Climate Variability, Dengue Vector Abundance and Dengue Fever Cases in Dhaka, Bangladesh: A Time-Series Study

Abstract

Numerous studies on climate change and variability have revealed that these phenomena have noticeable influence on the epidemiology of dengue fever, and such relationships are complex due to the role of the vector—the Aedes mosquitoes. By undertaking a step-by-step approach, the present study examined the effects of climatic factors on vector abundance and subsequent effects on dengue cases of Dhaka city, Bangladesh. Here, we first analyzed the time-series of Stegomyia indices for Aedes mosquitoes in relation to temperature, rainfall and relative humidity for 2002–2013, and then in relation to reported dengue cases in Dhaka. These data were analyzed at three sequential stages using the generalized linear model (GLM) and generalized additive model (GAM). Results revealed strong evidence that an increase in Aedes abundance is associated with the rise in temperature, relative humidity, and rainfall during the monsoon months, that turns into subsequent increases in dengue incidence. Further we found that (i) the mean rainfall and the lag mean rainfall were significantly related to Container Index, and (ii) the Breteau Index was significantly related to the mean relative humidity and mean rainfall. The relationships of dengue cases with Stegomyia indices and with the mean relative humidity, and the lag mean rainfall were highly significant. In examining longitudinal (2001–2013) data, we found significant evidence of time lag between mean rainfall and dengue cases.

How Do Climate Variables Affect the Transmission of Dengue Infection in South and Southeast Asia: A Scoping Review

“…In contrast to the above findings, a study conducted in Pakistan revealed that that the highest occurrence of dengue was reported when the rainfall is low (Fareed, Ghaffar, & Malik, 2016). This evidence is supported by the findings of a study conducted in Bangladesh, India and Sri Lanka and Pakistan (Islam, Emdad Haque, Hossain, & Hanesiak, 2021;Netrananda & Mani, 2021); (Mukhtar et al, 2021). Studies from Thailand, India and Sri Lanka have revealed that there is no significant association between dengue and rainfall (Chaiphongpachara et al, 2017;Goto et al, 2013;Noppradit et al, 2021;Pandey et al, 2012;Salam, 2018;Wijegunawardana et al, 2019).…”

A Retrospective Study of Climate Change Affecting Dengue: Evidences, Challenges and Future Directions

“…Obtaining a dengue dataset that is completely fit for the model and has all characteristics is difficult to find. There are many issues faced by the researchers in this area like i) data being incomplete, ii) data being not available in required time lag like weekly or monthly and for a specific time-period and iii) data that is available only on a macro level like country-level or state-level and not on micro-level like city-level ( 15 , 28 , 45 , 54 , 63 , 65 ).…”

“…Figure 6 shows the steps followed in information pre-processing. The major concern for reviewers is missing data and data not being available completely ( 28 ). Jorge et al ( 29 ) developed a three-stage to take the missing values in the dataset wherein first stage parameters with more than 20 per cent of missing values were eliminated.…”

“…As a result, the temperature has an impact on vectorial efficiency as well as the probability of an epidemic. Given the link between temperature and dengue cases, the predicted temperature change could worsen dengue transmission ( 28 , 32 ).…”

“…These obstructions can prevent complete water flow, resulting in water accumulation places that can provide favorable habitat for Aedes aegypti. A growing body of research suggests a link between drainage and the presence of Aedes aegypti ( 28 ).…”