Lecture 9 - Parasite Strategies, Life Cycles

Question 1

Mention some ways parasite may invade the body.

Answer 1

• Mouth
• Skin
• Sexual Intercourse
• Via vector/ intermediate host

Question 2

Explain how hookworms (nematode) invade the body.

Answer 2

Larave form penetrate skin into bloodstream, which then carries it to the lungs and airways before moving into the throat. It is then swallowed and the hookworm attaches itself to the intestine.

Question 3

Define intermediate host.

Answer 3

A host that harbors the parasite only for a short transition period, during which some developmental stage (asexual reproduction) is completed

Question 4

Cestode (Exp. Taenia saginata) uses _____ and ______ as intermediate hosts.

Answer 4

pigs and cows

Question 5

Mention some diseases transmitted by insects.

Answer 5

Sleeping sickness: Tsetse fly
Malaria, etc: Mosquito
Leishmaniasis: Sand flies
Bubonic plague: fleas

Question 6

Mention methods in which parasite survive in our bodies. Explain briefly.

Answer 6

• Genetically variable copies
• Avoiding recognition: coating themselves with host antigen protein (exp. Schistosome)
• Variable surface antigens: (exp. Trypanosomes)
• Hide from immune response: hide in cells, releases compounds reducing immune response (exp. tape worms)
• Attack immune system (HIV)

Question 7

Mention strategies of parasites for transmission.

Answer 7

• Exit the body ( faeces/urine/etc)
• free living stages
• using an intermediate host: transport + replication
• Asexual multiplication
• Sexual reproduction

Question 8

Final hosts are where the parasites undergo ________.

Answer 8

sexual reproduction