Plasmodium ovale in the highlands of Irian Jaya, Indonesia.
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Biomedical subjects
Publications and source records attributed to Purnomo.
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Malaria at an elevation of 1,500 meters is uncommon and is usually unstable when it occurs. To confirm reports of a recent increase in transmission of stable malaria in the Oksibil Valley, which is at an elevation of 1,250-1,500 meters in the Jayawijaya Mountains of Irian Jaya, Indonesia, five malariometric surveys were conducted in four villages between May 1990 and July 1991. A total of 3,380 blood smears, representative of 1,949 persons, was examined. Prevalence rates over the survey period were consistent in each of the four villages, averaging 10% for infants, 50% for children 1-4 years of age, 35% for those 5-9 years old, 28% for those 10-14 years old, and 16% for adults (greater than 15 years old). The spleen rate for the those less than five years old was 96%, with an average enlarged spleen score of 2.32. Plasmodium falciparum accounted for 55% of the infections in the valley, but P. vivax was the predominant species in those less than 10 years old. In the village of Kutdol at an elevation of 1,500 meters, P. malariae was identified in 43% of the positive smears. Four cases were diagnosed as P. ovale. Infection with P. falciparum without obvious clinical symptoms was common in both adults and children. Entomologic and epidemiologic data suggested that the recent upsurge in transmission coincided with the replacement of traditional village huts with the more modern social housing. This replacement required the extensive construction of drainage ditches, which inadvertently also served as additional vector breeding sites. We suspect that this manipulation of the environment, in an effort to improve the quality of life, created conditions conductive for heightened transmission of stable malaria.
Clinical trials of Ivermectin in single oral doses of 200, 400, and 1,000 mg/kg body weight or in multiple doses of 200 mg/kg body weight for 5 consecutive days were performed in leaf monkeys (Presbytis cristatus) infected with Wuchereria kalimantani. Optimal microfilaricidal effect occurred at 200 mg/kg body weight. The drug was less effective than diethylcarbamazine in this animal model for human filariasis but had no adverse effects.
The Quantitative Buffy Coat (QBC) system was used for the detection and identification of malaria parasites in blood specimens from 570 residents of Oksibil, an isolated highland valley in the eastern Jayawijaya Mountains of Irian Jaya (Indonesian New Guinea). The availability of a battery-powered centrifuge and a fiberoptic Paralens enabled us to complete and interpret the assay in this remote environment. Of 322 QBC tubes examined for 2-4 min each, results of 295 (92%) concurred with findings on the matched Giemsa-stained thick smear (GTS). The 27 discrepant results included 13 QBC+/GTS- that, upon reexamination, were found to be GTS+. When using the corrected GTS results as the standard, the sensitivity and specificity of the QBC were 94% and 96%, respectively. Because electricity was available only 3 hr per day, it was decided to decrease the examination for an additional 248 QBC to a maximum of 90 sec per tube. This shortened inspection time resulted in a reduction of sensitivity to 53% but specificity was preserved at 89%. Forty-two of 45 conflicting results, QBC-/GTS+ from cases of light Plasmodium falciparum infections with < 1 trophozoite or gametocyte per field, were resolved by reexamination of the QBC in the laboratory. Tubes held at 4 C could be reexamined, without noticeable loss of fluorescence, for at least 6 wk after collection. Despite some difficulty in the identification of Plasmodium species, it was concluded that the QBC is an easy, sensitive method for the rapid diagnosis of malaria in the field and that it provides the inexperienced microscopist with an additional means for on-site identification of individuals needing treatment.
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--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 less than 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.
Evidence of emerging resistance to chloroquine by Plasmodium vivax is described from Irian Jaya (Indonesian New Guinea). Sixteen of 24 residents in the village of Arso PIR II taking supervised weekly chloroquine prophylaxis (5 mg base/kg) had asexual parasitemia with P. vivax at least once during eight weeks of surveillance. An American working in the same village developed symptomatic P. vivax parasitemia despite chloroquine prophylaxis. Five days after therapy with 600 mg chloroquine base, the asexual parasitemia in the American increased 40-fold, but cleared after treatment with 1,500 mg chloroquine base. Serum samples were not available from many of the cases, but six local residents and the American had serum levels of chloroquine in excess of the ordinarily suppressive 15 ng/ml at the time of their asexual parasitemias (16-70 ng/ml). The weekly 300 mg base tablet of chloroquine, which has been the standard for prophylaxis against malaria for more than 40 years, was not effective against P. vivax in Arso PIR, Irian Jaya.
Between 1987 and 1990, susceptibility of Plasmodium falciparum to chloroquine and to Fansidar was measured in vivo in 151 volunteers using the standard 7-day test. All volunteers lived in Arso PIR, Irian Jaya. A 25 mg/kg dose of chloroquine base was administered over a three-day period to 92 volunteers positive for P. falciparum rings (greater than 10 rings/200 white blood cells). Fifty volunteers (54%) showed results consistent with resistance. Twenty-nine were classified RII, and 21 RIII. In November 1989, a single curative dose of Fansidar was administered to 59 volunteers divided among three groups with 18 months, four years, and life-long exposure to endemic malaria. The proportion of volunteers in each group still positive for P. falciparum on day 7 of followup was 54%, 0%, and 14%, respectively. Thus, immune status profoundly effected clinically response to Fansidar. Standard in vitro microtests were also performed on parasites from 11 volunteers against chloroquine, amodiaquine, quinine, pyrimethamine/sulfadoxine, and and mefloquine. Nine of ten isolates showed in vitro growth consistent with resistance to chloroquine. Tests with other drugs showed few isolates with results considered indicative of susceptibility. Arso PIR has a severe drug resistance problem.
An epidemiologic study of susceptibility to frequent and high-grade parasitemia by Plasmodium falciparum revealed that age-dependent acquired protection developed within a two-year period of exposure to hyperendemic infection pressure. The study was conducted in a single village in northeastern Irian Jaya, Indonesia, where half the residents were native to the province and the other half were transmigrants from areas of Java, where there is little or no malaria transmission. Five separate measures of susceptibility to the asexual parasitemia of falciparum malaria were derived from results of four months of biweekly surveillance of 240 volunteers. Increasing protection as a function of age among the Javanese was a consistent pattern among the five estimates of susceptibility. These age-dependent functions of protection were quantitatively parallel to those among life-long residents of Irian Jaya. When humoral immune responsiveness to ring-infected erythrocyte surface antigen (RESA) was measured by ELISA, a similar pattern emerged; the relative level of antibody to RESA increased as parallel functions of age among the two subpopulations. Acquired protective immunity against P. falciparum was not the cumulative product of many years of heavy exposure to antigen. Instead, the full benefit of protection appeared to develop quickly. The degree of protection was governed by recent exposure and age, independent of history of chronic heavy exposure.
The effect of ivermectin or diethylcarbamazine (DEC) on Wuchereria bancrofti molting from the third to the fourth larval stage (L3 to L4) was evaluated in vitro. L3 larvae were harvested from laboratory-reared Aedes togoi 2 wk after feeding upon a microfilaremic human volunteer. The larvae were kept in an artificial medium (Franke's NI medium) with 10% human serum under an atmosphere of 5% CO2 for 20 days. Experimental tubes also contained ivermectin (0.1-1,000 ng/ml) or DEC (0.1-10,000 ng/ml). An estimated concentration of 50 ng/ml ivermectin inhibited molting in 50% of the larvae expected to molt. For DEC, this value was roughly 1,000 ng/ml. In this in vitro culture system, ivermectin inhibited the L3 to L4 molt of W. bancrofti and was roughly 20-fold more potent in this activity than DEC.
We report 34 infections by Plasmodium ovale found among 15,806 blood film examinations taken between 1973 and 1989 from several sites in Indonesia. Twenty five of the P. ovale infections occurred in a single sample of 514 people living in Owi, Irian Jaya. We detected five additional infections at 3 other sites in Irian Jaya. Other infections by P. ovale occurred at two sites in West Flores. Another infection has already been reported from East Timor. Despite relatively frequent sampling of populations on Sumatra, Kalimantan, Java and Sulawesi, P. ovale has not been found on those islands. It appears that this parasite occurs only on the easternmost islands of the Indonesian archipelago where it is nonetheless a rare finding.
The results of mass treatment using 50 mg diethylcarbamazine per kg body-weight followed one year later by short term selective re-treatment in a highly endemic area of Brugia timori are described. The criteria for selection of re-treatment are simple and practical for use in rural areas. The microfilaria rate by finger prick decreased from 24% to 0 and by Nuclepore filtration from 30% to 2.5%. The disease rates were also affected favourably. 88% of persons receiving the drug reacted to treatment, this percentage slightly exceeding the total filarial infection rate (71%). The prevalence, onset, duration and nature of side reactions are briefly discussed and related to the presence of microfilaraemia and disease manifestations among the study population.
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Fifty-nine persons, who immigrated into a Brugia timori endemic area from non-filarial areas on the island of Flores, Indonesia were examined for filariasis after residing in the village for 2 to 10 years. Six persons had B. timori microfilaremia and 31 had filarial disease. The disease seems to affect immigrants from non-filarial areas severely within a relatively short period. Among those residing in the village, for 2 years, the microfilaria rate was 5% and the elephantiasis rate 21%. Selective treatment using 50 mg diethylcarbamazine per Kg body weight was given to all microfilaria (Mf) positive persons. Approximately one year later the Mf-rate by finger stick and Nuclepore filtration was 9% and 18% respectively. There was indirect indications that the Mf-rate might increase with the passage of time. However, the total filarial disease rate remained constant during the one year period. The relationship between these findings and American servicemen exposed to filariasis during World World II is briefly discussed.
Geographical and host occurrence records for Angiostrongylus cantonensis throughout the Indonesian archipelago a;e reported. A. cantonensis was found in the following provinces: West Sumatra, South Sumatra, Lampung, West Java, Central Java, North Sulawesi and East Nusa Tenggara. Infections were diagnosed in the following rodents: Rattus rattus diardii, Rattus exulans, Rattus tiomanicus jaloriensis, Rattus lepturus, Rattus norvegicus and Bandicota indica setifera and in the giant African land snail, Achatina fulica. Infection rates varied considerably.
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The microfilaria of Brugia timori was compared with microfilariae of Indonesian strains of periodic and subperiodic Brugia malayi using alcohol-fixed (stained) and formalin-fixed (unstained) preparations. As noted by other observers of the Timor microfilaria, the absence of a stained sheath in Giemsa preparations, a long cephalic space with a length-to-width ratio of about 3:1, and a great overall body length are features which most readily distinguish this parasite. Additionally, B. timori has greater numbers of single row nuclei in the terminal column of body cells and a lesser bulge of the cuticle surrounding nuclei in the distal portion of the tail than does B. malayi. About 60% of B. timori microfilariae were exsheathed in haemalum-stained thick blood films. Brugia timori microfilariae were found to be distinct from microfilariae of B. malayi by comparing percentages of total body length included between the cephalic tip and major internal anatomic markers.