Loiasis, an infection endemic in the jungles of west and central Africa, is produced by the adult form of the tissue
nematode,
Loa loa, which is transmitted through the bite of various flies including deer flies (
Chrysops species). Usually asymptomatic, this filarial disease may cause large
areas of transient edema (Calabar swelling) as the
worm migrates, and it may even migrate visibly
across the conjunctiva. Subcutaneous nodules may
also be seen in this disease, but the worm’s unique
migration habits lead to the common name
“eyeworm.”
