Differentiation of infective larvae of Brugia malayi and Wuchereria bancrofti by scanning electron microscopy.

A comparative scanning electron microscopy of the infective (third stage) larva of Wuchereria bancrofti and Brugia malayi revealed the following features: The lateral caudal papillae in both species are rounded and the terminal papilla is relatively pointed and smaller. The caudal papillae in W. bancrofti are more protruding while in B. malayi they are flattened. The lateral caudal papillae in B. malayi have an indentation around their bases which is absent in W. bancrofti. This is the most useful distinguishing feature and easily recognizable. The oral opening and the cephalic papillae in both the species are similar and not useful for differentiation.