“Every monsoon, Kolkata negotiates the same ancient bargain — rain for the water table, dengue for the streets.”
Kolkata Disease Surveillance
Outbreak trends, seasonal patterns, and vector-borne disease tracking for Kolkata (2018-2024).
Kolkata recorded 13,015 cases across six tracked diseases in 2024. Acute diarrhoeal disease accounts for most of that at 9,800 cases, but the number that moved is dengue: 2,750 cases, up 31% from 2023.
Malaria has gone the other way, falling 62.5% since 2018 — from 400 cases to 150. Two vector-borne diseases in the same city, on opposite trajectories, is the clearest signal on this page: sustained control programmes work, and dengue is outrunning the one aimed at it.
About this data
What this page shows
Annual trends for dengue, malaria, cholera, typhoid, acute diarrhoeal disease and chikungunya from 2018 to 2024, a monthly seasonal profile, the 2024 composition, a dengue and temperature overlay, and year-on-year change by disease. The seasonality is stark: 1,151 of the year's dengue cases fall in the June–September monsoon window, peaking in September, against 146 across the whole winter.
Where the data comes from
IDSP (Integrated Disease Surveillance Programme) weekly outbreak reports, NVBDCP annual summaries for vector-borne disease, and the West Bengal Directorate of Health Services.
Limitations worth knowing
These are surveillance figures, and surveillance undercounts. Cases are recorded when someone reaches a reporting facility and is tested — mild dengue treated at home, or diarrhoeal illness never presented to a clinic, does not enter the count. District-level reporting quality also varies year to year, so part of any change may reflect testing intensity rather than disease incidence; the 2020 dip in particular coincides with the pandemic disrupting both routine care and routine reporting. The underlying reports are published as PDFs and were curated by hand, so figures are best treated as indicative of direction and season rather than as exact case counts.
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