Parasites Focus

Question 1

What is the best knowledge to have about parasites, to aid in their control?

Answer 1

The lifecycle

Question 2

What is the definition of a parasite?

Answer 2

One organism living at the expense of another

Question 3

Can parasite life cycles involve many hosts or vectors?

Answer 3

Yes

Question 4

The host where sexual reproduction occurs is the ________ host

Answer 4

Definitive

Question 5

The host where immature forms develop to sexual maturity is the ________ host

Answer 5

Intermediate

Question 6

Vectors enable dispersal of parasite in dispersed host populations. What is usually the vector?

Answer 6

Flying insects

Question 7

Is a parasite eukaryotic or prokaryotic?

Answer 7

Eukaryotic

Question 8

What are the characteristics of a eukaryotic cell?

Answer 8

Has a nucleus, mitochondria etc

Question 9

What are the 2 types of eukaryotic parasites?

Answer 9

Protozoa (unicellular, like yeast) and Helminths (worms)

Question 10

What are 4 types of helminths?

Answer 10

• Nematoda (round worms)
• Flatworms (flukes, tapeworms)
• Horse hair worms (marine parasites)
• True segmented worms (leeches, earth worms)

Question 11

What is the protozoa that causes malaria?

Answer 11

Plasmodium spp

Question 12

What is the vector related to malaria, related to reproduction and then transmission?

Answer 12

Anopheles mosquito

Question 13

What does malaria do?

Answer 13

• Red blood cell destruction
• Lack of blood to brain tissue
• Death

Question 14

How is malaria diagnosed?

Answer 14

Blood test - find parasite in blood

Question 15

Who is the definitive host of malaria?

Answer 15

The mosquito (because sexual reproduction occurs in the mozzie)

Question 16

How do we prevent malaria?

Answer 16

Remove the vector

Question 17

What am I?
* Caused by eukaryotic parasite (protozoa) subphylum Mastigophora (flagellates)
* I cause diarrhoea
* Simple life cycle - cyst ingested in contaminated water/food > cyst ‘excyst’ & colonize small intestine > cysts passed in faeces > enters water/food
* 2 lifestyle stages
- motile, invasive, actively causes disease
- dormant cyst

Answer 17

Giardia lamblia (intestinalis)

Question 18

What am I?
* Protozoa parasite of cats and related animals
* oocysts transmitted to humans via cat faeces (unwormed cat) or from intermediate hosts that humans eat (undercooked meat etc)
* transplacental migration
* drastic affects on foetus (retardation, blindness, deafness)

Answer 18

Toxoplasma gondii

Question 19

Can helminths spread from human to human?

Answer 19

Yes - round worms can (nematoda)

Question 20

Describe the shape of round worms

Answer 20

Elongated and unsegmented

Question 21

Why is pinworm endemic in Australia, very common in children?

Answer 21

It has a simple life cycle, and eggs are immediately infective

Question 22

What type of helminth is the pinworm?

Answer 22

Round worm / Nematode

Question 23

Ascaris lumbricoides passes from human to environment to human, in conditions where sanitation is not available. Prevalent in PNG, sometimes patients pass adult worms. What are 3 symptoms?

Answer 23

Ascaris lumbricoides causes:
* GIT symptoms
* Bowel/biliary obstruction
* Pneumonia (eosinophilic - Eosinophilia happens when your body produces too many eosinophils. Eosinophils are one of several white blood cells that support your immune system)

Question 24

What is an example of a helminth that requires an animal reservoir to then transmit to a human?

Answer 24

Tapeworms

Question 25

What is the disease caused by the pig tapeworm Taenia solium, that is spread via ingesting undercooked infected pork?

Answer 25

Cysticercosis - lesions that may be cysts or calcified

Neurocysticercosis
* Mass effects/seizures
* Hydrocephalus
* Chronic meningitis
* Spinal cord compression

Other sites
* Cardiac
* Skeletal muscle

Question 26

What are control strategies for parasitic infection?

Answer 26

• If a vector is involved, eliminate the vector
• Stop faecal/oral transmission
• Prevent faecal contamination (waste hygiene, animals {cats!}, humans)
• Inspect meat and cook meat well!