衛(wèi)氏并殖吸蟲，又稱衛(wèi)氏肺吸蟲，其成蟲寄生于宿主肺內(nèi)，引起肺吸蟲病(paragonimiasis)。人的感染多因生食含囊蚴的溪蟹、喇蛄所致。本病分布廣泛，我國有23個(gè)省、區(qū)有本病流行。
一、形態(tài)
1. 成蟲
Paragonimus westermani.
showing the finely branched vitelline glands extending from the anterior to the posterior end. The ovary and testes are in the center. ×6. Enlarged by 5.4
Paragonimus sp from the lungs of an infected animal.
The parasites are fleshy worms with convex surfaces. The sides appear dark because of the presence of vitelline glands.
�。�1)長(zhǎng)7.5-12mm,寬4-6mm,厚3.5-5mm，體肥厚，活體呈紅褐色，背面稍隆起，腹面扁平。
�。�2)并列：子宮與卵巢；一對(duì)睪丸；一對(duì)卵黃腺。
2. 蟲卵 金黃色，卵殼厚，卵蓋明顯，對(duì)端明顯增厚。
A freshly passed egg of Paragonimus sp showing the distinct operculum and a thick shell. It is unembryonated at this stage. ×100. Interference contrast. Enlarged by 5.4.
二、生活史
1. 人或動(dòng)物因食入含囊蚴的溪蟹、喇蛄感染。
2. 童蟲、成蟲的移行和寄居引起肺吸蟲病，除肺部病變外，可累及全身多種器官。
3. 痰中蟲卵被吞入消化道后可從糞便排出。
4. 中間宿主：川卷螺→溪蟹、喇蛄
5. 保蟲宿主：多種家畜（如：狗、貓等)和一些野生肉食動(dòng)物（如虎等)
川卷螺
溪蟹、喇蛄
Potamon sp, a crab host of Paragonimus.
This is a fresh water crab and is sometimes eaten raw when is could transmit infection.
三、致病
