00:01
Cyclospora. A parasite.
00:04
The Cyclospora are also in
the genus of Eimerildae family,
Say that three times fast.
00:10
And if you've watched the session
on isospora,
you'll see a lot of similarities.
00:15
In fact, these all behave
exactly the same.
00:18
The Cyclospora are also
a coccidian protozoan parasite,
such as you see on the image
in front of you.
00:25
A very densely-walled
structure for a parasite.
00:30
The Cyclospora undergo a
fecal-oral spread of the oocysts
for their transmission,
very much like most of the parasites
that we talked about.
00:39
So they come from dirty
or contaminated water
and are ingested by their host.
00:45
Incubation after that ingestion
typically is for 2-11 days,
depending probably on the load
the amount of Cyclospora oocysts
that are ingested.
00:56
The typical human pathogen
that we talked about
is Cyclospora cayetanesis.
01:02
Say that three times fast as well.
01:14
So, if you will,
if you haven't already,
I urge you to do so.
01:18
But to look at several slides
from the isospora lifecycle,
because we'll describe
the same process here,
but in bullet form.
01:28
So the oocysts are ingested
and assist
sort of excysts itself.
01:34
It opens up to release
two sporozoites.
01:36
These attach as a
primary infection stage
to the brush border
of epithelial cells
in the gastrointestinal tract.
01:45
Next, those intracellular spores.
01:48
So they enter into the cytoplasm
of their target cell.
01:52
They undergo asexual reproduction
to create merozoites.
01:56
The merozoites excyst.
01:59
So they exit or lyse
their host cell,
creating a first stage
in inflammatory reaction,
and then autoinfect.
02:08
So within the lumen of the gut,
they will then target
another epithelial cell,
enter the cell,
the cytoplasm of the cell,
and then go to sexual reproduction,
to create first zygote,
and then together
and another oocyst.
02:22
The oocyst,
then ruptures that host cell.
02:26
So that's two rupture steps,
two lytic steps
after the asexual, and then after
the sexual reproduction stages,
and the cysts will either
passage into the stool
or potentially autoinfect again,
further down the intestine.
02:41
So the system cells undergo
a sporulation step
outside the human body.
02:47
So it's not our problem, although,
we've already had plenty of problem
with the initial stages
of inflammation,
but ultimately,
the cysts then become infectious,
contaminating the water
and another host or another victim
can become infected.
03:03
So diagnosis for Cyclospora
is to demonstrate presence
of the oocysts in stool.
03:10
And it's important
and somewhat difficult
to distinguish the appearance
of those cysts
from other possible pathogens,
especially including
Cryptosporidium parvum.
03:21
There are then
clinical manifestations
which are important to distinguish,
although believe it or not,
they are very much like other
parasitic gastrointestinal
infections.
03:31
So because of the
rupture of the cells,
there is ongoing
sort of scarring of the tissues,
and the gastrointestinal
epithelial cells
lose the ability
to absorb water and nutrients
as well as they did.
03:45
So the diarrhea associated
as with others, is watery,
it's a water loss
malabsorptive diarrhea,
and it also is associated
with loss of fat and some protein.
03:59
Now, as with other parasites,
there are still
normal bacterial flora,
which are able to process
this new load of food.
04:08
And so one gets gas production,
crappy abdominal pain, bloating,
and because of loss of appetite
and malabsorption, weight loss.
04:17
So there is a flatulence
along with the nausea and fatigue.
04:21
Low-grade fever
is really a byproduct
of this low level
inflammatory reaction to
to sequential epithelial cells
being ruptured
by the process of the parasite.
04:33
Treatment.
04:34
Well, fortunately, Cyclospora
infections are usually self-limited,
lasting up to 10
to maybe 14 days at the most.
04:42
So treatment
could be just supportive.
04:45
So providing fluids,
providing nutrition,
and then providing
lots of comfort and solace.
04:51
For those severe cases
that are not getting better
and certainly for those patients
who are immunocompromised
in any way,
then use of a sulfonamides,
such as
trimethoprim-sulfamethoxazole
is effective.
05:04
So cyclosporiasis or Cyclospora-associated
gastrointestinal disease
is another nasty
associated with contaminated water.
05:14
The key things to remember about
this particular parasite
are that it is coccidian in nature
and it undergoes both asexual
and then sexual replication steps
with autoinoculation
or autoinfection
occurring in between.
05:28
Again, watch what you drink.