Transcript Document

Other Human Amoebae
• Entamoeba dispar/E. hartmanni: Non
pathogenic; anatomically
indistinguishable from E. histolytica.
Entamoeba coli
Trophozoite
Cyst
Nucleus
Entamoeba coli
• Life cycle and location identical to E. histolytica.
Entamoeba coli
• Life cycle and location identical to E. histolytica.
• Most common endocommensal in people; has a
worldwide distribution and 10-50% of the
population can be infected in different parts of the
world.
Entamoeba coli
• Life cycle and location identical to E. histolytica.
• Most common endocommensal in people; has a worldwide
distribution and 10-50% of the population can be infected
in different parts of the world.
• Not pathogenic.
Entamoeba coli
• Life cycle and location identical to E. histolytica.
• Most common endocommensal in people; has a worldwide
distribution and 10-50% of the population can be infected
in different parts of the world.
• Not pathogenic.
• Feeds on bacteria and any other cells available
to it; does not invade tissue.
Other Hosts
Monkeys
Apes
Pigs
10 mm
Trophozoites 20-30 μm in
diameter (15-50 µm)
A
B
C
10 mm
D
E. coli
A
B
E. histolytica
C
10 mm
D
C
Cysts 10-30 μm
10 mm
Entamoeba gingivalis
Habitat: Mouth
Hosts: Humans, other primates,
dogs and cats.
Prevalence is from 50 to 95%.
Stage: Trophozoite, no cyst.
Entamoeba gingivalis
Trophozoite lives on the surface of teeth and gums.
Feed on epithelial cells of the mouth, bacteria, food
debris, and other cells available to them.
Entamoeba gingivalis
Trophozoite lives on the surface of teeth and gums. Feed on
epithelial cells of the mouth, bacteria, food debris, and other
cells available to them.
Organisms are more common in persons with
pyorrhea (gum disease) but they are not the cause of
the condition.
Entamoeba gingivalis
Trophozoite lives on the surface of teeth and gums. Feed on
epithelial cells of the mouth, bacteria, food debris, and other
cells available to them.
Organisms are more common in persons with pyorrhea (gum
disease) but they are not the cause of the condition.
Transmission mouth to mouth, droplet spray, or
sharing eating utensils.
Endolimax nana “The dwarf internal slug”
Trophozoite
Cyst
Nucleus
Endolimax nana
• Second most common endocommensal of
humans, worldwide distribution 30%.
Endolimax nana
• Second most common endocommensal of humans,
worldwide distribution 30%.
• Lives in the large intestine mainly near
the cecum and feed on bacteria; non
pathogenic.
Endolimax nana
• Second most common endocommensal of humans,
worldwide distribution 30%.
• Lives in the large intestine mainly near the cecum and
feed on bacteria; non pathogenic.
• Also occurs in monkeys.
Trophozoites are tiny
6-15 μm in diameter.
Large glycogen
vacuoles are often
present.
10 mm
Mature cyst is 5 – 14
μm in diameter;
contains 4 nuclei;
shape is round to
elliptical
10 mm
Iodamoeba buetschlii
Trophozoite
Cyst
Nucleus
Iodamoeba buetschlii
• Not very common endocommensal in
people.
Iodamoeba buetschlii
• Not very common endocommensal in people.
• Lives in the large intestine,
predominantly in the cecal areas.
Iodamoeba buetschlii
• Not very common endocommensal in people.
• Lives in the large intestine, predominantly in the cecal
areas.
• Has a very high prevalence in pigs; 50%
of pigs are infected with this amoeba in
France and Egypt; pigs are probably its
normal host.
10 mm
Trophozoites are 914 μm long but may
be as large as 20μm
10 mm
E. nana
10 mm
I. buetschlii
Cysts are 6-15 µm
long and have a
large glycogen
vacuole.
10 mm
Dientamoeba fragilis
Trophozoite
No Cyst
Nucleus
Dientamoeba fragilis
• LIFE CYCLE - it does not form cysts
and trophozoites cannot survive passage
through the small intestine.
Dientamoeba fragilis
• LIFE CYCLE - it does not form cysts and trophozoites
cannot survive passage through the small intestine.
• Humans probably get infected by this
endocommensal when they ingest
pinworm eggs!
Trophozoites small
6-12 µm long;
binucleated.
10 mm
Histomonas meleagridis
Cosmopolitan parasite of Birds in the order Galiformes.
Causes a severe and often fatal disease called histomoniasis,
“blackhead” in turkeys.
Only a trophozoite stage present; no cyst:
• trophozoite is irregular in shape
• may appear as an amoeboid form with pseudopodia or a
flagellated form with a single flagellum
You are not
responsible for all
9 topics for this
parasite
Histomonas meleagridis Life Cycle
Transmission is within
the egg of the cecal
nematode of chickens
and turkeys (Heterakis
gallinarum)
You are not
responsible for all
9 topics for this
parasite
Histomonas meleagridis Life Cycle
Transmission is within the egg of
the cecal nematode of chickens
and turkeys (Heterakis
gallinarum)
- trophozoites from the
cecum of an infected
bird are ingested by
the nematode and
invade the eggs
You are not
responsible for all
9 topics for this
parasite
Histomonas meleagridis Life Cycle
Transmission is within the egg of
the cecal nematode of chickens
and turkeys (Heterakis
gallinarum)
-trophozoites from the cecum of
an infected bird are ingested by
the nematode and invade the eggs
- infected eggs of the
nematode are released
onto the soil where
they are eaten by
young birds during
pecking activities
You are not
responsible for all
9 topics for this
parasite
Histomonas meleagridis Life Cycle
Transmission is within the egg of
the cecal nematode of chickens
and turkeys (Heterakis
gallinarum)
- trophozoites from the cecum of
an infected bird are ingested by
the nematode and invade the eggs
- infected eggs of the nematode are
released onto the soil where they
are eaten by young birds during
pecking activities
- as nematode eggs
hatch in the small
intestine, Histomonas
trophozoites are
released to invade the
cecum.
You are not
responsible for all
9 topics for this
parasite
Pinpoint ulcers
Histomonas meleagridis pathology
Habitat of trophozoites: Cecum
Pathology:
You are not
responsible for all
9 topics for this
parasite
Histomonas meleagridis pathology
Habitat of trophozoites: Cecum
Pathology:
Young turkeys are more susceptible to the
infection than are chickens.
Mortality can reach 100% in young turkeys millions of dollars worth of turkeys are lost to this
parasite.
Symptoms
• Infected birds develop
ruffled feathers, dark
skin pigmentation, and
hanging wings and tail
Look at
Mr. Pro
Diver!!!
Hello, The VISIBVILITY IS GREAT!!!!
Steering
Wheel
Matt’s hose
and his
bubbles
This is Matt!! Holding a steering wheel of a sunken boat!! Melissa
took the picture from too far away. Sorry Matt
Amoebic Meningitis
Naegleria fowleri
• Free-living in freshwater and soil including
thermal pools; are bacteriophagous.
• They have even been isolated from bottled
mineral water in Mexico.
Naegleria fowleri Life Cycle
Naegleria fowleri Pathology
• After entering the nose and nasal cavities, the
trophozoites migrate along the olfactory
nerves, through the cribriform plate, and into
the cranium.
Naegleria fowleri Pathology
• After entering the nose and nasal cavities, the
trophozoites migrate along the olfactory nerves,
through the cribriform plate, and into the cranium.
• Amoeboid trophozoites multiply rapidly by
binary fission in the brain and cause rapid
brain tissue destruction.
Naegleria fowleri Pathology
• After entering the nose and nasal cavities, the trophozoites migrate
along the olfactory nerves, through the cribriform plate, and into
the cranium.
• Amoeboid trophozoites multiply rapidly by binary
fission in the brain and cause rapid brain tissue
destruction.
• Symptoms include a headache, fever, neck
rigidity, and mental confusion followed by
coma and death.
Naegleria fowleri Pathology
• After entering the nose and nasal cavities, the trophozoites migrate
along the olfactory nerves, through the cribriform plate, and into
the cranium.
• Amoeboid trophozoites multiply rapidly by binary fission in
the brain and cause rapid brain tissue destruction.
• Symptoms include a headache, fever, neck rigidity, and
mental confusion followed by coma and death.
• Death usually occurs from brain destruction.
Trophozoites are clustered around
small vessels near the brain surface
Primary Amoebic Meningoencephalits (PAM)
Figure 1. A) Computed
tomographic scan: note the
right fronto-basal collection
(arrow) with a midline shift
right to left. B) Brain histology:
three large clusters of amebic
vegetative forms are seen (H-E
stain, x 250). Inset: Positive
indirect immunofluorescent
analysis on tissue section with
anti– Naegleria fowleri serum.
Naegleria in Oklahoma
• Two boys, ages 7 and 9, in Tulsa, Oklahoma, died
from rare parasite Saturday August 5, 2005 from
infection with Naegleria fowleri.
Naegleria in Oklahoma
• Two boys, ages 7 and 9, in Tulsa, Oklahoma, die from rare
parasite Saturday August 5, 2005 from infection with
Naegleria fowleri.
• The two boys were not related, but both came to
their doctors with symptoms of fever,
hallucinations, and headaches, and despite medical
care neither was able to survive the deadly
infection.
Naegleria in Oklahoma
• Two boys, ages 7 and 9, in Tulsa, Oklahoma, die from rare
parasite Saturday August 5, 2005 from infection with
Naegleria fowleri.
• The two boys were not related, but both came to their
doctors with symptoms of fever, hallucinations, and
headaches, and despite medical care neither was able to
survive the deadly infection.
• Of the 200 known cases of Naegleria infection in the
past 40 years, only two people have survived. Only
24 infections were documented in the U.S. between
1989 and 2000. Six confirmed cases in Oklahoma.
Acanthamoeba spp.
At least 5 species of Acanthamoeba have been identified in
human tissues, this is one of the most common amebas in
soil and freshwater.
Trophozoites occur only as amoeboid forms:
Life Cycle Stages
Free-living trophozoites and cysts occur in both
the soil and freshwater.
Acanthamoeba spp.
These species cause 2 pathological effects:
1) Over 100 cases of granulomatous amebic
meningoencephalitis caused by Acanthamoeba
have been documented.
2) Incriminated in a number of cases of
inflammation and opacity of the cornea.
Most of these ocular infections were in contact
lens wearers who used home-made saline.
Symptoms
• Foreign body sensation, severe ocular pain,
photophobia and blurred vision.
• Often pain is more severe than signs in early
course of the disease.
Pathology
• Usually unilateral diffuse punctate
epitheliopathy, dendritic epithelial lesion which
may gradually progress to stromal infection
associated with ring infiltrate formation.
Pathology
• Usually unilateral diffuse punctate epitheliopathy,
dendritic epithelial lesion which may gradually
progress to stromal infection associated with ring
infiltrate formation.
• Enlarged corneal nerve (keratoneuritis) is
pathognomonic of the infection.
Pathology
• Usually unilateral diffuse punctate epitheliopathy,
dendritic epithelial lesion which may gradually
progress to stromal infection associated with ring
infiltrate formation.
• Enlarged corneal nerve (keratoneuritis) is
pathognomonic of the infection.
• Scleritis may be found in advanced cases.
Acanthamoeba spp.
• Management:
– Early diagnosis is a prognostic factor of a
successful outcome.
– Topical anti-amoeba agents.
– Penetrating keratoplasty in a severe
progressive keratitis.