SAUSALITO -- Is an unknown disease hitting the Bay Area or is it just a case of mass delusion? If you ask intensive care nurse Cindy Casey she'll tell you that the mystery disease is very real and very painful.

Casey is one of at least 150 Bay Area residents battling the illness that is characterized by lesions and strange string-like fibers.

"It sounds really strange, it's kind of understandable why people don't believe us, because it sounds so weird," Casey said. "The lesions start out as bumps that are itchy, little round raised bumps. The fibers are quite alarming."

When she turned to doctors for help, her frustrations began to mount. Casey said dermatologists at her own hospital suggested she was mentally ill.

"It sounds so bizarre to them that they take the quick way out and say this can't be, you've got to be delusional or making this up," she said.

Susan Bishop of Santa Rosa has a similar story.

"It's the overall pain I have every day, my joints hurt," she said. "

For some, the pain and frustration simply gets to be too much. That was the case, friends and family say, for Dillon King of Soquel. Last month, friends and family eulogized the 37-year-old former medical assistant after he committed suicide.

"It was really so depressing the hardest thing was seeing him just get worse all the time," said Wendy Augason, King's mother.

King's fiancée -- Elizabeth Strong -- says she's certain he picked up some kind of weird infection and that she's now beginning to show the same symptoms.

"It started as a small sore and kept spreading," she said. "I had doctors tell me that basically, it was delusional, then because it was the two of us with it we were feeding on each other, and egging each other on."

KTVU broke this story last year and now we've learned more than 1,200 people nationwide say they have the same skin lesions and bizarre fibers. Ironically, most are in the medical profession. Adults as well as children have it and it may be contagious.

Evidence is beginning to mount linking this syndrome to Lyme Disease from tick bites.

"The population of people with Lyme Disease believe this is another infection that travels with the Lyme organism," said Dr. Jennifer Choate, a hematologist who helped treat Dillon. "It makes sense because it is in that group we are seeing this pattern."

Marin microbiologist Jenny Haverty has also be studying the mystery malady.

"I accepted specimens from four different people in four different counties in the Bay Area, and I looked at them very carefully over and over again under the microscope," she said. "The colors and shapes of the fibers of each individual were very, very similar."

Tests on similar fibers taken from Bishop's skin and those of several other patients in the Bay Area show them to be tiny tubes of protein. But how and why the filaments are formed remains a mystery for now.