Q 01/05

How long after exposure do influenza symptoms typically begin?

A) About two days

B) A few hours

C) About a week

D) Two weeks

Answer · why

A) About two days

The incubation period runs one to four days, and symptoms usually last two to eight days.

Q 02/05

How many types of influenza virus are there?

A) 2

B) 3

C) 4

D) 5

Answer · why

C) 4

Types A and B cause seasonal epidemics, C causes mild illness mainly in children, and D is found in cattle and pigs.

Q 03/05

Which animals are the primary reservoir of influenza A viruses?

A) Racehorses

B) Aquatic birds

C) Domestic pigs

D) Fruit bats

Answer · why

B) Aquatic birds

Ducks, geese, shorebirds and gulls carry them; the virus also circulates in pigs and marine mammals.

Q 04/05

Which type lives mainly in cattle and pigs and is not known to cause human illness?

A) B

B) C

C) A

D) D

Answer · why

D) D

It was only discovered in 2011 and is distantly related to type C.

Q 05/05

In the subtype name H1N1, what does the H stand for?

A) Haemagglutinin

B) Histocompatibility

C) Helicase

D) Haemolysin

Answer · why

A) Haemagglutinin

The N is neuraminidase; both are proteins in the viral envelope.