Final answer:
Septicemia refers to a severe condition where bacteria are present and multiplying in the bloodstream, which can lead to serious health complications.
Step-by-step explanation:
The term that refers to the extent of host involvement when there is growth of bacteria in the blood is Septicemia. While bacteremia simply refers to the presence of bacteria in the blood, septicemia indicates a more severe condition where bacteria are both present and multiplying in the blood, potentially leading to serious health complications. Conditions like septicemia require immediate medical attention as they can progress rapidly and may result in severe illness or death.