Plasmodium knowlesiMalaria in Children

Abstract

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/μL; 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.

Human Infections and Detection of Plasmodium knowlesi

“…In some hospitals in Malaysian Borneo, knowlesi malaria accounts for the majority of malaria cases admitted to hospitals (29,38,43). Human cases are not restricted to Malaysia, with reports of infections acquired in Thailand (48)(49)(50)(51)(52)(53), the Philippines (54-56), Myanmar (57,58), Singapore (59-61), Vietnam (62,63), Indonesia (64,65), Brunei (66), and Cambodia (67) (Fig.…”

“…Barber et al described retrospective findings of P. knowlesi infections in 16 children from the district of Kudat in Sabah, Malaysian Borneo (29). No children were found to have severe disease upon admission, and they all successfully responded to antimalarial treatment.…”

“…In the same year, a case of naturally acquired knowlesi malaria from southern Thailand was reported (48 (29,34,35). Although the literature covers patients from a wide geographical zone across Southeast Asia and of many ethnicities and various background levels of malaria immunity, most of the data are weighted to Malaysia.…”

“…Following the description of the large focus of human knowlesi malaria cases in the Kapit Division of Malaysian Borneo in 2004 (3), there have been reports of infections acquired in Kapit and other locations in Malaysian Borneo (28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43) and in Peninsular Malaysia (28,(44)(45)(46)(47). In some hospitals in Malaysian Borneo, knowlesi malaria accounts for the majority of malaria cases admitted to hospitals (29,38,43).…”

Evaluation of Recombinant Plasmodium knowlesi Merozoite Surface Protein-133 for Detection of Human Malaria

“…9,10 High numbers of knowlesi malaria have been reported in Borneo Malaysia states of Sabah and Sarawak. 4,11 Recently, the infection has been detected in several states in Peninsular Malaysia in rural or suburban areas. 12 Plasmodium knowlesi has a rapid replication cycle, which may cause hyperparasitemia within a short period.…”