Protozoan Diseases- week 4

The two strategies of parasites locating new host

Resistant stage in their life cycle

cysts or spores

Second host

part of the life cycle may occur in an alternative host or vector

Zoonosis

The parasite has an alternative animal host which is able to provide a source of infection for man

Trophozoites

Feeding or infective stages

What is Amoebic Dysentery?

Caused by Entamoeba histolytica

Endemic in warm climates

Associated with poor hygiene and inadequate water supply

Infection with entamoeba

Cyst stage(resistant phase)- ingested food or water with contaminated human decal material

SLIDE 9 CONTINUE

SLIDE 10

Mechanisms of pathogenesis

Infective trophozoites multiply

proteases destroy epithelial lining

feed on erythrocytes and bacteria

Treatments

Metronidazole

Nitroimdazole

Prevention better than a cure

Hygiene- clean water supplies

Destroy waterborne cysts

Chlorination/iodination of water