Answer:
A rise in the level of interferon suggests the outbreak of viral infection.
Step-by-step explanation:
Interferons are antiviral proteins produced in human body and stop the replication of virus thus prevent virus infection. Mechanism: When a virus attack on human body cells, the first part of cell to be affected is nucleus. viral nucleic acid take contol of the nucleus. At this time the genes of the human responsible for interferon production become active they produce chemical which move out from human cell and give signals to neighbouring cell to get ready for future artack by virus. As the progeny of virus attack on neighbouring cells they are faced by interferons which are already produced. In this way interferons protect body cells from virus attack.