know the signs of the two diseases and learn to differentiate the symptoms — English (Brazil)

Fever, headache, body aches and muscle fatigue. These are symptoms commonly reported by those who contract dengue or Covid-19, so it can be difficult to differentiate between the two diseases. But the evolution of signs and symptoms can give a clue to the diagnosis. The Ministry of Health reinforces that, with the appearance of any symptom, it is essential to seek medical attention.

Both diseases are caused by viruses, but transmission occurs differently: dengue is transmitted by the bite of the Aedes aegypti mosquito. Covid-19 is already transmitted by droplets of respiratory secretions from an infected person.


The main symptoms of dengue are:

  • High fever, greater than 38°C;
  • Pain in the body and joints;
  • Pain behind the eyes;
  • Malaise;
  • Lack of appetite;
  • Headache;
  • Red spots on the body.

However, dengue infection can be asymptomatic, present a mild condition or alarm and severity signs. Normally, the first manifestation of dengue is high fever (>38°C), with an abrupt onset, which usually lasts from 2 to 7 days, accompanied by headache, body and joint pain, in addition to prostration, weakness, pain behind the eyes and red spots on the skin.

The diagnosis of dengue can be made by clinical examination and confirmed by blood test.


In the case of Covid-19, signs of mild, moderate or severe cases may occur. Mild cases of the disease caused by the coronavirus are characterized by the presence of non-specific symptoms, such as:

  • Cough;
  • Sore throat followed by anosmia, ageusia, diarrhea, abdominal pain, fever, chills, myalgia, runny nose, fatigue and/or headache.

Moderate cases may include all of these symptoms and also signs of progressive worsening of another COVID-19-related symptom (muscle weakness, prostration, decreased appetite, diarrhea), in addition to the presence of pneumonia without signs or symptoms of severity.

Severe cases involve dyspnea/respiratory distress or persistent pressure in the chest or oxygen saturation less than 95% on room air or bluish discoloration of the lips or face.

The diagnosis of Covid-19 can be made by clinical examination and laboratory tests on samples taken mainly from the nose. Tests are available at SUS.

Nathan Victor
Ministry of Health

Official content – Fact Check – Verified