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Estimates of meteorological variability in association with dengue cases in a coastal city in northern Vietnam: an ecological study.

Xuan le TT, Van Hau P, Thu do T, Toan do TT - Glob Health Action (2014)

Bottom Line: To date, however, this relationship in coastal northern Vietnam has not been well documented.The estimation of regression parameters was based on the method of maximum likelihood using the R program package.DF cases in Haiphong were correlated with rainfall and humidity.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Health, Institute for Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam; lethithanhxuan@hmu.edu.vn.

ABSTRACT

Background: Dengue fever (DF) is a vector-borne disease that is sensitive to weather and climate variability. To date, however, this relationship in coastal northern Vietnam has not been well documented.

Objectives: This paper aims to examine the associations between meteorological variables and dengue incidence in Haiphong, Vietnam, over the period 2008-2012.

Methods: Monthly data on dengue incidence from all commune health stations and hospitals of Haiphong (with a total population of ~1.8 million) were obtained in accordance with the WHO's recommendations over a 5-year period (2008-2012). Temperature, rainfall, and humidity were recorded as monthly averages by local meteorological stations. The association between ecologic weather variables and dengue cases was assessed using a Poisson regression model. The estimation of regression parameters was based on the method of maximum likelihood using the R program package.

Results: From 2008 through 2012, 507 cases of dengue were reported. The risk of dengue was increased by sevenfold during the September-December period compared with other months over the period 2008-2012. DF cases in Haiphong were correlated with rainfall and humidity. In the multivariable Poisson regression model, an increased risk of dengue was independently associated with months with a higher amount of rainfall (RR=1.06; 95% CI 1.00-1.13 per 50 mm increase) and higher humidity (RR=1.05; 95% CI 1.02-1.08 per 1% increase).

Conclusion: These data suggest that rainfall and relative humidity could be used as ecological indicators of dengue risk in Haiphong. Intensified surveillance and disease control during periods with high rainfall and humidity are recommended. This study may provide baseline information for identifying potential long-term effects and adaptation needs of global climate change on dengue in the coming decades.

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Related in: MedlinePlus

Map of Vietnam showing Haiphong province (in dark grey area).
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Figure 0001: Map of Vietnam showing Haiphong province (in dark grey area).

Mentions: The study was conducted in Haiphong (Fig. 1), with the total square of 152.300 ha. The administrative levels in Vietnam are nation, province, district, and commune, and there are five biggest provinces in Vietnam also named city. Haiphong city has a population of about 1.837 million people in 2009 (43). Haiphong's climate is typically hot, humid, and rainy. The summer period from May to September receives highest amount of rainfall in the year (1,600–1,800 mm rainfall/year). The average temperature during the year was 23–26°C with the highest figure in June and July. The annual average humidity was about 80–85% with levels peaking in July, August, and September and lowest in December and January.


Estimates of meteorological variability in association with dengue cases in a coastal city in northern Vietnam: an ecological study.

Xuan le TT, Van Hau P, Thu do T, Toan do TT - Glob Health Action (2014)

Map of Vietnam showing Haiphong province (in dark grey area).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4265646&req=5

Figure 0001: Map of Vietnam showing Haiphong province (in dark grey area).
Mentions: The study was conducted in Haiphong (Fig. 1), with the total square of 152.300 ha. The administrative levels in Vietnam are nation, province, district, and commune, and there are five biggest provinces in Vietnam also named city. Haiphong city has a population of about 1.837 million people in 2009 (43). Haiphong's climate is typically hot, humid, and rainy. The summer period from May to September receives highest amount of rainfall in the year (1,600–1,800 mm rainfall/year). The average temperature during the year was 23–26°C with the highest figure in June and July. The annual average humidity was about 80–85% with levels peaking in July, August, and September and lowest in December and January.

Bottom Line: To date, however, this relationship in coastal northern Vietnam has not been well documented.The estimation of regression parameters was based on the method of maximum likelihood using the R program package.DF cases in Haiphong were correlated with rainfall and humidity.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Health, Institute for Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam; lethithanhxuan@hmu.edu.vn.

ABSTRACT

Background: Dengue fever (DF) is a vector-borne disease that is sensitive to weather and climate variability. To date, however, this relationship in coastal northern Vietnam has not been well documented.

Objectives: This paper aims to examine the associations between meteorological variables and dengue incidence in Haiphong, Vietnam, over the period 2008-2012.

Methods: Monthly data on dengue incidence from all commune health stations and hospitals of Haiphong (with a total population of ~1.8 million) were obtained in accordance with the WHO's recommendations over a 5-year period (2008-2012). Temperature, rainfall, and humidity were recorded as monthly averages by local meteorological stations. The association between ecologic weather variables and dengue cases was assessed using a Poisson regression model. The estimation of regression parameters was based on the method of maximum likelihood using the R program package.

Results: From 2008 through 2012, 507 cases of dengue were reported. The risk of dengue was increased by sevenfold during the September-December period compared with other months over the period 2008-2012. DF cases in Haiphong were correlated with rainfall and humidity. In the multivariable Poisson regression model, an increased risk of dengue was independently associated with months with a higher amount of rainfall (RR=1.06; 95% CI 1.00-1.13 per 50 mm increase) and higher humidity (RR=1.05; 95% CI 1.02-1.08 per 1% increase).

Conclusion: These data suggest that rainfall and relative humidity could be used as ecological indicators of dengue risk in Haiphong. Intensified surveillance and disease control during periods with high rainfall and humidity are recommended. This study may provide baseline information for identifying potential long-term effects and adaptation needs of global climate change on dengue in the coming decades.

Show MeSH
Related in: MedlinePlus