2D - Protozoa

Question 1

Protozoa

Answer 1

single cell eukaryotic organisms

Question 2

Cryptosporidiosis cause and disease process

Answer 2

caused by Cryptosporidium parvum
◦ Animals including humans ingest the infective stage, Oocysts, found in food and water contaminated with feces from infected animals
◦ Sporozoites are released from the oocyst and they infect the microvilli of the epithelial cells covering tips and sides of the intestinal villi and live in the space between the cell membrane and cytoplasm
◦ Damage the microvilli → interference with digestion and absorption → diarrhea
◦ Damaged enterocytes are sloughed from the villi and replaced with new cells
◦ Short lived disease

Question 3

Coccidiosis cause and disease process

Answer 3

aused by various species of coccidian protozoa
◦ The organism invades the cell and enters the cytoplasm and multiplies. The release of the organism causes the cell to rupture → damage
◦ Villus cells undergo hypertrophy (cells get bigger) and hyperplasia (replicate and increase in number)
‣ Proliferative enteritis secondary to coccidiosis in a goat (picture from notes)
◦ Coccidian oocytes survive very well in the environment
‣ Under the right conditions of correct temperature and humidity the oocyst sporulate and become infective
‣ Sporozoites are released from the oocyst, invade the enterocyte cytoplasm, replicate
‣ Cell damage occurs when new organisms rupture out of the GIT cells and into the lumen

Question 4

Babeosiosis caused by

Answer 4

caused by protozoan that infects blood
◦ The organism is spread by ticks
◦ Babesiosis caused by Babesia Boris is one of the most important disease of cattle in tropical areas
‣ Has been eradicated from North America
‣ The vector for the protozoa is back
◦ Associated with intravascular and extravascular hemolysis

Question 5

Babeosiosis disease process

Answer 5

‣ The protozoa invades and replicates in the red blood cells causing direct damage to the red blood cells → intravascular hemolysis (RBC’s rupture in the blood vessels)
‣ Or the infected red blood cells may be targeted by the immune system
• Red blood cells that are coated in antibody or slightly damaged are phagocytksed by the macrophages as they pass through the sinusoids in the spleen = extravascular hemolysis
• Leads to anemia and gundis

Question 6

What causes “red water”

Answer 6

‣ Intravascular hemolysis causes release of hemoglobin into the circulating blood → hemoglobin in urine → red urine (red water)
‣ Vaccination against this disease is called blooding
• Not used in the USA

Question 7

How can protozoa also affect the reproductive system

Answer 7

toxoplasmosis, caused by Toxoplasma gondii, during the class on zoonoses
‣ The cat is the definitive host (no clinical signs in a healthy adult)
‣ Sheep are the intermediate host
• May cause abortions in sheep without prior exposure and adequate immune response
‣ Humans are also the intermediate host
• Can cause abortions (early pregnancy) or birth defects
◦ Neospora canine causes abortions in mainly cattle but also in pigs, sheep and goats
‣ The dog is the definitive host
‣ All other animals are intermediate host
‣ Not known to be a zoonosis