**Core Concept**
Primary HSV infections, caused by the herpes simplex virus (HSV), typically manifest as oral herpes or cold sores. This condition primarily affects individuals with no prior immunity to the virus, resulting in a localized skin and mucous membrane infection.

**Why the Correct Answer is Right**
Primary HSV infections are primarily self-limiting and not contagious in the classical sense, unlike some other infectious diseases. However, they can be transmitted to others through direct contact with the infected individual's lesions or secretions. The primary mode of transmission is through skin-to-skin contact, particularly during oral-genital or oral-oral contact. Primary HSV infections do not occur as an epidemic due to their non-contagious nature before the appearance of the lesions.

**Why Each Wrong Option is Incorrect**
**Option A:** This statement is true as primary HSV infections primarily affect the anterior portion of the mouth, leading to the formation of cold sores or fever blisters.
**Option B:** This statement is true as primary HSV infections can cause acute gingivitis, which is an inflammation of the gums, often accompanied by pain and discomfort.
**Option D:** This statement is true as primary HSV infections often exhibit prodromal symptoms, which are warning signs that precede the onset of the disease. These symptoms can include tingling or burning sensations in the affected area.

**Clinical Pearl / High-Yield Fact**
It's essential to note that primary HSV infections can be triggered by various factors, including stress, fever, and hormonal changes. This knowledge can aid in the early diagnosis and management of the condition.

**✓ Correct Answer: C. Occurs as epidemic**