why are viruses called obligate intracellular parasites?
Rating Newest Oldest. Best Answer: Viruses are obligate intracellular parasites that can be maintained only inside living cells. Whern we refer to something as obligate that indicates that the virus (in this case) must do or behave in the specified manner. Since viruses are obligate intraellular parasites, the term conveys the idea that viruses must carry out their reproduction by parasitizing a host cell.