In vitro susceptibility of Plasmodium falciparum isolates to chloroquine and mefloquine in southeastern Mindanao Island, the Philippines

Toshimitsu Hatabu, Shin Ichiro Kawazu, Jun Suzuki, Reuben F. Valenzuela, Elena A. Villacorte, Mamoru Suzuki, Pilarita T. Rivera, Shigeyuki Kano

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8 Citations (Scopus)

Abstract

Although the presence of multi-drug-resistant falciparum malaria has been reported in the Philippines, the distribution of drug-resistant malaria parasites has not yet been determined in Mindanao Island. In vitro susceptibility of P. falciparum to both chloroquine and mefloquine was assessed to forecast the spread of drug-resistant parasites in various foci in southeastern Mindanao Island. Of the 33 isolates of P. falciparum successfully tested, 10 (30%) were susceptible, 12 (36%) showed decreased susceptibility (80 nM ≤ IC50 < 114 nM), and 11 (33%) were resistant (IC 50 ≥ 114 nM) to chloroquine. Ten (91%) of the resistant isolates and 9 (75%) of those with decreased susceptibility were from northern and northwestern Davao del Norte Province. Chloroquine-susceptible isolates were found among patients in the eastern parts of Davao del Norte and Davao Oriental provinces. Seven isolates from several foci in the study area were all mefloquine- susceptible (IC50 < 10 nM). This is the first report indicating the potential emergence of chloroquine-resistant P. falciparum on Mindanao Island, which is presently regarded as a drug-susceptible area.

Original languageEnglish
Pages (from-to)546-551
Number of pages6
JournalSoutheast Asian Journal of Tropical Medicine and Public Health
Volume34
Issue number3
Publication statusPublished - Sep 1 2003
Externally publishedYes

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Infectious Diseases

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