Caused by Loa Loa
AKA eye worm
Epidemiology: West Africa
Life-cycle: Chrysops fly
Clinical: adults in subcutanous tissue (), microfilariae migrate around
Diagnosis: blood film (nuclei go 'lower and lower')
What is LL?
Tissue nematode infection, microfilarial infection
Infected larvae of LL transmitted by the Chrysops fly which breeds in swamps (W/C Africa) (some overlap with Onco)
Usually results from years of exposure e.g. primatologist
Develop into adult worms in human host
adult worms migrate through (like LF, not Onc)
Symptoms from adult worm migrating through s/c and connective tissues, can be front, or under eye (eye worm)
What are the clinical features of Loa Loa?
Calabar swelling: s/c non-tender, non-itch swellings, intermittent swellings from worm migration
Eye worm: passes through bulbar sub-conjunctiva.. can take 30min-24 hours (pathopneumonic**)
Other systemic sx:
chronic fatigue, inc.
Cardiomyopathy: SVTs, pericardial effusions..EMF
nephropathy (GN, nephrotic syndrome)
encephalitis meningoencephalitis… (esp. post-DEC)
What is the differential diagnosis of skin swellings & eosinophilia?
Loa Loa (calabar)
Larva currens (Strongyloides)
Katayama fever (urticarial rash)
How is LL diagnosed?
Flitting s/c/ swellings & eosinophilia
Eye worm (ONLY LOA LOA)
Serology (not specific for LL)
Day bloods (c/w/ LF): look for adult worms (mf)
Sheathed mf, nuclei in tail? (produced by adult worms)
How is LL treated?
Not usually needed
only effective drug to kill adult worms
SE’s if treat with high mf load
Risk of Mazotti reaction if have Onco (must do skin snip)… if Onco, treat it first e.g. Doxy
Drugs to reduce mf load, pre-DEC: Albendazole, Ivermectin:
albendazole 200mg BD 21 days, then…
Ivermectin 150 mag/kg… then
ivermectin 150-200 mpg stat.. then…
DEC low dose
start DEC low-dose and titrate up
What is the issue with Onco and LL?
Ivermectin bad if Loa Loa (meningoencephalitis)
DEC bad if Oncho (Mazotti reaction)
How is LL prevented?
Same zone as Oncho eradication programmes
Ivermectin risk of precipitating severe encephalitis in patients with high mf Loa Loa load e.g. 0.1%
PH importance of Loa Loa concerned with Oncho eradication programmes: not done in these regions
rural C/W africa
worm inf. via chrysops fly
Sx: eye worm, calabar swellings or asymptotic
D: E0, serology, day bloods mf
rx: DEC curative, problems if concurrent Oncho or mf
Problem: Ivermectin for oncho causes problems if concurrent Loa Loa (difficult for control programmes)
Case 1: DM
Niger river to sea in Nigeria..
Crysops fly.. forest..
treatment depends on mf’aemia’
96. Loa loa
a. is confined to Central and West Africa
b. is spread by the vector Aedes aegypti
c. may cause a high eosinophilia (>10x10^9/L)
d. is diagnosed by histological examination of skin snips
e. is treated with DEC
High eosinophilia is particularly suggestive of infection with filarial worms or strongyloidiasis.
The vector is Crysops.
The diagnosis is usually made by finding microfilariae in the blood. Adult worms are sometimes (dramatically) seen crossing the eye subconjunctivally. Adult worms are also located in the pathognomonic Calabar swellings.