Which description best fits HSV?

The description that best fits herpes simplex virus (HSV) is one or many clusters of small vesicles, which are extremely contagious. HSV typically manifests as painful blisters or vesicles that can appear on or around the mouth (oral herpes) or on the genitals (genital herpes). These vesicles are usually fluid-filled and can break open, leading to sores that can be very uncomfortable.

The contagious nature of HSV is significant; the virus can be easily transmitted through skin-to-skin contact during outbreaks and even when there are no visible symptoms due to asymptomatic shedding. Thus, the combination of the appearance as clusters of small vesicles and the high potential for transmission defines HSV accurately, making this the correct description.