A viral organism was isolated from a painful blister on the lip of a girl. The agent was found to double-stranded, linear DNA and was enveloped. Most likely causative organism is:
**Core Concept**
The question requires identification of a viral organism based on its physical characteristics, specifically its genetic material (double-stranded, linear DNA) and its viral envelope. This involves understanding the fundamental properties of different types of viruses, particularly those that cause skin infections.
**Why the Correct Answer is Right**
The correct answer is likely a Herpes Simplex Virus (HSV). Herpes viruses are known to have double-stranded, linear DNA as their genetic material. They are enveloped viruses, meaning they have a lipid membrane surrounding their capsid. HSV is a common cause of painful blisters on the lips, known as cold sores or fever blisters. The virus enters the host cell through the fusion of the viral envelope with the host cell membrane, facilitated by the presence of glycoproteins on the surface of the virus.
**Why Each Wrong Option is Incorrect**
* **Option A:** Although some viruses with double-stranded DNA, like Adenovirus, may cause skin infections, they are not typically associated with painful blisters on the lip.
* **Option B:** Herpesviruses are enveloped, but other viruses like Adenovirus are also enveloped, and they don't typically cause painful blisters on the lip.
* **Option D:** This option is not a valid choice, as the question is missing a corresponding option.
**Clinical Pearl / High-Yield Fact**
Herpes Simplex Virus is a common cause of recurrent skin infections, particularly on the lips, and can be triggered by stress, sunlight, or other factors. Early recognition and treatment can help reduce the severity and frequency of outbreaks.
**Correct Answer:** C. Herpes Simplex Virus.