4
$\begingroup$
  1. The common cold and [some?] types of influenza are self-limiting. Some microorganisms cause self-limiting diarrhea. Is tuberculosis [potentially] self-limiting or not? To put it another way, suppose that ONLY ONE viable cell of Mycobacterium tuberculosis enters the respiratory system of a healthy human. Will the immune system of that healthy human be able to defeat, on its own, that lone Mycobacterium invading cell? Is the human immune system capable of defeating M. tuberculosis?
  2. If the answer to question number 1 is yes, then my follow up question is this: Is the human immune system capable of defeating, on its own, all other pathogenic microorganisms (bacteria)? How about pathogenic viruses (except HIV)?
  3. As a non-medical professional (although I am a medical enthusiast), I notice that self-limiting viral diseases are more common (both by type and prevalence) than self-limiting bacterial diseases. Is this observation correct?

Edit:

To clarify: Yes Chris, for "self-limiting", i mean an infection that resolves by itself without an external intervention (no antibiotics, antivirals, vaccines, etc.).

I am interested in the [theoretical] capabilities of the [unaided] human immune system. I live in a third world country where pulmonary TB is prevalent. Most of the self-limiting diseases i know are viral, and at this moment, i cannot name a bacterial infection that resolves without antibiotics. Nevertheless, i can't help but wonder why we humans can handle viral infections, but [apparently] not bacterial infections. And this got me asking long ago: is the human immune system incapable of defeating M. tuberculosis? Aside from bacteria that cause diarrhea, what are other examples of bacterial infections which the human immune system can clear on its own? What about fungal infections?

$\endgroup$
  • $\begingroup$ Do you mean by "self-limiting" the fact that an infection comes to an end without an external intervention? $\endgroup$ – Chris Nov 3 '14 at 15:42
3
$\begingroup$

To put it another way, suppose that ONLY ONE viable cell of Mycobacterium tuberculosis enters the respiratory system of a healthy human. Will the immune system of that healthy human be able to defeat, on its own, that lone Mycobacterium invading cell? Is the human immune system capable of defeating M. tuberculosis?

Yes, for example by vaccination you prepare the immune system for recognizing M. tuberculosis. After that it will have a greater chance to defeat the infection. Without vaccination it depends on the genetics, the immune system and the health state of the individual. E.g. starving people are more vulnerable to TBC.

The minimum infectious dose of M. tuberculosis is very low, so it is possible that a single organism can cause infection. Be aware that the infectious dose depends on the type of the disease. So by other diseases your immune system can defeat a large amount of invaders and you don't even recognize it, because you don't get sick.

If the answer to question number 1 is yes, then my follow up question is this: Is the human immune system capable of defeating, on its own, all other pathogenic microorganisms (bacteria)? How about pathogenic viruses (except HIV)?

It depends on the individual. As far as I know for a certain disease some percent of the population is always resistant. Even by HIV about 1% of the population is resistant. I think it is even possible that somebody defeat HIV without special genetic resistance, however this happens rarely, because the minimum infectious dose is very low by HIV too.

As a non-medical professional (although I am a medical enthusiast), I notice that self-limiting viral diseases are more common (both by type and prevalence) than self-limiting bacterial diseases. Is this observation correct?

I guess you mean that diseases with low fatality rate are more common. In western countries this is true, because the healthcare system prevents epidemics of lethal diseases with quarantines. In less fortunate countries I am not so sure about this...

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.