Efficacy of permethrin-impregnated bed nets on malaria control in a hyperendemic area in Irian Jaya, Indonesia III. Antibodies to circumsporozoite protein and ring-infected erythrocyte surface antigen.

A two years intervention study was carried out using permethrin impregnated bed nets in a hyperendemic area, in Irian Jaya, Indonesia. To assess the influence of this intervention on natural immunity, concurrent immunological studies to determine levels of antibodies to the circumsporozoite (CS) and ring-infected erythrocyte surface antigen (RESA) proteins were conducted. Prevalence and titers of immunoglobulins (Ig)G and IgG subclasses were periodically measured in 138 individuals (30 children under the age of ten and 108 villagers ten years old and older). In the younger group, seropositivity of total IgG against CS fluctuated according to the parasite infection rates; however, IgG seropositive reaction against RESA gradually increased. In the older age group, seropositivity of both kinds of antibodies was stable during the whole study period. Nevertheless, the geometric mean titers of total IgG against CS and RESA were significantly reduced in this latter group in individuals who contained these antibodies before and after intervention. The geometric mean titer of IgG3 subclass against RESA was decreased at a highly significant level (p = 0.0005), and that of IgG4 against the same antigen was also decreased although to a lesser extent (p = 0.02).

Efficacy of permethrin-impregnated bed nets on malaria control in a hyperendemic area in Irian Jaya, Indonesia: differentiation between two age groups.

A malaria intervention trial was conducted for two years to evaluate the efficacy of permethrin-impregnated bed nets in reducing malaria infection and splenomegaly in two different age groups, ie below and over age of ten, in a hyperendemic area in Irian Jaya, Indonesia. Permethrin-impregnated or placebo-treated bed nets were provided to a treated and a control village, respectively. Immediately after periods with moderate rainfall in the first year, treated bed nets decreased P. falciparum and P. vivax density in the blood of children <10 years (group 1) but did not reduce the percentage of infection with either species. Children >10 and adults (group 2) showed significant reduction only in P. falciparum infection rates and density, whereas P. vivax was not influenced. After an excessive rainfall season in the second year, the risk for P. falciparum infections in both age groups using treated nets was less than half of that in the control village. P. vivax infection rates were significantly lower in the treated village at the beginning of and after these heavy rainfalls. In the treated village, spleen enlargement was markedly reduced in the younger age group during the second year.

Efficacy of permethrin-impregnated bed nets on malaria control in a hyperendemic area in Irian Jaya, Indonesia: influence of seasonal rainfall fluctuations.

A malaria intervention study was carried out using permethrin impregnated bed nets in the south-central part of Irian Jaya with perennial transmission, from April 1993 to April 1995. Malariometric surveys were carried out periodically for parasite prevalence by species and for spleen rates. Prior to intervention, the percentage of Plasmodium falciparum infected inhabitants was significantly higher in Hiripau, where permethrin-impregnated bed nets were used during the study, than in the placebo-treated control village, Kaugapu. After two years of intervention the situation was reversed and figures higher in the control village (RR 0.19, 95% CI 0.10-0.36, p < 0.0001). Similarly, P. vivax infection rates, 12.4% in Hiripau vs 5.7% in Kaugapu in April 1993. were reversed in April 1995 (3.6% in Hiripau and 11.3% in Kaugapu, p < 0.001). In the treated village, pre-control hyperendemicity was reduced to a low mesoendemic level (spleen rate 12.5%) during two years of intervention, whereas the level was mesoendemic (spleen rate 35.2%) in the control village. Impregnated bed nets were found an effective intervention both in moderate (April 1993 through April 1994, 1,626 mm rainfall) and high (April 1994 through April 1995/1995, 3,321 mm) transmission seasons.

Malaria situation in several villages around Timika, south central Irian Jaya, Indonesia.

Malaria in Timika area, south central Irian Jaya, is a public health problem causing morbidity and mortality, particularly to the vulnerable age group. In August/September 1992 malariometric surveys were conducted simultaneously with sensitivity studies of Plasmodium falciparum to antimalarials, and bionomics of vectors in six villages around Timika (Mwapi, Kaugapu, Hiripau, Pomako, Mapurujaya, Kwamki Lama). The average overall spleen rate was 44.0%, the highest rate observed in Kwamki Lama (68.3%) and the lowest in Mapurujaya (13.7%). The average parasite rate in children aged 2-9 years was 60.6%. The highest rate was found in Mwapi (92.0%) and the lowest rate in Mapurujaya (4.8%). In the study area the dominant species was P. falciparum, (except in Kaugapu), followed by P. vivax. P. malariae and P. ovale were not observed. In vivo sensitivity studies done in 7 villages showed P. falciparum was resistant to chloroquine [51.3% S/R I (sensitive or 1st grade resistant), 43.6% R II and 5.1% R III] in Kwamki Lama, SP I and SP II (transmigrant settlements) and Timika health service center. In vitro sensitivity test in Kwamki Lama, SP I, SP II and Timika health service center showed 64.4% resistant to chloroquine, and remain sensitive to sulfadoxine-pyrimethamine, quinine and mefloquine. Vector studies revealed that Anophelese punctulatus and An. koliensis were the potential vectors as was confirmed by ELISA positive test with a sporozoite rate of 1.43% and 0.33% respectively. The vectors were indoor and outdoor resting.

Anthelminthic treatment raises plasma iron levels but does not decrease the acute-phase response in Jakarta school children.

The study was conducted to investigate the impact of intestinal helminthiasis and treatment on iron status and acute phase response (APR) among urban Indonesian primary school children, aged 8-11 years old. The prevalence of helminthiasis among these children was; Ascaris lumbricoides, 81.6%; Trichuris trichiura, 88.3%; and mixed infection of A. lumbricoides and T. trichiura, 70.0%. Of 120 children enrolled in the investigation, 59 received a single 400 mg dose of albendazole, and 61 received a placebo. Ten days following treatment, the prevalence of ascariasis and trichuriasis in the treatment group diminished to 0% and 27%, respectively, and in the placebo group to 63.9% and 68.9%. Plasma iron, hemoglobin, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cell (WBC), interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor (TNF) concentrations were determined prior to the intervention and 10 days after. Plasma iron concentrations and WBC count rose in the treatment group (p=< or =0.05) when compared to baseline status. Increases in hemoglobin concentrations observed in the treatment group 10 days post-treatment were not statistically significant. CRP, IL-1, IL-6 and TNF were found to be within normal limits for both groups both before and after treatment. ESR increased significantly in both treatment and placebo groups when compared the rates measured before treatment. These findings show that treatment with albendazole is associated not only with a decreased worm burden in school children, but also a rise in plasma iron.

Seroepidemiological studies of malaria in different endemic areas of Indonesia.

A total of 618 sera from inhabitants living in various endemic areas in Indonesia were examined for IgG against Plasmodium falciparum utilizing young trophozoites and mature schizonts as antigens by the method of ELISA and IFAT. In general, antibodies against trophozites (RESA) based on ELISA and antibodies against schizonts based on IFAT showed a correlation of malarial antibodies with the level of endemicity of the area examined. Anti-RESA antibody, detected either by ELISA or IFAT was more pronounced in the aparasitemic group compared to the parasitemic group. On the contrary, anti-schizont antibody measured by IFAT was more pronounced in the parasitemic group. Malarial antibody levels against the schizont-merozoite fraction of P. falciparum as assayed by ELISA appeared to develop more slowly compared to levels based on IFAT.

Adverse reactions to a single dose of diethylcarbamazine in patients with Brugia malayi infection in Riau Province, West Indonesia.

A study on the adverse reactions, occurring after treating microfilaremic patients infected with B. malayi, revealed that all reacted to a single oral dose of DEC (5 mg/kg). The major reactions were fever, headache, anorexia, abdominal pain, muscle and joint pains, nausea and vomiting. There seemed to be no association between the time of fever onset and microfilarial density, but the number of cases observed was too small to make any firm conclusion. There was a tendency for more severe reactions to occur in patients with higher microfilaria counts. Local reactions, probably due to destruction of adult worms, were seen in 3 patients. The reactions were serious enough to necessitate the patients spending approximately 48 hours in bed.