About the data
Frequently asked questions
Short answers to the questions people ask most about the map. For the full method, see data and methods.
What is the Diseases Map?
An interactive world map of the recorded history of infectious disease, from ancient plague evidence to COVID-19. Move the timeline to see which countries reported which diseases in each year.
Which diseases are included?
Thirteen: plague (1338–1900), dengue (1924–2025), cholera (1949–2024), measles (1974–2024, monthly from 2012), paralytic polio (1980–2023), tuberculosis (1980–2024), diphtheria, whooping cough, tetanus and yellow fever (1980–2025), rubella (1997–2025), mumps (1999–2025) and COVID-19 (2020–2026). Stories about malaria and smallpox use published sources instead.
Why is my country blank?
Blank means there is no report in the data for that year. It does not mean the disease was absent. A reported zero is shown in pale grey.
How do I show only one disease?
Choose a disease in the panel, or click its name or timeline under the slider. Click it again to return to all diseases.
Can I see data by month?
Yes. Switch the timeline from full history to fine navigation. It shows a ten-year window by month, with monthly values for measles from 2012, COVID-19 from 2020 and dengue where published.
Is this live data?
No. The map is a fixed snapshot of each source, taken in September 2026.
Can I use the data?
Yes, within each source’s terms. Download the processed files from the Sources panel. Attribute the original publishers: WHO, Our World in Data, OpenDengue for dengue, and Büntgen & Ginzler (EnviDat) for plague.
Is this medical advice?
No. The map describes historical reports. For health advice, consult a health professional or your national public health agency.