Lyme disease — a tick-borne illness of concern in horse and cattle country — has become a battleground where the interests of patients, physicians, researchers and insurance companies collide.

Those topics are woven together in “Under Our Skin,” a film showing locally this weekend, narrated by local author Jordan Fisher Smith, who also appears in the film discussing his own battles with the health care system.

Smith, whose book “Nature Noir” describes his time as a park ranger on the American River and details how he contracted Lyme disease, is just one of the people in the documentary who fights the insidious and debilitating disorder.

“Under Our Skin” also follows physicians who, after treating patients successfully with long-term antibiotic therapy, are persecuted by state medical boards whose members deny the existence of chronic Lyme disease.

Smith contracted Lyme disease in June 1998.

“I was a park ranger, I knew I had been bit, I had the tick, I had the rash, and I reported it — and it took five doctors and a year and a half to figure it out,” he said.

Even though Smith had both the culprit arachnid and a classic bull’s eye lesion at the bite site, his first blood test came back negative.

“I got sicker and sicker,” he said. “Within a month, I felt profoundly fatigued.”

Over time, Smith’s symptoms included memory loss, disorientation, arthritis, fatigue, loud ringing in his ears, exaggerated emotions (often called “Lyme rage”), numbness in his feet that would turn to burning pain and blurred vision.

“I went through hell and lost years of productivity,” he said.

Smith traveled to New York for treatment, taking heavy doses of antibiotics for more than seven years.

“The turning point was my third year of treatment, which I wouldn’t have gotten if I hadn’t fought for it,” he said. “Most people’s treatment gets denied after three weeks.”

Long-term intravenous antibiotic therapy is not listed as an accepted treatment for Lyme disease under the guidelines issued by the Infectious Diseases Society of America.

“What’s the alternative?” asked Smith. “To suffer and slowly be disabled, maybe die from Lyme? … We hear about the risks of antibiotic therapy. No one talks about the risks of chemotherapy in cancer.”

According to Smith, the common side effects of antibiotics are indigestion and diarrhea from the loss of intestinal flora.

“These side effects are so minor compared with a disease that, in its late stages, looks like (multiple sclerosis, Lou Gehrig’s disease) or severe arthritis,” he said. “I think a little indigestion is not too much to manage to be freed from this.”

Academic researchers who wrote the Lyme disease guidelines maintain the infection is rare, easily diagnosed and cured with two to four weeks of antibiotics.

This group also claims that chronic Lyme disease doesn’t exist.

The opposing camp is represented by physicians who argue that Lyme disease is not rare, and tick bites often go unnoticed.

Consequently, the disease often is not recognized and may persist in a large number of patients.

Why is there such a controversy over the existence of chronic Lyme disease?

“What we’re looking at is a perfect storm of factors,” Smith said. “One factor is there is no perfect blood test for Lyme. The worst test of all, ELISA, is used as the gateway for further testing. If you test positive, then they do further testing — but in a recent study, 75 percent of people with a bull’s-eye rash from a tick bite tested negative … The test only works at a certain phase of the disease.”

Another factor is that the managed health care system creates an environment where the physician has to rely on often-inaccurate tests for diagnosis, Smith said.

The third factor is that Lyme disease is “the new great imitator.” Similar to syphilis, Lyme disease can mimic a wide range of diseases and often is misdiagnosed as chronic fatigue syndrome, mental illness or multiple sclerosis.

“It’s common for victims to end up seeing multiple specialists,” Smith said.

The guidelines used by insurance companies to deny long-term antibiotic care were written by researchers with ties to insurance companies, Smith charged. In 2007, the panel was forced by a Connecticut antitrust settlement to rewrite those guidelines, which they are working on.

In the meantime, many Lyme disease specialists — including Smith’s physician, Dr. Joseph Burrascano — have had to surrender their licenses or close their practices.

“Burrascano saw thousands of patients,” Smith said. “When I was in his waiting room, there were people from all over the U.S. and Canada. So … the fact that he and others have been driven out of their practices by the IDSA standards, complaints by insurance companies and their handmaidens in the medical quality assurance boards, is a travesty and one that the film is trying to bring to justice.”

Lyme disease is more prevalent every year, Smith said.

Nationwide, 35,000 new cases were reported in 2008, a 29 percent jump from 2007, according to the Centers for Disease Control and Prevention — which also said Lyme is under-reported by a factor of 10.

In comparison, 1,356 cases of West Nile virus were reported in 2008.

“We have an unchecked epidemic right now,” he said.

After “Nature Noir” was published, Smith was able to use what he called his “tiny micro-fame” to help bring attention to Lyme disease: He was approached by Open Eye Pictures to be part of a documentary.

“Under Our Skin” has been on the film festival circuit since April 2008, found a distributor this year and is showing in limited release. Smith — who has been off antibiotics for two years — has been traveling with the film.

Helping with the production of “Under Our Skin” felt like a natural evolution for Smith.

“My work has always been about the way that people and nature interact, about connecting the dots,” he said. “Wherever I see a story that’s about that interaction, I find it interesting.

“This story came and bit me on the leg — and ruined my life,” he said wryly.