Efficacy of a single-dose treatment with 300 mg diethylcarbamazine and a combination of 400 mg albendazole in reduction of Wuchereria bancrofti antigenemia and concomitant geohelminths in Myanmar migrants in Southern Thailand.

BACKGROUND: There seems to be a large magnitude of parasitic worm loads caused by nocturnally periodic Wuchereria bancrofti and geohelminths, in cross-border Myanmar migrant workers in Thailand. We are therefore considering an effective Mass Drug Administration (MDA) with Diethylcarbamazine (DEC) and Albendazole (ABZ). Due to short periods of their residency and current situation of W. bancrofti antigenemics and concomitant geohelminths, treatment effects on the containment of the infections need to be analyzed. OBJECTIVES: Analyze short-term effects on reduction of W. bancrofti antigen (WbAg) and geohelminths' egg (GhE) loads. The efficacy of a single-dose combined treatment with 300 mg DEC (for filariasis) and 400 mg ABZ (for helminthiasis) was evaluated and compared with a single-dose treatment arm with 300 mg DEC alone. MATERIAL AND METHOD: A randomized clinical trial of two treatment choices in 28 Myanmar male workers (DEC/ABZ or group I = 15, DEC or group II = 13) was conducted in Phang Nga province, Southern Thailand. Because of the withdrawal of three subjects of the DEC group, all the 10 DEC subjects were follow-up monitored at post treatment 2, 4, 8 and 12 weeks. Their mean age was 26.4 years; worm loads (mean +/- SD x 10(3)) of W. bancrofti, Ascaris and Trichuris was 103.9 +/- 44.1 antigen units (AU)/ml, 47.3 +/- 38.7 eggs per gram (EPG) and 16.6 +/- 22.2 EPG respectively. The data on the 15 DEC/ABZ subjects showed a mean age of 25.7 years; corresponding worm loads = 96.1 +/- 54.6 AU/ml, 397.0 +/- 117.3 EPG and 54.5 +/- 42.8 EPG respectively. The Antigen Reduction Rates (ARR) and Egg Reduction Rates (ERR) were presented. RESULTS: At the 12-week post treatment, WbAg loads (mean +/- SD x 10(3) AU/ml) were 61.5 +/- 58.4 for group I and 76.8 +/- 40.7 for group II. A significant WbAg reduction was noted for both groups at weeks 8 and 12 (p < 0.05). Also, the significant reduction of GhE loads was more pronounced for both groups after week 2 (p < 0.05). When comparing efficacy of the treatment choices by the treatment retention time, it was more likely to show both groups had similar adulticidal effects on either WbAg, denoted as the ARR (F = 0. 064, p = 0.806) or GhE, denoted as the ERR (F = 0.196, p = 0.669). CONCLUSION: The single-dose 300 mg DEC plus 400 mg ABZ, or 300 mg DEC alone, can be effectively used for treating infections with W. bancrofti and concomitant geohelminths commonly observed in the area. But treatment rounds are required to clear the infections. The reduction of the parasitic worm loads in the legal Myanmar migrants provide values in monitoring and evaluating an effective MDA program with the DEC/ABZ at the provincial level.

Immunomodulation of pulmonary and hepatic granulomatous response in mice immunized with purified lung-stage schistosomulae antigen

The present objective was to investigate the possible effect of immunization protocol against Schistosoma mansoni infection using purified lung-stage schistosomulae antigen. Two experimental models [lung and liver] were used, each of 3 groups [Gs]: Immunized G. [10 mice] infected control G. [10 mice] and normal control G. [10 mice]. Hundred micro g of purified schistosomulae antigen followed by two booster doses each of 50 micro g antigen and at one week interval were injected intraperitoneally into Swiss albino mice three days prior to intravenous injection of 3000 viable S. mansoni eggs [lung model] or to exposure to 100 cercariae [hepatic model]. Mice were sacrificed 16 days post-injection [lung model] and 8 weeks post-infection [hepatic model]. Various parasitological parameters, histopathological assessments and immunological parameters were studied. The data revealed that immunization with purified lung-stage schistosomulae antigen induces protective effect against S. mansoni infection. The marked reduction in worm burden, egg load, granuloma diameter and collagen content were accompanied by increased percentage of degenerated ova and amelioration of the associated pathological changes in pulmonary and hepatic tissue. Increased levels of specific immunoglobulins particularly IgG and IgM and decreased ratio of T cell subsets [CD4+/CD8+] in granulomas of both models were also noticed

Wuchereria bancrofti antigenemia clearance among Myanmar migrants after biannual mass treatments with diethylcarbamazine, 300 mg oral-dose FILADEC tablet, in Southern Thailand.

Using qualitative ICT Filariasis and quantitative Og4C3 ELISA, we assessed a long-term macrofilaricidal effect of two-year biannual mass treatments with a 300 mg oral-dose FILADEC tablet, a reformulation of 6 mg/kg diethylcarbamazine (DEC), on clearance of the Wuchereria bancrofti adult worm circulating filarial antigens (CFA) in Myanmar migrants, at risk of emergence of imported bancroftian filariasis in Southern Thailand. Of the 34 antigenemic Myanmar index cases of varying initial CFA levels, who were initially screened out with the ICT Filariasis, 13 index cases were follow-up treated and monitored at the DEC post treatments, 6, 12, and 18 months. At the 18-month post treatment, residual antigenemias (%) in 4 of 5 index cases (group 1) with high antigen titers (99.7-181.6 x 10(3) AU/ml) were 54.44%, 33.58%, 27.43%, and 9.97%. Significant decreases of the CFA levels in only 3 out of 5 index cases were affected by the response to DEC treatments (p < 0.007). The treatment effects on clearance of the CFA in 8 index cases (group II) with low antigen titers (15.4-37.2 x 10(3) AU/ml) were shown for at least 6 months post DEC treatment and hence had 100% efficacy in the first 6 months of the first year of year round treatment. Group I, was more likely to show an increase of the DEC efficacy after the first 6 months of the second year round treatment, but there was no statistically significant difference (p = 0.063). We reemphasized that, for use in the national program to eliminate lymphatic filariasis (PELF) in Thailand, such a DEC regimen had a macrofilaricidal effect on antigenemia clearance, and confirmed its value in evaluating response to the treatment and monitoring the long-term efficacy of the DEC regimen in W. bancrofti adult worm burden reductions in Myanmar migrants on a wide scale.