# Has there ever been a disease that required two viruses to manifest? **URL:** \ **Category:** Factual Questions\ **Created:** [September 4, 2008, 4:57pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016 "2008-09-04T16:57:20Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [September 4, 2008, 4:57pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/1 "2008-09-04T16:57:20Z")
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. ---
**Author:** ![Cub\_Mistress](https://avatars.discourse-cdn.com/v4/letter/c/ea666f/32.png) [@Cub\_Mistress](https://boards.straightdope.com/u/Cub_Mistress)\ **Post date:** [September 4, 2008, 5:03pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/2 "2008-09-04T17:03:19Z")
Hepatitis D needs hepatitis B to be able to propagate itself, is that the sort of thing you are asking for? [wiki link](http://en.wikipedia.org/wiki/Hepatitis_D) does a decent job of explaining it. ---
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [September 4, 2008, 5:21pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/3 "2008-09-04T17:21:18Z")
> [@Cub\_Mistress](#): > > Hepatitis D needs hepatitis B to be able to propagate itself, is that the sort of thing you are asking for? [wiki link](http://en.wikipedia.org/wiki/Hepatitis_D) does a decent job of explaining it. I think that is very similar to what I was asking, but not quite. Still an interesting thing to know. ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [September 4, 2008, 6:12pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/4 "2008-09-04T18:12:21Z")
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. ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [September 4, 2008, 6:24pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/5 "2008-09-04T18:24:02Z")
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. ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [September 4, 2008, 6:29pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/6 "2008-09-04T18:29:42Z")
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. ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [September 4, 2008, 6:47pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/7 "2008-09-04T18:47:06Z")
[QUOTE=Quercus] 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. [/QUOTE] 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](http://en.wikipedia.org/wiki/AIDS_dementia_complex) ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [September 4, 2008, 6:50pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/8 "2008-09-04T18:50:27Z")
> [@Quercus](#): > > If you were infected with HIV and then kept in a sterile environment, you wouldn’t have any direct symptoms. 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. eta; What **Warmn** said. ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [September 4, 2008, 6:55pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/9 "2008-09-04T18:55:41Z")
Oh, I think I learned it from you **Qadgop**. ---
**Author:** ![coffeecat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/coffeecat/32/3405_2.png) [@coffeecat](https://boards.straightdope.com/u/coffeecat)\ **Post date:** [September 4, 2008, 8:24pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/10 "2008-09-04T20:24:00Z")
Cholera and diphtheria are caused by bacteria that are themselves infected with a virus. Not quite the OP’s question, but close. ---
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [September 5, 2008, 6:16pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/11 "2008-09-05T18:16:38Z")
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. ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [September 5, 2008, 10:34pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/12 "2008-09-05T22:34:01Z")
> [@Qadgop\_the\_Mercotan](#): > > 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. > > eta; What **Warmn** said. I can’t seem to figure out what the hell ETA stands for. I’ve seen it a lot lately. Something obvious, of course, but I’m missing it. ---
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [September 5, 2008, 10:38pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/13 "2008-09-05T22:38:34Z")
> [@CC](#): > > I can’t seem to figure out what the hell ETA stands for. I’ve seen it a lot lately. Something obvious, of course, but I’m missing it. Means: Edited to add. ---
**Author:** ![Iubaris](https://avatars.discourse-cdn.com/v4/letter/i/bb73d2/32.png) [@Iubaris](https://boards.straightdope.com/u/Iubaris)\ **Post date:** [September 6, 2008, 8:14am UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/14 "2008-09-06T08:14:51Z")
> [@Khadaji](#): > > 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. That’s all well and good, but why not just release a virus that kills on its own? Wouldn’t that be easier? 😛 ---
**Author:** ![groman](https://avatars.discourse-cdn.com/v4/letter/g/73ab20/32.png) [@groman](https://boards.straightdope.com/u/groman)\ **Post date:** [September 6, 2008, 6:23pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/15 "2008-09-06T18:23:18Z")
> [@Iubaris](#): > > That’s all well and good, but why not just release a virus that kills on its own? Wouldn’t that be easier? 😛 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. ---
**Author:** ![ataraxy22](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ataraxy22/32/307_2.png) [@ataraxy22](https://boards.straightdope.com/u/ataraxy22)\ **Post date:** [September 6, 2008, 6:51pm UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/16 "2008-09-06T18:51:35Z")
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: > **[Satellite (biology)](https://en.wikipedia.org/wiki/Satellite_virus)** > > Satellite viruses > Satellite nucleic acids > A satellite is a subviral agent that depends on the coinfection of a host cell with a helper virus for its replication. Satellites can be divided into two major classes: satellite viruses and satellite nucleic acids. Satellite viruses, which are most commonly associated with plants, are also found in mammals, arthropods, and bacteria. They encode structural proteins to enclose their genetic material, which are therefore distinct from the structural pro... 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.: [Sputnik virophage - Wikipedia](http://en.wikipedia.org/wiki/Sputnik_(virus))) ---
**Author:** ![T.Slothrop](https://avatars.discourse-cdn.com/v4/letter/t/3e96dc/32.png) [@T.Slothrop](https://boards.straightdope.com/u/T.Slothrop)\ **Post date:** [September 7, 2008, 5:42am UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/17 "2008-09-07T05:42:34Z")
> [@coffeecat](#): > > Cholera and diphtheria are caused by bacteria that are themselves infected with a virus. Not quite the OP’s question, but close. Interesting. could you give me a cite for this. I would like to read more. Thanks. ---
**Author:** ![groman](https://avatars.discourse-cdn.com/v4/letter/g/73ab20/32.png) [@groman](https://boards.straightdope.com/u/groman)\ **Post date:** [September 7, 2008, 7:12am UTC](https://boards.straightdope.com/t/has-there-ever-been-a-disease-that-required-two-viruses-to-manifest/462016/18 "2008-09-07T07:12:40Z")
> [@T.Slothrop](#): > > Interesting. could you give me a cite for this. I would like to read more. Thanks. It’s not exactly infection of cholera, but rather a virus that got integrated into the cholera DNA: [cite that mentions this](http://www.mrc-lmb.cam.ac.uk/genomes/madanm/articles/cholera.htm). A lot of parasites require to maintain a symbiotic nfection by a certain bacteria called [Wolbachia](http://en.wikipedia.org/wiki/Wolbachia) to survive.