Filarial Nematodes (Helminthic Infections)

Question 1

Lymphatic Filariasis/”Elephantiasis” (Wuchereria bancrofti)

Answer 1

• transmitted via mosquito bites
• inflammatory parasitic infection of lymphatic vessels: lymphangitis and sometimes lymphatic obstruction
• edema with thickening of the skin and underlying tissue-elephantiasis
• Often unilateral, involving scrotum/leg
• Occult filariasis (anti-filarial antibodies) produces tropical pulmonary eosinophilia–can lead to fatal pneumonia.

Question 2

Onchocerciasis / “river blindness” (Onchocerca volvulus)

Answer 2

• Transmitted by fly bite.
• Onchocerca volvulus is the nematode, which carries a bacterial endosymbiont: Wolbachia pipientis, which causes a severe immune response that can cause blindness.
• inlammatory response causes damage to cornea, choroids, retina

Question 3

Loiasis “African Eye Worm”

Answer 3

• Mango fly bite transmites loa loa (round worm), which travels to the conjunctiva, where it can be readily seen in patient.
• Does not cause blindness
• DO NOT give antifilarials–destructive inflammatory response (highly antigenic when worms dead).
• rarely lethal (sudden + diffuse cerebral ischemia)
• usually self limited with mild CNS involvement