BOTH How Do You Learn Viral Structures?

[aspiringdoc09]

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Hi All,

I was wondering if you guys had intuitive ways to learn the viral structures for DNA and RNA viruses? I can learn the disease presentation without problems, but trying to keep up with which is enveloped or DS vs SS vs linear, etc is confusing. Memorization is not my strength. I hate committing mnemonics to memory if I can't understand the logical relevance. First Aid is full of mnemonics, I know. Is it a skill you (or I) will pick up from doing the qBanks? Thanks.

 

[Suture15]

This is how I learnt them. If it helps you, great. If not then try flashcards they seem to work for a lot of people.

When I learnt virology in MS2, the prof had flowcharts for the RNA and DNA viruses. So it would start out as enveloped/non enveloped or ssDNA vs. dsDNA (whatever helps you better). I always refer to that flowchart and have it mostly committed to memory. It isn't a "conceptual" method because sometimes I will simply recall that adenovirus is on the left side of my mental diagram so I know it.

Another method I use is making up some sort of story to go along with each virus. By story I don't mean elaborate tales but just a quick blurb.

so for DNA viruses, enveloped is easy because there are only 2 - Herpes and Hepadnavirus. How do I remember this? Well herpes uses a nuclear envelope (that is a must know fact because viruses usually use cell membrane envelopes) and Hep B is a complex virus so it has an envelope (something elaborate) or you can use the fact that out of the hepatitis viruses, the non enteric ones all have envelopes, i.e Hep B, Hep C, Hep D. If you can remember that non envelope viruses are stronger and the GI is a very inhospitable place, then you can use the method of eliminating Hep A and E, so you know the remaining 3 are enveloped.

I remember parvovirus as being the simplest basic DNA virus you can find and it's the only one that is ssDNA. Exceptions are key!

All RNA viruses that cause GI related issues are non enveloped - Reoviruses, picornaviruses, hepeviruses, caliciviruses. Everything else is enveloped.

You can use the mnemonic of Positive RNA - PicoRNA which also works.

Togaviruses are enveloped because they are wearing a toga.

Little things here and there, but of course the more time you spend with them, more questions etc, the better.

 

[Jabbed]

IMO this is one of those things that's just easier to memorize than it is to "understand". To be honest, memorizing the structural characteristics of the different families actually helps in understanding pathogenesis.

With that said, the most effective way to organize them is by shared characteristics and rules/exceptions.

i.e.
Naked +ssRNA viruses: picornaviridae, hepeviridae, reoviridae, caliciviridae
Enveloped +ssRNA viruses: coronaviridae, flaviviridae, togaviridae, retroviridae
Enveloped -ssRNA viruses: arenaviridae, bunyaviridae, orthomyxoviridae, paramyxoviridae, rhabdoviridae, filoviridae, deltaviridae

Rules: All icosahedral RNA viruses are positive. All helical viruses are enveloped, negative ssRNA viruses that have polymerases in the virion. All RNA viruses replicate in the cytoplasm.
Exceptions: Reovirus is double stranded, coronavirus is helical, retrovirus/orthomyxovirus replicates in the nucleus, orthomyxo/arena/delta/bunyaviruses are segmented.

 

[aspiringdoc09]

Thanks guys. Appreciate it. I'll try these. I hate to keep missing the same gimme questions.

 

[IncognitoGuy]

This video was awesome.

 

[aspiringdoc09]

I like the DNA tree in his video. I would have to make up my own mnemonics in order for the RNA tree to be that useful, but I like the idea. Thanks for posting the video it was really good.