Lymphatic filariasis (LF) is among the poverty related neglected tropical diseases
earmarked for elimination using mass drug administration (MDA) strategy. Additional use of
insecticide treated mosquito nets (ITNs) might enhance elimination of LF infection. Between August
1998 and July 1999, all individuals aged ≥ 8 months from Magoda and Mpapayu villages in northeastern
Tanzania, were administered with monthly low dose diethylcarbamazine (DEC) at a dosage
of 50mg in children aged < 15 years and 100mg in adults aged ≥ 15 years. ITNs were also distributed
to Magoda in December 1998 and to Mpapayu in March 2001. The main objective of our study was to
assess the impact of ITNs and low dose DEC on microfilaria (
mf) prevalence and intensity and
incidence of new
mf infections. Four annual cross-sectional surveys were conducted between 1999 and
2004 in the two villages to screen for
Wuchereria bancrofti
microfilariae in individuals aged ≥ 1 year.
Overall, 80% of the population in Magoda and 66% in Mpapayu were covered during these surveys.
Results revealed a significant decrease in both
mf prevalence and intensity in both villages.
Furthermore, there was a steady decrease in
mf incidence in Magoda; with 36.7 cases per 1000 person
years in 2000 and 7.4 in 2004. In Mpapayu, the incidence initially increased from 20.8 cases in 2000 to
24.3 in 2001 and then decreased to 7.2 cases in 2004. Individuals using ITNs in Magoda had
significantly lower risk of
mf (OR=0.681; 95%CI: 0.496-0.934); and the risk of new infections was
reduced by 58.8% (95%CI: 30.3-75.4). These results suggest that when MDA is complemented with
ITNs there is high likelihood to half filariasis transmission within a shorter period than using
chemotherapy alone.
