flagellates lec Flashcards
taxonomy of flagellates
subphylum: mastigophora
class: zoomastigophora
intestinal spp:
Giardia intestinalis
Chilomastix mesnili
Dientamoeba fragilis
Trichomonas hominis
Enteromonas hominis
Retortamonas intestinalis
extraintestinal spp:
Trichomonas tenax
Trichomonas vaginalis
One to several long, delicate, thread-like extensions of the cytoplasm.
flagella
- move by whipping back and forth, like a tiny propeller.
- present in the trophozoite stage
- exception: Dientamoeba fragilis does not have flagella; instead, it moves using pseudopodia
What is the exception to protozoa having flagella in the trophozoite stage?
Dientamoeba fragilis – it moves using pseudopodia instead of flagella.
The basal body that anchors the flagellum.
Blepharoplast
A rudimentary mouth-like structure for ingestion.
Cytostome
A rod-like structure providing structural support.
Axostyle
A wavy membrane aiding in locomotion.
Undulating Membrane
reproduction of flagella
asexual
Binary fission or Longitudinal binary fission
types of flagella
Monotrichous – One flagellum at one end of the cell.
Example: Some bacteria.
Lophotrichous – A cluster of flagella at one end, like a ponytail.
Amphitrichous – One or more flagella at both ends.
Peritrichous – Flagella distributed all over the surface.
stages of flagellates
CYST & TROPHOZOITES:
TROPHOZOITES ONLY STAGE:
PATHOGENIC FLAGELLATES:
COMMENSAL FLAGELLATES:
CYST & TROPHOZOITES:
Giardia lamblia
Chilomastix mesnili
TROPHOZOITES ONLY STAGE:
other flagellates exist only in the trophozoite stage
PATHOGENIC FLAGELLATES:
Giardia lamblia
Dientamoeba fragilis
Trichomonas vaginalis
COMMENSAL FLAGELLATES:
other species are non-pathogenic and coexist in the human body without causing disease. [harmless; live in the body without causing illness]
where do the flagellates live, their habitat
digestive system – small intestine, cecum, and colon
*Giardia intestinalis specifically lives in the duodenum (the first part of the small intestine).
life cycle of flagellates
with a cyst stage:
without a cyst stage:
with a cyst stage:
ENCYSTATION - forms a protective cyst to survive harsh conditions
EXCYSTATION - conditions are favorable (inside a host), the cyst breaks open, and the parasite becomes active again
without a cyst stage:
do not form cysts but survive directly as trophozoites
pass through the stomach and external environments
Atrial vs. Intestinal Flagellates
atrial is also known as extracellular intestine
Intestinal flagellates (e.g., Giardia)
have a life cycle similar to amoebas, usually involving both cyst and trophozoite stages.
Atrial flagellates (e.g., Trichomonas vaginalis, which infects the reproductive tract)
do not follow the same cycle as intestinal flagellates and have different life cycle variations.
transmission of both pathogenic and nonpathogenic flagellates
Fecal-oral route (contact with feces or contaminated surfaces)
Contaminated water or food (eating or drinking contaminated substances)
how to distinguish the trophozoites and amoebas
flagella
what can help identify different types of flagellates.
number and position of nuclei
Staining Methods for Identification
Saline – Used to observe the movement of flagellates.
Iodine – Helps stain the flagellates for clearer viewing.
Permanent Stains – Allow for the identification of fine nuclear details and other features of the flagellate.
Giardia intestinalis is also known as
Giardia lamblia
Giardia duodenale
- formerly known as Cercomonas intestinalis
it is the only pathogenic intestinalis flagellates that inhabit in the small intestine
Giardia intstinalis
disease:
Giardiasis
Traveler’s disease
Giardia intestinalis morphology
ppt
Giardia intestinalis life cycle
NATURAL HOST:
man
MOT:
ingestion of mature, viable cyst in contaminated food or H2O
anal oral contact
EXCYSTATION:
can survive stomach acid
REPRODUCTION:
reproduce by binary fission
t stage - large no. of t attach to duodenum and proximal jejunum
(if heavy infections = reach bile ducts and gall bladder)
* do not invade tissue but feed on muscle secretions
ENCYSTATION:
in large intestine, c pass out thru faeces
ENVIRONMENTAL CONTAMINATION AND TRANSMISSION
contaminated flies, fingers, polluted water
improper waste disposal
RISK FACTORS:
poor sanitation
high- risk sexual behaviours in homosexual man
how does the Giardia intestinalis affect the body and its diagnosis
sticks to the wall of intestine causing irritation and inflammation
= excessive mucus production and poor absorption of nutrient (fats and carbs)
may experience:
Diarrhea with greasy, frothy stools (steatorrhea)
Weight loss & weakness due to poor nutrient absorption
Nausea, loss of appetite, and dehydration
Flatulence (gas) with a strong rotten egg smell
Deficiency in important vitamins (Vitamin B12, folate, carotene)
Occasionally, mild fever and chills
DIAGNOSIS
stool test
duodenal content test
entero-string test
biopsy
ELISA
Giardia intestinalis
- epdemiology
- prevention
- treatment
- epdemiology
warm, humid areas, especially in children.
spreads through contaminated water or food
sexually transmitted, especially in men who have sex with men (oral-anal contact). - prevention
Proper disposal of human waste to prevent water contamination.
Avoid using human feces as fertilizer for crops.
Good hygiene practices to prevent the spread from infected individuals. - treatment
Metronidazole (commonly used for adults).
Furazolidone (for children under 5).
Quinacrine hydrochloride (alternative treatment).
this is a commensal parasite that lives in the cecum of man. it has a composition distribution but more prevalent in warm countries than places with cool climate
chilomastix mensili
- does not cause disease
- habitat - cecum of small intestine
- global distribution: more
common in warm climates than colder region
chilomastix masnili morphology
ppt
disease and conditions of Dientamoeba fragilis
Dientamoeba fragilis infection (symptomatic)
- has flagellates characteristics
- used to be group under Rizopoda
Dientamoeba fragilis morphology
ppt
- progressive movement
Dientamoeba fragilis mode of transmission
unknown but may involve nematode eggs (enterobius vermicularis)
possible:
ingestion
inhalation
fecal oral route
oral-anal
person to person route
it is a feature diagnostic for the identification of D. fragilis
Hakansson phenomenon
how does Dientamoeba fragilis affect the body and what can they experience
lives in the large intestine, mainly in the cecum
does not invade tissues but causes irritation and increases mucus production
=
frequent, watery stools with mucus and bowel hyperactivity.
may experience:
Mucoid-watery diarrhea (mucus-filled stools).
Abdominal pain, especially in the lower right side.
Nausea, vomiting, gas, and bloating.
Low-grade fever and fatigue.
Occasional anal itching (not common).
D. fragilis diagnosis and treatment
DIAGNOSIS
examining stool samples:
Iron Hematoxylin stain is preferred to highlight parasite structures.
The parasite is bi-nucleated (has two nuclei) with distinct bead-like chromatin patterns.
Unlike other parasites, it does not ingest red blood cells.
TREATMENT
Iodoquinol (best)
Tetracycline or Oxytetracycline
Paromomycin
Metronidazole (least)
true or false:
Trichomonas species has cyst stage
false - do not have, only have trophozoite form
this disease is prevalent in the philippines, a common STI among women of reproductive age
Trichomoniasis
It describes a karyosome with four bead-like granules.
tetracocci
- suggest incomplete binary fission
*it differs from other intestinal protozoa as it lacks a cyst stage and has a fragmented karyosome.
What is the preferred staining technique for identifying Dientamoeba fragilis?
trichrome staining
Smallest of the trichomonads
Trichomonas tenax
Vincent’s angina
Trench mouth disease
Habitat of the trichomonas species
T. Tenax - oral cavity, tartar between the teeth
T.hominis - decal region of the large intestine
T. Vaginalis - urogenital tracts (vagina, prostate gland)
How long can the Trichomonas Vaginalis survive
Wet sponges - for hours
Urine - more than 24 hours
*it prefers slightly alkaline or mildly acidic environment
Manner of transmission of the Trichomonas species
T. Tenax - droplet spray from infected individuals (share utensils, poor oral hygiene)
T. Hominis - poor sanitation and fecal-oral route
T. Vaginalis - sex or mother to newborn transmission during childbirth, contaminated toilet seats)
This can contribute to infertility, pregnancy complications and increased HIV risk
Trichomonas vaginalis
- this causes Trichomoniasis
Female - vaginitis
Male - epididymitis
