Hi Vandemolen,
Herpes virus can be transferred through any bodily fluid, but the location of the infection in the body and the immune status of infected person determines which fluids will contain the viruses. If someone has a herpes simplex (HSV-1 or HSV-2) lesion on the skin and you have direct physical contact with that lesion (and fluid), then the virus can be transferred. Herpes simplex can also be transferred through sweat if the infected person has an outbreak on the skin (see
Herpes gladiatorum). The same is true for varicella-zoster virus (HHV-3, VZV, chicken pox) which is highly contagious. HSV-1 typically infects nerves of the brain that extend to the face and HSV-2 typically infects nerves of the spine that extend to the genitals. However, through oral sex, HSV-1 can be transferred from mouth-lesions to someones genitals/spine, or HSV-2 can be transferred from genital-lesions to someones face/brain.
Only HSV-1, HSV-2 and HHV-3 produce lesions like cold-sores, genital herpes or shingles respectively. The other 3 common herpes viruses do not produce outward physical lesions. These are generalizations, and there can be exceptions to the rule.
Epstein-Barr virus (HHV-4, EBV), Cytomegalovirus (HHV-5, CMV, HCMV) and HHV-6 are transferred most often through saliva (spit, kissing, sharing food). If you are shaking peoples hands that may have bodily fluid on them, remember to wash your hands before putting your fingers on food (eating), in your mouth or
nose. Unlike HSV-1, HSV-2 and HHV-3, the EBV and CMV virus can be contagious even when there are no physical signs of an outbreak or illness. This is how people get
mononucleosis through kissing. CMV can also be transferred from mother to child either in the womb, through saliva or breast milk (
Ref5). Mother-to-child transmission typically only occurs if the mother's immune system has been compromised by stress, a new/acute CMV infection or another infection like influenza. The rise in progesterone during pregnancy can suppress both viral activation and immune response to the fetus.
Herpes prevalence: 99% of all humans are infected with HHV-6 during childhood (
Ref1,
Ref2). 60 to 90% of humans are infected with HSV-1 depending on country/location (
HSV prevelance in the link, see table on the right). 50 to 75% of the world's population is infected with CMV. About 20% is infected with HSV-2 (
HSV prevelance). Usually what happens when a person is infected is that their immune system fights off the virus and removes it from the body before latency (dormancy) can occur. So being acutely infected with the virus does not mean it will remain and become latent in your body for life.
The prevalence of herpes in some African and European nations is higher than the rest of the world partly because pathogens like HIV compromise the immune system of some of these individuals making it easier for them to be infected with other viruses like herpes. We are all probably exposed to different herpes viruses at multiple times in your life, but it is only when you have a compromised immune system that the virus can establish latency. If a virus (or bacteria) does become latent, the immune system is responsible for keeping the virus latent and preventing it from replicating. So maintaining a healthy immune system is important!
In general, herpes is only contagious when an infected persons immune system is weakened (immunocompromised), the virus is activated and is being expelled in bodily fluid. So the vast majority of herpes infected individuals are not contagious. And even if they are contagious, hopefully your immune system can fight off the infection before latency occurs.
Location-specific infections = rare disease: In terms of POIS or any other disease,
the location of the infection in the body is more important than the fact that there is an infection (
post).
When there is no virus outbreak, herpes viruses tend to establish latency in specific locations and tissues of the body. For example, some herpes viruses (HSV-1 and HHV-6) are positively correlated with Alzheimer's disease (
Ref3,
Ref4), but not everyone that has these latent infections gets the disease. It is only when the infection reaches certain parts of the brain (i.e. hippocampus) that these infections become risk factors for the disease.
Many people can have the same virus. But if the location of the infection in the body is different, then the disease (Alzheimer's, IBS, CFS, arthritis, asthma, heart disease, etc...) that manifest will be different.
A hypothesis: I suspect that POIS can result from an infection of the brain vasculature (blood vessels) which are located near the base of the brain near the trigeminal nerve and basal root ganglia. Normally, there is no connection between vasodilation and inflammation. But if epithelial or nerve cells of the blood vessels are injured by infection, then vasodilation (vascular stretching) can cause local inflammation and
vice versa (
post). There are bacteria like
Toxoplasma gondii which have
herpes-like properties and can cause flu-like symptoms when activated. I recently got IgG tested for Toxoplasma gondii and expect to hear back from the lab soon. There is not enough
submitted virus and bacteria test to establish these hypotheses statistically. But hopefully our collective contributions can make a break-through.
