Microfilariae recovered from a midnight blood film of a patient from Kerala are sheathed. Examination of the tail shows two distinct nuclei lying separately at the tail tip, clearly separated from the column of body nuclei. This finding identifies the parasite as:

• A Wuchereria bancrofti
• B Loa loa
• C Brugia malayi ✓
• D Mansonella perstans

Explanation

Brugia malayi microfilariae are sheathed and show two discrete terminal nuclei at the tail tip, separated from the nuclear column, a feature absent in Wuchereria bancrofti whose tail is entirely free of nuclei. Both show nocturnal periodicity, so timing does not separate them. Loa loa is sheathed but diurnally periodic with nuclei extending to the tail tip continuously, while Mansonella perstans is unsheathed and non-periodic. Brugian filariasis predominates in Kerala and other coastal states.

Reference: Paniker's Textbook of Medical Parasitology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.