Definitions and symptoms

As the malaria parasites enter the blood stream they infect and destroy red blood cells. Destruction of these essential cells leads to fever and flu-like symptoms, such as:

  • chills
  • headache
  • muscle aches
  • tiredness
  • nausea
  • vomiting
  • diarrhea

These initial symptoms are non-specific: in other words, they are self-reported symptoms that do not indicate a specific disease process.

Uncomplicated malaria

(can be caused by all strains of Plasmodium)

Malaria is considered uncomplicated when symptoms are present but there are no clinical or laboratory signs to indicate severity or vital organ dysfunction.2 The symptoms of uncomplicated malaria are non-specific and include fever.

Severe malaria

(only caused by P. falciparum)

Infection with P. falciparum, if not promptly treated, can quickly progress to severe malaria. The main symptoms of severe malaria include: coma, severe breathing difficulties, low blood sugar, and low blood haemoglobin (severe anaemia). It is diagnosed on the basis of the presence P. falciparum parasites and one of the above symptoms with no other obvious cause. Children are particularly vulnerable since they have little or no immunity to the parasite. If untreated, severe malaria can lead to death.

Cerebral malaria

(only caused by P. falciparum)

Malaria is classified as cerebral when it manifests with cerebral symptoms, such as coma.


Learn about malaria diagnosis on the World Health Organization's website


1 Wells TN et al. New medicines to improve control and contribute to the eradication of malaria. Nat Rev Drug Discov. 8(11):879-91 (2009)
WHO Guidelines for the treatment of malaria, second edition