Protozoa

Question 1

Is there any significance for humans in terms of infection with Isospora spp?

Answer 1

No

Question 2

Infection of the definitive host with Isospora happens how?

Answer 2

Ingestion of sporulated oocysts

Ingestion of paratenic host with cysts in their tissues

Question 3

Sporozoites of Isospora will encyst in the small intestine and…?

Answer 3

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

Question 4

Describe the morphological changes of Isospora sporozoites as they develop to their sexual stages.

Answer 4

Sporozoite –> 2 merozoites (these will divide an indefinite number of times) –> multinucleate schizonts (meronts) will form and in time sexual stages will develop

Question 5

What structure may serve as a source of intestinal reinfection and replapse of coccidiosis in Isospora spp. infections?

Answer 5

Cysts in extraintestinal tissue containing sporozoites

Question 6

What age of dogs are most susceptible to Isospora canis infection?

Answer 6

Young animals

Adults tend to be resistant but will still act as a source of contamination to the environment

Question 7

How do dogs become infected with Isospora canis?

Answer 7

Ingestion of sporulated oocysts and tissues of mice, rats etc. that contain cysts

Question 8

Regarding Isospora canis: Sporulation may be as short as ___ ___ and may survive up to ____ ____ in the environment. Fill in the blanks.

Answer 8

6-12 hours

1 year

Question 9

Diarrhoea, vomiting, abdominal pain, anorexia, dehydration, weight loss and anaemia in a young, immuno-compromised dog indicates infection with which parasite?

Answer 9

Isospora canis

Question 10

How would you diagnose an infection of Isospora spp.?

Answer 10

History and detection of oocysts in the faeces of animals with clinical signs

Question 11

What drugs would you use to treat infections with Isospora spp.?

Answer 11

Toltrazuril (Baycox)

Toltrazuril + Emodepside (PROCOX)

Question 12

What drugs are registered for use in animals with Cryptosporidium infections?

Answer 12

There are currently no drugs registered for treatment of this infection

Question 13

What is the correct name for the protozoan parasite known as “smiling face”?

Answer 13

Giardia duodenalis

Question 14

What are the two lifecycle forms for Giardia duodenalis?

Answer 14

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)

Question 15

Where will the trophozoites of Giardia duodenalis locate in the dog and the cat?

Answer 15

Dogs: duodenum and jejunum
Cats: throughout the intestinal tract

Question 16

How does infection with Giardia duodenalis occur?

Answer 16

Ingestion of cysts with water/food

Question 17

What is the pathogenesis of Giardia duodenalis?

Answer 17

Enterocyte apoptosis -> shortening of epithelial microvilli -> maldigestion/malabsorption -> increased electrolyte secretion -> fluid accumulation in the lumen -> diarrhoea

Question 18

What are the diagnosis difficulties associated with Giardia duodenalis?

Answer 18

Intermittent shedding
Cysts might be in small numbers
Cysts small and might be distorted
Clinical signs may precede cyst shedding by 1-2 days

Question 19

How do you treat infections of Giardia duodenalis?

Answer 19

Fenbendazole, Drontal plus, Oxfendazole, Metronidazole

Question 20

This genera of protozoa is the most common coccidial parasite infecting dogs and cats. What is it and where does it locate?

Answer 20

Isospora/Cystoisospora

Small intestine