Emerging viruses arise by
A) mutation of existing viruses.
B) the spread of existing viruses to new host species.
C) the spread of existing viruses more widely within their host species.
D) mutation of existing viruses, the spread of existing viruses to new host species, and the spread of existing viruses more widely within their host species.
E) none of these.

Question

Quizplus · Accepted Answer

Emerging viruses can arise via mutation of existing viruses, which leads to the emergence of new strains that may have increased virulence or altered host ranges. The spread of existing viruses to new host species can also lead to the emergence of new diseases as viruses adapt to new hosts. Lastly, the spread of existing viruses more widely within their host species can also lead to the emergence of new diseases via increased transmission or a shift in the virus's virulence. Therefore, D is the most comprehensive answer.

Emerging Viruses Arise by