Inter and intra-specific diversity of parasites that cause lymphatic filariasis

Abstract

Lymphatic filariasis is caused by three closely related nematode parasites: Wuchereria bancrofti, Brugia malayi and Brugia timori. These species have many ecological variants that differ in several aspects of their biology such as mosquito vector species, host range, periodicity, and morphology. Although the genome of B. malayi (the first genome sequenced from a parasitic nematode) has been available for more than five years, very little is known about genetic variability among the lymphatic dwelling filariae. The genetic diversity among these worms is not only interesting from a biological perspective, but it may have important practical implications for the Global Program to Eliminate Lymphatic Filariasis, as the parasites may respond differently to diagnostic tests and/or medical interventions. Therefore, better information on their genetic variability is urgently needed. With improved methods for nucleic acid extraction and recent advances in sequencing chemistry and instrumentation, this gap can be filled relatively inexpensively. Improved information on filarial genetic diversity may increase the chances of success for lymphatic filariasis elimination programs.

Figure 1

Mf of lymphatic filariae stained by Giemsa: (A) W. bancrofti, (B) mixed infection, (C) B. malayi, and (D) B. timori. Panel (B) depicts the anterior end of a single B. timori Mf (arrow) next to W. bancrofti Mf (arrowhead) in a patient from central Flores. Note the long nucleus free cephalic space and the densely packed nuclei in B. timori. Arrows point to the cephalic space.