Answer 11: Periods of infectivity
The following infectious diseases are correctly matched to their period of infectivity:
False a. chicken pox: from appearance of rash until the last spot is crusted over
True b. rubella: 7 days before onset of rash until 4 days after onset of rash
False c. mumps: 7 days before salivary swelling until appearance of salivary swelling
True d. scarlet fever: from appearance of rash until completion of 1 day's penicillin
True e. measles: from onset of prodrome until 4 days after onset of rash
Chicken pox: 5 days before rash to six days after last crop.
Mumps: 3 days before until 7 days after salivary swelling.
Whooping cough: 1 week after exposure to 3 weeks after onset of symptoms. The period of infectivity may be shortened by antibiotics.
