The symptoms of these three mosquito-borne diseases are very similar, which makes the diagnosis more difficult. However, there are few differences that can be used to distinguish the disease and avoid misdiagnoses.

There is no cure for these virus diseases, the treatment consists on relieving the symptoms and a proper clinical management can improve outcome.

Zika virus disease

Most of the infections remain asymptomatic (approximately 80%);
The incubation period ranges between approximately 3 to 12 days after the bite of an infected mosquito;

The main symptoms are:

  • Low grade fever (less than 38.5°C)
  • Skin maculopapular rash (often appears in the first days of symptoms starting on the face and then spreading throughout the body)
  • Headache
  • Mild joint pain ( this symptom can persist for one month, in some rare cases)
  • Itching
  • Red eyes (non purulent conjunctivitis/conjunctival hyperaemia)
  • Fatigue

 Other less frequent symptoms:

  • Swelling (notably of the legs and small joints of the hands and feet)
  • Gastro-intestinal signs (such as vomit and diarrhea)
  • Muscle pain
  • Pain behind the eyes (retro-orbital pain)
  • Ganglion cysts
  • Sore throat

The Zika virus disease symptoms are usually mild, most people fully recover without severe complications, and hospitalization rates are low. However, zika might be linked with Guillain-Barré syndrome and birth defects (zika virus can be spread from a pregnant woman to her fetus).


The majority of people infected with chikungunya virus become symptomatic (approximately 70%);
The incubation period ranges from 2 to 12 days after the bite of an infected mosquito, with an average of 2 to 7 days;

The main symptoms are:

  • Abrupt onset of  high fever (over 39°C)
  • Severe joint pain - mainly on the hands, feet, ankles and wrists (present in most of the cases)*

*Most people recover fully but in some cases, joint pain may continue for weeks or, rarely, several months or even 3 years, in the chronic phase of the disease. 

Symptoms that can also occur:

  • Intense back pain
  • Headache
  • Skin maculopapular rash (often appears on the first 48 hours of symptoms, mainly on the trunk, hands and feet)
  • Muscle pain

Other less frequent symptoms:

  • Joint swelling
  • Nausea/vomit
  • Conjunctivitis 
  • Photophobia
  • Fatigue
  • Sore Throat

Chikungunya disease is very rarely fatal, but the virus sometimes causes serious complications, mostly in older people, babies or people with underlying medical conditions.

Dengue fever

The dengue infection can be asymptomatic (up to 40% to 80%), mild or cause a serious illness, which in extreme cases can cause death.
The incubation period ranges from 3 to 14 days after the bite of an infected mosquito, with an average of 4 to 7 days; 

 Usually, the main symptoms are:

  • Sudden onset of  high fever ( 39° to 40°C)
  • Severe headache
  • Severe muscle pain
  • Moderate joint pain
  • Severe pain behind the eyes, that gets worse with the eye movement (retro-orbital pain)
  • Skin maculopapular rash (usually appears from two to five days after the onset of fever) 
  • Itching
  • Prostration
  • Fatigue
  • Nausea
  • Low white cell count
  • Loss of appetite and taste

In the severe cases of the disease, the symptoms may include:

  • Bleeding (such as nose and gum bleed or easy bruising)
  • Abdominal pain
  • Persistent vomiting
  • Somnolence
  • Irritability
  • Hypotension
  • Dizziness
  • Vomiting blood
  • Breathing difficulty

Sometimes, symptoms are mild and can be mistaken for those of the flu or another viral infection. People with weakened immune systems and those with a second or subsequent dengue infection (there are 4 virus types) are believed to be at greater risk for developing dengue hemorrhagic fever, a rare complication that may progress fast to massive bleeding, shock and death in 24 hours (DSS - dengue shock syndrome). 

There is no commercial vaccine or specific antiviral drug treatment for dengue, chikungunya or zika virus infection. People infected should be protected from further mosquito exposure during the first few days of illness to prevent other mosquitoes from becoming infected and reduce the risk of local transmission. 

Once a person has been infected, he or she is likely to be protected from future infections of the same virus. 
Differential clinical diagnostic and co-infection with other mosquito-borne diseases should be considered.
Treatment with aspirin and other and non-steroidal anti-inflammatory drugs (NSAIDs) should be avoided because of a potential increased risk of hemorrhagic syndrome.

This article is not intended to provide medical advice, diagnosis or treatment, but simply to provide information about the diseases. If you develop the symptoms described above and have visited an area where these viruses have been reported you must see a doctor to identify the disease and indicate the correct treatment. These are also diseases that must be notified to the health authorities, which is very important to scientific studies about these viruses. Public health Authorities will take action to mitigate the risk of local transmission.


Picture: one of the Zika symptoms

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