Can asymptomatic mean the body isn’t fighting an infection?

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Questa volta abbiamo cercato una curiosità scientifica:

If something infects the body but doesn’t negatively impact the host, can the host carry the infection indefinitely?

Ed ecco le risposte degli esperti:


Firstly, you have bacteria all over your skin as well as tons of them in your gut called your commensal flora. I guess technically those could be considered nonharmful infections.

As for bacteria not part of the commensal flora, one example is men with prostate problems/chronic catheters. In these individuals you can usually find bacteria in their urine which reside in the bladder. Most of the times, these infections are asymptomatic and from where I am from is usually not treated. In such a case we might call it “bacteriuria” (bacterium in urine) instead of a UTI seeing as there are no symptoms.

EDIT: another example

The herpes virus is also a chronic infection which is usually asymptomatic while your immune system functions normally. How it works is that the virus lives in certain parts of your nerves, and is kept in check by a special kind of immune cell. Sometimes however it might “break out” giving symptoms, the frequency is related to the kind of herpes virus as well as if you have a functional or compromised immune system.

The classic example of this is Mary Mallon aka Typhoid Mary.

She was shedding high enough microbial loads to give an infective dose to others while all the while having no to little ill effects from the bacteria.

Put it this way: most of us are carriers for pathogenic microbes, but are immune system keeps things in check. There are probably incidental amounts of MRSA on our skin or C. diff in our colon. Our body is in a sort of constant state of “base-level” fighting BUT not in acute or chronic stress levels of constant fighting. Things get bad when some factor changes things like taking broad spectrum strong antibiotics for a bacterial lung infection leading to death of normal gut flora and allowing Clostridium to take over. Typhoid Mary’s personal infection was totally controlled. Don’t think about these things when using gym equipment in a large box gym. But basically, if there are a lot of pathogens around, then it mostly comes down to opportunity (Mary not washing her hands and giving folks food OR someone getting a deep cut in their skin).

Things are not usually a 0 or a 1, but a constant state of flux within a limited range. A carrier usually means some one able to have the pathogen replicate enough to make an infective dose while not suffering ill effects. A lot of ill effects are via acute pathways of inflammation. Assuming the body can clear and contain the pathogen, then there is no problem. Things get trickier when we start dealing with dormancy/latency issues where one might be a non-active carrier transition to carrier transition to diseased state.

Edit: typo Marty

Asymptomatic just means not showing symptoms. They could have the infection and not know it. I dont think they know why this virus affects people differently.

Most studies are showing that people do not get it more than once or maintain a chronic or carrier state.

That can happen with other microorganisms, and they were concerned about this.