Evidence for specific suppression of gametocytemia by Plasmodium falciparum in residents of hyperendemic Irian Jaya
Baird, J.K.; Jones, T.R.; Purnomo; Masbar, S.; Ratiwayanto, S.; Leksana, B.
American Journal of Tropical Medicine and Hygiene 44(2): 183-190
1991
ISSN/ISBN: 0002-9637 PMID: 2012262 Document Number: 375279
An epidemiologic study of hyperendemic malaria in Arso PIR, a village in northeastern Irian Jaya (Indonesian New Guinea), revealed evidence suggesting suppression of gametocytemia independent of immune control of the asexual parasitemia. A total of 240 people, representing ages between 2 and 60 years, were followed by biweekly blood film examination for 16 weeks beginning in November 1987. Two distinct subpopulations were represented.sbd.1) life-long residents of Irian Jaya, and 2) transmigrants from Java who arrived in Irian Jaya 20 months before the surveillance effort began. Twenty-five percent of blood films from natives and 31% from Javanese were positive for falciparum malaria; of these, the rate of gametocytemia was 21% for natives, and 42% for the Javanese transmigrants (P < 0.001). This difference could not be explained by differences in the frequency or grade of parasitemia, illness, or by known patterns of antimalarial consumption. Similarly, in Wor, a village near Arso PIR, the gametocyte rate for P. falciparum diminished from 83% to 25% in transmigrants from Java between their eleventh and twenty-fifth month of residence in Irian Jaya, a period during which the falciparum malaria rate remained stable between 30% and 50%. An immunofluorescent antibody test using whole, acetone-fixed gametocytes as substrate revealed correlation between antibody titer and protection from gametocytemia among the semi-immune natives of Arso PIR, but not among the Javanese. Specific immune suppression of gametocytes, independent of immune control of asexual parasites, can explain all of these observations.