10Giadriasis: 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
11Giardiasis: Laboratory diagnosis Stools examination :cysts or trophozoitsExamination of duodenal contents : trophozoites
12Giardiasis: Chemotherapy Drug of choice: Metronidazole
32ENTAMOEBA 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 disparhartmanni coligingivalis polecki
33E. histolytica vs E. dispar Entamoeba histolytica : amoebae that are pathogenic.E. dispar The non invasive form .The 2 amoebae can’t be distinguish by microscopicobservation.
34Entamoeba histolytica Mode of infectionWater, foodFlies can act as vector..Can be sexually transmitted person -to -person contactsNot a zoonosis
35Entamoeba histolytica Life cycleTrophozoite: 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.
36Entamoeba 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 doseCysts can survive for weeks at appropriate weeks at appropriate temperature and humidity.
37Entamoeba histolytica PATHOLOGYIntsetinal amoebiasis :Remarkable and unique ability a to hydrolyse host hosttissues 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. AmoebomaGranuloma obstructing the bowel