An assessment of remotely sensed environmental variables on Dengue epidemiology in Central India

Abstract

In recent decades, dengue has been expanding rapidly in the tropical cities. Even though environmental factors and landscape features profoundly impact dengue vector abundance and disease epidemiology, significant gaps exist in understanding the role of local environmental heterogeneity on dengue epidemiology in India. In this study, we assessed the role of remotely sensed climatic factors (rainfall, temperature and humidity) and landscape variables (land use pattern, vegetation and built up density) on dengue incidence (2012–2019) in Bhopal city, Central India. Dengue hotspots in the city were assessed through geographical information system based spatial statistics. Dengue incidence increased from 0.59 cases in 2012 to 9.11 cases in 2019 per 10,000 inhabitants, and wards located in Southern Bhopal were found to be dengue hotspots. Distributed lag non-linear model combined with quasi Poisson regression was used to assess the exposure-response association, relative risk (RR), and delayed effects of environmental factors on dengue incidence. The analysis revealed a non-linear relationship between meteorological variables and dengue cases. The model shows that the risk of dengue cases increases with increasing mean temperature, rainfall and absolute humidity. The highest RR of dengue cases (~2.0) was observed for absolute humidity ≥60 g/m3 with a 5–15 week lag. Rapid urbanization assessed by an increase in the built-up area (a 9.1% increase in 2020 compared to 2014) could also be a key factor driving dengue incidence in Bhopal city. The study sheds important insight into the synergistic effects of both the landscape and climatic factors on the transmission dynamics of dengue. Furthermore, the study provides key baseline information on the climatic variables that can be used in the micro-level dengue prediction models in Bhopal and other cities with similar climatic conditions.

Effect of environmental conditions on the wing morphometric variation inAedes aegypti(Diptera: Culicidae) in India

“…Although most of the Indian cities experience a tropical to subtropical climate, there exists a local variation in topography, and land use contributing to micro-climatic variations influencing dengue vector abundance and epidemiology (Sarma et al, 2022). Due to this environmental heterogeneity in India, six different geo-climatic regions can be identified: Himalayan, Desert, Semi Desert, Deccan Peninsular, Coast, and North East (Dimitrova and Bora, 2020).…”

Unraveling varying spatiotemporal patterns of dengue and associated exposure-response relationships with environmental variables in Southeast Asian countries before and during COVID-19

“…However, most existing studies have focused solely on either 2020 or 2021 without taking a holistic approach. In addition, existing research predominantly employs quantitative analysis methods to investigate the influence of environmental variables on dengue, yet overlooks the indirect impacts of COVID-19 lockdown measures on short-term environmental change may result in shifts in the relationship between environmental variables and dengue during the pandemic (Bonnin et al, 2022; Cheng et al, 2021; Chien and Yu, 2014; Chuang et al, 2017; Gui et al, 2021; Sarma et al, 2022; Wang et al, 2022; Xu et al, 2019; Yip et al, 2022).…”

Frequent outbreaks of dengue fever in South Asian countries—A correspondence analyzing causative factors and ways to avert

“…Additionally, the increased movement of people and goods in urban areas facilitated the spread of the virus to new areas. As a result, dengue became endemic in many urban areas of South Asia, and frequent outbreaks of the disease continue to occur 8 …”

“…As a result, dengue became endemic in many urban areas of South Asia, and frequent outbreaks of the disease continue to occur. 8 Climate conditions like temperature, humidity, and rainfall impact the life cycle of mosquitoes and the pathogen it harbors and influences the distribution and prevalence of both the virus and its vector. In South Asia, the peak season for dengue is from June to September, when climate conditions are most favorable for the mosquito to thrive and spread dengue.…”

“…Dengue cases rise from mid‐June to September due to heavy rainfall and humidity 9 . The mean temperature rises above 30°C from April to June is also responsible for an increase in dengue cases as warm temperature is crucial for the growth, development, and survival of vector mosquitoes and affect the length of the gonotrophic cycle, the incubation period 8 . The eggs of the mosquito can survive for several months in dry conditions and will hatch when they come into contact with water 10 .…”