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6. Parasitic diseases
Lymphatic filariasis (LF)
T h e d istribution of L F is linked to th at of its m osquito v ectors (Anopheles, Culex, Aedes,
etc.):
W. bancrofti: sub- Sah aran A frica, M ad ag ascar, E g ypt, I nd ia, South E ast A sia, P acific
reg ion, South A m erica, T h e C aribbean
B. malayi: South E ast A sia, C h ina, Ind ia, Sri L anka
B. timori: T im or
9 0 % of L F is d ue to W. bancrofti and 1 0 % to Brugia spp.
Clinical features
– A cute recurrent inflam m atory m anifestations
• A d enolym ph ang itis: lym ph nod e( s) and red , w arm , tend er oed em a along th e
leng th of a lym ph atic ch annel, w ith or w ith out system ic sig ns (e.g . fev er, nausea,
v om iting ). T h e inflam m ation m ay inv olv e th e low er lim bs, external g enitalia and
breast.
• I n m en: acute inflam m ation of th e sperm atic cord (funiculitis), epid id ym is and
testicle (epid id ym o-orch itis).
A ttacks resolv e spontaneously w ith in a w eek and recur reg ularly in patients w ith
ch ronic d isease. 6
– C h ronic m anifestations
• L ym ph oed em a: oed em a of th e low er extrem ity or external g enitalia or breast,
second ary to obstruction of th e lym ph atics by m acrofilariae. T h e oed em a is
rev ersible initially but th en becom es ch ronic and increasing ly sev ere: h ypertroph y
of th e area affected , prog ressiv e th ickening of th e skin ( fibrous th ickening w ith
form ation of creases, initially superficial, but th en d eep, and v errucous lesions).
T h e final stag e of lym ph oed em a is eleph antiasis.
• In m en: increase in v olum e of fluid d ue to accum ulation w ith in th e tunica v ag inalis
(h yd rocoele, lym ph ocoele, ch ylocoele); ch ronic epid id ym o-orch itis.
• C h yluria: m ilky or rice-w ater urine (d isruption of a lym ph atic v essel in th e urinary
tract).
I n patients parasitized by Brugia spp, g enital lesions and ch yluria are rare:
lym ph oed em a is usually confined to below th e knee.
Laboratory
– D etection of m icrofilariae in th e periph eral blood ( th ick film )7 ; blood specim ens
sh ould be collected betw een 9 pm and 3 am .
– In reg ions w h ere loiasis and / or onch ocerciasis are co-end em ic, ch eck for co-infection
if th e L F d iag nosis is positiv e.
Treatment
Antiparasitic treatment
– T reatm ent is not ad m inistered d uring an acute attack.
7 When test results are negative in a clinically suspect case, consider detection of antigens (ICT rapid test) and/or
ultrasound of the inguinal area in search of the « filarial dance sign ».
161
Lymphatic filariasis (LF)
T h e d istribution of L F is linked to th at of its m osquito v ectors (Anopheles, Culex, Aedes,
etc.):
W. bancrofti: sub- Sah aran A frica, M ad ag ascar, E g ypt, I nd ia, South E ast A sia, P acific
reg ion, South A m erica, T h e C aribbean
B. malayi: South E ast A sia, C h ina, Ind ia, Sri L anka
B. timori: T im or
9 0 % of L F is d ue to W. bancrofti and 1 0 % to Brugia spp.
Clinical features
– A cute recurrent inflam m atory m anifestations
• A d enolym ph ang itis: lym ph nod e( s) and red , w arm , tend er oed em a along th e
leng th of a lym ph atic ch annel, w ith or w ith out system ic sig ns (e.g . fev er, nausea,
v om iting ). T h e inflam m ation m ay inv olv e th e low er lim bs, external g enitalia and
breast.
• I n m en: acute inflam m ation of th e sperm atic cord (funiculitis), epid id ym is and
testicle (epid id ym o-orch itis).
A ttacks resolv e spontaneously w ith in a w eek and recur reg ularly in patients w ith
ch ronic d isease. 6
– C h ronic m anifestations
• L ym ph oed em a: oed em a of th e low er extrem ity or external g enitalia or breast,
second ary to obstruction of th e lym ph atics by m acrofilariae. T h e oed em a is
rev ersible initially but th en becom es ch ronic and increasing ly sev ere: h ypertroph y
of th e area affected , prog ressiv e th ickening of th e skin ( fibrous th ickening w ith
form ation of creases, initially superficial, but th en d eep, and v errucous lesions).
T h e final stag e of lym ph oed em a is eleph antiasis.
• In m en: increase in v olum e of fluid d ue to accum ulation w ith in th e tunica v ag inalis
(h yd rocoele, lym ph ocoele, ch ylocoele); ch ronic epid id ym o-orch itis.
• C h yluria: m ilky or rice-w ater urine (d isruption of a lym ph atic v essel in th e urinary
tract).
I n patients parasitized by Brugia spp, g enital lesions and ch yluria are rare:
lym ph oed em a is usually confined to below th e knee.
Laboratory
– D etection of m icrofilariae in th e periph eral blood ( th ick film )7 ; blood specim ens
sh ould be collected betw een 9 pm and 3 am .
– In reg ions w h ere loiasis and / or onch ocerciasis are co-end em ic, ch eck for co-infection
if th e L F d iag nosis is positiv e.
Treatment
Antiparasitic treatment
– T reatm ent is not ad m inistered d uring an acute attack.
7 When test results are negative in a clinically suspect case, consider detection of antigens (ICT rapid test) and/or
ultrasound of the inguinal area in search of the « filarial dance sign ».
161
