Intestinal Protozoa Giardia lamblia Giardia trophozoites SEM Giardia

Intestinal` Protozoa

Giardia lamblia Giardia trophozoites ( SEM) Giardia trophozoites (light microscope)

Giardia trophozoites (light microscope)

Giardia cyst (light microscope)

Giardia trophozoites (light microscope) Unstained Trichrome stain

Giardia lamblia : Life cycle

Giardia cyst (light microscope) Unstained Trichrome stain

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 trophozoite Endolimax nana cyst

• E. polecki cyst • E. polecki trophozoite

Entamoeba coli (drawing) Entamoeba coli (Eosin)

Entamoeba coli ( cyst )

Entamoeba coli ( trophozoite)

Entamoeba hartmanni

Entamoeba histolytica

Entamoeba histolytica

E. 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

E. histolytica vs E. dispar Entamoeba histolytica : amoebae that are pathogenic. E. dispar The non invasive form. The 2 amoebae can’t be distinguish by microscopic observation.

Entamoeba histolytica 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. The incubation period can be from few days to few weeks depending on the infective dose Cysts can survive for weeks at appropriate temperature and humidity.

Entamoeba histolytica PATHOLOGY Intsetinal amoebiasis : Remarkable and unique ability a to hydrolyse 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, My lead to a peritonitis that can lead to death. Amoeboma Granuloma obstructing the bowel

PATHOLOGY: Intsetinal amoebiasis :

PATHOLOGY : Intsetinal amoebiasis Complications

PATHOLOGY Intsetinal amoebiasis : Entamoeba histolytica

PATHOLOGY Intsetinal amoebiasis : E. Histolytica in mucosa. Numerous trophozoites can be seen with ingested erythrocytes.

PATHOLOGY: Extra-intsetinal amoebiasis :

Main Drugs for Treatment of Amoebiasis • Intestinal : – Asynpromatic (cysts only): diloxanide furoate (Furamide) – Sympromatic(cysts and trophozoites): metronidazole • Extra-intestinal: – Metronidazole

Free-living Amoebae: Naegleria fowleri and Acanthamoeba

Acanthamoeba keratitis • Patient upon presentation with Acanthamoeba keratitis. No severe pain was experienced by this patient, which made diagnosis difficult