Lecture 4 to 7

Question 1

What are the main features of the protozoa?

Answer 1

• very small - most animals will have one or more species within them

Question 2

How do protozoa acquire food and nutrients?

Answer 2

• enter by pores in the cell wall or by formation of vesicles - solid particles engulfed by pseudopodia or wafted by cilia into the cytosome (‘mouth’)

Question 3

What is the name of the phylum, subphylum, order and family of trypanosoma and leishmania?

Answer 3

Phylum: Sarcomastigophora Subphylum: Mastigophora Order: Kinetoplasdida Family: Tyrpanosomatidae

Question 4

Describe the structure of Trypanosoma:

Answer 4

Elongate, leaf-like with a single flagellum

Question 5

What are the two main hosts that are involved in Trypanosoma?

Answer 5

Insects (specifically the tsete fly) and mammals

Question 6

What is a common feature of all members of kinetoplasdida?

Answer 6

All members have a kinetoplast at the base of the flagellum

Question 7

Fill in the blanks:

Answer 7

Question 8

Name the two different types of transmission that occur in trypanosomes:

Answer 8

Salivarian trypanosomes: saliva to the blood or vertebrate hosts, all of these are transmitted via the tsetse fly vector

Stercorarian trypanosomes: faeces of the insect is transmitted to the bite site of the animal (depends on the animal stratching)

Question 9

What is a symptom of African animal trypanosomosis (AAT) and what is the name of the parasite that causes it?

Answer 9

• T.evansi
• Cause fo surra = weight loss and weakness within cattle
• Involves a fly ingesting trypomastigotes and then the fly transmits it to the blood of a host via metacyclic trypomastigotes

Question 10

What is the principle cause of dourine within horses?

Answer 10

T. equiperdum:

Results in neurological signs and emanciation

Question 11

What is the cause of “chagus” disease?

Answer 11

• T. Cruzi
• Acute swelling/redness at the skin infection site
• Chronic symptoms can include eventually heart failure

Question 12

What are the two basic life stages of Leishmania?

Answer 12

Question 13

Describe the basic life cycle of Leishmania?

Answer 13

1. Sand-fly bites the host and takes up amastigotes in the blood
2. Amastigote becomes a promastigote in the sand-fly
3. Sand-fly bites another host and the promastigote enters a phagosome
4. In the phagosome the sand-fly then becomes a amastigote again
5. Proliferates and causes cell lysis and then enters more cells
6. Taken up by an insect in the blood again

Question 14

What is the name of the parasite that causes Visceral Leishmaniasis and what are the basic symptoms of this condition?

Answer 14

• Leishmania infantum
• Second largest parasitic killer in the world
• Affects many internal organs
• Fever and weight loss result, enlargement of liver and the spleen

Question 15

What are the basic symptoms of cutaneous Leishmaniasis and what is the main parasitic reservoir?

Answer 15

• Lesions at the bite develop into nodules
• Infected dogs are parasite reservoirs

Question 16

What are the basic symptoms of Mucocutaneous Leishmaniasis?

Answer 16

• Caused by Leishmaniasis Braziliensis-
• Form of cutaneous leishmaniasis
• Affects mucous membranes of nasopharyngeal complex

Question 17

Why does the family trichomonadidae not require a cyst stage?

Answer 17

Don’t require a cyst stage as they are always in a comfortable environment.

Question 18

How is trichomonas transmitted?

Answer 18

• drinking water/crop milk

Question 19

What are the symptoms of tritrichomonas?

Answer 19

• early fetal death and infertility
• cats- diaherrea
• genital tract of cattle- vagina of cows, prepuce of bulls

Question 20

What are the basic symptoms of Histomonas and where does the parasite occur?

Answer 20

• Extensive and severe necrosis cecum and parenchyma of liver
• Depression, reduced appetite, poor growth, increased thirst
• Occurs in caeca and liver

Question 21

What are the three different morphological stages of the histomona parasite?

Answer 21

• Amoeboid form- intestinal lumen
• Tissue form- singly or in clusters
• Luminal form- 1-2 flagella

Question 22

Where does the Giardia parasite infect the host and what are the basic symptoms that are involved?

Answer 22

The symptoms include violent diarrhea and GI stress affecting the duodenum. The morphology of giardia includes 2 nuclei, adhesive disk on the ventral surface, 8 flagella (4 pairs) and a cyst phas exists.

Question 23

Explain the basic life cycle of the giardia parasite:

Answer 23

• the parasite loosly resembles casper the ghost
• able to transform into a cyst so that it can survive in the outside environment