Which virus is responsible for causing cold sores?

Herpes simplex virus type 1 (HSV-1) is the virus responsible for causing cold sores, also known as fever blisters. These lesions typically appear around the lips and mouth and are characterized by a painful, blistering eruption. HSV-1 is a member of the herpesvirus family and is highly contagious. It is primarily transmitted through direct contact with an infected person's lesions, saliva, or surfaces where the virus is present.

The reason HSV-1 is associated specifically with cold sores lies in its ability to establish latency in the sensory neurons after the initial infection, which can be reactivated by various triggers, such as stress, sunlight, or illness, leading to recurrent outbreaks. Understanding this relationship between HSV-1 and cold sores is crucial in both clinical settings and everyday life, as managing the virus can help reduce the incidence and severity of outbreaks.

Other viruses mentioned have different roles: human papillomavirus is primarily linked to warts and some cancers, influenza virus causes respiratory infections, and varicella-zoster virus is responsible for chickenpox and shingles. Thus, HSV-1 is the sole virus from the list that specifically causes cold sores.