Protozoa Flashcards
Is there any significance for humans in terms of infection with Isospora spp?
No
Infection of the definitive host with Isospora happens how?
Ingestion of sporulated oocysts
Ingestion of paratenic host with cysts in their tissues
Sporozoites of Isospora will encyst in the small intestine and…?
Invade the small intestine where they will divide
Some may penetrate the intestine and get to mesenteric lymph nodes, liver, spleen etc. and form cysts there
Describe the morphological changes of Isospora sporozoites as they develop to their sexual stages.
Sporozoite –> 2 merozoites (these will divide an indefinite number of times) –> multinucleate schizonts (meronts) will form and in time sexual stages will develop
What structure may serve as a source of intestinal reinfection and replapse of coccidiosis in Isospora spp. infections?
Cysts in extraintestinal tissue containing sporozoites
What age of dogs are most susceptible to Isospora canis infection?
Young animals
Adults tend to be resistant but will still act as a source of contamination to the environment
How do dogs become infected with Isospora canis?
Ingestion of sporulated oocysts and tissues of mice, rats etc. that contain cysts
Regarding Isospora canis: Sporulation may be as short as ___ ___ and may survive up to ____ ____ in the environment. Fill in the blanks.
6-12 hours
1 year
Diarrhoea, vomiting, abdominal pain, anorexia, dehydration, weight loss and anaemia in a young, immuno-compromised dog indicates infection with which parasite?
Isospora canis
How would you diagnose an infection of Isospora spp.?
History and detection of oocysts in the faeces of animals with clinical signs
What drugs would you use to treat infections with Isospora spp.?
Toltrazuril (Baycox)
Toltrazuril + Emodepside (PROCOX)
What drugs are registered for use in animals with Cryptosporidium infections?
There are currently no drugs registered for treatment of this infection
What is the correct name for the protozoan parasite known as “smiling face”?
Giardia duodenalis
What are the two lifecycle forms for Giardia duodenalis?
Trophozoite (usually passed in diarrhoeic stools and won’t survive long in environment)
Cyst (usually passed in well formed stools and may survive for several months in the environment)
Where will the trophozoites of Giardia duodenalis locate in the dog and the cat?
Dogs: duodenum and jejunum
Cats: throughout the intestinal tract
How does infection with Giardia duodenalis occur?
Ingestion of cysts with water/food
What is the pathogenesis of Giardia duodenalis?
Enterocyte apoptosis -> shortening of epithelial microvilli -> maldigestion/malabsorption -> increased electrolyte secretion -> fluid accumulation in the lumen -> diarrhoea
What are the diagnosis difficulties associated with Giardia duodenalis?
Intermittent shedding
Cysts might be in small numbers
Cysts small and might be distorted
Clinical signs may precede cyst shedding by 1-2 days
How do you treat infections of Giardia duodenalis?
Fenbendazole, Drontal plus, Oxfendazole, Metronidazole
This genera of protozoa is the most common coccidial parasite infecting dogs and cats. What is it and where does it locate?
Isospora/Cystoisospora
Small intestine
