Biological Sciences 318- Parasitology Lab
Professor:
Carl Lowenberger (clowenbe@sfu.ca)
Office SSB 6121
tel 2-3985
Laboratory SSB 6151
tel 2-4391
Lab Instructor
Tammy McMullan (tmcmulla@sfu.ca)
Office BISC 9241
tel 2-3983
TA
Sharra Farivar (sfa19@sfu.ca)
Contact via email is best: please put BISC 318 in the subject line and
indicate you are a student in the course!
Organization
Handout Materials:
Lab handout materials will be posted on Sunday/Monday before each lab. YOU
should print it out and bring it to the lab.
Lab book! Keep your notes for review, for exam preparation, for the future, or
just to get a good mark. Follow standard procedure for lab notes.
Time schedule ONLINE
LAB 1: Parasitic Protozoa
- Different stations with slides
- Only 1 slide per person at a time.
- Don´t break your slides!!!!!
- All organisms of today´s lab will be studied under oil immersion.
- Clean your slides with glass cleaner after using them!
- Don´t give up! It is difficult to recognize and identify today´s samples.
Lab Evaluation
Grading:
Lab exam 1
Lab exam 2
Participation: class and lab
Group Presentation
10%
10%
5%
10%
Total
35%
Group Presentation
Each lab will contain 24 students. We will break you up into groups of 4. Each
group will choose a parasitic disease not covered in the course. The group will
present a 20-30 minute presentation on the problems associated with this
parasite and disease and based on this course, other courses, and readings,
propose what might be done differently from current strategies to
reduce/eliminate problems and suffering from with this parasite. Presentations will
be made in the lab sessions in the week of March 24 (subject to change).
Protozoan Parasites
What are Protozoa – Protista?
• Single-celled eukaryotes
• Some have >1 nucleus during all or part of their life cycles
• ~ 5 - 250 µm
Largely recognized after the development of microscopes
van Leeuwenhoek described all sorts of protozoa
• many form cysts (protection)
• invaded every ecological niche imaginable
• nearly every species of metazoan has a complement of protists living in it
Protozoa represent a unique type of evolution
Organelles are cellular elaborations performing the
same functions as tissue and organs in “higher
organisms“
• Locomotion and feeding: cilia, flagella, pseudopodia
• Osmoregulation: pulsatory vesicle, contractile vacuole
• Infraciliature: coordinating system of cilia
• Rhoptries: penetration of cells (Apicomplexa)
• Cell covered in 3-layered Plasma membrane
Giardia lamblia
Kingdom I Archetista (Archezoa)
Phylum Metamonada
Order Diplomonadida
Amitochondriate flagellated protozoan
Bilaterally symmetrical
Most primitive eukaryotes in existence
Organism and Disease Associations
Giardia lamblia, Giardia duodenalis, Giardia intestinalis
Giardiosis (back-packers diarrhea), beaver fever (but no fever)
Hosts and Host Range
Humans, dog, cats, beaver (reservoir), coyote, cattle
Geographic Distribution and Importance
Cosmopolitan
Most commonly reported human intestinal parasitic infection
Sporadic individual infections / epidemic form (drinking water)
Morphology
Trophozoite (motile, active feeding stage; vegetative stage)
BB
N
is pear shaped, 10-20 µm long, 7-10 µm diameter
AD
8 flagella
MB
A
PF
Binucleate - both nuclei are transcriptionally active
2 rigid median bodies
No mitochondria, peroxisomes, hydrogenosomes or other subcellular
organelles for energy metabolism
Anterior region contains structure for attachment to epithelial cells
Structure is maintained with tubulin and giardins (calcium binding
annexins)
Surface is covered with cysteine-rich molecules
Cysts (protective, infective stage)
N
A
F
ellipsoid
excyst in response to physiological / environmental stimuli
Following a series of stimuli: acid, pancreatic enzymes
CW
Motile parasite divides into 2 binucleate parasites
Morphology
Slide: Giardia lamblia
trophozoite:
This parasite is generally teardrop shaped with two visible
nuclei.
If you use the fine focus knob to
focus in and out on the parasite
you will be able to see the
bi-lobed adhesive disc (smiley
face).
BB
N
AD
MB
A
PF
Theory
N
A
F
CW
Practice
Slide: Giardia lamblia cyst:
Giardia cysts are slightly
smaller than trophozoites and
have 4 visibly distinct nuclei.
A median rod, known as an
axostyles, is often visible down
the centre of the organism.
Life cycle
 direct
1. Cyst
2. Cyst ingested, swallowed
3. Excysts in duodenum, trophozoites
attach to epithelial cells in small
intestine
4. Division: Binary fission
5. Form cysts  feces
Pathogenesis
Tissue: small intestine
Nausea, Diarrhea (> 7 days), weight loss, Steatorrhea, Malabsorption
Diagnosis
ELISA
Microscopic examination of stool
trophozoite
cysts
Trichomonas vaginalis
Kingdom II Euprotista
Phylum Parabasalia
Order Trichomonadida
Nearly all parasitic
Small flagellates
Only exist as trophozoites
Organism and Disease Associations
Trichomonas vaginalis
Trichomonad vaginitis or Trichomoniasis in women
Hosts and Host Range
Humans (men & women)
Geographic Distribution and Importance
Cosmopolitan
Prevalence of infection of 10 – 25% among women
Estimated 7.4 million new cases occur each year in women and men (CDC)
Men asymptomatic
Morphology
Oval and flagellated
Basal body
Nucleus
Undulating membrane
Axostyle
Terminal flagellum
Karyomastigont apparatus:
• anterior tuft of flagella
• axostyle
• parabasal body (equivalent of GA)
• costa
• costal granules (hydrogenosomes energy metabolism)
• nucleus
Life cycle
1. Trophozoite
2. Binary fission
3. Direct transmission through sexual
intercourse (no cyst stage)
Pathogenesis
Remain and multiply in vagina and cause inflammation of the epithelium.
excessive production of mucus; pain. Can invade other organs such as
kidney
Diagnosis
Microscopic examination vaginal swab, urethal swabs
Entamoeba histolytica
Entamoeba coli
Kingdom II Euprotista
Phylum Rhizopoda
Order Entamoebidae
Amoeba: organism that moves and feeds with pseudopodia.
Parasites (E. histolytica) or commensals (bulk; E. coli) of digestive
system.
Organism and Disease Associations
Entamoeba histolytica
Amoebiasis, amoebic dysentery
Hosts and Host Range
Mainly humans
But: higher primates, dogs, cats and some rodents
Geographic Distribution and Importance
Cosmopolitan
50 million cases of invasive amoebiasis annually
50000 – 100000 deaths
3rd most common cause of parasitic death in the world
Morphology
Slide: Entamoeba histolytica
trophozoite: Trophozoites are
round with large lobular
pseudopodia and a clock-face
nucleus. The nuclear endosome
is typically (but not always)
centrally located.
You may see erythrocytesin in
the cytoplasm, indicating
digestion of erythrocytes.
GE
E
N
En
P
Theory
4N
En
Practice
Slide: Entamoeba histolytica
cyst: Cysts are smaller
than trophozoites. They contain 4
nuclei and chromatoid bars
(tightly packed messenger
RNA with rounded ends).
Morphology
Species 2: Entamoeba coli: Another species that occurs in the intestine of humans. It is a
harmless commensal of the human large intestine, but looks similar to Entamoeba histolytica.
Therefore it is important to be able to distinguish between these two forms.
Slide: Entamoeba coli
trophozoite: distinguished from
E. histolytica by its coarser
chromatin, eccentrically located
endosome and the absence of
erythrocytes in the cytoplasm.
N
En
Theory
8N
Practice
Slide: Entamoeba coli cyst:
E. coli cysts contain 8 nuclei
(compared to 4 nuclei seen in E.
histolytica) and smaller chromatid
bodies that are often filamentous.
Life cycle
1. Cysts and trophozoite in feces
2. Direct transmission; Ingestion of
mature cysts
3. Excystation in small instestine
4. & 5 Tetranucleate amoeba divides
into four amoebas which are carried
to the large intestine.
Pathogenesis
Tissue: large intestine (colon, cecum)
Amoebic dysentery, erosion of mucosa and coating of the epithelium in the
intestine, invasion of tissue causing flask-shaped ulcer
 can reach the bloodstream
can finally result in peritonitis (bacteria reach abdominal cavity)
Diagnosis
Microscopic examination of stool
Balantidium coli
Kingdom II Euprotista
Phylum Ciliophora
Family Balantidiidae
Largest protozoan parasite of humans
Heterokaryotic (i.e. two kinds of nuclei)
Conjugation (temporary union of individuals and interchange of
genetic material)
Only member of its phylum known to be pathogenic to humans
Organism and Disease Associations
Balantidium coli
Balantidiosis and balantidial dysentery
Hosts and Host Range
Humans, other primates, swine
Geographic Distribution and Importance
Cosmopolitan
Balantidiasis in humans is common in the Philippines, but it can be
found anywhere in the world, especially among those that are in
close contact with swine
Morphology
Slide: Balantidium coli
trophozoite: trophozoites are
oblong with a prominent kidney
shaped macronucleus and a
smaller micronucleus. B. coli is
uniformly ciliated over its body
but this is rarely visible on these
slides.
FV
C
MiN
MaN
M
Theory
N
MiN
MaN
CW
Practice
Slide: Balantidium coli cyst:
cysts are round with a rounder
and thicker macronucleus.
Life cycle
1. Cyst
2. Cyst ingested, swallowed
3. Excysts, Trophozoites
4. Division: Binary fission in small
intestine. Trophozoite then colonize
the large intestine, where they live in
the lumen and feed on the intestinal
flora. Some trophozoites invade the
wall of the colon using proteolytic
enzymes and multiply, and some of
them return to the lumen.
5.
Form cysts  feces
Pathogenesis
In acute disease, explosive diarrhea may occur as often as every twenty
minutes. Perforation of the colon may also occur in acute infections which
can lead to life-threatening situations.
Diagnosis
Microscopic examination of stool
trophozoite
cysts
Giardia lamblia
Trophozoite
Trichomonas vaginalis
Cyst
Learning Objectives
1.Know general featrues of protozoans
2.Order Diplomonadida
- Visual ID Giardia lamblia – cyst + troph
- Life cycles and roles of cyst + troph
- Anatomy of troph + cyst
- Transmission: from who, how, what stage, to who
- Tissue where it is found
- Pathology = symptoms and disease
3.Order Trichomonadida
- What makes them special? (2 things)
- Visual ID Trichomonas vaginalis
- Life cycle, anatomy and transmission
4.Order Amoebida, Family Entamoebidae
- How do they move
- Visual ID Entamoeba histolytica and Entamoeba coli (trophs + cyst)
- be able to visually differentiate between the two species
- how do they differ in other ways
- Life cycle, Transmission, Epidemiology, Pathology
5.Phyllum Ciliophora, Family Balantidiidae
- Visual ID Balantidium coli troph + cyst
- What makes B.coli special
- Life cycle, Pathology
- Host, Tissue , Transmission
Vocabulary
Protozoan
Trophozoite
Cyst
Giardiosis
Flagella
Axostyle
Amoeba
Pseudopodia
Pathology
Transmission
Epidemiology
Erythrocyte
Erythrocytosine
Cilia
Commensal
Pathogenic
Endosome
Ulcer