News reaches the world that the troubled inhabitants of Lokastan have begun to perish in steadily increasing numbers from a contagion. The disease organism is reportedly so virulent that all exposed fall ill and nearly all the ill die.

By rare good fortune, researchers quickly hit upon a cure. This compound, taken regularly, also promises to render the uninfected immune. Soon, brave rescue workers enter Lokastan in force to treat as many as possible as quickly as possible.

High hopes for a prompt end to the plague are swiftly dashed. The disease turns out to have an unusual feature that trumps all favorable factors.

The organism begins its systematic destruction of the body almost immediately upon infection. At the same time, passing unchecked through the blood-brain barrier, it takes possession of the mind of the afflicted. The victims, now mortally ill, develop a delusional mentality: They become convinced that their disease is nature’s own remedy for all that troubles body, mind, and spirit.

(Pathogens that manipulate the mind of hosts are known to the researchers. They think of Toxoplasma gondii, the parasite that alters the brains of rodents so that they are attracted to—rather than repelled by—the cats that eat them.)

In the infected brains of the Lokastanis, a remarkably altered chemistry masks their disintegration with a sense of profound well-being. In this way the very agent of their destruction makes the victims certain that they are becoming, for the first time, deeply sound and healthy. They come to cherish the pathogen itself, for they are sure it transmutes them to an unprecedented level of well-being. To the doomed, their future is bright.

In their delusion, they deliberately—even systematically—infect others.

For this reason, their rescuers are greeted with hostility and suspicion. In rare moments of lucidity, the afflicted may believe the truth their deliverers reveal to them, but such moments are short lived. For the most part, the healers find themselves locked in a contest—even combat—with those who most need their help.

In the end stage of the disease, the afflicted often return to a terminal lucidity. The reason for this cruel disenchantment is in dispute. Some researchers argue it takes place simply because sheer reality overwhelms delusion; others believe that the pathogen itself efficiently cuts off production of the masking agents. And in many cases delusion goes on increasing until the end.

The medical workers and researchers work hard at developing ways of dispelling the delusions of the afflicted, but it has proven to be slow and difficult work.

The cure must be taken in graduated doses over a period of time, and those under treatment are for some time susceptible to relapse.

It remains an arduous touch-and-go effort.