The Wraith pathogen is a core element of Wraith biotechnology.
The Wraith pathogen is designed to infect a host and grow outward from there, using the host as a sort of central processor. As the pathogen spreads, it manifests tendrils outside the body which search for raw materials. The tendrils break down and consume raw materials as they expand over an area, eventually growing into whatever structure it was meant to become. The host's brain is likewise slowly consumed, until nothing remains but the mind of the organism. The pathogen is capable of sentience and higher reasoning, such as defending itself against attacks.
The tendrils will usually attach to nearby energy sources in order to feed the pathogen's growth. Its body consists of a bio-polymer with metallic traces present in its form which eventually harden, similar to the growth of an exoskeleton on a beetle. The organic elements were resistant to energy, heat and even radiation.
It was speculated that the particular pathogen encountered by Atlantis was meant to grow into a Hive ship. The developing pathogen stated that it had no name and its designation would be given to it after it reached maturity.
Until it is fully grown, the pathogen relies on its host to survive. If the pathogen inside of the host is killed, then the tendrils it grows will die.
The pathogen was released at Michael Kenmore's hidden base that the Atlantis expedition encountered when they attempted to free Teyla Emmagan, infecting several members. It remained inert and was not contagious.
It first manifested Dr. Jennifer Keller, who woke up at her workstation with her right hand covered in a translucent sticky substance. Several days later when she went to sleep, she went into a coma-like state while her body was being engulfed by organic tendrils. The tendrils began to spread and infiltrated numerous positions in Atlantis while beginning to siphon off power from the main power conduits in order to speed its growth. Eventually, it spread to numerous positions with the tendrils attacking threats to their existence. Keller's personality was being consumed by the pathogen, which stated that it simply wished to become what it was designed for, namely that it was growing into a Wraith vessel.
Dr. Carson Beckett managed to develop a phage that was capable of destroying the pathogen but it needed to be delivered to the host body if it was to be successful in destroying the organism. Lt. Colonel John Sheppard was successful in reaching the chamber and delivering the cure after which the organism died. Following this, the other infected expedition members were treated. (SGA: "The Seed")