Case Definitions & Diagnosis

Clinical description

Suspected Malaria

Malaria should be suspected in any under five children or pregnant women who present with fever (or history of fever) and in over five children and adults with fever or history of fever plus one other symptom or sign suggestive of malaria. The health care personnel in this case must try to clinically exclude other common causes of fever, such as tonsillitis, chest infections, abscess, urinary tract infection, and otitis media.

Confirmed Malaria

A malaria case is confirmed by demonstration of asexual forms (trophozoite stage) of the parasite in the thick or thin peripheral blood film or by a positive malaria rapid diagnostic test (mRDT) result in the presence of fever or history of fever. Clinically, malaria falls into two categories — uncomplicated and severe, depending on degree of symptoms. However, clinical diagnosis in uncomplicated malaria is not recommended; a confirmatory test should always be performed.

A patient who presents with symptoms of malaria and positive parasitological tests (microscopy or mRDT) but with no features of severe malaria is defined as having uncomplicated malaria. Treatment should only be given to those patients who test positive.

Investigations

Malaria Rapid Diagnostic Tests (mRDTs)

All suspected uncomplicated malaria cases at all levels of the health care delivery system should be tested using an approved mRDT prior to initiating treatment. MoH recommends WHO pre-qualified brands of mRDTs.

Microscopy

Microscopy remains the gold standard for the diagnosis of malaria in Malawi. In Malawi, approximately 96.3% of malaria infections are due to P. falciparum (MIS 2021). Thick films are recommended for parasite detection and quantification. Thin films are recommended for species identification.