Director: Rob Bowman
When Assistant Director Skinner assigns agents Mulder and Scully to assist the Federal Marshals office in a man hunt for two escaped prisoners, they are confused about the reasons for the involvement of the FBI. On their arrival at Cumberland State Correctional Facility, Scully discovers a break out of a highly contagious and deadly disease in the prison. She questions Dr Osbourne, who claims to be from the Centre for Disease Control. A flu-like condition has claimed the lives of ten inmates and the two escaped prisoners may also be infected.
As Scully enters the prison to see if she can help. Mulder joins the man hunt to track down the two fugitives before they contaminate the public. Further investigation by Scully reveals that patient zero, Bobby Terence received a package from Pinck Pharmaceutical just before the contagion broke out. Dr Osbourne, who works for Pinck Pharmaceutical not the CDC, is accidentally infected and near death explains to Scully that the company funds exploration of rain forests for potential drug application.
One of their entomologists discovered an insect Faciophagia Emasculata, which carries a parasite that attacks the human immune system. Now the company and the government are attempting to cover up the fact that the prisoners were used as guinea pigs. When Mulder and Scully discover the involvement of the Cigarette Smoking Man, they suspect the whole incident is an attempt to eliminate them and debunk the X-files.
The producers debated whether to delay the airdate because of its proximity to the release of the similarly themed movie ''Outbreak'' but ultimately decided that the episode stood on its own.
The title of this episode refers to the name of the insect carrying the infection, Faciphaga emasculata. Although this particular insect is fictitious, there are diseases with symptoms which resemble those depicted in this episode, such as myiasis, in which certain species of fly larvae grow under the skin and emerge from abcesses or boils. On the reality side of the story, scientists do hunt through rain forests for plants and insects for pharmaceutical research, like the unfortunate Dr. Torrance.
Mulder: I thought this was about escaped prisoners.
Scully: It is.
Mulder: Then who are the men in funny suits?
Skinner: You never had a chance, Agent Mulder. For every step you take, they're three steps ahead.
Mulder: Well, what about you?Where do you stand?
Skinner: I stand right on the line that you keep crossing.
Mulder: You can't protect the public by lying to them.
Cigarette-Smoking Man: It's done every day.