第十三章 虱蚤(1)

1、虱louse,體外永久性寄生蟲(chóng)。寄生于人體的虱有人虱和恥陰虱。人虱分為人體虱和人頭虱兩個(gè)亞種。,人虱體狹長(zhǎng)，背腹扁平?！饪蛇_(dá)4.4mm，♂稍小。雄虱末端近似“V”形，雌虱末端呈“W”形。 頭呈菱形，有觸角一對(duì)。胸部三節(jié)愈合有足三對(duì)，各足脛節(jié)內(nèi)側(cè)的指狀脛突與末端的爪相對(duì)，形成強(qiáng)有力的抓握器。 頭虱較體虱略小，顏色稍深。恥陰虱體形短而寬，呈蟹狀。,一、形態(tài),,,二、生活史與生態(tài)習(xí)性,1、寄生部位人頭虱：頭發(fā)人體虱：貼身

2、衣服的縫、褶恥陰虱：陰毛、肛毛2、與傳病有關(guān)的習(xí)性 吸血特性； 對(duì)溫度，濕度均敏感；爬行速度快。,卵——————若蟲(chóng)——————成蟲(chóng),Head Lice - NitNits are head lice eggs.  They are hard to see and are often confused for dandruff or hair spray droplets.  Nits are laid

3、by the adult female and are cemented at the base of the hair shaft nearest the scalp.  They are 0.8 mm by 0.3 mm, oval and usually yellow to white.  Nits take about 1 week to hatch (range 6 to 9 days).  Vi

4、able eggs are usually located within 6 mm of the scalp.,Head Lice - nymph hatching through the operculum of an egg.The egg hatches releasing a nymph.  The nit shell then becomes a more visible dull yellow and

5、remains attached to the hair shaft.  The nymph looks like an adult head louse, but is about the size of a pinhead.  Nymphs mature after three molts and become adults about 7 days after hatching.,三、傳播疾病,流行性斑疹傷寒（

6、高熱、頭痛、惡心、發(fā)狂、昏迷） 病原為普氏立克次氏體， 虱糞傳播傷口，吸入虱糞回歸熱（3-9天間斷性高熱、皮疹） 病原為俄拜氏疏螺旋體， 虱子破碎、體液污染傷口,四、防治,加強(qiáng)衛(wèi)生宣教，注意個(gè)人衛(wèi)生 滅虱措施：燙、凍、毒（20%百部酒精浸液或0.01%二氯苯醚菊酯）,五、流行,世界性分布，兒童比成人多，女性比男性多。,蚤 Flea,寄生于恒溫動(dòng)物體表。2000多種，我國(guó)454種，少數(shù)傳播疾病，如印鼠客蚤

7、、致癢蚤、具帶病蚤?鼠疫 犬櫛首蚤、貓櫛首蚤 ? 膜殼絳蟲(chóng),一、形態(tài)左右側(cè)扁。頭呈三角形，觸角1對(duì)，藏于觸角窩內(nèi)。全身鬃、毛、櫛向后長(zhǎng)。足強(qiáng)壯發(fā)達(dá)，善跳。,,二、生活史,三、與疾病的關(guān)系,騷擾吸血及寄生外，還可傳播疾?。?、鼠疫 鼠疫桿菌2、鼠型斑疹傷寒 莫氏立克次氏體3、絳蟲(chóng)病 微小膜殼絳蟲(chóng) 縮