What do You Call This

I have a personal hypothesis that there are lot of viral and bacterial diseases out there with symptoms mild and/or subtle enough that for the most part people don’t know that they have been infected.

Surely I am not the first person to have this idea.

My question is whether there is a formal name for these sorts of diseases. And if so, what it is.

Weak antigens?

To clarify, you mean bacteria that cause ACTUAL diseases, and not just make up the intestinal/gut/skin/etc flora right?


Yes, but with effects that are not obvious. For example, a venerial disease which simply lowers a man’s sperm count by 10% but doesn’t result in lesions or pain.


I’m pretty sure that this is more or less what the OP is looking for. See Wiki.

Low-grade infection is what I’ve heard in the most layman of terms.

Edit: OTOH, you’re saying no awareness of being infected. So, never mind.

It’s close, but not quite. The thrust of the article is that some people carry around the disease without any ill effects or symptoms and give it to people who have symptoms and ill effects as a result.

What I have in mind is diseases where most (or all) people don’t have obvious symptoms, but most (or all) people with the disease suffer effects which are not obviously the result of an infection.

The term “occult” might be applicable, but even in the strictly medical sense, it’s probably broader than you want.

It’s always been something I wonder about - whether any disease that “magically” appears is triggered by some non-obvious infection - ie does an infection of the artery trigger the buildup of a clot or plaque? Does a low-grade infection of the pancreas or something trigger childhood diabetes? Are various other diseases - Parkinsons, Alzheimers, arthritis, etc. caused by an infection that tricks the antibodies into attacking the body part instead?

It took 6 months to find the AIDS virus when they knew they were looking for something. At this point, we don’t know what we are looking for. The trick with AIDS was that the level of virus was significantly lower than usual number found with truly infectious and lethal diseases.

Yes, I’ve thought of it before. When I or a friend have one of those weeks when we’re just really tired but no other symptoms, I alsways think we’ve got some bug, but our immune systems are winning the fight. Still takes a lot of energy though.

There are lots of diseases like that. Chronic Hepatitis B and Hepatitis C are generally asymptomatic, but eventually cause cirrhosis and/or hepatic cancer (particularly in combination with other risk factors like alcohol and aflatoxin exposure).
Cytomegalovirus is a herpes virus related to chickenpox, and 50 to 80 percent of people in western nations appear to be infected. It was assumed to be harmless except in combination with HIV, but it appears that ongoing viral activity in healthy sufferers consumes T-cells, immune system cells of which we have a limited lifetime supply. CMV positive people appeare to have a 4 year reduction in lifespan due to reduced immunity later in life.
HPV has few external symptoms, but can lead to cancers (cervical, throat).

Stealth viruses, we got them.


Yes I wonder it too. Given that viruses vary a lot in the obviousness of their symptoms, common sense says that there are likely to be viruses out there which are very subtle.

And given that the interests of viruses are frequently in conflict with those of their hosts, it seems likely that a lot of these viruses have deleterious effects.

Yes, this is exactly what I was thinking of. Does this phenomenon have a name besides “stealth virus”?

I don’t see why they would have any special name, because their mildness might be due to the resistance of the host.

I’m thinking of the diseases that caused only mild symptoms in the European colonists a few centuries ago, but were devastating to the Indians.

It also might be a result of the virus’ reproductive strategy being more subtle than that of, say, the common cold.

In any event, I do think that this phenomenon deserves a name. For example, it’s common nowadays for people to have lots and lots of sexual partners. This kind of activity may be a lot more dangerous than people realize.

Viral reproductive strategy is never subtle - infect cell, replicate, burst, lather and repeat. In many cases it is the individual immune system response that decides between acute and chronic, symptomatic and asymptomatic etc.

For example, I got exposed to Hepatitis B when I was a child (at least, under 17). Don’t know where, when or how. My immune system jumped on the virus before it got established, and I did not turn yellow and get sick, as most people with Hepatitis B do. But because my immune system did not have to really kick in and fight a raging infection, the HBV was able to hide in my liver for years. I never got sick, but I never got rid of the virus either. And now I rely on antivirals to prevent my liver getting damaged, and will probably do so for the rest of my life.
Hepatitis C is different, only a few people get immediately ill. Most people develop an asymptomatic chronic infection slowly damaging their liver (along with alcohol and drugs, maybe), so that decades after initial infection, they suddenly end up with acute liver disease, and there is very little time to treat them.

Doctors have a suitable array of terms, most of them already mentioned in this thread - chronic (as opposed to acute), subclinical, asymptomatic, occult, latent, suppressed. All perfectly good terms that describe what you want. Just not overarching. But I do like occult. Occult HBV sounds better then chronic HBV (and suppressed occult HBV sounds even better).


I recall a book review on the analysis of the smallpox outbreak for indians and eskimos on the northwest coast in the later 1800’s - one of the last such big outbreaks. Based on journals of the time, especially missionaries, the author concluded: smallpox was no more lethal in itself to the unexposed locals than to europeans - about 1 in 10 died. What killed them in lage numbers was mass susceptibility. Where there was at least one immune person to tend to the sick (i.e. a missionary, a peviously exposed local), a decent number survived. In a village of subsistence hunters, where everyone became sick at once, the majority died of dehydration and starvation during the fever.

There also seems to be a pattern we see with many diseases. Black death seems to have killed about 1 in 3 or so when it first hit Europe. Later epidemics were nowhere near as bad. Similarly, AIDS in the 80’s usually meant death in a few years; today it seems to be much milder - I guess the less lethal forms are more likely to stick around and infect others.

A virus that manages to “stay under the radar”, cause fewer reactions from the body and perhaps mimic some body cells to avoid being attacked, may go completely unnoticed.

Plus, some things the researchers have an idea what causes something, and don’t look closely at other issues. My favourite example of all this - who remembers that until the 80’s stomach ulcers were believed to be lifestyle and stress related? Then it was realized they were simple infections, and the proper drugs would heal them.

Even if that’s true for smallpox, there were other diseases like measles that were much more lethal to Indians than to the Europeans who carried them.