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.