Abstract
India has witnessed a five-fold increase in dengue incidence in the past
decade. However, the nation-wide distribution of dengue vectors, and the
impacts of climate change are not known. In this study, species
distribution modelling was used to predict the baseline and future
distribution of Aedine vectors in India on the basis of biologically
relevant climatic indicators. Known occurrences of Aedes aegypti and
Aedes albopictus were obtained from the Global Biodiversity Information
Facility database and previous literature. Bio-climatic variables were
used as the potential predictors of vector distribution. After
eliminating collinear and low contributing predictors, the baseline and
future prevalence of Aedes aegypti and Aedes albopictus was determined,
under three Representative Concentration Pathway scenarios (RCP 2.6, RCP
4.5 and RCP 8.5), using the MaxEnt species distribution model. Aedes
aegypti was found prevalent in most parts of the southern peninsula, the
eastern coastline, north eastern states and the northern plains. In
contrast, Aedes albopictus has localized distribution along the eastern
and western coastlines, north eastern states and in the lower Himalayas.
Under future scenarios of climate change, Aedes aegypti is projected to
expand into unsuitable regions of the Thar desert, whereas Aedes
albopictus is projected to expand to the upper and trans Himalaya
regions of the north. Overall, the results provide a reliable assessment
of vectors prevalence in most parts of the country that can be used to
guide surveillance efforts, despite minor disagreements with dengue
incidence in Rajasthan and the north east, possibly due to behavioural
practices and sampling efforts.