NEMATODES 線蟲 NEMATODES 線蟲 Blood and Tissue Nematode ( 血液及組織線蟲 ) Intestinal Nematodes ( 腸道線蟲 ) Ascaris lumbricoides ( 蛔蟲 ) Enterobius vermicularis ( 蟯蟲

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1 鄧致剛 Platyhelminthes 扁平蠕蟲 TREMATODA (Flukes) 吸蟲 Human Parasitic Helminthes 人體寄生蠕蟲 CESTODA (Tapeworms) 絛蟲 Nemathelminthes 線形蠕蟲 NEMATODA (Roundworms) 線蟲 Shape 外型 Anterior end 蟲体前端 Digestive tract 消化系統 Sexes 性別 Tape-like and segmented 扁平 分節 Suckers 吸盤 & Hooks 鉤 No mouth Absent Cestodes ( 絛蟲 ) Hermaphrodite 雌雄同體 Trematodes ( 吸蟲 ) Leaf-like 葉狀 and Unegmented 不分節 Suckers but no hooks No suckers or hooks Mouth present Mouth present Present, Present with anus no anus 無肛門 Hermaphrodite except schistosomes Nematodes ( 線蟲 ) Cylindrical 柱狀 and Unsegmented 不分節 Separate sexes 雌雄異體 Tapeworm Flukeworm Roundworm

2 NEMATODES 線蟲 NEMATODES 線蟲 Blood and Tissue Nematode ( 血液及組織線蟲 ) Intestinal Nematodes ( 腸道線蟲 ) Ascaris lumbricoides ( 蛔蟲 ) Enterobius vermicularis ( 蟯蟲 ) Trichuris trichiura ( 鞭蟲 ) Hookworms ( 鉤蟲 ) Necator americanus ( 美洲鉤蟲 ) Ancylostoma duodenale ( 十二指腸鉤蟲 ) Ancylostoma caninum ( 犬鉤蟲 ) Strongyloides stercoralis ( 糞小桿線蟲 ) Capillaria philippinensis ( 菲律賓毛線蟲 ) Trichostrongylus spp. ( 毛圓線蟲 ) Nematode General Morphology 線蟲基本形態 Cylindrical and unsegmented body 線形, 不分節 Bilateral symmemstery 兩側對稱 Sexes are separated (Dioecious) 雌雄異體 Males are smaller than females and usually cruved ventrally 雄蟲體形較小且尾端捲曲 Nematode General Morphology 線蟲基本形態 Nematode General Morphology 線蟲基本形態 Comparative size of Nematodes (1) A. lumbricoides 蛔蟲 m:150~130mm, f:200~350mm (2) T. trichiura 鞭蟲 m:30~45mm, f:35~50mm (3) Hookworm 鉤蟲 m:5~11mm, f:9~13mm (4) E. vermicularis 蟯蟲 m:2~5mm, f:8~13mm (5) Trichostrongylus spp. 毛圓線蟲 m:3.4~7.9mm, f:4.3~6.5mm (6) S. stercoralis 糞小桿線蟲 m:0.7 mm, f:1.0 mm body wall section of male A. lumbricoides Body Wall 體壁 Cuticle 表皮層 Hypodermis 皮下層 Somatic muscles 肌肉層 Pseudocoel 假體腔 Digestive system 消化系統 Reproductive system 生殖系統 Excretory system 排泄系統 Nervous system 神經系統 HY CU SM

3 Nematode General Morphology 線蟲基本形態 Nematode General Morphology 線蟲基本形態 Smooth Body wall - Cuticle 表皮層 Noncellular, shinning, may be smooth or 透明 非細胞性 表面平滑或具突起 Hypodermis 皮下層 具有細胞 形成四條索 (cord) one dorsal cord, one ventral cord and two lateral cord which containing excretory canal Ridges Spines Ala Bosses Nematode General Morphology 線蟲基本形態 Somatic muscles 肌肉層 Polymyrin type 多肌型 依肌肉細胞的多少及排列形式可分為 Meromyrian type 少肌型 Holomyrin type 全肌型 Nematode Digestive System 線蟲消化系統 Mouth 口 Bucal capsule 口腔 Oesphagus 食道 Dorsal lip Papilla Mouth Lateroventral lip Intestine 腸道 MU MU Pseudocoel 假體腔 A. lumbricoides male E. vermicularis male T. trichiura female Anus 肛門 Nematode Reroductive System 線蟲生殖系統 All Nematodes are Dioecious 雌雄異體 Didelphic Male reproductive system Excretory pore 排泄孔 Testis 睪丸 Vas deferens 輸精管 Seminal vesicles 貯精囊 dorsal ray 背面枝 posterolatero ray 後側枝 Copulatory bursa 交尾囊 externo-dorsal ray 外背側枝 medio-lateral ray 內側枝 ventral ray 腹面枝 externo-lateral ray Spicules 交尾刺 Nematode Reroductive System 線蟲生殖系統 Vulva 外陰部 Vagina 陰道 ovary 卵巢 Uterus 子宮 Monodelphic ovary 卵巢 Uterus 子宮 Vagina 陰道 Vulva 外陰部 Ovijector Uterus 子宮 ovary 卵巢 Ejacuatory duct 射精管 Spicules 交尾刺 Copulatory bursa A. duodenale Gubermaculum 引刺帶

4 Nematode Life Cycle 線蟲生活週期 Direct 直接 and Indirect 間接 life cycles Adult worms Female + oviparous 卵生 male worms vlarviparous 胎生 腸道寄生線蟲感染人體途徑 Soil-transmitted helminth Infections ( 土源性線蟲感染 ) L3 L4 moulting 蛻皮 L2/3 Infective 感梁期 Hatch (L1/2) Infective 感梁期 Unfertilised eggs 末受精卵 Fertilised eggs 受精卵 Embryonated eggs 胚卵 1 st stage larva (L1/2) 吃入蟲卵 ( 蛔蟲, 鞭蟲, 蟯蟲 ) 吃入被感染的食物 ( 菲律賓毛線蟲 ) 幼蟲穿入皮膚 ( 鉤蟲, 糞小桿線蟲 ) 自體感染 ( 蟯蟲, 糞小桿線蟲, 菲律賓毛線蟲 ) Life Span of some common intestinal Nematodes Parasite Enterobius vermiculars 蟯蟲 Ascaris lumbricoides 蛔蟲 Trichuris trichiura 鞭蟲 Necator americanus 美洲鉤蟲 Ancylostoma duodenale 十二指腸鉤蟲 Strongyloides stercoralis 糞小桿線蟲 Life Span 3 months 1 year 1~3 years 4~20 years 5~7 years > 30 years Drugs for Intestinal Nematode Infections Mebendazole Albendazole Thiabendazole Levamisole Pyrantel Piperazine Bephenium Tetrachloroethylene A.l. T.t. E.v. N.a. A.d. S.s 蛔蟲鞭蟲蟯蟲鉤蟲糞小桿線蟲 High anthelminthic activity Moderate anthelminthic activity

5 Enterobius vermicularis 蟯蟲 Also known as pinworm or threadworm Cause enterobiasis ( 蟯蟲症 ) World-wide distribution Commonly found in temperate and tropic regions Children are more commonly infected than adults Group infection 群體感染 Adult Morphology 成蟲形態 female 頸翼 蟲體呈淡黃色, 體形細小口週圍有三片唇, 前端兩側的表皮膨大形成頸翼 (cervical alae), 食道未端呈球形 (oesphagus bulb) 食道球 雄蟲 長寬約 2~5 x 0.1~.2 mm, 尾部彎曲蟲體未端有一對尾翼及, 單一交尾剌 male 雌蟲 長寬約 8~13 x 0.3~0.5 mm, 尾部細長 可佔蟲體長的 1/3 孕後可見兩個膨大的子宮 female Male & female Mating in ileum (1 month) 迴腸和盲腸的交接處交配 Gravid females in ileum, caecum, appendix and ascending colon migrates to perianal region 雌蟲爬出肛門外於肛門四周產卵 Transmission 傳播方式 Develops in mucosa 沿消化道向小腸的方向移行 Larva hatches in intestine (duodenum) 蟲卵在十二指腸孵化 embryonated egg (infective stage) Ingested MAN eggs on perianal skin (diagnostic stage) EXTERNAL ENVIRNOMENT ano-oral transmission 15~43 days Infective stage: embryonated egg A mature female lay approximately eggs/day. Eggs become infective after 6 hours Remain infective for 2 weeks Ingestion of infective eggs 食入感染性蟲卵 Autoinfection 自體感染 Airbrone transmission 空氣傳播 Retroinfection 逆行感染蟲卵在肛周皮膚上孵化出幼蟲, 然後幼蟲經肛門進入腸內, 並可發育為成蟲

6 Laboratory Diagnosis 實驗診斷 玻璃膠帶肛圍擦試法在早晨沐浴及排便前以膠帶黏貼肛圍四周, 並將膠帶置於顯微鏡下檢查是否有蟲卵 Finding eggs in sample collected from perianal skin in the morning before bath and defaceation by - Celulose adhesive tape 膠帶粘貼 (Scotch tape) - Anal swab 肛門拭子 Finding worms in feaces 蟯蟲玻璃膠紙 撕開第一日蟯蟲檢查透明玻璃膠紙 用綠色圓圈那一面, 對準肛門口,, 以手指用力壓貼 5-6 次 將透明玻璃膠紙貼回, 完成第一日採樣 Eggs of E. vermicularis 老師戰力超過 要小心聽課不要再抓寶 幼蟲 L1 卵無色, 外殼厚而透明不對稱卵圓形 一側扁平 一側稍凸大小約 50~60 x 20~30 um 卵內可見感染性幼蟲 Clinical Features 臨床徵候 Rarely cause serious symptoms Migrating gravid female worms on the perianal & perineal skin Nocturnal anal pruritus 晚間肛門搔癢 煩燥不安 失眠 食慾減退 消庾 E.v. in appendix section Adult worms in intestine Leisons limited to the GI tract minute ulcer mild inflammation 2 nd bacterial infections submucosal abscesses E.v. in appendix section Adult worms in intestine Leisons limited to the GI tract minute ulcer mild inflammation 2 nd bacterial infections submucosal abscesses Cross-section of human appendix containing Enterobius vermicularis.

7 Ectopic migration 異位性移行 Migrating worms or eggs in superfical muscosa Granulomatus reaction 蟯蟲性肉芽腫 Female urinary and genital tract 泌尿生殖道 -vagina 陰道, fallopian tube 輸卵管 and ovary 卵巢 Gastro-intestinal tract 消化道 -mucosa 腸壁, peritoneum 腹腔, omentum 盆腔 and appenidix 蘭尾 Other organs 其它器宮 -lung, urethra, urinary bladder, lymph node, spleen, liver and kidney Prevention and Control 預防及控制 Washing of the anal skin each morning 早上沐浴 Washing and changing of bedcover and clothing worn at night everyday 每天更換及清冼棉被床單等寢具 Personal hygiene 注意個人衛生 Group therapy 團體治療 : 若家中有人感染可全家一起投藥

8 Trichuris trichiura - whipworm 鞭蟲 Adult Morphology 成蟲形態 Male Female 寄生於人體盲腸前端細長 約佔體長 3/5 口腔極小, 具一尖刀狀口牙食道細長 外層為紋細胞 (stichocytes) 後端較粗腸道及生殖系統 World-wide distribution Commonly found in tropical & subtropical regions High infections rates in high risk groups 雄蟲 長約 30~45 mm 尾部彎曲蟲體未端有一交尾剌 雌蟲 長約 35~50 mm 尾部呈圓形子宮位於蟲體後半內含大量蟲卵 Penetrates and develops in mucosa Larva hatches in intestine Female Adults in Caecum 成蟲於盲腸寄生 Male Clinical Features 臨床徵候 成蟲寄生於盲腸, 蟲體前端鑽入腸黏膜, 後端游離於腸腔中, 以腸細胞及宿主血液作食物 Embryonated egg MAN Egg in feaces Eggs/day Infective stage 感染期 EXTERNAL ENVORNOMENT 3-5 weeks Diagnostic stage 診斷期 Clinical Features 臨床徵候 成蟲寄生於盲腸, 蟲體前端鑽入腸黏膜, 後端游離於腸腔中, 以腸細胞及宿主血液作食物 Light infection 輕度感染 No recongizable clinical manifestations Parasite is discovered only on routine stool examination Heavy infection 重度感染 No of worms > 800 Systemic symptoms 全身性症狀 Gastrointestinal symptoms 腸胃道症狀 T. trichiura Clinical Features 臨床徵候 Heavy infection 重度感染 The worms are distributed throughout the colon 大腸 and rectum 直腸 Systemic symptoms 全身性症狀 Anemia 貧血, eosinophilia 嗜酸性白血球增多, malabsorption 吸收不良 Gastrointestinal symptoms 腸胃道症狀 Frequent small blood-streaked diarrhoeal stools 血痢, Abdominal pain and tenderness 腹痛, Nauesa 噁心 and vomiting 嘔吐, Occassional rectal proplase 脫肛

9 male female Laboratory Diagnosis 實驗診斷 Finding eggs in feaces Sigmoidoscopy 結腸鏡 or proctoscopy 直腸鏡 Egg of T. trichiura 黃棕色 大小約 50~54 x 25 m 呈紡錘形或酒桶形 卵殼厚 兩端各有一透明塞狀突起 (plug) 卵內細胞尚未分裂 T. trichiura

10 Capillaria philippinensis 菲律賓毛線蟲 A very small whipworm which is normally parasitic in fish-eating birds Philippine islands 菲律賓群島 - Northern Luzon 呂宋島西北部海岸 - North eastern Mindanao 民答那峨 Thailand 泰國 Japan 日本, Indonesia, India, Taiwan Morphology of C. philippinensis 形態與鞭蟲相似但較小食道由桿狀細胞 stichocytes 組成 雄蟲大小約 2.1~3.7 x 0.02~0.04 mm 尾端有兩對乳突 ( 尾翼 ) 及一交尾剌雌蟲 大小約 2.6 ~4.9 x 0.04~0.06 mm 陰道口微突子宮位於蟲體中央, 內含蟲卵及 ( 或 ) 幼蟲 vulva vagina Female C. philipinensis stichosome esophagus ovary uterus Transmission 傳播途徑 Infective stage 感染期 : larvae 幼蟲 Intermediate host 中間宿主 : fish 淡水或海水魚類 Natural definitive host ( 終宿主 ) : fish- eating birds Ingestion of infective eggs in raw,undercooked, or pickles fish 吃入含有感染期幼蟲而末經煮熟的魚類 Autoinfection 自體感染 幼蟲在小腸內發育為成蟲 人類食入被含有感染性幼蟲之魚類 Life Cycle 生活週期 雌雌交配產卵 自體感染 蟲卵在腸內孵化發育為幼蟲 體內體外 蟲卵 厚殼卵薄殼胚卵 隨糞便排出體外 5~10 days 蟲卵在水中發育成胚卵 被淡水或海水魚類吞食在腸道中發育成感染性幼蟲 3 wks

11 Life Cycle of Capillaria philippinesis Unembryonated eggs are passed in the human stool Embryonated in the external environment Clinical Features 臨床徵候 Adults and larvae can be found in the crypts of small intestine especially jejunum, upper ileum and less often, in the duodenum Ingestion by freshwater fish, larvae hatch, penetrate the intestine, and migrate to the tissues. Ingestion of raw or undercooked fish results in infection of the human host. Adults of in the human small intestine burrow in the mucosa. The females deposit unembryonated eggs. The anterior ends sometimes penetrate into the lamina propria Villi tends to be flattened and atrophic Some of these become embryonated in the intestine, and release larvae that can cause autoinfection. This leads to hyperinfection (a massive number of adult worms). Capillaria philippinesis is currently considered a parasite of fish eating birds, which seem to be the natural definitive host 5-10 days Early and mild infections Adult C. philippinensis in the mucosa of small intestine Abdomminal pain 腹痛, intestinal gurgling 腸鳴 and chronic watery diarrhoea 慢性水瀉 Clinical Features 臨床徵候 Heavy infections Laboratory Diagnosis Finding eggs, adult worms or larvae in feaces Anorexia 食慾不振, nausea 噁心, vomiting 嘔吐 Watery diarrhoea (5~10 times/day) Severe malabsorption of fats and sugar Protein losing enteropathy (15X than normal) Reduced level of carotene, plasma K, Na and Ca salts 電解質流失 Decreased excretion of xylose Decreased level of IgM and IgG 菲律賓毛線蟲卵 長寬約 36~45 x 19~21 mm 形狀較接近長方形 Plug ( 卵塞 ) 較不突出卵殼外層有橫紋土黃色, 無閃亮光澤 鞭蟲卵 長寬約 50 x 25 mm 酒桶形卵塞突出無橫紋褐黃色, 有閃亮光澤 cachexia 惡體質, muscle wasting 肌肉萎縮, oedema 水腫 Cardic failure 心臟衰竭, hypotension 低血壓 DEATH in 2~8 wks (mortality rate 6.7~20%) Prevention and Control

12 Ascaris lumbricoides 蛔蟲 The largest Intestinal Nematode Male:15~31 cm x 2~4 mm Female: 22~35 cm x 3~6 mm Cylindrical and white to tan with tapered ends The mouth surrounded by 3 lips Cuticle has both annulations and striations ASCARIASIS 蛔蟲症 About 1/4 of the world population is infected Infection is world-wide distribution common in areas where human feaces are used as fertilizer Children are more often and mor heavily infected than adults Females Didephic Ovaries, oviducts & uteri are in the posterior 2/3 Vulva is located 1/3 from the anterior ens Males Posterior end curved Reproductive tube in the posterior half of the body Has 2 copulatory spicule Life Cycle of Ascaris lumbricoides Ingested Lungs (L3) Portal circulation Larva hatches in intestine L4 Embryonated egg Trachea MAN Pharynx Swallowed Eggs in faeces Adults in small intestine 200,000~250,000 eggs per day 3~4 wks Infective stage (L2) EXTERNAL ENVIRNOMENT Fertilised Diagnostic stages Unfertilised Advanced cleavage 2-cell stage Pathogensis 致病機轉 Amount of worms infected 感染蟲數 Effects of visceral larval migration (VLM) 內臟幼蟲移行 Mechanical effects due to adult worms 成蟲機械式傷害 Nutritional deficiencies Larvae migration ( 幼蟲移行 ) Mechanical damage ( 機械式傷害 ) cause inflammatory ( 發炎 ), bacterial infection ( 細菌性感染 ) and hypersensitive reaction 過敏反應 In lung cause Loeffler's syndrome Coughing, bronchial asthma and pneumonia- like symptoms Infiltartion of eosinphils, macrophages, and epitheloid cells around the larvae Abdominal pain, nausea, diarrhoea and vomiting Impaired absorption ( 吸收不良 ) Malnutrition ( 營養不良 ) Allergic reaction consisting of dyspena, a dry or productive cough, transient eosinophilia, wheezing ot coarse rales, fever, and a chest X-ray suggestive of viral pneumonia. Sputum contain eosinophils, Charcot-Leyden crystal and sometimes larvae

13 Heavy Infection 重度感染 Heavy Infection 重度感染 Pass or vomit of worms 排出或吐出成蟲 Intestinal obstruction by worm bolus 腸阻塞 Intestinal perforation 腸穿孔 Bile duct and pancreatic duct obstruction 阻塞膽管及胰管 cholangitis 化膿性膽道炎 multiple liver absceses 多發性肝膿腫 ascarid chronic pancreatitis 慢性胰臟炎 Can be fatal Heavy Infection 重度感染 Atopic Ascariasis 蛔蟲異位感染 Adult in bile duct Liver egg granuloma Adult in liver Laboratory Diagnosis Fertilized females lay about 200,000 eggs per day Finding A. lumbricoides eggs in faeces Fertilized egg 受精卵 Unfertilized egg 未受精卵 Decorticated egg 去蛋白膜卵 Identifying A. lumbricoides worms expelled through the anus or mouth Bile duct Pancreatic duct Liver Peritoneal cavity Kidney Appendix Pleural cavity Upper respiratory tract

14 A. lumbricoides eggs Fertilized egg 受精卵 oval or round, 60 x 40 mm, yellowish brown egg shell covered by an uneven albuminous coat contains a central grandular mass Unfertilized egg 未受精卵 elongated, 90 x 45 mm, darker and more albuminous contains a central mass of large refractile grandules Decorticated egg 去蛋白膜卵 pale yellow or colourless smooth egg shell no albuminous coat Embryonated egg 胎蟲卵 (infective) pale yellow or colourless contains a larva (R-form, 1 st or 2 nd stage ) Prevention and Control 預防及控制 Preventing soil becoming faecally polluted by Providing and using adequate latrines Avoding the use of human feaces as fertilizer Treating infected individuals as part of a control programme especially children Preventing eggs being ingested by Washing the hands before eating Avoid the eating of uncooked vegetables, green salads and fruits Treatment Pyrantel pamoate single dose, 10 mg/kg, max. 750 mg/adult Levamisole single dose, children (5 mg/kg), adult (150 mg) Albendazole single dose, children from 2~12 yr. (200 mg), adult (400 mg) Mebendazole single dose, twice a day, 100 mg/each

15 Hookworms 鉤蟲 Distribution between 45 o N and 30 o S Approximately 9 billion people infected Over 20 million showed clinical manifestations Hookworms 鉤蟲 Distribution between 45 o N and 30 o S Approximately 9 billion people infected Over 20 million showed clinical manifestations Necator americanus 美洲鉤蟲 Ancylostoma duodenale 十二指腸鉤蟲 Ancylostoma caninum 犬鉤蟲 Ancylostoma braziliense 巴西鉤蟲 Ancylostoma ceylanicum 鍚蘭鉤蟲 Ancylostoma malayanium 馬來亞鉤蟲 Necator americanus 美洲鉤蟲 Ancylostoma duodenale 十二指腸鉤蟲 Ancylostoma caninum 犬鉤蟲 Ancylostoma braziliense 巴西鉤蟲 Ancylostoma ceylanicum 鍚蘭鉤蟲 Ancylostoma malayanium 馬來亞鉤蟲 N. americanus 美洲鉤蟲 A. duodenale 十二指腸鉤蟲 腹齒板 附齒 腹齒 次腹齒刀 A. duodenale 十二指腸鉤蟲 Middle East Mediterranean countries North China Africa South-East Asia South America Pacific Islands Between 45 o N and 30 o S N. americanus 美洲鉤蟲 Far East South Asia Pacific Islands Tropical Africa Central and South America Posterior end of N. americanus Copulatory bursa 交尾囊 Anus 雌美洲鉤蟲 7~9 x 0.3 mm externo-dorsal ray 外背側枝 dorsal ray 背面枝 posterolatero ray 後側枝 medio-lateral ray 內側枝 ventral ray 腹面枝 externo-lateral ray Spicules 交尾刺 雄美洲鉤蟲 9~11 x 0.4 mm Bursa 交尾囊

16 Transmission Active penetration of skin by infective filariform larvae (L3) Ingesting of infective larvae in A. duodenale Transmammary transmission of larvae in A. duodenale 1 wk Swallowed Attached to Pharynx small intestine 2~3 wks Trachea Lungs Circulation 4~6 wks 3 days MAN Penetrates skin Filariform larva (L3) 絲狀幼蟲 Egg in faeces infective filariform larvae (L3) Infective stage 感染期 EXTERNAL ENVIRONMENT 2 nd stage larva (L2) in soil Rhabditiform larva hatches (L1) 桿狀幼蟲 Diagnostic stage 診斷期 Clinical Pathology Pentration of skin by F- form larvae (L3) Gound itch Skin reaction (uritcaria 蕁痲疹 )at the site of larval pentration Stinging sensation followed by irration, erythea, oedema and papulovesicular eruption Creeping eruptions 匍行性疹 A. braziliense and A. caninum wandering through the cutaneous layer (cutaneous larva migrans) cause intense irritation and iflammaton. Most of the larva die in the skin. Clinical Pathology Migration of F-form larvae (L3) During invasion of the circulation: Usually no ill-effects During migration through the lungs: Pneumonitis ( 肺炎 ) with cough ( 咳嗽 ), wheeze ( 哮喘 ), fever ( 發燒 ), transient X-ray shadows (Not as severe as Ascaris) In lungs Haemorrhages and leukocytic or eosinophilic infiltrations In respiratory tract Coughing due to irritation of the bronchial and tracheal mucous membranes Clinical Pathology Established intestinal infection by adult worms Epigastric duodenal-type pain, indigestion, loss of appetite or diarrhoea Clinical Pathology Clubbed Fingers & Ascites Hookworm anaemia (HWA) Losses of blood, iron and proteins Occassionally associated with folate deficiency Adult worms attach to duodenum and jejunum by teeth or cutting plates (mechanical) Worms move every 4-6 hours (blood leaking) Worrms feed on blood from cut vessels and mucosal tissue (chronic blood loss)

17 Laboratory Diagnosis Direct smear for eggs Egg culture for 1 st stage larva (L1) Colourless with a thin shell which appears as a black line aroung the ovum Oval in shape, measuring about 65 x 40 m Contains an ovum which usually appears segmented Larva may be seen inside in some specimen Early stage Advanced stage Gastrula stage Embryonated stage Hookworm Rhabditiform Larva (L1) Hookworm Filariform Larva (L3)

18 Trichostrongylus spp. 毛線蟲屬 Tricho- (hair or thread) + strongylus (round) Pseudo-hookworms 假鉤蟲 Parsites of ruminants ( 反芻類 ), equines ( 馬 ), and rodents ( 嚙齒類 ). Human infections have been reported from parts of Africa, Indonesia, Egypt, Iran, South-east Asia, India, Japan, Korea, Russia and Chile. Trichostrongylus orientalis ( 東方毛線蟲 ) Trichostrongylus colubriformis ( 蛇形毛線蟲 ) Trichostrongylus probolurus ( 槍形毛線蟲 ) Trichostrongylus axei ( 艾氏毛線蟲 ) Trichostrongylus vitrinus ( 透明毛線蟲 ) Trichostrongylus skrjabini ( 斯氏毛線蟲 ) Trichostrongylus brevis Trichostrongylus orientalis ( 東方毛線蟲 ) Trichostrongylus colubriformis ( 蛇形毛線蟲 ) Trichostrongylus probolurus ( 槍形毛線蟲 ) Trichostrongylus axei ( 艾氏毛線蟲 ) Trichostrongylus vitrinus ( 透明毛線蟲 ) Trichostrongylus skrjabini ( 斯氏毛線蟲 ) Trichostrongylus brevis Morphology 形態 Pseudo-hookworms 假鉤蟲 形態與鉤蟲相似, 但無口囊及口齒 蟲體白色透明, 前端呈圓形 Transmission 傳播途徑 雄蟲大小約 4.3~5.5 x 0.072~0.079 mm, 尾端具由兩葉組成之交尾囊, 內含一對交尾剌 Infected by ingesting third stage larvae in contaminated food or drink 吃入受到第三期感染性幼蟲污染的食物而受感染 雌蟲大小約 5.5~6.5 x 0.07 mm, 尾端較狹, 具一對子宮, 內含 5~16 個蟲卵 Parasite in stomach and small intestine of host 幼蟲在宿主體內不需移行, 直接發育為成蟲 Life Cycle 生活週期 雌雌交配 產卵蟲卵隨糞便排出體外 Clinical Features 臨床徵候 蟲卵在土壤中孵化 Usually asymptomatic 無症狀 在宿主小腸及胃內蛻皮兩次???? 以頭端插入腸粘膜內發育為成蟲 幼蟲在土壤中蛻皮兩次發育成第三期感染性幼蟲 隨被污染之食物進入宿主消化道 Heavy infection may cause gastrointestinal disturbance 腸胃道不適 and anemia 輕微貧血 Eosinophilia 嗜酸性白血球增加 (<10%~32%)

19 Egg of T. orientalis 形狀與鉤蟲卵相似但較狹長長寬約 80~100 x 40~50 m 卵殼很薄無色透明新鮮糞便中蟲卵含 12~20 個胚細胞 東方毛線蟲卵 鉤蟲卵

20 Strongyloides stercoralis - threadworm 糞小桿線蟲 World-wide distribution Endemic in tropical and subtropical countries Free-living Life Cycle 生活週期 雌雄交配或孤雌生殖 成蟲 童蟲 IN SOIL 產出受精卵 第三期絲狀幼蟲 Filariform larva 第一期桿狀幼蟲 Rhabditiform larva 第二期幼蟲 Life Cycle 生活週期 Free-Living 自由營生世代 (Inirect development) 成蟲不需宿主, 在體外 ( 土壤 ) 完成整個生活週期童蟲 雌雄交配或孤雌生殖 產出受精卵 Parasitic Generation 寄生世代 (Direct development) 幼蟲在宿主體內發育為成蟲 產卵 孵化 幼蟲再隨糞便排出體外 第三期絲狀幼蟲 第二期幼蟲 第一期桿狀幼蟲 Trachea Lung Pharynx Circulation Penetrates intestine Penetrates skin or perianal skin Filariform larva (L3) 第三期絲狀幼蟲 Rhabditiform larva (L1) in soil 土壤中第一期桿狀幼蟲 L3 Autoinfection Soil 在土壤中 Swallowed 自體感染 1 自體感染 2 自體感染 3 Eggs in soil 卵胎生 Adult worms in mucosa of small intestine 成蟲於小腸組織中產卵 Eggs in mucosa 蟲卵孵化 Rhabditiform larva (L1) in faeces 第一期桿狀幼蟲 在土壤中發育為成蟲 Free living adults in soil Transmission 傳播途徑 Active penetration of skin by infective filariform (L3) larvae 土壤中的第三期感染性絲狀幼蟲直接穿透宿主皮膚 Transmammary transmission of larvae in breast milk 幼蟲經由哺乳傳給後代 Autoinfection 自體感染 (1) 宿主體腸道內之第一期桿狀幼蟲 (rhabditiform) 直接進入血液循環再發育成絲狀幼蟲 (2) 宿主體腸道內之第一期桿狀幼蟲直接發育成絲狀幼蟲再進入血液循環 (direct development) (3) 絲狀幼蟲隨糞便排出後再自肛週皮膚穿入體內

21 Clinical Features 臨床徵候 Laboratory Diagnosis 實驗診斷 Cutaneous 絲狀幼蟲穿透皮膚 Itchy dermmatitis 皮膚炎, pruritus 搔癢症狀 and rash 紅腫 Pulmonary 幼蟲心肺移行 Allergic 過敏 and respiratory symptoms Haemorrhages in the lung alveoli, pneumonitis 肺炎 Intestinal 成蟲寄生腸道 Diarrhoea with blood and muscus 腹瀉, ulcerative enteritis 化膿性腸炎, anaemia 貧血, malabsorption 吸收不良, steatorrhoea 脂肪便, epigastric pain 上腹部疼痛, electrolyte disturbance 電解質不平衡 and eosinophilia 嗜酸性白血球增加 Disseminated Hyperinfection Infection 擴散性感染 Infection can be found in almost all organs Finding rhabditiform larvae 桿狀幼蟲 in faeces (each gram of faeces contain about 1~3 larvae) Finding R-form larvae in duodenal aspirates 十二指腸抽取液 Examination of faeces for S. stercoralis Direct saline preparation 直接抹片 Formol ether concentration technique 糞便濃縮 Stool culture 糞便培養 Morphology - Rhabditiform larvae 桿狀幼蟲形態 口腔食道神經環腸壁 桿狀幼蟲 長寬約 200~300 m x 15 m 無外鞘 (Unsheathed) 具典形桿狀食道 (R-form oesophagus) 口腔 (buccal cavity) 較鉤蟲桿狀幼蟲短 生殖原基 肛門