Elephantiasis Patients Research Articles

Aedes aegypti as potential vector of filariasis in Pekalongan, Central Java Province, Indonesia

Background: The filariasis elimination program in Indonesia has been conducted, but new cases and some chronic cases are still often found. Objective: This study aims to determine levels of endemicity and to identify filarial worm species in filariasis cases and s and their surrounding communities by using microscopic examination, polymerase chain reaction (PCR), and to examine levels of infection in vectors mosquito by surgery and PCR. Also to to determine that Ae. aegypti can act as vector of filariasis. Methods: This study was conducted at 10 locations in Pekalongan Regency, Central Java Province, with a cross sectional design. Intravenous blood sampling was conducted on 102 respondents consisting of 10 elephantiasis patients and 92 non-elephantiasis patients at night, starting at 8 pm, then examined microscopically and PCR. Mosquitoes in this study were collected by using a human landing collection method for 12 hours from 6 pm to 6 am by volunteers. Artificial infection of microfilaria W. bancrofti was held against Cx. quinquefasciatus and Ae.aegypti from laboratory collection. Results: Results of this study found that there were 5.729 of mosquitos, consisting of 8 species, namely Culex quinquefasciatus, Culex vishnui, Culex tritaeniorhynchus, Aedes aegypti, Aedes albopictus, Anopheles subpictus, Anopheles vagus, and Armigeres kesseli. Microfilarial (mf) rate was 0.89%, and and the blood PCR showed infection rate of 3.92% and the blood PCR showed infection rate of 3.92%. No larva was found in female mosquito dissection. The PCR results showed that the infection rate was 9.10% in Ae. aegypty pool respectively. Artificial infection results was negative both dissecting microscopis and PCR. Conclusion: This study revealed that the locations were low of filariasis endemicity. The mf rate was less than 1%, and there was a moderate density to high density of microfilaria in the patients. The low level of infection rates in mosquito is suggested as an alert to its potential transmission.

TINJAUAN PSIKOLOGI KESEHATAN PADA PENDERITA PENYAKIT KAKI GAJAH KRONIS DI KABUPATEN BANDUNG

Elephantiasis or Filariasis has been reported endemic in Kabupaten Bandung with potentially result in defects. This research aimed to explore health psychology of chronic Elephantiasis patients in Kabupaten Bandung. Qualitative-descriptive method has been used to explore the respondent’s psychodynamics, health behavior, and treatment seeking behavior, while quantitative-descriptive method has been used to determine the percentage distribution. The result showed that there were three kind of respondent’s psychodynamic namely denial (7.7%), anxiety (85%), and depression (7.7%). Due to the lack of knowledge about the disease, the majority of respondents (77%) were hiding their disease.Type of treatment seeking behaviors has been chosen by respondent namely relying to the paranormal (92%), doctors (23%), traditional physician (54%), and acupuncturist (15%).

Real-time PCR detection of the HhaI tandem DNA repeat in pre- and post-patent Brugia malayi Infections: a study in Indonesian transmigrants.

BackgroundLymphatic filariasis caused by Wuchereria bancrofti or Brugia spp. is a public health problem in developing countries. To monitor bancroftian filariasis infections, Circulating Filarial Antigen (CFA) test is commonly used, but for brugian infections only microfilariae (Mf) microscopy and indirect IgG4 antibody analyses are available. Improved diagnostics for detecting latent infections are required.MethodsAn optimized real-time PCR targeting the brugian HhaI repeat was validated with plasma from microfilariae negative Mongolian gerbils (jirds) infected with B. malayi. Plasma samples from microfilaremic patients infected with B. malayi or W. bancrofti were used as positive and negative controls, respectively. PCR results of plasma samples from a transmigrant population in a B. malayi endemic area were compared to those of life-long residents in the same endemic area; and to IgG4 serology results from the same population. To discriminate between active infections and larval exposure a threshold was determined by correlation and Receiver-Operating Characteristics (ROC) curve analyses.ResultsThe PCR detected HhaI in pre-patent (56 dpi) B. malayi infected jirds and B. malayi Mf-positive patients from Central Sulawesi, Indonesia. HhaI was also detected in 9/9 elephantiasis patients. In South Sulawesi 87.4% of the transmigrants and life-long residents (94% Mf-negative) were HhaI PCR positive. Based on ROC-curve analysis a threshold for active infections was set to >53 HhaI copies/μl (AUC: 0.854).ConclusionsThe results demonstrate that the HhaI PCR detects brugian infections with greater sensitivity than the IgG4 test, most notably in Mf-negative patients (i.e. pre-patent or latent infections).

Human Lymphatic Filariasis: Genetic Polymorphism of Endothelin-1 and Tumor Necrosis Factor Receptor II Correlates With Development of Chronic Disease

Hydrocele and elephantiasis are 2 clinically very diverse and often mutually exclusive chronic manifestations of human bancroftian filariasis. Plasma levels of endothelin-1 (ET-1), a major angiogenic factor, and tumor necrosis factor receptors (TNFRs) that regulate host inflammation have been associated with development of chronic filariasis, although their genetic basis are not known. We studied polymorphisms of ET-1 (Ala288Ser) and TNFR-II (Met196Arg) genes by means of the polymerase chain reaction confronting 2 pairs primers method and restriction fragment length polymorphism, respectively. Plasma ET-1 level was measured by enzyme-linked immunosorbent assay. Met196Arg genotype frequency of TNFR-II polymorphism was significantly greater in hydrocele patients, compared with elephantiasis patients (OR, 4.34 [95% CI, 2.04-9.20]). Conversely, a significantly high prevalence of the Ala288Ser mutation of ET-1 was observed in elephantiasis patients, compared with hydrocele cases (OR, 2.15 [95% CI, 1.13-4.10]). Decreased plasma ET-1 levels associated significantly with Ala288Ser mutation in the study population. A combined analysis indicated a 23-fold higher risk for developing elephantiasis in individuals with TNFR-II (Met196Met) and ET-1 mutants (Ala288Ser + Ser288Ser). ET-1 (Ala288Ser) and TNFR-II (Met196Arg) polymorphisms are associated with development of one or the other form of chronic disease in bancroftian filariasis.

Diagnostic value of IgG isotype responses against Brugia malayi antifilarial antibodies in the clinical spectrum of brugian filariasis

To study the diagnostic significance of antifilarial IgG subclasses in the clinical spectrum of brugian filariasis, IgG1, IgG3 and IgG4 antifilarial antibodies were determined in an exposed population comprising 74 asymptomatic amicrofilaraemics, 30 microfilaraemics, 20 lymphangitis and 16 elephantiasis patients resident in Narathiwart province, an area endemic for Brugia malayi lymphatic filariasis in southern Thailand. The dominant isotype of antifilarial antibody was IgG4. A significantly higher percentage of individuals were positive for IgG1 in the microfilaraemic and lymphangitis groups compared with the elephantiasis and endemic normal patients, while a significantly higher positive rate of IgG3 was found in those with lymphangitis. The possible role of these isotypes for diagnostic purposes and the pattern of antibody response in various clinically manifesting groups are discussed.

Circulating fibrosis markers, eosinophil cationic protein and eosinophil protein X in patients withWuchereria bancroftiinfection: association with clinical status

We measured the concentrations of several circulating fibrosis markers (type I collagen I, type III procollagen, hyaluronan) and eosinophil granule proteins (ECP and EPX) in lymphatic filariosis patients to investigate their relationship with clinical, parasitological and immunological data. This study was conducted in Polynesian patients with various stages of the disease (acute lymphangitis, chyluria, hydrocoele, elephantiasis), a closely related microbial lymphangitis and endemic controls. We observed modifications of the different markers in this pathology. Serum type I collagen and PIIINP were decreased. Serum hyaluronan, linked to perilymphatic granulomatous inflammation, was significantly increased in acute lymphangitis and elephantiasis patients. Serum ECP was also increased, at the limit of significance in our sample, in elephantiasis patients. These two last markers, already validated in another helminth disease, schistosomiasis, have potential interest in terms of follow-up of morbidity in these parasitic diseases.

Inflammatory cytokines following diethylcarbamazine (DEC) treatment of different clinical groups in lymphatic filariasis

In an earlier study in Indonesia we reported on adverse reactions to diethylcarbamazine (DEC) in brugian filariasis patients identified as microfilaraemics ( n = 26), endemic normals ( n = 11) and elephantiasis patients ( n = 17). To assess the link between adverse reactions and cytokines we have now analysed an array of inflammatory mediators in plasma samples collected during the same study. Pre-treatment levels of interleukin (IL)-6 and soluble tumour necrosis factor receptor 75 (sTNF-R75) were higher in elephantiasis patients compared to microfilaraemics and endemic normals, indicating the presence of an ongoing inflammation in patients with chronic disease. After initiation of treatment, the levels of IL-6 and LPS-binding protein (LBP) were consistently and significantly higher in microfilaraemics who suffered most from adverse reactions compared with endemic normals and elephantiasis patients. In microfilaraemics the levels of sTNF-R75 increased after treatment to reach levels recorded in elephantiasis patients. IL-6 increased early, concurrent with the development of adverse reactions and peaked by 24 h post treatment. The levels of LBP and sTNF-R75 in microfilaraemics also increased to peak, later than IL-6, at 32 h post DEC therapy. Although changes were recorded in IL-8 and IL-10 levels in some individuals, no significant differences were found between the 3 clinical groups. These results demonstrate that intake of DEC leads to an increase in a selected number of inflammatory mediators in the group of filarial patients who suffer most from adverse systemic reactions.

Adverse reactions following diethylcarbamazine (DEC) intake in ‘endemic normals’, microfilaraemics and elephantiasis patients

This paper reports on adverse reactions following a 12-day course of 6 mg/kg diethylcarbamazine (DEC) therapy in brugian filariasis patients in Indonesia. Microfilaria-positive individuals ( n = 26), ‘endemic normals’ ( n = 12) and elephantiasis patients ( n = 17) were included in the study. Fever, headache and body aches started between 2 and 24 h after DEC intake. Adverse reactions were categorized into ‘no or mild’, ‘moderate’ or ‘severe’ depending on the total reaction score. Four microfilaraemic individuals (15·4%) suffered from severe adverse reactions and their pre-treatment microfilarial levels (geometric mean, GM = 3060 mf/10 mL) were significantly higher than in the 5 microfilaraemic individuals (19·2%) suffering from moderate reactions (GM = 1268 mf/10 mL) and in the 17 microfilaraemic patients (65·4%) who experienced no or mild reactions (GM = 6 mf/10 mL)( P < 0·001 and P < 0·001, respectively). Endemic normals showed no or mild adverse reactions. No or mild adverse reactions were also recorded in all but 2 elephantiasis patients after DEC intake. Two elephantiasis patients with moderate reactions had high levels of circulating microfilariae at pre-treatment (2097 and 7375 mf/10 mL). Concentrations of DEC were measured in plasma, but could not explain the differences in the severity of adverse reactions.

ABrugia malayiAntigen Specifically Recognized by Infected Individuals

Western blot analyses were performed on 444 serum specimens: 40 sera from microfilaraemic individuals, 10 sera from elephantiasis patients, 24 treated individuals, 50 sera from residents of endemic areas without anti-filarial IgG4 antibodies (endemic normals), 20 sera from amicrofilaraemic individuals with high anti-filarial IgG4 antibodies, 200 sera from healthy city-dwellers (non-endemic samples), and 100 sera from soil-transmitted helminth-infected individuals. Phast electrophoresis system was used to electrophoreseBrugia malayisoluble adult worm antigen on 10–15% SDS-PAGE gradient gels followed by electrophoretic transfer onto PVDF membranes. Membrane strips were then successively incubated with blocking solution, human sera, and monoclonal anti-human IgG4 antibody-HRP, with adequate washings done in between each incubation step. Luminol chemiluminescence detection was then used to develop the blots. An antigenic band with the MW of ∼37 kDa was found to be consistently present in the Western blots of all microfilaraemic sera, all amicrofilaraemic sera with high titres of anti-filarial IgG4 antibodies, some treated patients, and some elephantiasis patients. The antigen did not occur in immunoblots of individuals with other helminthic infections, normal endemic individuals, and city dwellers. Therefore theB. malayiantigen of with the MW of ∼37 kDa demonstrated specific reactions with sera ofB. malayi-infected individuals and thus may be useful for diagnostic application.

PCR- elisa for the detection of Brugia malayi infection using finger-prick blood

A polymerase chain reaction assay based on the enzyme-linked immunosorbent assay (PCR- elisa) has been developed to detect Brugia malayi infection in an area of low endemicity in Malaysia. Blood samples from 239 subjects were tested: 192 amicrofilaraemic individuals, 14 microfilaraemic persons and 3 chronic elephantiasis cases from endemic areas and 30 city-dwellers (non-endemic controls). PCR products were examined by elisa and Southern hybridization. In the PCR- elisa, digoxigenin-labelled PCR products were hybridized to a biotin-labelled probe. This was followed by incubation in streptavidin-coated microtitre wells and detection using anti-digoxigenin-peroxidase and ABTS TM [2,2′-azinobis(3-ethylbenzthiazoline-6-sulphonic acid)]. All microfilaraemic samples were positive by PCR- elisa and Southern hybridization and all samples from non-endemic subjects and chronic elephantiasis patients were negative. The PCR- elisa detected 12 times as many B. malayi infections as did thick blood film examination. Nineteen of the 194 samples from the endemic area gave positive results by both PCR- elisa and Southern hybridization, and an additional 5 samples were positive by PCR- elisa only. The PCR- elisa was specific and sensitive, detected more infections, and was more reproducible than Southern hybridization.

Antibody responses to filarial infective larvae are not dominated by the IgG4 isotype.

The humoral immune response in humans to filarial parasites is generally dominated by the IgG4 isotype, when measured by ELISA against somatic adult worm extract. In contrast, as we report here, antibodies reactive to somatic extracts of infective larvae are more equally represented by IgG1 and IgG4. Moreover, binding to surface exposed epitopes in immunofluorescence on larval stages is mediated foremost by IgG1 and IgM, secondarily by IgG2 and IgG3, and very little by IgG4. Both anti-L3 surface and somatic antibodies are strongest in elephantiasis patients, and tend to increase with age. Antibody to the L3 surface is also present in most microfilaraemic individuals who bear no detectable antibodies to the surface of the microfilarial stage. These results demonstrate that a stage- and isotype-specific response is mounted to the L3 surface which should be considered as a possible mediator of concomitant immunity in filariasis.

Differential Decline in Filaria-Specific IgG1, IgG4, and IgE Antibodies in Brugia malayi-Infected Patients after Diethylcarbamazine Chemotherapy

In human filariasis, the predominant serum antibody is IgG4, accompanied by significant IgE production. The ratio of IgG4 to IgE is highest in asymptomatic microfilaremic carriers, while chronic disease is associated with elevated IgG1-3. The changes in isotypes following chemotherapy with diethylcarbamazine (DEC) were studied in 2 groups of Brugia malayi-infected patients from Sumatra and South Kalimantan, Indonesia. Similar results were obtained from each group. IgG4 levels decreased sharply (65%-78%) within 12 months. IgG1 levels declined in a less consistent and extreme manner, and levels of IgG2 and IgG3 declined only in patients with elephantiasis, who also had the highest initial levels of these antibodies. IgE responses were relatively stable to therapy in microfilaremic patients (7%-28% reduction) and showed only moderate decline (56% over 2 years) in elephantiasis patients. Active filarial infection is thus associated with specific IgG4 antibodies, but there is independent expression of the IgE and IgG4 isotypes in filariasis.

Specific T cell unresponsiveness in human filariasis: diversity in underlying mechanisms.

In an attempt to overcome T cell unresponsiveness to filarial antigens, 65 individuals belonging to the three clinical groups of elephantiasis patients, microfilaraemics, and asymptomatic amicrofilaraemics who exhibited unresponsiveness to Brugia malayi adult worm antigen (BmA) were studied. Peripheral blood mononuclear cells were cocultured with antigen and one of the following reagents that have been reported to be effective in reconstituting T cell proliferation: interleukin-2 (IL-2), interleukin-7 (IL-7), anti-interleukin-4, anti-interleukin-10, anti-CD2, anti-CD27, anti-CD28, indomethacin, phorbol myristate acetate (PMA), or calcium ionophore (A23187). We were able to overcome antigen-specific unresponsiveness in only a minority of the individuals studied. Co-culture with IL-2, IL-7, indomethacin and PMA were the only conditions which resulted in enhanced proliferation to BmA in these individuals. In general, unresponsiveness in elephantiasis patients was easier to reverse than in other clinical groups: in 50% of elephantiasis patients, in 12.5% of microfilaraemics and in 20% of asymptomatic amicrofilaraemics. The results indicate that more than one distinct immunological mechanism may account for the antigen-specific unresponsiveness in individuals exposed to and infected with brugian filariasis.

Differential antibody isotype reactivity to specific antigens in human lymphatic filariasis: gp15/400 preferentially induces immunoglobulin E (IgE), IgG4, and IgG2.

Lymphatic filarial infection in humans is associated with a strong skewing of the immune response towards the TH2 arm, with prominent interleukin 4-producing cells and elevated levels of immunoglobulin G4 (IgG4) and IgE antibodies in peripheral blood. To determine how such a generalized TH2 imbalance governs responses to individual parasite antigens, the profiles of isotypes of antibodies to two recombinant proteins of Brugia spp. were studied. One molecule was the C-terminal portion of the filarial heat shock protein 70 (Bpa-26), representative of a cytoplasmic protein, and the second antigen was a single unit of the tandem repeats of a Brugia polypeptide (BpL-4), a secreted product which is prominently exposed to the immune system. Serum samples from 146 individuals resident in areas in which brugian filariasis is endemic were used, and it was found that whereas the levels of IgG1 and IgG3 responses to both Bpa-26 and BpL-4 were high, IgG4 and IgE antibodies to only BpL-4, not to Bpa-26, were prominent. Thus, an antigen which is chronically exposed to the immune system elicited a TH2-dependent isotype switch, as manifested by increased IgG4 and IgE responses. Moreover, IgG4 and IgE responses to BpL-4 showed a strong negative association, suggesting that mediators other than interleukin 4 must be responsible for such differential regulation of these two isotypes. When the data were analyzed as a function of clinical status, a striking association between elevated levels of IgG3 antibodies to Bpa-26 and manifestation of chronic obstructive disease was found; elephantiasis patients showed significantly higher levels of IgG3 antibodies to Bpa-26 than microfilaremics and asymptomatic amicrofilaremics. This indicates that an imbalance of isotypes of antibodies to particular filarial antigens might play a role in the pathogenesis of chronic disease.

HLA and elephantiasis in lymphatic filariasis

Lymphatic filariasis presents a spectrum of manifestations with infection-free asymptomatics at one end and elephantiasis at the other. In order to determine if any HLA antigens are associated with the development of elephantiasis, we compared the HLA frequencies in 55 elephantiasis patients with those in 40 controls consisting of individuals older than 45 years of age without any signs of elephantiasis. The only significant difference in class I antigen frequencies was observed for B27, which was present in 11% of the patients and absent in the controls. More differences were observed in HLA class II antigen frequencies. Both DR3 and the 2B3 epitope (on DQ6, DQ8, and DQ9 molecules) were significantly decreased in patients with elephantiasis whereas the DQ5 frequency was significantly higher in patients than in controls. Analysis of specific antibody isotype profiles revealed that DQ5-positive individuals had increased levels of antifilarial IgG3, an isotype known to be involved in tissue damage. These data suggest that HLA class II genes may control the course of Brugian filariasis by influencing the T-cell-dependent antibody repertoire.

Elevated cellular immune responses and interferon-gamma release after long-term diethylcarbamazine treatment of patients with human lymphatic filariasis.

Cellular immune responses to filarial antigens were examined in persons before and 1 year after beginning treatment with diethylcarbamazine (DEC). The subjects (17 microfilaremics, 13 asymptomatic amicrofilaremics, and 13 with elephantiasis) had not responded to Brgia malayi adult worm antigen (BmA) before chemotherapy. T cell proliferative responses to BmA improved significantly after therapy in the 3 clinical groups (P < .05) but was highest in the elephantiasis patients and asymptomatic amicrofilareimics. Cytokine release profiles after stimulation with parasite antigen were analyzed. Production of interferon (IFN)-gamma by BmA-stimulated mononuclear cells increased significantly after DEC treatment (geometric mean, 39.6-55.7 U/mL; P < .05), largely due to improved responses in elephantiasis patients and asymptomatic amicrofilaremics. In contrast, BmA-induced interleukin (IL)-4 release did not change significantly in these same patients after treatment. Thus, both microfilaremic and amicrofilaremic infections with B. malayi are associated with similar down-regulation of proliferative T cell function and IFN-gamma release.

Bancroftian filariasis in Kwale District of Kenya. I. Clinical and parasitological survey in an endemic community.

A cross-sectional parasitological and clinical survey for Wuchereria bancrofti infection was carried out in an endemic community of south-eastern Kenya, to obtain background epidemiological information for detailed serological studies on bancroftian filariasis in the same community. Quantitative examination of night blood samples (100 microliters) from 1129 individuals (76% of the population), using the counting chamber technique, revealed circulating microfilariae in 13.7% of the study group. Prevalence increased with age, and was higher in males (15.9%) than in females (11.6%). The geometric mean intensity among infected individuals was 223 microfilariae/ml blood (336 microfilariae/ml for males and 212 microfilariae/ml for females). Approximately 16.5% of the males aged > or = 15 years had hydrocele and 2.4% of the population had elephantiasis. The prevalence of these conditions increased with age; in those aged > or = 50 years, 23.8% of males had hydrocele and 6.1% of the total population had elephantiasis. Acute cases of epididymo-orchitis, adenolymphangitis and funiculitis were also seen. The microfilarial prevalence in males with hydrocele was not significantly different from that in asymptomatic males, but none of the elephantiasis cases had microfilaraemia. The striking difference in microfilaraemia pattern between hydrocele and elephantiasis patients may reflect different mechanisms underlying the development of these two chronic manifestations. The overall prevalences of microfilaraemia and clinical manifestations in this community were moderate when compared with those found in other studies carried out along the coast of eastern Africa.

Elevated levels of T cell activation antigen CD27 and increased interleukin‐4 production in human lymphatic filariasis

To assess the immunological changes occurring during filarial infection with or without elephantiasis, 145 patients in different clinical groups from an endemic area in Indonesia were compared with respect to plasma levels of both soluble CD25 (sCD25) and sCD27; interleukin-4 (IL-4) and interferon-gamma release by peripheral blood mononuclear cells was also measured in a smaller subset of individuals. Levels of sCD27 were significantly elevated in elephantiasis and microfilaremic patients compared with endemic normals (p < 0.002), whereas sCD25 levels remained low in microfilaremics and was only slightly elevated in elephantiasis patients compared with endemic normals (p < 0.02). As activated T cell populations release both sCD27 and sCD25, these findings imply that there is filarial-driven activation of a T cell subset that releases sCD27 rather than sCD25. The expansion of a particular T cell population by filarial parasites is further suggested by the enhancement in both IL-4-producing and CD4+CD27-T cells in PBMC from elephantiasis and microfilaremic patients compared with endemic normals. More detailed characterization and comparison of CD27-lymphocytes from these individuals may identify mechanisms involved in the pathogenesis of lymphatic filariasis.

T cell responsiveness correlates differentially with antibody isotype levels in clinical and asymptomatic filariasis.

To establish the relationships among T and B cell responses, active infection, and clinical manifestations in lymphatic filariasis, filarial-specific lymphocyte proliferation, IgG antibody isotypes, and IgE levels were determined in an exposed population: 31 asymptomatic amicrofilaremics, 43 microfilaremics, 12 symptomatic amicrofilaremics, and 52 elephantiasis patients. Lymphocyte proliferation was higher in elephantiasis patients and asymptomatic amicrofilaremics than in microfilaremics (P < .004). A proportion of asymptomatic amicrofilaremics (32%), elephantiasis patients (37%), and symptomatic amicrofilaremics (58%) showed antigen-specific lymphocyte unresponsiveness, and lymphocyte proliferation to filarial antigens correlated negatively with specific IgG4 levels (rho = -0.315, P < .001). As elevated specific IgG4 is an indicator of active infection, it is argued that active infection may result in lymphocyte hyporesponsiveness irrespective of clinical category. Of those with elevated specific IgE levels and high T cell proliferative responses, 70% had elephantiasis, suggesting these factors have a role in pathology. However, the existence of a proportion of elephantiasis patients with low anti-filarial IgE and T cell unresponsiveness to filarial antigens suggests that elephantiasis can be caused by distinct processes.

Sharing of antigens among filarial species revealed by antibody dependent cell-mediated reactions

Antisera raised in albino rats against microfilariae ofLitomosoides carinii, Brugia pahangi, Brugia malayi and sera fromBancroftian elephantiasis patients promoted rat neutrophil-mediated adherence and cytotoxicity to the microfilariae. Pre-treatment of the immune sera, with microfilarial antigen at a final concentration of 5 and 25μg per ml blocked cellular adherence and cytotoxicity to the microfilariae indicating the presence of cross-reactive antibodies. The heterologous immune sera were effective in eliminating the circulatingLitomosoides carinii microfilariae inMastomys natalensis.