Evolution, epidemiology and transmission of infection

Question 1

An association between two organisms in which one benefits and the other derives neither benefit nor harm.

Answer 1

Commensalism

Question 2

Symbiotic relationship in which both species benefit

Answer 2

Mutualism

Question 3

A symbiotic relationship in which one species (the parasite) benefits while the other species (the host) is harmed.

Answer 3

Parasitism

Question 4

What is an endosymbiont? e.g?

Answer 4

An endosymbiont or endobiont is any organism that lives within the body or cells of another organism in a mutualistic relationship with the host body or cell e.g mitochondria

Question 5

Define retrovirus?

Answer 5

A group of RNA viruses which insert a DNA copy of their genome into the host cell in order to replicate, e.g. HIV.

Question 6

What is vertical transmission?

Answer 6

Passage of a disease-causing agent (pathogen) from mother to baby during the period immediately before and after birth.

Question 7

How can vertical transmission occur?

Answer 7

Transmission might occur across the placenta, in the breast milk, or through direct contact during or after birth.

Question 8

What is the incubation period?

Answer 8

The period between exposure and onset of clinical symptoms

Question 9

What is the latent period?

Answer 9

The period between exposure and infection

Question 10

If an infectious disease has a reproductive number of less than one what does this indicate?

Answer 10

The disease will be eradicated from the population

Question 11

If an infectious disease has a reproductive number of one what does this indicate?

Answer 11

Endemic - the disease will stay within the population