Exanthematous fevers are a global public health problem. The spread of arboviruses due to various factors, including climate change, has resulted in major epidemics such as the one that occurred in Brazil in 2024, representing an extremely concerning scenario from both epidemiological and healthcare perspectives. In addition to this, the reemergence of childhood exanthematous diseases in several countries, including Brazil, is alarming and occurs due to declining vaccination coverage and increased migratory movements. These diseases present overlapping clinical symptoms, and their differential diagnosis is often challenging, which, in a context of dengue and Chikungunya epidemics like the current one, may lead to underreporting of diseases such as measles and rubella. This project aims to build a prospective registry of the occurrence of dengue, Chikungunya, measles, and rubella in various healthcare centers in Brazil, in order to better understand the epidemiological scenario, identify clinical variables associated with different diagnoses, and describe healthcare bottlenecks that may hinder proper reporting and identification of these diseases.

Inclusion Criteria:

Individuals from newborns (zero years old) to 18 years of age, of both sexes.

Suspected individuals with the following criteria:

Measles: Presenting fever and rash associated with cough and/or runny nose and/or conjunctivitis, regardless of age or vaccination status;

Rubella: Presenting fever, rash, and lymphadenopathy, regardless of age or vaccination status;

Dengue and Chikungunya: Presenting myalgia, arthralgia, headache, retro-orbital pain, nausea, vomiting, rash, petechiae, positive tourniquet test, or leukopenia and/or lymph node enlargement;

Individuals who, meeting the above criteria, underwent sample collection for viral panel testing for the differential diagnosis of exanthematous diseases."

Exclusion Criteria:

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Participants without symptoms suspicious for the diseases presented.

Individuals with confirmed cases of the aforementioned infections prior to recruitment.

Individuals who, even presenting the symptoms described in the inclusion criteria, did not have samples collected for viral panel testing.