BIOLOGY OF PARASITISM - LECTURE NOTES - Loa loa
CLASS: SECERNENTEA
ORDER: SPIRURIDA
SUPERFAMILY: FILARIOIDEA
FAMILY: ONCHOCERCIDAE
Loa loa
- Common name - eye worm
- Disease - loaisis, loiasis, loaiasis
Characteristics:
Hosts: humans
Distribution: rain forest areas of west Africa and equatorial Sudan
Life Cycle:
- Adults live in subcutaneous tissues.
- Microfilariae are periodic (in peripheral blood during day, in lungs at night).
- Intermediate host is deer fly (Chrysops).
Symptoms/Pathogenicity:
- Adults tend to wander through the subcutaneous connective tissues.
- "Calabar swellings," appear when the worms are still and disappear when the worms move on.
- Adults also migrate through the conjuctiva and cornea with swelling of the orbit and psychosomatic results to the host.
Management:
- Diagnosis is by finding microfilariae in blood.
- Surgical removal of swellings.
- Chemotherapy.
- Control of deer flies is difficult because breeding areas are widespread.
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