Researchers find some protists use beneficial viruses to fend off lytic viruses

Contrary to common belief, not all viruses are harmful to their hosts. Sometimes viruses can even protect their hosts from infection by other viruses. Scientists at the Max-Planck-Institute for Medical Research in Heidelberg and their collaborators have now demonstrated that this is the case for so-called endogenous virophages: small DNA viruses that are mostly found inserted into the genomes of single-cell eukaryotes—organisms whose cells have a membrane-bound nucleus. In addition, the scientists show that virophages are highly specific towards giant viruses, focusing on the CroV type in the present study.

Phys.org
Scientists present evidence for a billion-years arms race between viruses and their hosts

Researchers have proposed a new evolutionary model for the origin of a kingdom of viruses called Bamfordvirae, suggesting a billion-years evolutionary arms race between two groups within this kingdom and their hosts.

Phys.org