Parasitology

Question 1

List & describe 2 types of hosts (in parasite relationships)

Answer 1

1. Definitive host: animal where parasite develops into adulthood &/ undergo sexual REPRO. phase
2. Intermediate host: short-term host (parasite not grow till adult & NO repro.)

Question 2

Give e.g. of geographical factors affecting the distribution of parasites

Answer 2

• Climate
• Soil type
• Coprozoic organisms (digest poo e.g. earth worms)
• surface water
• vegetation

Question 3

Give e.g. of socio-economic factors affecting the distribution of parasites

Answer 3

• Housing
• Coprophagic animals
• Urbanisation
• Economic activities
• Domestication of animals
• Migration, war, tourism

Question 4

What is a common name for Enterobius vermicularis (& the type of parasite it is)?

Answer 4

Pinworm or thread worm (nematode= roundworm)

Question 5

What stage & location does the eggs of Enterobius vermicularis become infective?

Answer 5

when eggs have been outside the body, in perineal area (in b/w anus & genital organ), for 4-6hrs

Question 6

Which protozoan parasite is responsible for causing diarrhoea, mucous secretion, flatulence & foul & pale stools (fat malasorption)?

Answer 6

Giardia lamblia

Question 7

What’s the definitive host for Taenia saginata & T. solium?

Answer 7

Humans

Question 8

What’s the intermediate host for Taenia saginata & T. solium?

Answer 8

T. saginata: beef

T. solium: pork

Question 9

List 5 ways parasite can harm host?

Answer 9

1. mechanical inquiry
2. Obstruction
3. produce metabolic products = toxic to host
4. competing w/ host for nutrients
5. Host IR when parasite dies = inflammation

Question 10

List 4 ways parasites may gain entry from host

Answer 10

• Oral (bc poor food hygiene)
• percutaneous (penetrate through soft skin
• Inhalation (of eggs)
• Sexual intercourse
  ~ Intraplacenta (applicable to bact.)

Question 11

Types of parasites

Answer 11

• Helminths (worms)
• Protozoa: single-cell eukaryotes (e.g. malaria)
• Arthropods (e.g. ticks, mites)

Question 12

List the types of helminths & give e.g. of each (Genus species) (3)

Answer 12

1. Platyhelminths (flatworms):
   - Trematodes (flukes): Schistosoma mansoni, S. haematobium, S. japonicum
   - Cestodes (tapeworms): Taenia saginata, T. solium
2. Nematodes (roundworms): Enterobius vermicularis

Question 13

Host/s of Schistosoma haematobium?

Answer 13

Intermediate: water snail

Definitive host: humans

Question 14

Symptoms of Schistosoma haematobium?

Answer 14

• fever, abdominal pain, diarrhea

Question 15

What are the (infective &) diagnostic stages of Schistosoma haematobium?

Answer 15

(Infective: released from snail -> penetrate through skin)

Diagnostic: eggs in faeces

Question 16

What are the infective & diagnostic stages of Taenia sp.?

Answer 16

Infective: egg bound to muscle of pork/beef
Diagnostic: eggs / “pregnant” proglottid (section of worm)