Evolution and emergence of new viruses

Question 1

What is quasispecies?

Answer 1

-viral genomes are slightly different becuase they evolve while they are in the host

Question 2

What is antigenic drift?

Answer 2

antigens gradually change over a period of time due to pressure exerted by antibodies

Question 3

What type fo viruses don’t show antigenic drift

Answer 3

Rhinoviruses

Question 4

Define zoonosis

Answer 4

A disease which can be transmitted to humans from animals

Question 5

Defne arboviruses

Answer 5

A class of viruses transmitted to humans by arthropods such as mosquitos and ticks

Question 6

What does West Nile virus cause?

Answer 6

• cause diseas by going to the brain
• belongs to japanese encephalitis group of flaviviruses (have single stranded RNA positive sense RNA genomes)
• arbovirus
• The replication cycle involves infection of mosquitoes and birds are the natural host.

Question 7

What is antibody dependant enhancement of the infection

Answer 7

when the antibodies you developed in your first exposure makes you even sicker on a seconary exposure

Question 8

What is SARS?

Answer 8

Severe acute respiratory syndrome

• transmitted via respiratory droplets
• normally found in bats

Question 9

what animal is an important reservoir of coronaviruses that can cross into humans

Answer 9

Bats

Question 10

what can be the source of antigenic variability?

Answer 10

process of
reassortment.

This is a special form of recombination between two different viruses that infect the same cell of the same host.
New virions that result can contain mixtures of genes from each of the parental viruses.

Question 11

what are noroviruses and what do they cause?

Answer 11

small RNA viruses that cause diarrhoea and vomiting.