Current status of filariasis in Indonesia.

Filariasis in Indonesia is widely distributed. Three species consisting of 5 ecologically different types have been identified infecting man. Compared to older data, infection rates are much lower, partly due to environmental change and partly as a result of control programs. Various dosage treatments have given good results. The higher dosage treatment gave severe reactions especially in brugian filariasis. Pockets of high endemicity can still be found in remote rural areas. Therefore a weekly low dosage treatment of 40 weeks through the Primary Health Care approach has been adopted. Filariasis research in Indonesia at present is concentrating on the use of biotechnological tools, especially for diagnostic and vector identification purposes, and to understand better the pathophysiology. Treatment trials with new drugs such as Ivermectin and DEC are being conducted both in man and experimental animals.

Social and behavioral aspects of filariasis transmission in Kumpeh, Jambi, Indonesia.

Studies on the social and behavioral aspects of filariasis transmission were conducted in the transmigration area of Kumpeh, in the province of Jambi, Sumatra, Indonesia. Three methods were used in the study namely, interview, participation observation and focus group discussion. A total of 266 respondents (136 males and 130 females) were interviewed. The results of the study showed the most of the transmigrants were not familiar with the word "filariasis". They were more used to the name of "penyakit kaki gajah" or "elephant's leg" disease or "untut". The word "untut" is similar to what people of Selangor, Malaysia call this disease. The community attitude towards control efforts against filariasis was positive, as evidenced by their readiness in being bled and their readiness to help change the environment which serves as mosquito breeding places. Usually the transmigrants live in the "ladang" or dry farming area for 3-4 months to protect their crops from damages by pests. This habit was rather negative, because in their "ladangs" they exposed themselves to high risk of mosquito bites and thus to filariasis infection.

The role of primary health care in filariasis control in Indonesia.

In filariasis control in Indonesia, various regimes of DEC administration have been tried out with good results. However, the higher dosage regimes gave severe reactions. Since a trial with low dosage administration by community leaders gave very good results with minimal side effects, the execution of the control program was handed over to the Primary Health Care unit whose personnel trained community leaders to recognize the symptoms of the disease, distribute the drugs and treat side effects when they occurred. Communicable disease control through health care approach is now being promoted. The activities in the Integrated Services post are carried out by volunteers through village organizations supervised by the health care unit was established, using 1 cadre to look after the health of 10 households.

The importance of communication with the foci of infection in the transmission of filariasis in Indonesia.

Studies on the occurrence of early symptoms of filariasis have been conducted in two transmigration Units in the valley of the Wae Apu river, Buru island, Maluku Province, Indonesia. In both Units, higher disease rates were found in areas, where there was a closer contact with positive natives, higher density of the vector mosquito, and higher infective rates in the mosquitoes.

Low dosage diethylcarbamazine administered by villagers for the control of timorian filariasis.

The results of mass treatment using low dosage diethylcarbamazine (DEC) in three small villages in West Flores, Indonesia, endemic for Brugia timori are described. DEC was distributed on a weekly basis by motivated persons in the community to nearly all villagers for 18 months. An educational programme was developed which focused on describing the relationship between microfilaraemia, vector and disease manifestations, the danger of repeated attacks of adenolymphangitis, and the efficiency of DEC in eliminating the parasites and attacks. During the consolidation phase motivated persons were assigned to treat promptly all cases with acute filariasis and to distribute DEC to all new residents. With this programme the microfilaria rates decreased to very low levels, even as detected by the use of membrane filtration techniques. The adenolymphangitis rates also decreased. An unexpected bonus was the cure of "elephantiasis" in many people. Mild side effects attributed to DEC were encountered only during the first few weeks of treatment.

Cross-reactive surface antigens on three stages of Brugia malayi, B. pahangi and B. timori.

Surface antigens of three stages of three species of the filarial nematode genus Brugia have been analysed by radio-iodination and immunoprecipitation. These surface antigens have been shown to be characteristic for each stage by polyacrylamide gel electrophoresis. For example, infective larvae and adult worms have relatively complex patterns while microfilariae have few bands which are not found when other stages are radio-isotope labelled by the same technique. The surface antigens of Brugia malayi, B. timori and B. pahangi adult worms are all closely homologous, as are the surface antigens of infective larvae of the same three species, and of microfilariae of B. malayi and B. pahangi. Immunoprecipitation revealed that antibody raised in mice against one stage or species reacted with surface antigens from other stages and species. For example, sera raised against B. pahangi male adults reacted strongly with surface antigens from all three species. This cross-reactivity was dominant despite the apparent stage-specificity of the surface pattern seen on SDS-PAGE analysis. Moreover, in cross-immunization experiments, infective larvae were able to stimulate a secondary antibody response in mice previously primed with microfilarial surface antigens. The major microfilarial surface antigens (of mol. wt 65-70 000 Daltons) were recognized by serum antibody from microfilariae-, infective larvae- or adult-infected animals. Thus, although the dominant antigens from each stage are of different molecular weight, cross-reactions with stage-specific antisera suggest that there must be shared epitopes on Brugia surface antigens from each stage. Such shared antigenic determinants dominate the immune response, although other evidence, including the differences in molecular weight, indicates the existence of stage- and species-specific components.

Antigenic analysis of Brugia timori, a filarial nematode of man: initial characterization by surface radioiodination and evaluation of diagnostic potential.

The antigenic composition of Brugia timori has been investigated with surface labelling techniques and defined sets of parasite molecules have been identified on infective larvae, adult worms and microfilariae. Iodinated preparations from all three stages were assessed for immunodiagnostic potential with a small number of serum samples from human filariasis patients. In these tests, reaction with infective larval antigen was the clearest indicator of infection. Reactivity to microfilarial antigens however, correlated poorly with incidence of infection. These experiments show that levels of anti-parasite antibody appear to increase as filarial disease becomes more severe. In contrast to some reports, antibody to microfilarial surface antigens is present in sera from several patients with circulating microfilariae. The immunodiagnostic potential of these tests is indicated by the detection of a few individuals who have high levels of antibody but no outward signs of infection.

The long term effects of repeated diethylcarbamazine administration with special reference to microfilaraemia and elephantiasis.

The result of mass treatment with 50 mg diethylcarbamazine (DEC) per kg body weight followed by two annual selective retreatments in an area highly endemic for Brugia timori infections are described. The criteria for selective re-treatment are simple and practical for use in rural areas. An education programme was developed which focused on describing the relationship between adenolymphangitis and filarial infections, the danger of repeated attacks and the efficiency of DEC in eliminating these attacks. Motivated persons in the community were charged with the responsibility of promptly treating all cases with acute clinical manifestations. With this programme the microfilaria rate by finger prick decreased from 24% to 0%, and by Nuclepore filtration from 30% to 5%. The adenolymphangitis rate decreased from 46% to 11% and the "elephantiasis' rate from 17% to 4%.

Further studies on the development of Wuchereria bancrofti in laboratory animals.

In an attempt to obtain a small animal laboratory model for Wuchereria bancrofti Mongolian gerbils and hamsters were infected with third-stage larvae of strains of the parasite from Indonesia and China. Gerbils were necropsied at 7 to 591 days and larvae recovered up to 219 days. The third molt occurred on or before 10 days and worms found after 14 days were in the fourth stage. More worms were recovered early in the infection (7 to 30 days) than in older infections. The worms were usually recovered from the testes, pelt and carcass and heart and lungs. An adult male worm was recovered on one occasion from the lung of a gerbil at 92 days. The parasite was also found to develop in hamsters with results similar to those in gerbils. Gerbils and hamsters were given antithymocyte sera before and after infection and more worms were recovered and the worms larger in size in some treated animals. Continued studies with geographic strains of W. bancrofti in various animals should be encouraged in order to find a small laboratory animal model for the parasite.

Experimental transmission of Wuchereria bancrofti to monkeys.

Infective larvae of Wuchereria bancrofti from laboratory-raised Culex pipiens fatigans and Aedes togoi mosquitoes fed on human volunteers in Jakarta, Indonesia (J strain) and Kinmen Island, China (K strain) were introduced into Taiwan monkeys (Macaca cyclopis) by subcutaneous inoculation, by foot puncture, or by permitting infected mosquitoes to feed weekly on the monkeys. Some animals were splenectomized and others were treated with varying regimens of immunosuppressants. Necropsy was done on monkeys that died or were killed and the entire bodies were examined for worms. A total of 78 monkeys (43 males and 35 females) were exposed to infection and parasites were found in 29% of the females and 63% of males. In infections of 38 days or less worms were recovered from the testes of males and the pelt, carcass and lymph nodes of both sexes, but after 42 days of infection most worms were in the testes of males, and a few were recovered from lymph nodes and carcasses of females. Worms recovered at 8-11 days were third-stage, those found between 14 and 38 days fourth-stage, and ones found between 42 and 103 days were young adults. After 148 days most were adults and microfilariae were seen in the uteri of female worms at 160 days and later. The parasites continued to grow in size with time. Microfilariae were detected in the blood of nine monkeys between 8 and 18 months and the patent period varied from 5-21 months. Microfilarial densities were low and erratic, and periodicity could not be determined. The effectiveness of methods of administering infections and the value of various treatment regimens seem uncertain; monkey antilymphocytic sera, however, appeared to have some influence. Parasites were found in 36% of the Taiwan monkeys given the J strain and 54% of those given the K strain. A limited number of M. mulatta (3), M.irus (fascicularis) (3) and Aotus trivirgatus (4) were also given infective larvae and adult W. bancrofti were recovered from the testes of one male M. mulatta and one male M. irus; uterine microfilariae were found in one female worm from the latter monkey. A. trivirgatus were negative. Low numbers of infective larvae recovered from mosquitoes fed on patent monkeys were introduced intermittently into seven clean monkeys and one became microfilaremic between 11 and 17 months postinoculation.

Serum immunoglobulin levels in Indonesians with bancroftian filariasis.

Serum immunoglobulin (Ig) levels (IgA, IgM, IgG, IgE) were determined on 185 Indonesians mostly males with and without microfilaremia and with and without clinical disease (hydrocele and elphantiasis). No significant differences were found in IgA and IgE levels in any of the groups but significantly higher IgG levels were found in microfilariae positive persons than those without microfilaremia. Persons with microfilariae alone and symptoms alone, but not both, had higher levels of IgM. There were no correlations between disease category and Ig levels.

Brugia malayi in Kresek, West Java, Indonesia: the effect of environmental changes of filarial endemicity.

A survey was conducted in Kresek, West Java, Indonesia and 813 persons from six villages examined for filariasis. Only eight had microfilaremia and one male person had elephantiasis. Comparing results obtained approximately ten years earlier and the present survey, there was a marked decrease in the microfilarial rate in Kresek, especially in Penameng, during the interim. There was no drug treatment, insecticide application or any dramatic population movement. The development of a well-organized irrigation system and the conversion of the swamps into rice-fields resulted in a decrease of breeding sites for Mansonia mosquitoes and subsequently a decrease in filariasis.

The association of clinical filariasis and Wuchereria bancrofti infections in Jakarta.

In a study carried out in Jakarta, Indonesia between 1969--1977, patients with clinical manifestations of filariasis were examined for microfilaremia. Finger blood (3 X 20 microliter) were examined by conventional methods, venous blood by membrane filtration, urine and hydrocele fluid by concentration methods. A total of 1,422 patients were examined and 182 (12.8%) were positive by blood smear; however, examination by membrane filtration and concentration of urine and hydrocele fluid did not appreciably increase the association between clinical manifestations and Wuchereria bancrofti infection. Approximately 16% of the patients without patent infection were indirectly associated with filariasis, since they co-habitated with persons with microfilaremia. Results of these studies showed that more than 60% of the patients were without patent infection. Factors that may be responsible for these findings are briefly discussed.

Malayan filariasis in Central Sulawesi (Celebes), Indonesia.

Seven villages in Central Sulawesi were surveyed in September 1971 and finger blood samples from 3,658 persons examined for microfilariae. Periodic, nocturnal Brugia malayi was endemic in all seven villages with microfilarial rates (Mf-rate) of 10-42% (av. 25%). The median microfilarial density (MfD50) averaged 5.4 and varied from 0.8 to 9.4 microfilariae per 20 microliter of blood. Males had higher Mf-rate and MfD50 value than females and in males Mf-rates and MfD50 values increased with age. In the female population, however, neither Mf-rates or MfD50 values varied significantly with age. Clinical manifestations of filariasis were found in 12% of 2,412 persons examined and only 2% had elephantiasis. Clinical signs of disease with the exception of elephantiasis, showed good correlations with Mf-rates but not with MfD50 values. Transmigrants experienced clinical manifestations of filariasis earlier and more often than the indigenous population.

Filariasis in West Kalimantan (Borneo), Indonesia.

A survey was carried out among persons residing in 8 villages in the Province of West Kalimantan, Indonesia to determine the prevalence of filariasis. Finger tip blood smears were obtained at night from over 3,000 people and microfilariae of Brugia malayi were found in 108 (3.5%) and Wuchereria bancrofti in 10 (0.3%). Most B. malayi (96 carriers) was found in Kakap, a village near the coast, 20 km from the provincial capital of Pontianak. Nine of 10 cases of W. bancrofti were located in Pahauman, a village 130 km northeast of the provincial capital. Periodicity studies indicate the strain of B. malayi to be subperiodic. In Kakap 18% of 226 persons examined had a clinical history of filariasis and elephantiasis was seen in 13%. This is the first report of rural bancroftian filariasis in the area. A few Mansonia species of mosquitoes were examined but none were infected with filarial larvae.

Brugia malayi in seven villages in South Kalimantan, Indonesia.

Seven villages in South Kalimantan were visited in 1971 and night peripheral blood smears from 2,764 people examined for microfilariae. Brugia malayi was found endemic in all villages with microfilarial rates of 12--46% (average 25%) and the median microfilarial density (MfD50) of 6 to 15 microfilariae per 20 microliter of blood. The microfilariae showed a typical subperiodic pattern. The disease was more common in males than females and the prevalence increased with age. Clinical manifestations of filariasis were found in 20% of 1,099 persons examined. Mansonia species are considered important vectors and cats important reservoir hosts. In addition to B. malayi, Dirofilaria repens and an unknown microfilaria were found in cats in the area and strains of the B. malayi and D. repens have been established in the laboratory.

Brugia timori sp. n. (nematoda: filarioidea) from Flores Island, Indonesia.

Brugia timori sp. n. from experimentally-infected Mongolian jirds (Meriones unguiculatus) is described. The adult male differs from other Brugia species, except Brugia malayi, in having a spicular ratio of 3 : 1; it differs from B. malayi in having greater numbers of subventral adanal papillae (up to 5 on each side) that are loosely spaced and irregularly positioned about the cloaca, a greater diameter of the capitulum of the left spicule, greater lengths of the proximal- and midsections of the left spicule, and a greater length of the proximal section of the right spicule. The adult female has an ovejector of greater length and width than that of B. malayi. Microfilariae in the blood of persons from whom the parasite lines of this study originated were typical of the Timor type, having a greater total body length than other Brugia spp., a length to width cephalic space ratio of about 3 : 1, and a sheath which did not stain when processed in the usual manner with Giemsa.

Parasitic infections in humans in West Kalimantan (Borneo), Indonesia.

A survey was carried out among inhabitants of eight villages in West Kalimantan Province (Borneo), whereby blood smears were examined for malaria, stools examined for intestinal parasites and sera tested by the indirect hemagglutination test for antibodies to Entamoeba histolytica and toxoplasma gondii. The prevalence of malaria among 3017 people examined was 5.6% (Plasmodium vivax 2.8%, Plasmodium falciparum 2.8%). Brugia malayi microfilariae were found in 3.6% and Wuchereria bancrofti in 0.3%. Ninety-seven percent of 2101 stool specimens examined contained evidence of intestinal parasites. Trichuris trichiura (90%) was most common followed by Ascaris lumbricoides (76%), hookworm, (60%), Etamoeba coli (23%), Entamoeba histolytica (6%), Endolimax nana (6%), Iodamoeba butschlii (4%), Giardia lamblia (3%), Chilomastix mesnili (1%) and Strongyloides stercoralis (1%). Other parasites found were Entamoeba hartmanni, Trichomonas hominis, Balantidium coli, Enterobius vermicularis, Hymenolepis nana, Echinostoma sp. and Physalopterid, Dicrocoeliid, and Heterophyid type-eggs. The amoeba prevalence rate was 30%. Indirect hemagglutination antibody titers equal to or greater than 1:128 for Entamoeba histolytica and 1:256 for Toxoplasma gondii were detected in 7% and 3%, respectively, of 1511 sera tested.