# Are there viruses that infect \*other\* viruses? (biology related, not computer)

**URL:** <https://boards.straightdope.com/t/are-there-viruses-that-infect-other-viruses-biology-related-not-computer/384455>\
**Category:** Factual Questions\
**Created:** [December 17, 2006, 12:16am UTC](https://boards.straightdope.com/t/are-there-viruses-that-infect-other-viruses-biology-related-not-computer/384455 "2006-12-17T00:16:39Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\
**Post date:** [December 17, 2006, 12:16am UTC](https://boards.straightdope.com/t/are-there-viruses-that-infect-other-viruses-biology-related-not-computer/384455/1 "2006-12-17T00:16:39Z")

</div>

Are there viruses that infect _other_ viruses, rather than cells?

On the one hand, I know (at least, I think I know) that viruses need living cells to reproduce, so “infecting” another virus isn’t productive. On the other hand, I could see a weaker, simpler virus taking advantage of another virus’s ability to infect a cell by piggy-backing itself.

---

<div class="post-metadata">

**Author:** ![bbs2k](https://avatars.discourse-cdn.com/v4/letter/b/e495f1/32.png) [@bbs2k](https://boards.straightdope.com/u/bbs2k)\
**Post date:** [December 17, 2006, 12:23am UTC](https://boards.straightdope.com/t/are-there-viruses-that-infect-other-viruses-biology-related-not-computer/384455/2 "2006-12-17T00:23:39Z")

</div>

This isn’t answering your question, which is a good one because I can’t recall an answer off the top of my head. But in the topic of discussion I just wanted to add that there does exist the [bacteriophage](http://micro.magnet.fsu.edu/cells/viruses/images/bacteriophage.jpg) , a virus designed to “attack” bacteria.

---

<div class="post-metadata">

**Author:** ![mr.jp](https://avatars.discourse-cdn.com/v4/letter/m/48db29/32.png) [@mr.jp](https://boards.straightdope.com/u/mr.jp)\
**Post date:** [December 17, 2006, 12:38am UTC](https://boards.straightdope.com/t/are-there-viruses-that-infect-other-viruses-biology-related-not-computer/384455/3 "2006-12-17T00:38:48Z")

</div>

I’m rather certain the answer is no. A virus is just a shell plus some DNA/RNA. If a virus infected another virus, all it would have achieved would be changing shells. Plus there is no room for more DNA in a typical virus shell.

---

<div class="post-metadata">

**Author:** ![lazybratsche](https://avatars.discourse-cdn.com/v4/letter/l/ba8739/32.png) [@lazybratsche](https://boards.straightdope.com/u/lazybratsche)\
**Post date:** [December 17, 2006, 1:12am UTC](https://boards.straightdope.com/t/are-there-viruses-that-infect-other-viruses-biology-related-not-computer/384455/4 "2006-12-17T01:12:46Z")

</div>

Actually, in a sense, what you talk about does exist. [Satellites](http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/fs_satel.htm) are viruses which are further dependent on other “helper” viruses to infect a common host. [Here’s](http://math.ucr.edu/home/baez/subcellular.html#Satellites) another good source, though one a bit less authoritative. One variety are the satellite viruses, which include genes for their own protein capsule, but are still dependent on that helper to infect and reproduce within a host. Then there are satellite nucleic acids, which are simply short lengths of DNA or RNA that literally hitch a ride in the protein coat of its helper virus – probably the closest to what you are asking about.

The impression that I get is that in some cases, satellites could be considered parasites, but in others they confer an advantage to their helper. Things get really ambiguous at this level of life.