[logfromblammo]

If I recall correctly, Morgellon's Disease is a mental illness that spreads via social interactions with an affected person, or journalism featuring such a person.

The disease itself is a delusion, regarding microscopic fibers in the skin. Sufficiently impressionable people simply hear about it, convince themselves that they have it, then they go on to try to convince others that it is a physical ailment rather than a mental illness.

If you are politically incorrect enough to classify religions as mental illnesses, many of those appear to be contagious as well.

But on a smaller scale, workplace morale is definitely infectious. If someone is having a particularly stressful day, they may be rude to someone else, who then feels worse as a result, and may propagate that to yet another co-worker. Of particular interest is that such transmission need not take place in person. A person with a common cold could work from home to keep everyone else from catching it, but someone with malaise or anxiety could transmit that via any medium that can include emotional undertone, such as a voice or video call.

[0xcde4c3db]

As far as I've read, Morgellons is only "contagious" in the sense that people who already had symptoms of delusional parasitosis or undiagnosed/misdiagnosed skin conditions gravitate toward it as an explanation.

[logfromblammo]

Contagions always spread through only the susceptible fraction of the population. Prior to mass communications, there were too few susceptible individuals in any given population for it to spread. The herd was immune, because any infected person would die before ever meeting another susceptible person.

Enter the Internet. Now all the susceptible people can aggregate around their own forums/boards/podcasts/groups/subreddits and infect each other with their unique strains of madness.

There's no more herd immunity, because all the susceptible people can find each other instantly.