Dengue in Rio de Janeiro: alert in Rio de Janeiro and the largest cities

How to read the alert levels and the trend

• GreenWeather conditions not favorable to transmission (temperature or humidity) and low viral activity. This does not mean there are no cases.
• YellowWeather conditions favorable to transmission (temperature or humidity) and viral activity present, with at least 1 case.
• OrangeRising incidence, with at least 2 weeks of Rt above 1, but still within historical levels.
• RedHigh incidence by the municipality's historical standards, above 90% of the threshold calculated with the Moving Epidemic Method (MEM).

InfoDengue calculates the levels for each municipality from case reports and climate data; the description of each level, using the terms above, is in the InfoDengue glossary, and “Rt” is the disease's reproduction number. The information is organized by epidemiological week: by international convention, according to the the Health Ministry's Sinan notification calendar, weeks are counted from Sunday to Saturday, and the first week of the year is the one containing the most days of January. So “39/2026” is the 39th epidemiological week of 2026. The estimated cases are the week's cases after correcting for notification delays, and the incidence is the estimated number of cases per 100,000 residents for the week. Estimated cases are a statistical estimate and are not the same as individually confirmed cases.

The trend is RaisLife's reading of the estimated cases: it compares the total for the last two weeks with the two weeks before and shows a rise when the number went up 25% or more, a drop when it fell 20% or more, and stable in all other cases. When the four weeks add up to fewer than 100 estimated cases, the panel says "few cases," because with a small number, a change from one week to the next tells you little. Since the most recent weeks are the most likely to be revised, the trend can also change.

Where the numbers and guidance come from

Alert levels, estimated cases and incidence come from InfoDengue, a system run by Fiocruz and the Getulio Vargas Foundation that cross-references case notifications from Sinan, the Health Ministry’s reporting system, with climate data. RaisLife keeps a copy of these figures and updates it often, with each new epidemiological week released, always stating the week they refer to.

The guidance on symptoms, warning signs and prevention follows the dengue page of the Ministry of Health, checked on Oct 14, 2026. Each municipality's population is the estimate from IBGE, Brazil's statistics institute, for 2026, and the choice of cities tracked (the capital and the four largest in each state) is RaisLife's.

Because case reports arrive late, InfoDengue estimates the cases for the most recent weeks, and those values are revised every week; today’s number may change in the next update. The data here does not replace the bulletins from your city’s or state’s epidemiological surveillance.

Public information; it does not replace an assessment by a health professional. This content does not provide a diagnosis or recommend treatment. If you have a fever or other symptoms, go to a health clinic.