結膜(mo)(mo)吸吮(shun)(shun)線蟲(chong)(chong)(Thelazia callipaeda(Railliet&Henry,1910)是指(zhi)吸吮(shun)(shun)科吸吮(shun)(shun)線蟲(chong)(chong)屬的一種(zhong)線蟲(chong)(chong)。主要寄生(sheng)于(yu)(yu)犬、貓等動物(wu)眼(yan)結膜(mo)(mo)囊內,也可寄生(sheng)于(yu)(yu)人眼(yan),引起結膜(mo)(mo)吸吮(shun)(shun)線蟲(chong)(chong)病(thelaziasis)。因(yin)本病多流行于(yu)(yu)亞洲地(di)區,故(gu)又稱東方眼(yan)蟲(chong)(chong)病。成蟲(chong)(chong)蟲(chong)(chong)體細長呈(cheng)線狀,圓柱形,在人眼(yan)結膜(mo)(mo)囊寄居時呈(cheng)淡紅色,離開人體為乳(ru)白(bai)色。蟲(chong)(chong)體表面具有(you)邊緣銳利的環形皺褶,側面觀其(qi)上(shang)下排列呈(cheng)鋸齒狀。
成蟲(chong)(chong)(chong)(chong)(chong)蟲(chong)(chong)(chong)(chong)(chong)體(ti)細長呈線狀,圓柱形,在人眼結(jie)膜囊寄(ji)居時呈淡紅色,離開(kai)人體(ti)為(wei)(wei)乳白色。蟲(chong)(chong)(chong)(chong)(chong)體(ti)表面(mian)具(ju)有(you)(you)邊緣銳(rui)利的(de)環形皺褶,側面(mian)觀其(qi)上下(xia)排列呈鋸齒(chi)狀。雄蟲(chong)(chong)(chong)(chong)(chong)大(da)小(xiao)一般為(wei)(wei)(4.5~15.0)mm×(0.25~0.75)mm,尾(wei)端(duan)向腹(fu)(fu)(fu)面(mian)彎曲(qu),由泄殖腔伸出2根交(jiao)合刺,長短及(ji)形狀各異。雌(ci)(ci)蟲(chong)(chong)(chong)(chong)(chong)大(da)小(xiao)為(wei)(wei)(6.2~20.0)mm×(0.30~0.85)mm,蟲(chong)(chong)(chong)(chong)(chong)體(ti)腹(fu)(fu)(fu)面(mian)尾(wei)端(duan)有(you)(you)肛(gang)門,食管與腸(chang)結(jie)合處(chu)的(de)腹(fu)(fu)(fu)面(mian)有(you)(you)陰(yin)(yin)門,雌(ci)(ci)蟲(chong)(chong)(chong)(chong)(chong)生(sheng)殖系統發達,為(wei)(wei)雙管型(xing),近陰(yin)(yin)門端(duan)子宮(gong)內的(de)蟲(chong)(chong)(chong)(chong)(chong)卵(luan)逐漸發育(yu)為(wei)(wei)盤曲(qu)的(de)幼蟲(chong)(chong)(chong)(chong)(chong),雌(ci)(ci)蟲(chong)(chong)(chong)(chong)(chong)直(zhi)接產出幼蟲(chong)(chong)(chong)(chong)(chong),為(wei)(wei)卵(luan)胎生(sheng)。雌(ci)(ci)、雄蟲(chong)(chong)(chong)(chong)(chong)尾(wei)端(duan)肛(gang)門周圍均有(you)(you)數對乳突。食管陰(yin)(yin)門幼蟲(chong)(chong)(chong)(chong)(chong)子宮(gong)腸(chang)雌(ci)(ci)蟲(chong)(chong)(chong)(chong)(chong)頭(tou)部(bu),雄蟲(chong)(chong)(chong)(chong)(chong)尾(wei)部(bu)乳突交(jiao)合刺。
初產(chan)幼蟲大(da)小為(wei)(350~414)μm×(13~19)μm,外被鞘(qiao)膜,呈盤曲(qu)狀,尾部連接一膨大(da)氣球狀的鞘(qiao)膜囊(nang)。
成(cheng)蟲(chong)(chong)主(zhu)要寄(ji)生于(yu)(yu)犬(quan)、貓(mao)等動物的(de)眼結膜囊(nang)及(ji)淚管(guan)內,偶爾寄(ji)生于(yu)(yu)人、兔等動物的(de)眼部(bu)。本蟲(chong)(chong)屬卵胎生。雌成(cheng)蟲(chong)(chong)直接產幼(you)(you)蟲(chong)(chong)于(yu)(yu)結膜囊(nang)內,當中間(jian)宿(su)(su)(su)主(zhu)果蠅舐吸(xi)(xi)終宿(su)(su)(su)主(zhu)眼部(bu)分泌物時(shi)而被(bei)吸(xi)(xi)入(ru)蠅體內,經2次蛻(tui)皮發(fa)育(yu)為感(gan)(gan)染期幼(you)(you)蟲(chong)(chong)后(hou)進人蠅的(de)頭(tou)部(bu)口器。當蠅再舐吸(xi)(xi)入(ru)或其他動物眼部(bu)時(shi),感(gan)(gan)染期幼(you)(you)蟲(chong)(chong)自蠅口器逸(yi)出(chu)并侵(qin)入(ru)宿(su)(su)(su)主(zhu)眼部(bu),經15~20天發(fa)育(yu)為成(cheng)蟲(chong)(chong)。成(cheng)蟲(chong)(chong)壽命可(ke)達2年以上(shang)。終宿(su)(su)(su)主(zhu):犬(quan)、貓(mao)(人);中間(jian)宿(su)(su)(su)主(zhu):蠅;感(gan)(gan)染階段:絲(si)狀蚴;感(gan)(gan)染方式(shi):媒介(jie)昆蟲(chong)(chong)舔舐眼部(bu)。
成(cheng)蟲(chong)(chong)寄生(sheng)(sheng)于(yu)人眼結(jie)(jie)膜(mo)囊內,以上(shang)結(jie)(jie)膜(mo)囊外眥側為多(duo)見,也可見于(yu)眼前(qian)房(fang)、淚小(xiao)(xiao)管、淚腺及眼瞼、結(jie)(jie)膜(mo)下(xia)(xia)等處。多(duo)侵犯一側眼,少數(shu)病例可雙眼感(gan)(gan)染。寄居蟲(chong)(chong)數(shu)1條(tiao)至數(shu)條(tiao),最(zui)多(duo)可達20余條(tiao)。由于(yu)蟲(chong)(chong)體(ti)表面銳利環形皺折的(de)摩擦、頭端口囊吸附作用等的(de)機械性(xing)損傷,加上(shang)蟲(chong)(chong)體(ti)分泌(mi)物、排泄(xie)物的(de)刺(ci)激及繼(ji)發(fa)細(xi)菌感(gan)(gan)染等,可引(yin)起眼結(jie)(jie)膜(mo)炎(yan)癥(zheng)反(fan)應及肉芽腫(zhong)形成(cheng)。輕者(zhe)無(wu)明顯(xian)癥(zheng)狀,或(huo)有眼部異物感(gan)(gan)、癢感(gan)(gan)、刺(ci)痛、流淚、畏(wei)光、分泌(mi)物增多(duo)、疼痛等,一般無(wu)視(shi)力障礙。嬰幼兒不(bu)敢睜眼,有手抓眼的(de)動(dong)作。家長可發(fa)現患兒眼球有白色細(xi)小(xiao)(xiao)的(de)蟲(chong)(chong)體(ti)爬行。重感(gan)(gan)染者(zhe)可發(fa)生(sheng)(sheng)結(jie)(jie)膜(mo)充血,形成(cheng)小(xiao)(xiao)潰瘍(yang)面,角膜(mo)混(hun)濁(zhuo)(zhuo)、眼瞼外翻等。如寄生(sheng)(sheng)在(zai)眼前(qian)房(fang),可有絲狀陰影(ying)移動(dong)感(gan)(gan)、睫狀體(ti)充血、房(fang)水(shui)混(hun)濁(zhuo)(zhuo)、眼壓升(sheng)高、瞳孔擴(kuo)大、視(shi)力下(xia)(xia)降等。如淚小(xiao)(xiao)管受損,可出現淚點外翻。
診斷(duan)(duan)主要(yao)用(yong)鑷子(zi)或(huo)棉簽自(zi)眼(yan)部取出蟲體,置(zhi)盛有生理鹽水的(de)平皿中,可(ke)見蟲體蠕動,用(yong)顯微(wei)鏡檢查蟲體特征即可(ke)明(ming)確診斷(duan)(duan)。
本蟲主(zhu)(zhu)(zhu)(zhu)要(yao)(yao)分布在(zai)(zai)亞洲(zhou)。印度(du)、緬甸、菲(fei)律(lv)賓、泰國(guo)、日(ri)本、朝(chao)鮮及俄(e)羅(luo)斯的(de)(de)(de)(de)遠東地區(qu)均有(you)(you)病(bing)例(li)報告(gao)。我(wo)國(guo)的(de)(de)(de)(de)病(bing)例(li)報告(gao)始于(yu)(yu)1917年,為世界(jie)最(zui)(zui)早發現。現已知我(wo)國(guo)有(you)(you)25個(ge)(ge)省、市(shi)、自治區(qu)有(you)(you)人體感染的(de)(de)(de)(de)病(bing)例(li)報道,其中(zhong)以江蘇、湖(hu)北、安(an)(an)徽、河南(nan)、山東等地的(de)(de)(de)(de)病(bing)例(li)較多。近年已證實岡田繞眼果(guo)蠅(Amiota okadai)是(shi)我(wo)國(guo)結膜吸(xi)吮(shun)線蟲的(de)(de)(de)(de)中(zhong)間宿主(zhu)(zhu)(zhu)(zhu),是(shi)本病(bing)的(de)(de)(de)(de)傳播媒(mei)(mei)介(jie)。感染季(ji)節以夏(xia)秋季(ji)為主(zhu)(zhu)(zhu)(zhu),與蠅類的(de)(de)(de)(de)季(ji)節消長相吻合(he)。感染者最(zui)(zui)小(xiao)3個(ge)(ge)月,最(zui)(zui)大者88歲,但以嬰幼兒為主(zhu)(zhu)(zhu)(zhu)。本病(bing)在(zai)(zai)農村(cun)多于(yu)(yu)城市(shi)。傳染源主(zhu)(zhu)(zhu)(zhu)要(yao)(yao)為家(jia)犬,其次是(shi)貓(mao)、兔(tu)等動物(wu)。根據1982~1991年的(de)(de)(de)(de)調查,安(an)(an)徽淮北重流(liu)行(xing)地區(qu)的(de)(de)(de)(de)某些村(cun)鎮(zhen)家(jia)犬的(de)(de)(de)(de)感染率高達76.7%,每(mei)犬的(de)(de)(de)(de)感染蟲數可在(zai)(zai)30~60條。保蟲宿主(zhu)(zhu)(zhu)(zhu)家(jia)犬的(de)(de)(de)(de)普遍存在(zai)(zai),媒(mei)(mei)介(jie)中(zhong)間宿主(zhu)(zhu)(zhu)(zhu)果(guo)蠅的(de)(de)(de)(de)廣泛(fan)分布,再加上幼童不潔的(de)(de)(de)(de)眼部衛生(sheng),是(shi)結膜吸(xi)吮(shun)線蟲病(bing)流(liu)行(xing)的(de)(de)(de)(de)主(zhu)(zhu)(zhu)(zhu)要(yao)(yao)因素(su)。
防(fang)(fang)蠅、滅蠅,搞(gao)好環境(jing)衛生(sheng),加強(qiang)犬、貓(mao)等動(dong)物管理,注(zhu)意個(ge)人衛生(sheng),特別(bie)注(zhu)意眼(yan)(yan)部清潔(jie)是預防(fang)(fang)感(gan)染的主要(yao)措施。治療可用1%~2%可卡因或地(di)卡因溶液滴(di)眼(yan)(yan),蟲體受刺激(ji)從眼(yan)(yan)角爬出(chu),或用鑷(nie)子取(qu)出(chu)。
病(bing)原體(ti)最初是從印度旁遮普(pu)的犬(quan)眼中發現(xian)的,以后在美(mei)國、緬甸、菲律賓、朝鮮、印度、日本、泰(tai)國、蘇聯、遠東地區(qu)等地陸續有(you)犬(quan)體(ti)寄生(sheng)的報道。我國犬(quan)、貓的感(gan)染甚為普(pu)遍(bian)而嚴(yan)重。
人體(ti)病例首先于1917年發現在我國。迄今報道已有百例以(yi)上(shang),分(fen)(fen)布(bu)于河北(bei)(bei)、福建(jian)、北(bei)(bei)京(jing)、江蘇、四(si)川、貴州、河南、安徽、湖(hu)南、湖(hu)北(bei)(bei)、東北(bei)(bei)、山東、天津、上(shang)海、云南、廣西等省市、自治區。其(qi)中以(yi)湖(hu)北(bei)(bei)、山東、江蘇部(bu)分(fen)(fen)地區為最(zui)多。人體(ti)感(gan)染者年齡(ling)、性別無特殊性,最(zui)小4個月,最(zui)高76歲。
成(cheng)(cheng)蟲(chong)寄生(sheng)(sheng)(sheng)在(zai)結(jie)膜囊(nang)中,以口囊(nang)吸附(fu)在(zai)眼(yan)結(jie)膜上(shang),并能自由移動,體(ti)表的皺褶對(dui)患者眼(yan)部造成(cheng)(cheng)機(ji)械(xie)性(xing)損傷,加(jia)之蟲(chong)體(ti)分泌物(wu)(wu)(wu)和排泄物(wu)(wu)(wu)的化學性(xing)刺激(ji),導致炎癥(zheng)反應或肉芽腫(zhong)形(xing)成(cheng)(cheng)。輕者可無癥(zheng)狀(zhuang),也可有(you)眼(yan)部異(yi)物(wu)(wu)(wu)感或癢(yang)感、流淚、畏光(guang)、眼(yan)部分泌物(wu)(wu)(wu)增(zeng)多(duo)、結(jie)膜充血或水腫(zhong),甚至眼(yan)痛,但視(shi)力一(yi)般不受影響。取出蟲(chong)體(ti)后癥(zheng)狀(zhuang)便可消失。如寄生(sheng)(sheng)(sheng)于眼(yan)前房,可見絲狀(zhuang)物(wu)(wu)(wu)浮動,房水混濁(zhuo),眼(yan)壓增(zeng)高,并可形(xing)成(cheng)(cheng)小潰瘍,重者形(xing)成(cheng)(cheng)疤痕(hen),造成(cheng)(cheng)角膜混濁(zhuo)等(deng)(deng)損害,也可引起繼發性(xing)青光(guang)眼(yan)、眼(yan)瞼外(wai)翻等(deng)(deng)并發癥(zheng)。以單側眼(yan)部感染多(duo)見,雙眼(yan)感染者少見。成(cheng)(cheng)蟲(chong)寄生(sheng)(sheng)(sheng)的數目常為1~10條,最(zui)多(duo)的一(yi)例多(duo)達21條。
可(ke)無明顯自覺(jue)癥狀(zhuang)(zhuang)(zhuang)。成蟲(chong)在(zai)(zai)眼結膜(mo)囊自由行動(dong),此蟲(chong)體的分泌物、排泄(xie)物可(ke)引起局部刺激癥狀(zhuang)(zhuang)(zhuang),眼部有(you)異物感、癢感、畏光、流淚、分泌物增多。如寄生在(zai)(zai)前房可(ke)見絲狀(zhuang)(zhuang)(zhuang)物飄動(dong),眼瞼水(shui)腫,結膜(mo)充血等癥狀(zhuang)(zhuang)(zhuang)。有(you)時出(chu)(chu)現眼瞼痙攣及瞼外翻。在(zai)(zai)取出(chu)(chu)蟲(chong)后(hou)癥狀(zhuang)(zhuang)(zhuang)即消失。預后(hou)佳(jia)。如果此蟲(chong)在(zai)(zai)眼部時間較長,可(ke)因此蟲(chong)口端角(jiao)(jiao)質(zhi)反復磨擦(ca)角(jiao)(jiao)膜(mo)引起擦(ca)傷,偶(ou)可(ke)遺留云翳而輕度影響視力。
根據病史、蟲體特征(zheng)及家畜和蒼蠅接觸史可與蠅蛆癥(zheng)相鑒別,鏡(jing)下作成蟲形態學鑒定(ding),診(zhen)斷并不難。