Dengue outbreaks follow a curious pattern. Once in five years, the case burden shifts to southern India. In 2022, Tamil Nadu, Karnataka and Andhra Pradesh formed 60% of India’s cases. Similar spikes in the south were recorded in 2012 and 2017. A month-wise breakup of cases reveals another interesting trend. The dengue infections mimic the progression of the south-west and northeast monsoons. The share of dengue deaths is disproportionately higher in Maharashtra and Kerala.
Back in the south
The table shows a State’s share of India’s total dengue cases. For instance, Tamil Nadu accounted for 32% of all cases reported in 2022 (till May). In 2022, the dengue burden shifted to the south as three States — Tamil Nadu, Karnataka and Andhra Pradesh — accounted for 60% of the dengue cases reported. The shift is part of a cycle in which cases in the south increase once in five years.
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Monsoon sickness
The maps show dengue outbreaks across time periods. Each dot represents an outbreak. The size of the dot corresponds to the number of cases. The outbreak pattern is in sync with the movement of the south-west and north-east monsoons.
Disease burden
The table below lists a State’s share of India’s total cases and deaths between 2008 and 2022. The share of deaths in Maharashtra and Kerala is particularly disproportionate than their share in cases.
The yearly and monthly data were sourced from Arun (tweets as @amasaesle) who compiled it from the National Vector Borne Disease Control Programme and IDSP weekly bulletins
Also read | Taking a holistic approach to dengue
