In vivo responses to antimalarials by Plasmodium falciparum and Plasmodium vivax from isolated Gag Island off northwest Irian Jaya, Indonesia.

Abstract

Abstract. There is renewed interest in the rich nickel and cobalt deposits of Pulau Gag, an isolated but malarious island off the northwest coast of Irian Jaya. In preparation for an expanded workforce, an environmental assessment of malaria risk was made, focusing upon malaria prevalence in the small indigenous population, and the in vivo sensitivity of Plasmodium falciparum and P. vivax to chloroquine (CQ) and sulfadoxine/pyrimethamine (S/P), the respective first-and second-line drugs for uncomplicated malaria in Indonesia. During April-June 1997, mildly symptomatic or asymptomatic malaria infections were found in 24% of 456 native residents. Infections by P. falciparum accounted for 60% of the cases. Respective day 28 cure rates for CQ (10 mg base/kg on days 0 and 1; 5 mg/kg on day 2) in children and adults were 14% and 55% (P Ͻ 0.005). Type RII and RIII resistance characterized only 5% of the CQ failures. Re-treatment of 36 P. falciparum CQ treatment failures with S/P (25 mg/kg and 1.25 mg/kg, respectively) demonstrated rapid clearance and complete sensitivity during the 28-day follow-up period. More than 97% of the P. vivax malaria cases treated with CQ cleared parasitemia within 48 hr. Three cases of P. vivax malaria recurred between days 21 and 28, but against low drug levels in the blood. The low frequency of RII and RIII P. falciparum resistance to CQ, the complete sensitivity of this species to S/P, and the absence of CQ resistance by P. vivax are in contrast to in vivo and in vitro test results from sites on mainland Irian Jaya.

In vitro Anti-Malarial Drug Susceptibility of Temperate Plasmodium vivax from Central China

“…Multiple cross-sectional and longitudinal surveys performed in different regions of Indonesia showed considerable geographic variations in the proportion of CQR P. vivax parasites. [51][52][53][54][55][56][57] In Vietnam, CQR P. vivax infection was not found 10 years ago, 58 but a more recent survey found 25% of patients in a study had recurrent P. vivax infections after standard treatment, suggesting of emerging CQ resistance. 59 These studies highlight the geographic heterogeneity and temporal dynamics of drug resistance in P. vivax , which further emphasizes the importance of continued surveillance efforts.…”

Effectiveness of Antimalarial Drugs

“…8 Studies in Southeast Asia indicated that the rates of parasitologic failure at day 7 and day 28 were 36 percent and 49 percent, respectively. [74][75][76][77][78][79] Good efficacy (80 percent) persisted elsewhere -in southwestern Asia and on the Horn of Africa, where no parasitologic failures were reported among 362 evaluations 80,81 ; in southern Asia, where the failure rate was 18 percent (of 339 evaluations) by day 28 [55][56][57] ; and in South America, where the failure rate was 9 percent (of 50 evaluations) by day 7, 14 percent (of 42 evaluations) by day 14, and 6 percent (of 119 evaluations) by day 28. [82][83][84] The risk of resistance to sulfadoxine-pyrimethamine is relatively high in Southeast Asia and eastern Africa.…”

Chloroquine Resistance inPlasmodium vivax

“…Among 88 subjects treated up to 1995, 41% had a response consistent with resistance (8,81). Among 282 subjects evaluated since then, 39% were infected with resistant isolates (9,11,48,52,102,106). However, all 38 subjects evaluated on a small, isolated island in Papua had infections with sensitive organisms (52).…”

“…Among 282 subjects evaluated since then, 39% were infected with resistant isolates (9,11,48,52,102,106). However, all 38 subjects evaluated on a small, isolated island in Papua had infections with sensitive organisms (52). In western Indonesia two separate surveys at Nias, near northern Sumatra, found 9 inadequate responses among 49 subjects (18%) (16,50).…”