Plasmodium knowlesi malaria in children

Emerg Infect Dis. 2011 May;17(5):814-20. doi: 10.3201/eid1705.101489.


Plasmodium knowlesi can cause severe malaria in adults; however, descriptions of clinical disease in children are lacking. We reviewed case records of children (age <15 years) with a malaria diagnosis at Kudat District Hospital, serving a largely deforested area of Sabah, Malaysia, during January-November 2009. Sixteen children with PCR-confirmed P. knowlesi monoinfection were compared with 14 children with P. falciparum monoinfection diagnosed by microscopy or PCR. Four children with knowlesi malaria had a hemoglobin level at admission of <10.0 g/dL (minimum lowest level 6.4 g/dL). Minimum level platelet counts were lower in knowlesi than in falciparum malaria (median 76,500/μL vs. 156,000/mL; p = 0.01). Most (81%) children with P. knowlesi malaria received chloroquine and primaquine; median parasite clearance time was 2 days (range 1-5 days). P. knowlesi is the most common cause of childhood malaria in Kudat. Although infection is generally uncomplicated, anemia is common and thrombocytopenia universal. Transmission dynamics in this region require additional investigation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Age Factors
  • Anemia / etiology
  • Antimalarials / therapeutic use
  • Child
  • Child, Preschool
  • Chloroquine / therapeutic use
  • Female
  • Humans
  • Malaria / complications
  • Malaria / diagnosis
  • Malaria / drug therapy*
  • Malaria / physiopathology*
  • Malaria / transmission
  • Malaria, Falciparum / drug therapy
  • Malaria, Falciparum / physiopathology
  • Male
  • Plasmodium knowlesi / physiology*
  • Primaquine / therapeutic use
  • Retrospective Studies
  • Sex Factors
  • Thrombocytopenia / etiology
  • Treatment Outcome


  • Antimalarials
  • Chloroquine
  • Primaquine