan University, No.17 Section 3, South Renmin Road, 610041, Chengdu, China;West China School of Public Health, Sichuan University, No.17 Section 3, South Renmin Road, 610041, Chengdu, China;Department of Biostatistics, School of Public Health, University of Washington, NE Pacific Street, 98195, Seattle, USA;

关键词: Malaria;    Malaria Transmission;    Temperature Fluctuation;    Malaria Case;    Malaria Incidence;   

DOI  :  10.1186/1475-2875-13-192

 received in 2014-03-09, accepted in 2014-05-20,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundMalaria transmission is strongly determined by the environmental temperature and the environment is rarely constant. Therefore, mosquitoes and parasites are not only exposed to the mean temperature, but also to daily temperature variation. Recently, both theoretical and laboratory work has shown, in addition to mean temperatures, daily fluctuations in temperature can affect essential mosquito and parasite traits that determine malaria transmission intensity. However, so far there is no epidemiological evidence at the population level to this problem.MethodsThirty counties in southwest China were selected, and corresponding weekly malaria cases and weekly meteorological variables were collected from 2004 to 2009. Particularly, maximum, mean and minimum temperatures were collected. The daily temperature fluctuation was measured by the diurnal temperature range (DTR), the difference between the maximum and minimum temperature. The distributed lag non-linear model (MDLNM) was used to study the correlation between weekly malaria incidences and weekly mean temperatures, and the correlation pattern was allowed to vary over different levels of daily temperature fluctuations.ResultsThe overall non-linear patterns for mean temperatures are distinct across different levels of DTR. When under cooler temperature conditions, the larger mean temperature effect on malaria incidences is found in the groups of higher DTR, suggesting that large daily temperature fluctuations act to speed up the malaria incidence in cooler environmental conditions. In contrast, high daily fluctuations under warmer conditions will lead to slow down the mean temperature effect. Furthermore, in the group of highest DTR, 24-25°C or 21-23°C are detected as the optimal temperature for the malaria transmission.ConclusionThe environment is rarely constant, and the result highlights the need to consider temperature fluctuations as well as mean temperatures, when trying to understand or predict malaria transmission. This work may be the first epidemiological study confirming that the effect of the mean temperature depends on temperature fluctuations, resulting in relevant evidence at the population level.

【 授权许可】

Unknown   
© Zhao et al.; licensee BioMed Central Ltd. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.