Parasite multiplication potential and the severity of Falciparum malaria.
The multiplication rates and invasiveness of Plasmodium falciparum parasites isolated from adult Thai patients hospitalized with uncomplicated malaria (n=34) were compared with those from persons with severe malaria (n=42). To simulate severe malaria and control for host effects, the in vitro cultures were adjusted to 1% parasitemia and used the same red blood cell donor. P. falciparum isolates from persons with severe malaria had initial cycle multiplication rates in vitro that were 3-fold higher than those from uncomplicated malaria (median [95% confidence interval], 8.3 [7. 1-10.5] vs. 2.8 [1.7-3.9]; P=.001). Parasites causing severe malaria exhibited unrestricted red blood cell invasion, whereas those from uncomplicated malaria were restricted to a geometric mean of 40 (31%-53%) of red blood cells. P. falciparum parasites causing severe malaria were less selective and multiplied more at high parasitemias than those causing uncomplicated malaria.
Chotivanich
K
K
Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
Udomsangpetch
R
R
Simpson
J A
JA
Newton
P
P
Pukrittayakamee
S
S
Looareesuwan
S
S
White
N J
NJ
D000818:Animals; D004912:Erythrocytes / Q000469:parasitology; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000502:physiology*