OK, so I’m probably using terms wrong. Let me make up an example to try and frame my question.
*Pretend *that AIDS required both HIV and SymbioticViro VIII to be present before it manifested. Most people have SymbioticViro VIII present, so AIDS spreads quickly, but for those who don’t, they do not get symptoms of AIDS.
So: Most people have SymbioticViro VIII - no symptoms.
Some people have HIV - no symptoms.
Only when they have *both *does AIDS manifest.
Has there ever been a disease like that?
Please note: I am NOT suggesting that this is indeed the case with AIDS. I am using this made up scenario as an example of what I’m trying to ask.
Hepatitis D needs hepatitis B to be able to propagate itself, is that the sort of thing you are asking for? wiki link does a decent job of explaining it.
In some ways, AIDS actually does sort of fit your OP, I think.
If you were infected with HIV and then kept in a sterile environment, you wouldn’t have any direct symptoms. It’s only when something else infects you (and gets out of control because your immune system is damaged) that you have a problem.
So, in some sense, having the ‘disease’ of AIDS requires two infections: one to knock out the immune system, and one to do the real damage.
One of the current theories about diabetes is that people with a family history are prone to a virus which attaches itself to the Islet of Langerhans, the outlet ports on the surface of the pancreas which pump out insulin. The body creates antibodies which go through the system fighting this virus and, just to make sure, whatever it’s attached to, which results in fewer (if any) islets, and an insulin deficiency occurs.
By this model, diabetes isn’t technically a disease in and of itself, but rather a condition resulting from an overactive immune system’s attempts to fight off a virus, however, it kind of fits the OP being what many consider to be a disease, which most people only get because they caught something else first.
One of the current theories about diabetes is that people with a family history are prone to a virus which attaches itself to the Islet of Langerhans, the outlet ports on the surface of the pancreas which pump out insulin. The body creates antibodies which go through the system fighting this virus and, just to make sure, whatever it’s attached to, which results in fewer (if any) islets, and an insulin deficiency occurs.
By this model, diabetes isn’t technically a disease in and of itself, but rather a condition resulting from an overactive immune system’s attempts to fight off a virus, however, it kind of fits the OP being what many consider to be a disease, which most people only get because they caught something else first.
By the time you get HIV, you already are host to enough microbes to bring on AIDS. Also, I’m not entirely certain that AIDS is symptom free on its own. AIDS dementia complex
Untrue. HIV can do damage in and of itself; in addition our bodies have microbes in it that normally co-exist peacefully with us. But when the immune system is impaired, these microbes become pathogenic, and cause disease.
Thanks for all the answers. Although I am unlikely to follow up, I had this thought that it might make an interesting plot for a bio-terrorist novel. What if they designed two such viruses and released one. No one would know it because it would not manifest any symptoms. And then after it had spread for to the four corners of the earth, what if they released the other? (Or at least threatened to.)
I of course do not have enough medical background to do justice (and well, probably not enough writing talent) to the concept, but I thought it was an interesting concept.
The first creates a vulnerability – once you start threatening to release the second, and everybody realizes they already have the first they are more likely to take your threat seriously.
There are diseases in which the causal agent is a satellite virus that requires another virus to be present for infectivity. Wikipedia has a page which lists many of them:
There are some applications being explored in which a type of satellite virus called a “virophage” is used for beneficial purposes (gene therapy), e.g.:
It’s not exactly infection of cholera, but rather a virus that got integrated into the cholera DNA: cite that mentions this.
A lot of parasites require to maintain a symbiotic nfection by a certain bacteria called Wolbachia to survive.
