Lymphatic filariasis

• ヒト体内でadultから生まれたmicrofilariaは吸血で蚊に移行し，蚊の体内で3回moltを繰り返してL3 larvaeに至る．

• L3は1.7mmまで体長を増し，吸血によって蚊の体外に放出され，蚊が生じた穿刺口等から皮内に侵入する

1.7mmもの体長のlarvaeがどうやって体長10mmに満たない蚊の体内で共存できるのか？

• Onchocerciasisのヒト体内の病態生理はmicrofilariaによるが，lymphatic filariasisはadultによる．

• Lymphatic filariasisでリンパ浮腫を生じている患者の下肢をエコーで観察すると，拡張したリンパ管内で蠢くadult filariaを観察できる．

Brugia malayi

Intermediate host
Category	mosquito, female
Latin	Mansonia spp. Aedes spp.
Inward infection	blood-feeding of human
Organ	midgut, thoracic muscle, proboscis
Reproduction
Course	microfilariae lose sheath migrate to thoracic muscle metamorphoses L1→L2→L3 in thoracic muscle L3 migrate to proboscis
Detection
Outward transmission	blood-feeding of human through proboscis

Definitive host
Category	human
Latin
Inward infection	blood-feeding by mosquito
Organ	skin, lymphatics
Reproduction	sexual
Course	L3 invade through cleavage on skin L3 migrate to lymphatics develop to adult female 43-55 mm, male 13-23 mm obstruct lymphatics resulted in elephantiasis and hydrocele in years mate in lymphatics produce sheathed microfilariae nocturnal periodicity microfilariae migrate to blood circulation mechanism unknown
Detection	microscopy, microfilariae, Giemsa stain, blood taken nocturnally concentration technique 2% formalin to blood (Knott's technique) polycarbonate membrane filtration
Outward transmission	blood-feeding by mosquito