The impact of single-dose diethylcarbamazine treatment of bancroftian filariasis in a low-endemicity setting in Egypt.

Abstract

Abstract. This study was designed to evaluate the effect of a single dose of diethylcarbamazine (DEC, 6 mg/kg) on Wuchereria bancrofti infections in a low-endemicity setting in Egypt (microfilaremia, or MF, 3.7%, median MF 34/mL). Subjects with MF or filarial antigenemia were treated and restudied 1 year later. Treatment with DEC dramatically reduced blood MF counts, with clearance in 69% of subjects. Treatment also reduced filarial antigen levels, but low clearance rates suggest that some adult worms survived treatment in most patients. Mass treatment was administered in one village; 27 months later, MF prevalence had decreased 84% (from 4.9% to 0.8%). These results show that singledose DEC treatment can have a major effect on MF prevalence rates and levels in low-endemicity settings. Although the World Health Organization advocates repeated multidrug regimens for filariasis elimination, mass treatment with DEC alone may be sufficient to interrupt transmission in areas with low infection intensities and prevalence rates.

Current Evidence on the Use of Antifilarial Agents in the Management of bancroftian Filariasis

“…Single-dose therapy with DEC has been assessed in several trials (Table 1). In a prospective study in Egypt, a single dose of DEC achieved a microfilaria-clearance rate of 69% ( n = 20) after 1 year while the reduction in antigenaemia was less satisfactory ( n = 86, 40.7%) [16]. A prospective trial in Sri Lanka recorded a 74–80% reduction in microfilaria density (19–28% microfilaria-clearance rate) with a single dose of DEC 6 mg/Kg, 1 year after treatment [17].…”

Are coinfections of malaria and filariasis of any epidemiological significance?

“…For instance, substantial information is available on the vectors of LF and knowledge concerning the site-specific disease transmission and prevalence of human infection (Appawu et al 2001;Ngwira et al 2002;Muturi et al 2006a;Muturi et al 2006b). Information on the impact of various drug regimens (Kazura 1993;Ramzy et al 2002;Alleman et al 2006) and vector control (Maxwell et al 1990;Maxwell 1999) in disease management is also available.…”

Relationships Between Wuchereria Bancrofti Microfilaria Counts in Human Blood and Parasite Uptake and Maturation in Culex Pipiens, With Observations on the Effects of Diethylcarbamazine Treatment on These Parameters

“…Microfilaremic subjects were treated with a single oral dose (6 mg/kg of body weight) of DEC (Pharmamed, Ltd., Zejtun, Malta). 26 Pretreatment MF levels for human subjects in this substudy were determined by membrane filtration of 1 mL of venous blood collected at night after 10:00 PM, just before treatment. Mosquito feeding studies were performed as described earlier, 6−7 months following DEC treatment.…”

“…We have recently reported results of a study of the impact of mass treatment with single-dose DEC in an area of low filariasis endemicity in Egypt. 26 We now report results of companion entomologic studies that were performed as part of the single-dose DEC project. The primary goal of these entomologic studies was to examine relationships between MF levels in human blood and Wuchereria bancrofti infection in Cx.…”