Pathogenic amoebae and ciliate - Chiang Mai · PDF fileGeneral morphology of pathogenic amoebae and ciliate 2. Life cycle of Entamoeba histolytica, ... Extraintestinal amoebiasis :
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Pathogenic amoebae and ciliate
Dr. Narissara JariyapanDepartment of ParasitologyFaculty of MedicineChiang Mai University
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
Classification of Protozoa
Based on locomotive organs :
• Amoebae : Pseudopodia
• Flagellates : Flagella
• Ciliates : Cilia
• Sporozoa : Body flexion or Gliding
pseudopodia
Amoebae
Flagellates
flagella
Ciliates
cilia
.......
.
......
No locomotive organMovement bybody flexion or gliding
Sporozoa
Microsporidia
No locomotive organ
Polar tube for penetrationhost cell membrane
Pathogenic amoeba
Parasitic : Entamoeba histolytica
Free-living :Naegleria fowleriAcanthamoeba spp.Balamuthia mandrillaris
Disease AmoebiasisDistribution Worldwide
esp. tropics
Entamoeba histolytica
Entamoeba histolytica
• Size : 20-30 mm
• 1 spherical nucleus :
- small & central karyosome
- chromatin granules evenly line nuclear membrane
• Finely granular endoplasm
• Rapid movement by finger-like pseudopodia
• Irregular shape
(food vacuoles + RBC)
Trophozoite
chromatin granules evenly line nuclear membrane
finely granular endoplasm
irregular shape
(food vacuoles + RBC)
small & central karyosome1 spherical nucleus
size : 20-30 mm
Rapid movement by finger-like pseudopodia
food vacuoles + RBC
Entamoeba histolytica
round or oval shape
1- 4 nuclei
size : 10-20 um
thin, tough cyst wall
chromatoid bar with rounded ends-Cigar shaped
immature mature
Cyst
Cyst
chromatoid bar
Life cycle
Transmission
By ingestion
of
4 nuclei cyst
I. Intestinal amoebiasis
II. Extraintestinal amoebiasis
Amoebiasis :
Pathogenesis
I. Intestinal amoebiasis :
Asymptomatic cyst passer
Amoebic colitis
Fulminant colitis
Amoeboma , etc.
Amoebic colitis (flask shaped)
Amoebic dysentery
Symptom and sign
tenesmus mucous bloodydiarrhea
fever
water depletion
secondary bacterial infection
Amoebic colitis
Amoebic colitis
Amoebic colitis
rectal biopsy: trophozoite
II. Extraintestinal amoebiasis :
Amoebic hepatitis & liver abscess
Pulmonary amoebiasis
Amoebic brain abscess
Amoebic vaginitis & cervicitis
Amoebic cutis , etc.
Amoebic hepatitis& liver abscess
Most common extraintestinal amoebiasis
- abdominal pain
- fever, diarrhea
- hepatomegaly & splenomegaly
- jaundice
- weight loss
Liver abscess
Amoebic hepatitis
I. Stool examination : cyst & trophozoite
V. Colonoscopy & Sigmoidoscopy
III. Coproantigen detection
IV. PCR techniques
Diagnosis
II. Serological test (ELISA)
Amoebic vaginitis
- Early diagnosis and treatment
- Good sanitation & personal hygiene
Prevention of transmission :
Prevention and control
Pathogenic Free-living Amoebae
Naegleria fowleri
Acanthamoeba spp.
Balamuthia mandrillaris*
cyst
Naegleria fowleri
Amoeboid trophozoite10-12 mmbig karyosome with halo
Flagellated trophozoite1-4 flagella
lobopodium
Naegleria fowleri
Flagellated trophozoite Amoeboid trophozoite Cyst
lobopodia
Naegleria fowleri
Flagellated trophozoite
1-4 flagella
Amoeboid trophozoite
lobopodia
amoebostome
Cyst
ostiole
flagella
Life cycle
Parasites olfactory nerves
Persons with history of swimming
nasopharyngeal mucosa
Brain
CNS infection:
Transmission
Primary amoebic meningoencephalitis : acute
Symptoms : 3-7 days - fever, headache, rhinitis, stiff neck, seizure, coma
Dead within 10 days
Diagnosis
• Culture in NNA seeded with intestinal bacteria
Naegleria fowleri :
• Cerebrospinal fluid examination
• Histosy of swimming
• Brain tissues – autopsy found trophozoiteswith large karyosome, no cyst
trophozoite
Prevention
- Avoid - contact with contaminated water, natural ponds
- Chlorine in swimming pool 1-2 ppm
- Wear nose clip
- Blow nose
Treatment
- Combination anti-microbial therapy: amphotericin B, Azithromycine, rifampin, and azole drugs
- Intensive supportive care – required
- Mortality rate – 100%
Trophozoite
10-20 mm
slow movement
Cyst 1 nucleus
2 layers cyst wall
Acanthamoeba spp.spiky acanthopodia
Cyst 1 nuc. 2 layers of cyst wall
karyosome
Acanthamoeba spp. most common : A. castellani
Trophozoite spiky acanthopodia
Acanthomoeba spp.
Trophozoite Cyst
Transmission
Parasites blood stream- respiratory tract
- skin
- mucosa, etc.
- genitrourinary tract
Brain
Immunocompromised persons
Immunocompetent persons- Eye (corneal) infection:
- CNS infection:
1. Granulomatous amoebic encephalitis(GAE): subacute
Symptoms : fever, headache, neurologic disturbance, seizures
2. Amoebic keratitis (AK)
Clinical features : ocular pain, corneal epithelial breakdown and ringlike corneal infiltrate
Diseases and Symptoms
Mostly in immunocompromised persons
Mostly in healthy persons
Symptoms : foreign-body sensation, pain, tearing, photophobia, blepharospasm, blurred vision
Acanthamoebic keratitis
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
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 diamidinesuch as propamidine (0.1%) or hexamidine (0.1%).
- Duration of therapy may last six months to a year.
Treatment
Prevention- Cautious wearing of contact lens
- Prompt treatment of lesions in the skin, eyes, genitrourinary or respiratory tract
Disease : Balantidiasis, Balantidiosis
Largest protozoa found in human
Worldwide distribution
Trophozoite
• 40-70x50-200 um• Cilia cover around
trophozoite
• 2 nucleus:-- A bean shaped
macronucleus- A less conspicuous
micronucleus
Cyst
• Oval shape• Thick cyst wall
45-75 um
• 2 nucleus:--Macronucleus-Micronucleus
Balantidium coli
Balantidium coli cyst and trophozoite(in a wet mount at 1000x)
Life cycle
• Habitat : large intestine of human, pig, monkey•Infective stage : cyst• Replication by transverse binary fission or conjugation
• Parasites - hyaluronidase enzyme - degrade intestinal tissue and facilitates penetration of the mucosa - 2nd 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
Clinical Presentation
Mucosa of large intestine (cecum and colon) - ulcerations
Sigmoidoscopy
Treatment
• Tetracyclines
• Metronidazole
• Iodoquinol
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
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