The Morticoccus Virus is a highly evolved nanite virus that is capable of adopting and altering the genetic code of its host. The virus is capable of instant mutation, able to mask its presence and expand its methods and scope of transmission.
Capable of infecting both humans and animals, those infected by the virus are genetically altered; becoming more animalistic in nature and adopting physical characteristics of hosts the virus had previously infected (for example; if a human was infected by the virus by a dog host, the human would form animosity and canine physical characteristics. Following that, if the virus than infected a mouse, the mouse would form animosity as well as humanoid physical characteristics.).
First notations of discovery of the virus were made by Ray Palmer of Earth-51 who recorded a case of that Earth's Justice League that involved a bioweapon called Morticoccus. Having earlier conducted an experiment on himself to isolate a genetic anomaly that made him immune to all viruses, Ray Palmer-51 discovered that the virus' genetic structure mirrored his immunity anomaly.
After the League discovered the existance of the Multiverse, Ray theorized that versions of Morticoccus might exist on other Earths and attempted to create a portal that could access other Earth's so that he could spread his immunity gene and negate the threat of the virus in the Multiverse.
Following Ray Palmer-51's death while attempting to building the portal, Ray Palmer of New Earth found and continued his work until his discovery by the Challengers of the Unknown and the destruction of Earth-51.
The first known host of the virus is Val Armorr (Karate Kid), it is unknown how he contracted the disease. As Patient 0, the virus first assimilated itself to Armorr's blood and genetic code, which possessed traces of advanced medicines and illnesses from the 31st century.
Eventually the virus was released into the reconstructed reality of Earth-51 in which the virus, due to having formed countermeasures against the advanced strains of 31st century medicine assimilated in Armorr's blood, evolved beyond the ability of 21st century technology to contain, transformed into an airborne strain and spread across the planet via biological couriers. Following the outbreak, Hal Jordan became an unwitting courier; spreading the virus throughout the universe in his attempt to get help for Earth.
The first mass outbreak of Morticoccus on Earth-51 occured in Gotham City, mass histeria resulted in the city destroying itself. In response political opportunists began fanning the flames of terrorism, blaming other countries for unleashing the virus as a weapon against the United States of America.
Eventually the virus traveled overseas, infecting Europe and Asia with the same results as seen in Gotham while other as-yet uninfected countries such as India and Pakistan began accusing each other of setting loose the virus; until they destroyed each other with nuclear weapons. Washington, Moscow, Tehran soon followed, destroying each other as the virus infected the survivors.
On New Earth, a de-evolved version of the virus was delivered into Wonder Woman's body following an encounter against Mary Marvel in Bludhaven. Enslaved as a Female Fury for Darkseid, Wonder Woman proceeded to infect all those she encountered during Darkseid's rise to power and the unleashing of the Anti-Life Equation.
During the final battle of Bludhaven, Diana was cured of the virus thanks to a serum created by Doctor Sivanna and Lex Luthor. The serum was further used to irradicate the virus from Earth.