Opportunities For Evaluating Malaria Vaccines In Indonesia

Di Indonesia, khususnya di Irian Jaya dan daerah malaria tinggi lainnya terdapat kesempatan yang sangat baik untuk mengevaluasi vaksin malaria. Hal ini antara lain disebabkan tersedianya data epidemiologi termasuk insidens, risiko malaria yang tinggi dan merata pada berbagai kelompok umur, jenis kelamin dan pekerjaan, adanya kelompok masyarakat yang sesuai untuk penelitian (transmigran dan angkatan bersenjata), lokasi desa yang memungkinkan randomisasi serta tersedianya fasilitas laboratorium di dekat daerah penelitian. Pemberantasan malaria dengan vaksinasi diharapkan akan menjadi fokus dari penelitian kesehatan menjelang akhir abad ke-20. Indonesia yang terdiri dari berbagai pulau memungkinkan konsolidasi pemberantasan malaria secara bertahap. Pengalaman yang diperoleh dengan pemberantasan malaria di suatu pulau akan sangat bermanfaat untuk menghadapi masalah yang lebih berat yakni malaria di daratan luas seperti Afrika atau daratan Asia Tenggara

Mefloquine Is Highly Efficacious against Chloroquine-Resistant \u3ci\u3ePlasmodium vivax\u3c/i\u3e Malaria and \u3ci\u3ePlasmodium falciparum\u3c/i\u3e Malaria in Papua, Indonesia

Background. During the period of 1996–1999, we prospectively monitored 243 Javanese adults and children after arriving in Papua, Indonesia, and microscopically documented each new case of malaria by active surveillance. Methods. In a randomized, open-label, comparative malaria treatment trial, 72 adults and 50 children received chloroquine for each incident case of malaria, and 74 adults and 47 children received mefloquine. Results. Among 975 primary treatment courses, the cumulative 28-day curative efficacies were 26% and 82% for chloroquine against Plasmodium falciparum malaria and Plasmodium vivax malaria, respectively. Mefloquine cure rates were far superior (96% against P. falciparum malaria and 99.6% against P. vivax malaria). Conclusions. Mefloquine is a useful alternative treatment for P. vivax malaria and P. falciparum malaria in areas such as Papua, where chloroquine is still recommended as the first-line therapeutic agent

INCIDENCE OF SYMPTOMATIC AND ASYMPTOMATIC \u3ci\u3ePLASMODIUM FALCIPARUM\u3c/i\u3e INFECTION FOLLOWING CURATIVE THERAPY IN ADULT RESIDENTS OF NORTHERN GHANA

Adult residents of holoendemic malaria regions in Africa have a naturally acquired immunity (NAI) to malaria that renders them more resistant to new infections, limits parasitemia, and reduces the frequency and severity of illness. Given such attributes, it is not clear how one might evaluate drug or vaccine efficacy in adults without serious confounding. To determine symptomatic and asymptomatic malaria attack rates in adults of northern Ghana, 197 men and women underwent curative therapy for any pre-existing malaria infections at the start of the high transmission (wet) season. They were monitored for first parasitemia and first clinical episode of infection by Plasmodium falciparum over a 20-week period (May–October 1996). The cumulative incidence of primary infection by P. falciparum was 0.98 and incidence density of infection was calculated to be 7.0 cases/person-year. Symptoms were reported by 19.5% of the individuals at the time of first recurrent parasitemia. Incidence of infection, parasite density, and the frequency of symptoms were comparable in males and females. The results suggest that NAI did not provide these adults with significant defense against rapid re-infection and suggest that this population-infection design could serve to demonstrate the efficacy of a drug or vaccine in preventing parasitemia

Cyclospora cayetanensis among expatriate and indigenous populations of West Java, Indonesia.

From January 1995 through July 1998, we investigated the occurrence of Cyclospora cayetanensis infection associated with gastrointestinal illness or diarrhea in foreign residents and natives of West Java, Indonesia. We found that C. cayetanensis was the main protozoal cause of gastrointestinal illness and diarrhea in adult foreign residents during the wet season. The parasite rarely caused illness in the indigenous population or in children

Treatment of Chloroquine-Resistant \u3ci\u3ePlasmodium vivax\u3c/i\u3e with Chloroquine and Primaquine or Halofantrine

Optimal therapy gor infection by chloroquine-resistant Plasmodium vivax has not been established. From 1992 to 1994 during three separate studies, 147 Javanese residents of Irian Jaya infected by P. vivax were treated with either chloroquine (2 5 mg of base/kg during 3 days or 10mg of base/kg in one dose) plus primaquine (1 0 mg/kg during 28 days or 2.5 mg/kg during 3 days)( n = 78), chloroquine plus placebo( n = 50), or halofantrine (24 mg base/kg in 12 h; n = 19). There was no difference in tolerance to or side effects of any of the regimens. Within 14 days of starting therapy, therapeutic failure among these patients was 44% for chloroquine, 5% for chloroquine plus primaquine (P \u3c .001), and 0 for halofantrine (P \u3c .001). After 28 days, therapeutic failure was 78%, 15%, and 6% respectively. Thus, chloroquine plus primaquine in combination and halofantrine alone are effective therapies for chloroquine-resistant P. vivax

Malaria in a cohort of Javanese migrants to Indonesian Papua

The epidemiology of infection by Plasmodium falciparum and P. vivax was investigated among Javanese migrants to an endemic region of Papua, Indonesia. A cohort of 243 migrants from Java was followed for malaria in a new settlement village in the endemic Armopa area of north–eastern Papua, beginning on the day each migrant arrived in the village. The subjects were monitored during home visits (three/week) and by the twice-monthly production of bloodsmears that were checked for malarial parasites. At the end of 33 months, 159 (65%) of the subjects remained under follow-up. The prevalence of parasitaemia in the village declined from 16% among those already living there when the study began in August 1996, to 5% when the study finished in June 1999. Over this period, 596 infections by P. falciparum and 723 by P. vivax occurred in the cohort, 22 and 27 of the subjects each experiencing at least six infections by P. falciparum and P. vivax, respectively. The incidence of malarial infection was higher during the first and second years post-migration (3.2 and 2.7 infections/person-year) than during the third (1.2 infections/person-year). Although the geometric mean parasite counts for P. falciparum increased over time (1209, 1478, and 1830 parasites/ml in the first, second and third years, respectively), the corresponding values for P. vivax (497, 535 and 490 parasites/ml ) showed no such trend. Only one of the nine subjects who developed severe malaria (requiring intravenous quinine therapy) was a child, giving an odds ratio for a case of severe malaria being in an adult of 6.1 (P=0.08)

Failure of Supervised Chloroquine and Primaquine Regimen for the Treatment of Plasmodium vivax in the Peruvian Amazon

The widespread use of primaquine (PQ) and chloroquine (CQ), together, may be responsible for the relatively few, isolated cases of chloroquine-resistant P. vivax (CQRPV) that have been reported from South America. We report here a case of P. vivax from the Amazon Basin of Peru that recurred against normally therapeutic blood levels of CQ. Four out of 540 patients treated with combination CQ and PQ had a symptomatic recurrence of P. vivax parasitemia within 35 days of treatment initiation, possibly indicating CQ failure. Whole blood total CQ level for one of these four subjects was 95 ng/ml on the day of recurrence. Based on published criteria that delineate CQRPV as a P. vivax parasitemia, either recrudescence or relapse, that appears against CQ blood levels >100 ng/mL, we document the occurrence of a P. vivax strain in Peru that had unusually high tolerance to the synergistic combination therapy of CQ + PQ that normally works quite well

A Randomized, Double-Blind, Placebo-Controlled, Dose-Ranging Trial of Tafenoquine for Weekly Prophylaxis against \u3ci\u3ePlasmodium falciparum\u3c/i\u3e

Tafenoquine is a promising new 8-aminoquinoline drug that may be useful for malaria prophylaxis in nonpregnant persons with normal glucose-6-phosphate dehydrogenase (G6PD) function. A randomized, doubleblind, placebo-controlled chemoprophylaxis trial was conducted with adult residents of northern Ghana to determine the minimum effective weekly dose of tafenoquine for the prevention of infection by Plasmodium falciparum. The primary end point was a positive malaria blood smear result during the 13 weeks of study drug coverage. Relative to the placebo, all 4 tafenoquine dosages demonstrated significant protection against P. falciparum infection: for 25 mg/week, protective efficacy was 32% (95% confidence interval [CI], 20%–43%); for 50 mg/week, 84% (95% CI, 75%–91%); for 100 mg/week, 87% (95% CI, 78%–93%); and for 200 mg/week, 86% (95% CI, 76%–92%). The mefloquine dosage of 250 mg/week also demonstrated significant protection against P. falciparum infection (protective efficacy, 86%; 95% CI, 72%–93%). There was little difference between study groups in the adverse events reported, and there was no evidence of a relationship between tafenoquine dosage and reports of physical complaints or the occurrence of abnormal laboratory parameters. Tafenoquine dosages of 50, 100, and 200 mg/week were safe, well tolerated, and effective against P. falciparum infection in this study population