by Oshin Manoharan Government medical college Palakkad

1. Oshin Manoharan
Roll no 10
LOA LOA

2. • AFRICAN EYE WORM
• phylum : nematoda
LOA LOA
LOIASIS

3. • First detected in the eye of the patient in West Indies
in 1770
• Now limited in the forest of West and Central Africa
• About 10 million people are affected
EPIDEMIOLOGY

4. HABITAT
 Adult worm : subcutaneous tissue
Microfilariae : blood

5. MORPHOLOGY
Morphological stages :
Adult worm
Microfilariae
Infective stage larvae

6. ADULT WORM
 Thin ,transparent, whitish,
thread like worm
Anterior end tapers to a narrow head
Surface of the body is covered with
small knobs

7. Male worm
 30-34mm in length
0.35-0.43mm in diameter
Tail end has spicules
unequal length
Female worm
40-70mm in length
0.5mm in diameter
The vulva opens in the
cervical region
ADULT WORM

8. MICROFILARIA
 Sheathed with column of nuclei extending from tip of the tail
 250-300µm : length
 Stain : iron haematoxylin
 Diurnal periodicity : peripheral blood during day
time (12-2pm)

10. LIFE CYCLE
• Life cycle : Two host
• Definitive host : man
• Intermediate host : Chysops
(C.dimidiata , C.silacea)

12. LIFE CYCLE
Bite of infected
chrysops
subcutaneoustissue
moult and develops
into mature adult
worm
Female
produce
sheathed
microfilaria
Microfilaria
ingested by
chrysops
Cast of their
sheath
penetrate
stomach wall
Thoracic
muscle
Develops into
infective larvae
Migrateinto
sub.tissue

13. PATHOGENESIS
 Mode of transmission : bite of infected chrysops
 Pathogenesis depends upon the migratory habit of adult worm

14. PATHOGENESIS
Site of entry
Subcutaneous
tissue
Foci of
inflammation in
extremities
Disappears within
days
Reappear
elsewhere
CALABAR
SWELLING

15. CLINICAL MANIFESTATIONS
• Calabar/ fugitive swelling
• Ocular lesions include
 Granulomata of
bulbar conjuctiva
 Painless edema of
eyelid
 Proptosis

16. COMPLICATIONS
 Nephropathy
 Encephalopathy
 Cardiomyopathy

17. LAB DIAGNOSIS
• Definitivediagnosisinclude
Detection of microfilaria in peripheral smear
Isolation of adult worm from eye
• 12 - 2pm (diurnal periodicity)
• Skin
• Conjunctiva
• subcutaneous biopsy specimen
 High eosinophilic count

18. TREATMENT
 DEC 8-10mg/kg per day for 21 days
• adult worm and microfilaria
• Multiple course
• Severe adverse effects
• Administration of corticosteroids minimises such reactions
Ivermectine or albendazole is effective in reducing filarial load
• Contraindicated in heavy microfilaremia
 Surgical removal of adult worm is rarely done

19. PREVENTION
Mass chemotherapy
• DEC 5mg/kg for 3 days
• Kills microfilariae
Personal protection
• Insect repellent
• Protective clothing
• Avoid visit to endemic areas