Case 188. Filariasis (elephantiasis) (28 y-o M)
    Biopsy from the groin lymph node and thickened scrotal skin of a Formosan patient    
Key words : 
Wuchereria bancrofti, elephantiasis, Brugia malayi, Loa loa, microfilaria    
The groin node shows eosinophilic abscess containing female adults of Wuchereria bancrofti. Numerous microfilaria are seen in the uterine cavity, and the gut component is also recognized (HE).   Marked lymphangiectasia is seen in the fibrotic dermal connective tissue (HE). The epidermis is acanthotic. The features represent chronic lymph stasis.
Reference case 188A
A microfilaria of Brugia malayi seen in the peripheral blood of a resident of Hachijo islet in the Paciffic orcean (Giemsa). The sheathed microfilaria is characteristic of Brugia malayi. Brugian filariasis is endemic in subtropical Asia. Scrotal swelling is not seen in brugian filariasis.
  Microfilaria of Dirofilaria immitis in the peripheral blood of dog
The microfilaria of D. immitis, 200-300 μm in length, is unsheathed. Compare with the sheathed brugian and loian microfilaria. Carrier dogs are often asymptomatic. Regarding the incidental infestation of D. immitis microfilaria in humans, refer to cases 97 and 194.
Reference case 188B
A sheathed microfilalria of Loa loa in the peripheral blood of an African male (Giemsa). Note sheath and tail with nuclei to tip. The adults (African eye worms) parasitize the conjunctiva. The microfilariae are transmitted by deerfly Chrysops. Loiasis is endemic in west and central Africa.