Viruses affect their hosts many different ways: instant hostile takeover of cellular machinery, lurking unseen in the genome for generations, inducing reduced cell division or excessive cell division, and more. Archaeal viruses are relatively unknown in their genetic abilities and lifestyles, but we do know that they tend not to destroy their hosts through explosive viral reproduction, and that some archaea have eukaryote-like cell cycle phases.

 

In this study, some viruses infecting a thermophilic archaeon interrupt its cycle in the growth phase, so hosts expand in size up to around 17 times normal, continuously releasing new viruses over time. Eventually some archaea in the population gain resistance to the viruses via their CRISPR/Cas systems, and normal-sized cells dominate the population again.