Parasites

Question 1

What is a parasite?

Answer 1

Only organism that lives within or on a host animal to the detriment of that host

Question 2

What is symbiosis?

Answer 2

A long-term interaction between organisms belonging to 2 different species

Question 3

What are physical and chemical effects of a parasite on a host?

Answer 3

Direct tissue damage at the site of infection

Question 4

What are nutritional effects of a parasite on a host?

Answer 4

Direct uptake of host nutrients

Question 5

What resource allocations occur as an effects of a parasite on a host?

Answer 5

Diversions of resources to anti-parasite responses

Question 6

What are physiological and molecular interference effects of a parasite on a host?

Answer 6

Secreted molecules, interfere with host pathways manipulating , signalling, endocrine and immune responses

Question 7

What are immunopyhology effects of a parasite on a host?

Answer 7

Collateral damage from immune responses against the parasite

Question 8

Define what a definitive host is?

Answer 8

In which stages occur that are associated with maturation and sexual reproduction

Question 9

Define what an intermediate host is?

Answer 9

In which immature stages occur

Question 10

What are micro parasites?

Answer 10

Small organisms with short generation times that multiply within their definitive or final host eg-bacteria / virus’s

Question 11

What can the most dangerous form of malaria develop into?

Answer 11

Cerebral malaria

Question 12

What are 2 of the most clinical manifestations attribute to?

Answer 12

1- host inflammatory responses (fever, chills)

2- anaemia (destruction of RBC)

Question 13

What is a malaria fever stimulated by?

Answer 13

•waste products of parasites

•released when RBC breaks up

Question 14

Anaemia results from?

Answer 14

-destruction parasitized RBC

-destruction non-parasitized cells

-inability of body to recycle iron bound to hemozoin

• inadequate formation of new RBC by bone marrow

Question 15

Outline the tapeworm adaptions for surface nutrient absorption:

Answer 15

1) tapeworms produce their own digestive enzymes

2) tegument has carriers for amino acids, purines, sugars and fatty acids

3) tapeworms capture host enzymes such as pancreatic alpha amylase and bind them to the tegument

Question 16

Describe the tapeworm abbreviated metabolic pathway:

Answer 16

Lowered pH of host intestinal fluid

Lowered sugar and fluid absorption by host

Increased sugar uptake by worm

Question 17

What type of host does a tapeworm exploit as?

Answer 17

-definitive host

-intermediate host

Question 18

What are pigs infection by tapeworm through?

Answer 18

Faecal contamination

Question 19

How are humans affected by tapeworm?

Answer 19

Through ingestion of Eggs

Question 20

When does auto-infection occur?

Answer 20

When proglottid transported back to stomach though reverse peristalsis

Question 21

Genus contains two of the best known parasites;

Answer 21

Ascaris lumbricoides-> infects humans

Ascaris suum-> infects pigs

Question 22

What do adult worms have?

Answer 22

3 curved lips,

On the inner edge of each lip is a single row of tiny teeth

Question 23

Where do adult worms live and what do they consume?

Answer 23

Live in small intestine

Consume digesta - feed on host tissues and blood

Question 24

How many eggs can a female worm lay a day?

Answer 24

200,000

Question 25

What are fertilised eggs resistant to and how long do they survive?

Answer 25

Resistant to environmental conditions

Survive 5 years

Question 26

How long does development to the infectious stage lead to?

Answer 26

9-13 days

Question 27

What is transmission for adult worms?

Answer 27

Passive faecal-oral contamination

Question 28

Where do the eggs hatch?

Answer 28

In the hosts intestine

Question 29

What burros through mucosa ?

Answer 29

Larvae burrow through mucosa and enter venous or lumps this circulation

Question 30

How do larvae reach the liver?

Answer 30

Via the hepato-portal blood supply after 24 hours

Question 31

Where do larvae travel and are transported?

Answer 31

Travel through hepatic venules

Transported to the right heart

Question 32

What are 3 pathology distinct points during the life cycle?

Answer 32

1) during migration through the liver

2) migration through the lungs

3) as adults in the small intestine

Question 33

What causes tissue damage and haemorrhages?

Answer 33

Large numbers of larvae moving through the intralobular veins cause haemorrhage and tissue damage

Question 34

What is caused by when larvae penetrate into the air spaces?

Answer 34

Loefflers pneumonia , in several cases this can be fatal

Question 35

What do wondering worms cause ?

Answer 35

Appendicitis

Blockage of the bile duct

Phycological trauma when coughed up or worms attempt to exit via nose

Question 36

Why are ticks important to study?

Answer 36

• global distribution
• no. Of emerging and re-emerging infections continues to increase
• second only to mosquitoes as vectors of human and animal diseases

Question 37

How does tick paralysis occur?

Answer 37

• not caused by infectious agent but by neurotoxin produced in saliva glands

• caused distribution of motor coordination, leading to paralysis

• symptoms appear 5-7 days after whist tick is still attached

• may be depending on number of feeding ticks

Question 38

Outline treatments of ticks

Answer 38

In North America cases- simply removing feeding tick

Removal of I.holocyclus leads to rapid increase in severity or symptoms and possible death

Treatment involves injection with anti-toxin before tick-removal