Given the recent interest in monkeypox, here's a few things that people should know about poxviruses from a virologist point of view (1/14)
Virologists classify Poxviruses as a kind of large DNA virus in the kingdom "Bamfordvirae" (no known relation) alongside other animal viruses like adeno- and asfari-viruses, all of which have a protein with a "double jelly roll" fold. 
Poxviruses (and some related viruses) are unusual for DNA viruses in that they replicate in the host cell cytoplasm and not the nucleus. Poxvirus particles also have an enigmatic and complex structure.
Poxviruses are considered fairly generalist with regard to what they infect, in that they don’t use specific receptors, have lots of genes, replicate in the cytoplasm, and are super stable in the environment.
Although large DNA viruses have a low mutation rate, this isn’t really a hindrance for poxviruses when they encounter a new environment as they already harbour lots of genetic diversity (and genes!), can recombine, and can adapt by amplifying gene numbers.
The most well known poxvirus is the virus that caused the devastatingly lethal, debilitating, and history-changing, smallpox disease in people known as variola virus of which there two types: major and minor
After killing 500 million people since 1880, variola virus was controlled using an original “Jennerian” vaccine based on inoculation with a related virus (vaccinia) found in animals, providing cross protection against variola virus but was less likely to cause significant disease
Thankfully the variola virus was eradicated in 1980, leaving humans with only a single endemic poxvirus, the relatively benign molluscum contagiosum virus, which is actually distantly related to the variola-like "orthopox" viruses. Humans don’t have any para- or yata-poxviruses.
Outside of humans there is a substantial diversity of pox viruses across animals, including arthropods and vertebrates, encompassing significant pathogens of wildlife (e.g. myxoma) and farm (e.g. orf) animals.
Given their significant diversity and generalist predisposition, poxviruses often jump from one host species to another (likely from rodents). One of the best known examples is monkeypox or cowpox, both of which are actually rodent-borne.
Given their less picky nature,poxviruses can infect things through diverse means including touch, droplet,and airborne modes where they can spread from initial inoculation site causing systemic disease over several days.Severe illness is often associated w/ bacterial coinfection
Poxvirus diseases are known to be vaccine preventable (even as post-exposure) and there's significant cross-protection between different orthopox infections meaning our smallpox vaccine may protect against related viruses. There are even some useful antivirals that could be used.
Their diversity and their generalist capabilities make poxviruses an obvious threat.The eradication of variola virus has left space for another related infection.Although replaced initially by widespread use of vaccinia,widespread vaccination ceased 50ya and immunity is waning.
We must be careful w/ orthopox's and not let novel ones adapt further to us.Control of future pox threats should involve limiting global zoonosis, population level surveillance, and shutting down transmission chains. Ensuring we have enough vaccine/antivirals should be paramount.
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