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  1. Introduction to Parasitology Suggested Textbook : Markell and Voge’s Medical Parasitology. 9th ed. John DT & Petri WA. 2006.

  2. Helminth 蠕蟲 (-ology) Nematoda 線蟲 Trematoda 吸蟲 Cestoda 絛蟲 Protozoa 原蟲 (protozoology) Arthropoda 節肢動物 (Entomology 昆蟲學) Vector 媒介 :biological 生物性, mechanical 機械性 Parasitic zoonoses 人畜共通寄生蟲病

  3. Parasite 寄生蟲: infection temporary暫時性, stationary定留性 ecto-, endo- obligatory 專性, facultative 兼性 pathogenic 致病性, non-pathogenic 非致病性 spurious 假性, pseudo- 假的 accidental 偶然 Host 宿主 : Final host (FH) (definitive host) 終宿主 Intermediate host (IH) 中間宿主 Paratenic host (transport host) 保幼宿主 Reservior host (RH) 保蟲宿主

  4. Mode of infection : oral, skin penetration, • congenital infection • Infective form 感染型 • Effects of parasites on hosts : • Compete for the nutrients • Feed on host tissue • Mechanical damage • Toxic substance • Others

  5. -osis -asis • Prevention : • Treatment of patients and reservoir hosts • Treatment of excreta of final hosts • Control of vectors and intermediate hosts • Prophylaxis against infections • Scientific nomenclature :

  6. The “top ten” human parasites Parasite No. infected (億) Deaths/year (萬) Ascaris 蛔蟲 13 2-6 Hookworms 鉤蟲 13 5-9 Trichuris 鞭蟲 9 Amebae 阿米巴 5 4-11 Malaria 瘧疾原蟲 4-4.9 250 Giardia 梨形鞭毛蟲 2 Schistosomes 血吸蟲 1.5 50-100 Filarias 絲蟲 1.46 Trypanosomes 錐蟲 0.25 6.5-10 Leishmania 利什曼原蟲 0.12 8

  7. Outline of Nematoda (約50萬種) Morphology : generally elongated and cylindrical, tapering at both end Differ greatly in size : (F > M) Strongyloidesstercoralis 糞線蟲 2 mm Dracunculusmedinensis麥地那蟲 > 1 m Body wall : cuticle 角皮層 hypodermis 皮下層 musculature 肌肉層

  8. Digestive system : mouth  buccal cavity  esophagus  intestine  rectum  anus Reproductive system : male : single coiled tubule accessory copulatory apparatus : spicule 交尾刺 bursa 交尾囊 female : single or double tubules

  9. Life cycle : Egg  L1  L2  L3  L4  Adult Oviparous 卵生  mature egg  FH Egg embryonated egg  IH ( infective larva)  FH  hatched larva  infective larva  FH  IH ( infective larva)  FH Larviparous 幼生 (ovoviparous 卵胎生) Larva  IH ( infective larva)  FH

  10. No reservior host Transmission control 90%於下肢 No immunity and cure

  11. I. Ascarislumbricoides蛔蟲 The giant intestinal roundworm Ascariasis, ascariosis Distribution : worldwide Morphology : Male : 15–30 cm x 2–4 mm Female : 20–35 cm x 3–6 mm Egg : unfertilized, fertilized, embryonated, mature

  12. Life cycle Prepatent period : 2 –3 months Life span : 1 – 2 years RH : pig (Ascarissuum ?) Infective form : mature egg (soil–transmitted) Mode of infection : contamination of food and water Habitat : small intestine

  13. 2-3 wks

  14. Pathology and Symptomatology : Migrating larvae : fever, cough, hemmorrhage, eosinophilia, increased level of IgE pneumonitis (heavy infection) Adult worms : protein–energy malnutrition, vague abdominal discomfort, intestinal obstructions heterotopic (ectopic) 異所寄生 Pica 異嗜症 Loffler syndrome

  15. Diagnosis : stool examination (20萬 eggs/隻/天) Treatment : Mebendazole (Vermox) Albendazole (Zentel) Pyrantel pamoate (combantrin) Levamisole (Tetramisole) Piperazine salts (Antepar) Surgical consideration Prevention : Epidemiology :

  16. II. Toxocara canis 犬蛔蟲 Toxocaracati貓蛔蟲 toxocariasis Distribution : cosmopolitan Morphology : cervical alae 頸翼 T. canis male : 4–6 cm (max. 13) female : 6–10 cm (max. 20) T. cati male : < 6 cm female : < 12 cm Egg : pitted shell

  17. Encyst? L2 T. cati不經胎盤感染

  18. Infective form – mature egg (Soil–transmitted parasite) PH : man, mice, rat, rabbit, chicken, etc. Pathology and Symptomatology : Granuloma in liver, lung, kidney, heart, striated muscle and eye VLM (visceral larva migrans): asymptomatic or characterized by eosinophilia, hepatomegaly, pulmonary infiltration, hyperglobulinemia, fever and cough OLM : eye lesion usually painless, unilateral and symptomless, may lead to total retinal detachment (retinoblastoma ?)

  19. Diagnosis : Biopsy Serologic tests Treatment : Mebendazole Albendazole + Corticosteroids (anti–inflammatory) Surgery (OLM) Epidemiology : children, owners of dogs or cats (seroprevalence : 5% in USA, France) Prevention :

  20. III. Anisakine Nematodes 海獸胃線蟲 Herring worm, codworm Anisakis spp. : A. simplex, A. typica, A. physeteris Pseudoterranova (=Teranova, Phocanema) spp. Contracaecum spp. etc. Distribution : cosmopolitan

  21. Morphology : Anisakis sp. : male 3–9 cm female 6–10 cm infective larva 2–3.5 cm x 0.3–0.6 mm Life cycle : IH : small marine crustaceans PH : marine fishes and squids FH : marine mammals Habitat : FH – stomach Man – stomach, intestine, throat

  22. Pathology and Symptomatology Transient anisakiasis : throat irritation nausea, gastric distress within a few hours after ingestion of fish Eosinophilia Pain, ulcer and granuloma of stomach and small intestine; bloody stool; severe appendicitis; usually mistaken for carcinoma

  23. Diagnosis : Identification of specimens removed by gastric endoscopy or surgery Treatment Pluck out the worms by using a gastroscope Surgical operation Prevention

  24. 據台大獸醫系費昌勇教授報告,他們對自1994年1月到1997年據台大獸醫系費昌勇教授報告,他們對自1994年1月到1997年 6月這段期間在台灣擱淺的十七種鯨豚205隻作樣本採集,發 現其中就有29.27%的鯨豚感染有海獸胃線蟲的成蟲;而太平洋 岸的海魚中有80%以上的魚帶有海獸胃線蟲幼蟲。

  25. IV. Gnathostoma spp. 棘口線蟲 Gnathostoma spinigerum , gnathostomiasis Distribution : Far East Morphology : headbulb 頭球, hooklets, cuticular spines Male : 11–25 mm Female : 25–54 mm

  26. G.I.

  27. Life Cycle : 1st IH : copecopds 水蚤(Cyclops spp.) 2nd IH and PH : crustaceans (experimentlly), freshwater fish, amphibians, reptiles, birds and mammals (except felines and canines) RH : felines and canines Mode of infection

  28. Pathology and Symptomatology : CLM : rash, stabbing pain, pruritis VLM Neurological g. : eosinophilic myeloencephalitis Ocular gnathostomiasis : palpebral edema (長江浮腫), exophthalmos, subconjunctival hemorrhage, blindness Diagnosis : history Identification of the removed worms Treatment : Albendazole, surgery Prevention

  29. V. Enterobious vermicularis 蟯蟲 pinworm (spindle–shaped) Distribution : worldwide 溫帶多於熱帶, 都市多於鄉村 Morphology : cephalic alae, esophageal bulb Male : 2–5 mm Female : 8–13 mm Egg : asymmetrical shape

  30. Life Cycle : Infective form : emberyonated egg (6–7 hrs after oviposition) Prepatent period : 15–43 days (3–4 weeks is more common) Life span : 4–8 weeks Habitat : cecum Mode of infection *Family infection, retroinfection

  31. 幼蟲不會移行

  32. Pathology and Symptomatology : Asymptomatic or Peranal, perineal or vulval pruritis Appendicitis Heterotopic parasitism : peritonitis Diagnosis : Anal swab (Graham’s Scotch tape swab technique)

  33. Treatment : Mebendazole Albendazole Pyrantel pamoate Pyrvinium pamoate Piperazine salts Prevention :

  34. VI. Angiostrongyluscantonensis廣東血線蟲 Rat lung worm, angiostrongyliasis Distribution : Southeast Asia and pacific islands 日、中、台、泰、越、馬來西亞、夏威夷、大溪地等 Morphology : Male : 16–19 mm (small bursa) Female : 21–25 mm Barber’s pole pattern – white uterine and black intestine Egg : hatch in the lung of rat

  35. Life cycle : IH : land snail – 非洲大蝸牛、扁蝸 freshwater snail – 圓田螺、福壽螺、元寶螺 slug 蛞蝓 PH : 渦蟲、蛙、蛇、蝦、蝲蛄、螃蟹等 RH : rat, bandicoots Accidental host Mode of infection ? Habitat ?

  36. F.H. I.H.

  37. Pathology and Symptomatology : Asymptomatic or Eosinophilic meningitis Eosinophilic meningoencephalitis Fever, vomiting, nausea, severe headache, stiff neck, sensory impairment, death Eye invasion – visual impairment, ocular pain

  38. Diagnosis : Young adults in CSF Blood and CSF : eosinophilia, pleocytosis CT, ELISA Treatment : Anthelmintic treatment is not recommended Supportive treatment, corticosteroid Removal of CSF Immunotherapy ? Prevention :