Pathogenic amoebae and ciliate. Dr. Narissara Jariyapan Department of Parasitology Faculty of Medicine Chiang Mai University

Transcription

1 Pathogenic amoebae and ciliate Dr. Narissara Jariyapan Department of Parasitology Faculty of Medicine Chiang Mai University

2 Objectives After the lecture, students must know 1. General morphology of pathogenic amoebae and ciliate 2. Life cycle of Entamoeba histolytica, free living pathogenic amoebae and Balantidium coli 3. Diseases caused by Entamoeba histolytica, free living pathogenic amoebae and Balantidium coli

3 Classification of Protozoa Based on locomotive organs : Amoebae : Flagellates : Flagella Pseudopodia Ciliates : Cilia Sporozoa : Body flexion or Gliding

4 Amoebae pseudopodia

5 Flagellates flagella

6 Ciliates cilia

7 Sporozoa No locomotive organ Movement by body flexion or gliding

8 Microsporidia No locomotive organ Polar tube for penetration host cell membrane

9 Pathogenic amoeba Parasitic : Entamoeba histolytica Free-living : Naegleria fowleri Acanthamoeba spp. Balamuthia mandrillaris

10 Entamoeba histolytica Disease Distribution Amoebiasis Worldwide esp. tropics

11 Entamoeba histolytica Trophozoite Size : mm Irregular shape 1 spherical nucleus : - small & central karyosome - chromatin granules evenly line nuclear membrane Finely granular endoplasm (food vacuoles + RBC) Rapid movement by finger-like pseudopodia

12 size : mm irregular shape finely granular endoplasm (food vacuoles + RBC) 1 spherical nucleus small & central karyosome chromatin granules evenly line nuclear membrane

13 Rapid movement by finger-like pseudopodia

14 food vacuoles + RBC

15 Entamoeba histolytica Cyst size : um round or oval shape thin, tough cyst wall immature mature 1-4 nuclei chromatoid bar with rounded ends-cigar shaped

16 Cyst chromatoid bar

17 Life cycle Transmission By ingestion of 4 nuclei cyst

18 Pathogenesis Amoebiasis : I. Intestinal amoebiasis II. Extraintestinal amoebiasis

19 I. Intestinal amoebiasis : Asymptomatic cyst passer Amoebic colitis Fulminant colitis Amoeboma, etc.

20 Amoebic colitis Amoebic colitis (flask shaped) Amoebic dysentery Symptom and sign tenesmus diarrhea mucous bloody fever water depletion secondary bacterial infection

21 Amoebic colitis

22 Amoebic colitis

23 rectal biopsy: trophozoite

24 II. Extraintestinal amoebiasis : Amoebic hepatitis & liver abscess Pulmonary amoebiasis Amoebic brain abscess Amoebic vaginitis & cervicitis Amoebic cutis, etc.

25 Amoebic hepatitis& liver abscess Most common extraintestinal amoebiasis - abdominal pain - fever, diarrhea - weight loss - hepatomegaly & splenomegaly - jaundice

26 Liver abscess

27 Amoebic hepatitis

28 Diagnosis I. Stool examination : cyst & trophozoite II. Serological test (ELISA) III. Coproantigen detection IV. PCR techniques V. Colonoscopy & Sigmoidoscopy

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30 Amoebic vaginitis

31 Prevention and control Prevention of transmission : - Early diagnosis and treatment - Good sanitation & personal hygiene

32 Pathogenic Free-living Amoebae Naegleria fowleri Acanthamoeba spp. Balamuthia mandrillaris*

33 Naegleria fowleri lobopodium Amoeboid trophozoite mm big karyosome with halo Flagellated trophozoite 1-4 flagella cyst

34 lobopodia Flagellated trophozoite Amoeboid trophozoite Cyst Naegleria fowleri

35 flagella amoebostome ostiole Flagellated trophozoite 1-4 flagella Amoeboid trophozoite lobopodia Cyst Naegleria fowleri

36 Life cycle

37 Transmission CNS infection: Persons with history of swimming Parasites nasopharyngeal mucosa olfactory nerves Brain Primary amoebic meningoencephalitis : acute Symptoms : 3-7 days - fever, headache, rhinitis, stiff neck, seizure, coma Dead within 10 days

38 Diagnosis Cerebrospinal fluid examination Naegleria fowleri : trophozoite Culture in NNA seeded with intestinal bacteria Brain tissues autopsy found trophozoites with large karyosome, no cyst Histosy of swimming

39 Prevention - Avoid - contact with contaminated water, natural ponds - Chlorine in swimming pool 1-2 ppm - Wear nose clip - Blow nose

40 Treatment - Combination anti-microbial therapy: amphotericin B, Azithromycine, rifampin, and azole drugs - Intensive supportive care required - Mortality rate 100%

41 Acanthamoeba spp. spiky acanthopodia Trophozoite mm slow movement Cyst 1 nucleus 2 layers cyst wall

42 karyosome Trophozoite spiky acanthopodia Cyst 1 nuc. 2 layers of cyst wall Acanthamoeba spp. most common : A. castellani

43 Trophozoite Cyst Acanthomoeba spp.

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45 Transmission - CNS infection: Parasites Immunocompromised persons - respiratory tract blood stream - genitrourinary tract - skin - mucosa, etc. Brain - Eye (corneal) infection: Immunocompetent persons

46 Diseases and Symptoms 1. Granulomatous amoebic encephalitis (GAE): subacute Symptoms : fever, headache, neurologic disturbance, seizures Mostly in immunocompromised persons 2. Amoebic keratitis (AK) Symptoms : foreign-body sensation, pain, tearing, photophobia, blepharospasm, blurred vision Clinical features : ocular pain, corneal epithelial breakdown and ringlike corneal infiltrate Mostly in healthy persons

47 Acanthamoebic keratitis

48 Diagnosis 1. GAE - Brain tissues: trophozoites and cysts - CSF: trophozoites - Culture in NNA seeded with E. coli 2. AK - Corneal scraping staining or culture - Confocal microscopy - Molecular techniques - DNA

49 Treatment 1. GAE - Combination anti-microbial therapy: amphotericin B, Azithromycine, rifampin, and azole drugs 2. AK - A topical cationic antiseptic agent such as polyhexamethylene biguanide (0.02%) or chlorhexidine (0.02%) with or without a diamidine such as propamidine (0.1%) or hexamidine (0.1%). - Duration of therapy may last six months to a year.

50 Prevention - Cautious wearing of contact lens - Prompt treatment of lesions in the skin, eyes, genitrourinary or respiratory tract

51 Disease : Balantidiasis, Balantidiosis Worldwide distribution Largest protozoa found in human

52 Trophozoite 40-70x um Cilia cover around trophozoite 2 nucleus:- - A bean shaped macronucleus - A less conspicuous micronucleus

53 Cyst Oval shape Thick cyst wall um 2 nucleus:- -Macronucleus -Micronucleus

54 Balantidium coli Balantidium coli cyst and trophozoite (in a wet mount at 1000x)

55 Life cycle Habitat : large intestine of human, pig, monkey Infective stage : cyst Replication by transverse binary fission or conjugation

56 Clinical Presentation Parasites - hyaluronidase enzyme - degrade intestinal tissue and facilitates penetration of the mucosa - 2 nd infections Asymptomic Symptoms - chronic diarrhea, occasional dysentery (blood or mucus), nausea, foul breath, colitis, abdominal pain, weight loss, deep intestinal ulcerations, and possibly perforation of the intestine (similar to amebic dysentery) Dysentery due to bleeding - shock and death

57 Mucosa of large intestine (cecum and colon) - ulcerations Sigmoidoscopy

58 Treatment Tetracyclines Metronidazole Iodoquinol

59 Public Health Interventions Prevented by improved hygiene practices, water sanitation, and proper disposal of fecal material Asymptomatic carriers should be treated with antibiotics along with symptomatic patients