Blood fever is a disease in the Pegasus galaxy that can infect humans and is also one of the few diseases that has adapted to infect the Wraith as well. While Blood fever is not in-variably fatal to the Wraith, it is dangerous and contagious enough that hives go out of their way to avoid it, to the point of abandoning hunting grounds for a generation or two. (SGA: "Lost Queen")
Engineered strain
Queen Death was determined to force all hives to be dependent upon her alone. Changes were made to the nucleic acid of blood fever to make a deadlier strain. Later on, Bell, a Wraith loyal to Death, used this engineered strain to infect Queen Moonwhite and her scout ship the Nimble. The ship crashed onto the planet Teseirit, which infected the planet's inhabitants with the disease. Outbreaks spread between the villages and people died from it. Moonwhite was fed upon by an Iratus bug queen and ended up surviving the blood fever.
When the Atlantis expedition tried to help the people of Teseirit, Dr. Carson Beckett suspected that the Wraith were trying to make the virus only affect humans, however, Forge pointed out that the strain's changes to the disease weren't done to the icosahedral center's point of infection for both Wraith and humans and instead the changes were to the nucleic acid. He speculated that any difference in the infection rate between species was an unintentional byproduct. (SGA: "Lost Queen")