Final answer:
The nurse should advise the parents to wait for at least 24 hours after all the lesions have crusted over before their child is no longer contagious.
Step-by-step explanation:
The nurse should respond by saying, "Wait for at least 24 hours after all the lesions have crusted over."
Chickenpox is caused by the varicella-zoster virus and individuals are contagious from about 2 days before the outbreak of the rash until all the lesions have scabbed over. Once the fever is gone or the rash appears does not necessarily indicate that the child is no longer contagious.
Source:
Roseola and Fifth Disease, Infectious diseases can be contagious during all five of the periods of disease.