Final answer:
HSV-1, also known as oral herpes, is a viral infection commonly causing oral lesions like cold sores or fever blisters on or around the lips. It is highly contagious and transmitted through direct oral contact. Although primarily associated with oral herpes, HSV-1 can also cause genital herpes through oral-genital contact.
Step-by-step explanation:
The correct answer to the question 'Which of the following is true of HSV-1?' is b) It is also known as oral herpes. Herpes simplex virus type 1 (HSV-1) commonly causes oral lesions, which are colloquially referred to as cold sores or fever blisters. These are typically found on or around the lips, and the virus is extremely contagious, often transmitted through direct oral contact. HSV-1 can also cause acute herpetic gingivostomatitis. While it is most commonly associated with oral herpes, HSV-1 can also be responsible for genital herpes, especially through oral-genital contact, though this is less common than genital herpes caused by HSV-2.
Additionally, the statement that HSV-1 is caused by a protozoan is incorrect; HSV-1 is a viral infection. HSV-1 is also not directly associated with koilocytes; this term is more often associated with HPV (human papillomavirus) infection. Therefore, the oral herpes option provides the most accurate description of HSV-1.