A longitudinal study of Bancroftian filariasis in the Nile Delta of Egypt: baseline data and one-year follow-up.

Abstract

Abstract. We initiated a longitudinal study of Bancroftian filariasis to improve understanding of dynamics and risk factors for infection in villages near Cairo, Egypt. Baseline prevalence rates for microfilaremia and filarial antigenemia for 1,853 subjects more than 9 years of age were 7.7% and 11.2%, respectively. Microfilaria counts, antigen levels, and microfilaremia incidence over a 1-year period were all significantly lower in older people. These findings suggest that humans develop partial immunity to Wuchereria bancrofti over time. One-year incidence rates for microfilaremia and antigenemia were 1.8% and 3.1%, respectively. Filarial antigenemia, IgG4 antibody to recombinant antigen BmM14, and household infection were all significant risk factors for microfilaremia incidence. Microfilaria counts and parasite antigen levels were significantly reduced by diethylcarbamazine therapy, but many infected subjects refused treatment, and most treated people were still infected one year later. Incident infections approximately balanced infections lost to produce an apparent state of dynamic equilibrium.

Multiplex Bead Assay for Serum Samples from Children in Haiti Enrolled in a Drug Study for the Treatment of Lymphatic Filariasis

“…20 In our study, the prevalence of MF and intensity of antigenemia either remained static or significantly decreased ( P < 0.001), respectively, among children who received DEC. For children who received placebo, the intensity of antigenemia significantly increased ( P = 0.039) at the end of the study. As in other studies that showed decreased antibody responses to Bm14 by ELISA after DEC treatment, 20,[25][26][27][28] we showed decreases in antibody responses to Bm14 by MBA among children who received drugs containing DEC ( Figure 1A and B). Interestingly, antibody responses to Bm14 and Bm33 decreased among children who received drugs containing DEC, even among children who were MF-/ Og4C3-( Figures 1A and 2A ).…”

Bancroftian filariasis infection, disease, and specific antibody response patterns in a high and a low endemicity community in East Africa.

“…13 Other studies have indicated that children of both mf-positive mothers and fathers are more likely to be mf positive than children of mf-negative parents. 37,38 Based on these studies, it appears that parental and not only maternal infection is the more important risk for infection in the offspring, probably due to increased household exposure. The present study analyzed the relationship between infection status of parents and that of their children not only for mf, but also for the first time for CFA.…”

“…However, in both communities its prevalence of positivity was much higher than that of both mf and CFA, as also observed by others. 29,38 Therefore, being IgG4 positive does not necessarily denote active infection but may be related to intensity of exposure to infective larvae. 42 The higher IgG3 prevalence and intensity in the low endemicity community was surprising, and this observation is not in agreement with earlier suggestions that IgG3 is associated with pathology in lymphatic filariasis.…”

Macrofilaricidal Activity and Amelioration of Lymphatic Pathology in Bancroftian Filariasis after 3 Weeks of Doxycycline Followed by Single-Dose Diethylcarbamazine

“…With regard to this study, one must take into consideration that the trial took place in a low-endemicity area in Egypt without much transmission where the baseline incidence of Mf was < 1%. 26 A low transmission rate would result in a higher proportion of older worms that are more susceptible to drug action and may explain the better performance of DEC in this study compared with the others, which were carried out in areas of high endemicity (i.e., ongoing high levels of transmission). In addition, volunteers in the Egyptian study also participated in the annual mass treatment on top of receiving the study medication and therefore received the antifilarial drug DEC two times within the 12-month observation period.…”