Intestinal` Protozoa

Giardia lamblia

Giardia trophozoites

( SEM)

Giardia trophozoites

(light microscope)

Giardia trophozoites

(light microscope)

Giardia cyst

(light microscope)

Giardia trophozoites

(light microscope)

Trichrome stainUnstained

Giardia lamblia :

Life cycle

Unstained Trichrome stain

Giardia cyst (light microscope)

Giardia trophozoites in tissue section

Giardia cyst and trophozoites IH stain

Giadriasis: Clinical Picture

Asymptomatic infections ( majority)

Symptomatic Infections:

Typical picture: IP 1-2 wks followed by diarrhoea for about 6 wks,

Atypical : Severe diarrhoea , malabsorption especially in children

Giardiasis: Laboratory diagnosis

• Stools examination :cysts or trophozoits

• Examination of duodenal contents : trophozoites

Giardiasis: Chemotherapy

• Drug of choice: Metronidazole

Intestinal Amoebae

Entamoeba coli

Iodamoeba butschlii trophozoite

Iodamoeba butschlii cyst

Endolimax nana cyst

Endolimax nana cyst

Endolimax nana trophozoite

Endolimax nana cyst

• E. polecki cyst

•E. polecki trophozoite

Entamoeba coli (drawing) Entamoeba coli (Eosin)

Entamoeba coli ( cyst )

Entamoeba coli ( trophozoite)

Entamoeba coli ( trophozoite)

Entamoeba coli ( trophozoite)

Entamoeba hartmanni

Entamoeba hartmanni

Entamoeba histolytica

Entamoeba histolytica

E. histolytica E. histolytica

Entamoeba histolytica

Entamoeba histolytica

ENTAMOEBA HISTOLYTICA…

500 million people are infected. 100,000 deaths per year. Worldwide distribution. It is a waterborne infection.

There are 6 species of Entamoeba:

histolytica dispar

hartmanni coli

gingivalis polecki

Entamoeba histolytica : amoebae that are pathogenic.

E. dispar The non invasive form .

The 2 amoebae can’t be distinguish by microscopic

observation.

E. histolytica vs E. dispar

Mode of infection

Water, food

Flies can act as vector..

Can be sexually transmitted person -to -person contacts

Not a zoonosis

Entamoeba histolytica

Life cycle

Trophozoite: vegetative stage, must encyst to survive in the environment. It is a fragile structure. Pre cyst: encysting trophozoites disgorging any undigested food.

Cyst: infective stage. Resist to the harsh conditions of the environment.

Entamoeba histolytica

The infective dose can be as little as 1 cyst. be as little as 1 cyst.

The incubation period can be from few days to can be from few days to few weeks depending on the infective dose

Cysts can survive for weeks at appropriate weeks at appropriate temperature and humidity.

Entamoeba histolytica

PATHOLOGY

Intsetinal amoebiasis :

Remarkable and unique ability a to hydrolyse host host

tissues with their active cysteine proteases present on the surface membrane of the trophozoite.

Lesions are found in the caecum, appendix, or colon.

They may heal. If perforation of the colon occurs, They may heal. If perforation of the colon occurs,

My lead to a peritonitis that can lead to death. Amoeboma

Granuloma obstructing the bowel

Entamoeba histolytica

PATHOLOGY:Intsetinal amoebiasis :

PATHOLOGY:Intsetinal amoebiasis :

PATHOLOGY : Intsetinal amoebiasis

Complications

Entamoeba histolytica

PATHOLOGY

Intsetinal amoebiasis :

Entamoeba histolytica

PATHOLOGY

Intsetinal amoebiasis :

E. Histolytica in mucosa. in mucosa.

Numerous Numerous

trophozoites can be

seen with ingested seen with ingested erythrocytes.

PATHOLOGY

Intsetinal amoebiasis :

PATHOLOGY: Extra-intsetinal amoebiasis :

Free-living Amoebae

Acanthamoeba in corneal scraping

• Acanthamoeba trophozoite

Acanthamoeba brain

Acanthamoeba

Acanthamoeba ulcer

• Naegleria brain

Cryptosporidium oocysts

Cryptosporidium , safraninCryptosporidium , acid-fast stain

Cryptosporidium , acid-fast stain

Cryptosporidium