Intestinal Coccidia

BY: Hanan Mahmoud

Phylum Apicomplexa
Single-celled-
organisms
All are parasitic-
Almost all are intra--
cellular parasites
Anterior end has-
apical complex
i.e:Set of organelles
that allow the
parasite to invade
host cells
 Phylum
Apicomplexa
Most have a complex -
two host life cycle
-Involves several stages that are
morphologically similar
-Asexual and Sexual
reproduction occur in all species
-Zygotes are diploid
but all other stages are haploid
 Generalized Coccidian Life Cycle
Meronts (1N) Gametogony
Schizonts

microgamete macrogamete
(1N) (1N)
Merogony
Schizogony
Microgamete finds and
invades cell containing
macrogamete

Sporozoites Zygote (2N)

Sporogony
(1N) in oocyst Ookinete
(Meiosis)
CRYPTOSPORIDIUM
 TAXONOMY
KINGDOM:Animalia
.Sub-KINGDOM:Protozoa
PHYLUM:Apicomplexa
CLASS:Conoidasida(sporoz
.oa)
SUB-CLASS:Coccidiasina
.ORDER:Eucoccidiida
SUB-ORDER:Eimeriorina
.FAMILY:Cryptosporidae
.GENUS:Cryptosporidium
 Family:Cryptosporiidae
This family contains the single genus-
Cryptosporidium of many species of mammals
( C.parvum,C.felis,C.muris,C.wrairi), birds
)C.baileyi,C.meleagridis(
.Reptiles(C.serpentis),and fishes(C.nasorum)
most human isolates are now referred to as-
,Cryptosporidium parvum
Lack of host specificity is one major characteristic -
that sets C.parvum apart from many of other
coccidia
 Cryptosporidium parvum
Definitive Host: Humans, most mammals
Reported from 150 different mammals species
Has also been reported in chickens and turkeys
.First reported as human parasite in 1975
.Intermediate Host: None
.Geographic distribution: Cosmopolitan
Mode of Transmission: - Ingestion of oocysts in
contaminated water, food less frequently
Oocysts are too small to be filtered out by normal water-
treatment facilities
auto-infection-
mechanical transmission by house flies-
.associated with epidemic diarrhea in institutions and hospitals-
Location in Definitive Host: Invades cells lining the small
.intestines, particularly the ileum

Pathology: Invades and lyses intestinal epithelium cells.

Symptoms: Causes Cryptosporidiosis. Causes severe watery

diarrhea, abdominal cramping, and weight loss.

In immunocompetent patients, the infection is self-limiting,

lasting 1-10 days.

-In young and elderly, infections last longer and are more
severe,Can be deadly.

-in developing countries Cryptosporidium is considered a cause

of diarrhea especially in children below the age of 5 years .
N.b:it should be noted that C.felis (isolated from cats )has been
.reported in AIDS patients
:Most severe in AIDS patients-
Can’t fight infection (cell mediated immunity is thought to-
be the corner stone of immunity against Cryptosporidium
.particularly CD4+cells)

.bowel movements per day 6-25-

.liters of feces per day 1-17-

Parasite may invade other organs causing respiratory-

.infections ,cholecystitis ,hepatitis and pancreatitis

Eventually leads to dehydration, electrolyte imbalance, and-

.death
Morphology: = oocyst round or slightly oval-shaped, 4 – 6um
enclosing 4 spindle–shaped sporozoites
Diagnosis:-
1)Macro-scopic:stool is loose and may be watery.

2)Micro-scopic:

a)Examination of direct smears or after Formol –ether

concentration Technique are specially stained by
Modified Ziehl Neelsen Staining demonstrate oocyst
(red color round or oval bodies –Acid fast )against green
background in feces ,can also be found in doudenal
aspirates and doudenal biopsies.

b) Direct exam. of fresh fecal specimen by immuno-flourescence

Technique(using flourescein labeled polyclonal or monoclonal

Ab) is the method of choice (followed by enzyme
immunoassay),molecular methods are mainly research tools.
N.B:Commercially available diagnostic Kits are used for
detection of cryptosporidial Ag in stool specimen ,it also
offers a highly sensitive method ,even in specimens that
. are preserved

Treatment: Nitazoxamide is effective against

.cryptosporidial diarrhea,including that in AIDS patients

:Prevention
ordinary water systems can’t filter out the oocysts and-
.chlorine does not kill oocysts
.Boiling and freezing below -10oF does kill it-
Outbreaks have occurred in many areas Particularly-
.in the spring
This is another organism that has only become-
.known due to AIDS research
CYCLOSPORA
 TAXONOMY
KINGDOM:Animalia
Sub-KINGDOM:Protozoa
PHYLUM:Apicomplexa
CLASS: Conoidasida
.(Sporozoa)
SUB-CLASS:Coccidiasina
.ORDER:Eucoccidiida
SUB-ORDER:Eimeriorina
FAMILY:Eimeriidae
GENUS:Cyclospora
 Cyclospora

Specie: C. cayetanensis
-one of the medically important parasite recognized today.

-1st infection in human was diagnosed in 1977.

-1986 cases of prolonged watery diarrhea among

immunocompromised (AIDS) patient has been reported
worldwide

-parasite infect vertebrates including reptiles, insect &rodents.

-direct human to human transmission is un-likely.

-recent outbreaks has been blamed on contaminated fresh fruits

Such as raspberries,typically served at social events.
 Pathogenesis:
- infection typically confined to the jejunum charac.
By inflammatory changes, villous atrophy and hyperplasia of
the jejunal tissue.

Morphology:
- oocyst spherical-shaped 8-10um
- mature oocysts contains 2 sporocyst with 2 cresent-
shaped sporozoites.(di-sporocystic,di-sporozoic).
Sporozoite Sporocyt
s Acid Fast
Disease: Cyclosporiasis

- disease is clinically indistinguishable from Cryptosporidiosis and

Isosporiasis

- charac. by persistent watery diarrhea that tends to recur in a

relapsing pattern and last for 3-4 weeks, associated with
abdominal cramps, nausea, vomiting, low grade fever, weight loss
and anorexia

-Infection is typically concentrated in the jejunum ,although in

people with AIDS the bile duct may also be involved .The diarrhea
is usually self limiting in immunocomptent hosts but prolonged in
AIDS patients.
Lab. Diag: -Microscopy of fecal material by modified acid
fast staining or safranin stain(concentration methods should
be used prior to the staining to maximize recovery of
oocysts)
= demonstrate spherical-shaped body of oocyst
-N.B:oocyst autofluoresce under ultra-violet light .(like
Isospora ,unlike Cryptosporidium oocysts)

Acid –fast stain of oocyst

Treatment: Trimethoprim 160mg + Sulfamethoxazole
ISOSPORA
 TAXONOMY
KINGDOM:Animalia
SUB-KINGDOM:Protozoa
PHYLUM:Apicomplexa
CLASS:Conoidasida(Sporoz
.oa)
SUB-CLASS:Coccidiasina
ORDER:Eucoccidiida
SUB-ORDER:Eimeriorina
FAMILY:Eimeriidae
GENUS:Isospora
ISOSPORA:

-Closely related to Eimeria.

-Smaller genus than Eimeria.

-Mostly parasites of birds.

-Isospora belli is the one of the few that is parasitic in

humans.

-previously considered a rare parasite, now known to be

.cosmopolitan in distribution
No intermediate or reservoir hosts,Isospora canis in dogs-

and Isospora felis in cats though more commonly

. distributed are not infectious to man

.Most cases are reported from tropics-

Located in small intestines, causing fever, malaise,-

persistent diarrhea

Can cause death in AIDS patients-

Morphology:
- Oocyst elongate ovoidal-shape
- 20 – 33 um X10 – 19 u m.
- cyst wall double-layered, smooth, thin & colorless
- unsegmented oocyst contains spherical mass of
granule with visible nucleus
- mature oocyst has 2 sporocyst and each contains 4
cresent-shaped sporozoites (disporocystic –
tetrasporozoic).
Habitat:

- intestinal tract probably in the ileum and cecum

Disease: Isosporosis/Intestinal coccidiosis

- mild self-limiting infection charac. by fever, colicky
abdominal pain, severe diarrhea, steatorrhea
(fatty stool) and weight loss, indiacating the inability
of patient to absorb Fat adequately( as in Giardiasis ).
- seen most often in patient with AIDS
- transmitted fecally in contaminated food and drink
with oocyst

Pathology and Symptomatology:

- intracellular development occurs in the intestinal
mucosa (lamina propria) mucosal atrophy
- charac. chronic diarrhea (months to years) abdominal
discomfort, low grade fever
Lab. Diagnosis:
-Demonstration of oocyst in feces by
Formalin – Ether Conc. Technique
(Unstained or Iodine stained)
-Modified Ziehl – Neelsen staining of fecal smear.

TREATMENT- Combination of Sulfadiazine + Pyrimethamine

(very effective).
- Combiantion of Cotrimoxazole (Trimethroprim)
+ Sulfamethoxazole (alternate drug)
Prevention:
= Avoid drinking and eating contaminated food.
EIMERIA
 Family Eimeriidae
.Very large family with several large genera-

.Many are of veterinary and medicinal importance-

There may be as many as 34,000 species in the genus -

.Eimeria alone

parasite of domestic animals and rabbits in which it causes-

.Coccidiosis ,also a parasite of fish

Its medical importance that : It may be found in faeces of -

man as a spurious (coprozoic)parasite passing
unchanged through the human intestine after ingestion
.of infected flesh
.Some hosts have several species at same time-
Eimeria tenella infects intestine of chickens-
Eimeria perforans infects intestine and Eimeria-
. stiedae Infects the liver of rabbits
. Eimeria sardiane infects fish-
.Eimeria gubleri has been reported in human Liver-
.the oocysts are( tetra-sporocystic dizoic)-
SARCOCYSTIS
 TAXONOMY
KINGDOM:Animalia
.Sub-Kingdom:Protozoa
.PHYLUM:Apicomplexa
CLASS:Conoidasida(sporoz
.oa)
SUB-CLASS:Coccidiasina
.ORDER:Eucoccidiida
SUB-ORDER:Eimeriorina
FAMILY:Sarcocystidae
GENUS:Sarcocystis
 Genus Sarcocystis

Speices: S. bovihominis(cattle)
S. Suihominis(pigs)
S. lindemanni

Geog. Dist.: Cosmopolitan

Definitive Host: Carnivores, including dogs and humans

(rarely)

Intermediate Host: Herbivores, including cattle and ducks.

Mode of Transmission: Ingestion of muscle with sarcocyst of

D.H., I.H(cattles and pigs) ingests oocysts in environment.
Disease: Sarcocystosis

- disease uncommon and rare in human

- considered as zoonotic

- domestic animals are intermediate host of the parasite

that pick up infective cyst while grazing on grasses
contaminated with human excreta .

- human infection are acquired through ingestion of

uncooked meat (beef, pork, lamb) or contaminated
food and drink containing the infected sarcocyst

- symptoms includes diarrhea, nausea, vomiting,

abdominal pain which occurs 1 – 2 days after
ingestion and may last for 2 weeks
When humans become infected with sarcocysts of
non-human species, the infections are not
intestinal but rather result in muscle
cysts;symptoms such as myalgia, muscle
weakness and transitory edema may occur.  In
these cases, humans are dead-end intermediate
. hosts e.g Sarcocyst lindemanni
Morphology:
-Oocyst broadly oval lying along infected muscle fibers,
hyaline appearance and enclosed in a membrane .
- contains 2 large sporocyst inside tubular mass (Meischer
tube) filled up with 4 mature cresent-shaped sporozoites and a
refractile residual body.
Lab. Diag.:
-Demonstration of oocyst in feces / duodenal aspirate.

- Biopsy of tissue demonstrate Meischer tube (Sarcocyst).

Treatment:
- None for tissue infection (Supportive – self-limiting)
- For intestinal infection:
Trimethoprim + Sulfamethoxazole
Pyrimethamine + Sulfadiazine (alternate drug)

Prevention:
- Avoid contact with infected animal host
- Adequate cooking of all meat
Species Shape Size Other
features
Isospora
belli

Cryptospori Mature oocyst

contains
dium 4"sporozoites”.
parvum No sporocysts
.are present