Criteria of Cox-Singh et al for the Diagnosis of Plasmodium knowlesi Infection (Pseudo-Plasmodium malariae)

 

The normal host for Plasmodium knowlesi is the long-tailed or pig-tailed macaques monkeys. Humans who go into or near the forest are at greatest risk for exposure to infected mosquitoes.

 

Criteria for the diagnosis of Plasmodium knowlesi:

(1) having been in an endemic area (Malaysia and Borneo)

(2) presence of a hyperparasitemia resembling falciparum malaria

(3) parasite morphology resembling Plasmodium malariae

 

Patients with severe disease may develop

(1) renal failure

(2) jaundice

(3) thrombocytopenia

(4) hypotension

 

The diagnosis can be confirmed by PCR.

 

Any patient with suspected Pl. knowlesi infection should be treated aggressively since this can be a fatal disease.

 

Differential diagnosis:

(1) mixed malaria infection (Plasmodium falciparum and Plasmodium malariae)

(2) Plasmodium malariae with bacteremia