Night blood films from a patient in rural Kerala show sheathed microfilariae. Close examination reveals that the column of nuclei extends completely to the rounded tip of the tail, with two distinct nuclei separated at the caudal end. The species demonstrated is:

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

Explanation

Brugia malayi microfilariae are sheathed and show a distinctive tail pattern: nuclei extend to the tail tip with two separate terminal nuclei and a gap between them. Wuchereria bancrofti microfilariae are also sheathed, but the tail ends free of nuclei beyond the last somatic nucleus. Loa loa is sheathed with nuclei reaching the tip but occurs in Africa with diurnal periodicity, and Mansonella perstans microfilariae are unsheathed.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.