Protozoa Flashcards
What is the definition of pathogenicity?
the potential capacity of a particular species of microorganism to cause disease
whats the definition of virulence?
the degree of pathogenicity within a group
What is the feeding stage of coccidia protozoa called?
trophozoite
what is the multiplication stage of coccidia protozoa called?
Schizogony
What is the major species of coccidia which affects poultry?
Eimeria
How is the host infected with eimeria?
Ingesting sporulated oocytes
What does eimeria cause?
inflammation and haemorrhage of caecum
Bloody diarrhoea
What main protozoa is a zoonotic disease?
Cryptosporidium
What does cryptosporidium develop in?
schizonts in the brush border of the stomach
What type of life cycle is eimeria and crypto?
Direct life cycle
What does an indirect life cycle require?
a definitive and intermediate host
sexual stage occurs in difinitive host
What species does toxoplasma gondii affect?
most animals
cats are the definitive host
What problems does toxoplasmosis cause?
abortion and foetal abnormality
What is the toxoplasma gondii life cycle?
intermediate host life cycle cat eats intermediate host sheds unsporulated oocytes over 1-2 weeks oocytes sporulate and become infectious intermediate host ingests oocytes
How does toxoplasma gondii develop in the intermediate host?
Tachyzoites - acute stage of tissue infection
Bradyzoites - slow development in cycts
What are bradyzoites?
Slow growing
comma shaped
found in cysts in muscles/brain
causes chronic toxoplasmosis
What are trophozoites?
Multiply asexually in cells
feed
move around in blood
What is the definitive host and intermediate host of neospora?
Dog - young
cows - intermediate
What does neospora cause?
abortion in cows - intermediate hosts
can cause encephalomyelitis and paralysis in dogs
What is the life cycle of neospora?
calves born infected abortion occurs can also be healthy born and become replacement heifers dogs eat contaminated placenta dogs release oocytes in faeces
What are the hosts of sarcocystitis?
Carnivores - definitive
herbivores - intermediate
What is the sarcocystitis life cycle?
Intermediate host ingests sporulated oocysts
Asexual repro in endothelial cells of intermediate host
Sarcocysts form in muscles
Definitive host eats sarcocysts
sexual repro occurs in lamina propria of gut of definitive host
What is transstadial transmission?
When a pathogen remains with the vector from one life stage to the next
Ticks cant be a reservoir for disease
What is transovarial transmission?
Where there is transmission of an infectious agent from parent to offspring
The tick is a reservoir for disease in absence of disease
