I’ve had HSV-1 my whole life, I’m aware that it has the potential to spread to the genitals and through my paranoia came a question:
Why does the virus have to potential to spread to the genitals and not other areas of the body? Is it the nerves? The tissue difference?? Thank you in advance, tried to google but couldn’t find any straightforward answers
EDIT: Wow. Thank you all so much for your answers, I’ve gone 23 years not knowing a whole lot about HSV-1 and your responses have truly been enlightening! Appreciate you all 🙂
Comments
HSV-1 escapes from the immune system by hiding out within nerve cells, namely the peripheral ganglia. Our nervous system is famously very bad at dealing with inflammation so the evolutionary balance that has been struck is for our immune system to basically ignore the inside of nerve cells.
When outbreaks occur it’s typically only within the innervated area of the ganglia they have infected. But you can always auto-inoculate yourself, i.e. physically spread the infection to other parts of your body.
It CAN spread to other parts of the body. Herpetic whitlow refers to HSV on the hands / fingers, typically associated back in the day before dentists regularly wore gloves. It just isn’t as prone to spreading to areas it’s not designed to infect.
Herpes viruses do transfer to other parts of the body. However, unlike neurons, most other tissues are not immunoprivileged. So when virions do infect other cells in your body, the immune reponse simply kills those cells with the viruses in them.
It also has the potential to ride a facial nerve into your brain and cause hermetic encephalitis. It’s similar to NMDA receptor encephalopathy, with awful hallucinations and feeling like you don’t exist. It’s often fatal.
It’s rare for this to happen. But it can.
Side note: so many people have HSV-1 and don’t know it. You can be asymptomatic your entire life. Your body is usually good at dealing with it, but another disease can weaken you and cause a flare up. This is why chicken pox becomes shingles later in life.
Short answer: you develop immunity that is sufficient to stop infection at a new location (although it won’t evict the original infection).
Edit: I now realize I didn’t answer OP’s specific question, which is more about which parts of the body are susceptible under any circumstances. Other replies covered that nicely. I hope my reply helps OP (and others) feel less anxious about self-transmission, though!
Longer answer: the process you’re talking about is called autoinoculation, and there’s a frustrating dearth of information about it (for HSV). This article is dedicated to the topic, and it still fails to mention that it’s very rare for someone to "give themself" HSV at a second site. When does it happen? Primarily two scenarios: (1) during an initial infection, when the person hasn’t developed antibodies yet, and (2) when the person is severely immunocompromised (this is not a state that you simply wouldn’t notice – you’d be incredibly sick and/or dealing with an actual immune disorder). For the latter case, this article (top-right on page 7) notes that eczema can impair skin’s immune protection, making autoinoculation more common. I welcome additional links on this general topic – resources are scant.
This process of immunity & protection has implications for transmission between people as well. As oral HSV-1 has been in decline, rates of genital HSV-1 have increased in response. I believe this image captures the trend. In retrospect, oral HSV-1 was protecting lots of people from genital HSV-1. If two people both get cold sores, it’s likely neither will ever get genital HSV-1 (low risk of oral-genital transmission).
The real take-home here is that it’s very important to be careful during an initial outbreak of oral HSV-1 (since getting it in your eye or your rectum would be drag). The first three months are the danger zone. After that, it’s very unlikely that you’d give it to yourself, or to anyone else who already has HSV-1 somewhere on their body.
I got my Ph.D. in HSV-1 biology, this is a really interesting question! There have been some really good answers, too, so I won’t re-hash what’s been said about latent, long term infection and recurrence being a result of sensory neurons.
It can infect skin cells, but doesn’t typically infect non-mucosal skin because that skin is protected by a layer of keratin to which the virus cannot bind nor can it infect. This ability to infect skin cells has actually led to the development and approval of an FDA approved treatment for skin cancer using genetically engineered HSV-1!
Typically, the most common secondary location for HSV-1 infection is the eye (which also happens to be enervated by the same ganglia as the lips and mouth). In the United States, for example, HSV-1 is the leading cause of blindness due to an infectious agent.
If you have other questions about HSV-1 I would be happy to answer!
HSV1 is far more common with almost universal infection by late adulthood. It is typically seen on the mouth, but can erupt anywhere it initially makes contact (skin, rectum, lips, etc). It is a far more common cause of genital sores than HSV 2. Episodic recurrences occur anywhere initial contact was made. Either can cause sores anywhere.
Hijacking this, as this is my greatest obsessive fear – what is the realistic likelihood of transference of hsv-1 to another body part? For example, cold sore on lip in blister stage, touch with finger and then touch eye.
Can HSV2 present orally? I’ve gotten cold sores occasionally since teen years (50s now) and have never had any genital issues, but I did the whole slate of tests after getting roofied a few years back and came back positive for both 1 and 2. Could they both be oral?