Nine years ago, Lisa Schneiderman contracted malaria on trip to Sierra Leone.

Little did she know that her bout with the disease could trigger another condition -- one that would leave her exhausted for hours after simply getting up to fetch a cup of tea.

Schneiderman has CFS, or chronic fatigue syndrome, an illness that she says makes her feel like she just ran a marathon.

"It is a complete exhaustion … where you have nothing left and you feel like you are completely wiped out and your body feels like it (weighs) 1000 pounds," she told CTV News.

However, some have questioned the legitimacy of Schneiderman's condition, including some of her friends and family.

"I think it is really hard to understand an illness you can't see," she said. "We are used to thinking of a disability in terms of a wheel chair or being on crutches."

One doctor thought a urine infection was the cause of her symptoms, and another told her depression was at the root of her problems.

"It just didn’t seem like those were the issues I was facing," she said. "I was really happy with my life at the time and I didn’t think something like a urine infection would cause my activity levels … to change quite so dramatically, to the point where I had to leave my job and I couldn’t exercise the way I wanted to."

'Unequivocal' evidence

But new research says that "unequivocal" evidence shows that chronic fatigue syndrome is not an imaginary illness, but a genuine condition that causes the immune system to go into overdrive, leaving patients feeling perpetually exhausted.

The findings, the researchers say, could lead to new paths of treatment that would perhaps bring the illness under control in its earliest stages.

"We found evidence that strongly supports, for the first time, in a very large cohort of subjects, that we are seeing a disorder that is not psychological but is biological," said author Dr. Mady Hornig, with the Center for Infection and Immunity and associate professor of Epidemiology at Columbia University.

"People are left wondering why they are not getting better; maybe they are not trying hard enough and pulling up on their boot straps. (But) it is something that is not a matter of the will to get better; it is … a physical condition that is preventing people from getting better," Hornig added.

Delays in diagnosis

The research team conducted blood tests on close to 300 CFS patients, some who had been diagnosed years before and others who had only recently been given a diagnosis. They then compared them with almost 350 people without chronic fatigue, or "systemic exertion intolerance disease," as it's being renamed.

What the researchers noticed were distinct immune changes in the patients who were in the "early stages" of CFS, or less than three years. These patients had increased levels of immune molecules called cytokines.

In particular, the team noticed high levels of a cytokine called interferon gamma, which has been linked to the fatigue that follows many viral infections, including Epstein-Barr virus. The full results of their findings are published in Science Advances.

Hornig says blood tests in these early stages may be able to help clinicians speed up their diagnosis. She says "up to 70 per cent" of CFS sufferers experience delays in their diagnosis for at least a year.

"With blood tests, this can bring individuals who have been denied a diagnosis, denied recognition of their illness … to an early diagnosis that may, in addition, tell us something about what is causing their illness and how potentially to treat it," she said.

A 'hit-and-run' event

The findings also support the idea that chronic fatigue syndrome acts like a "hit-and-run" event, with patients reporting getting sick with an infection and then never fully recovering.

The new research suggests these infections somehow block the immune system's ability to quiet down after a sudden infection, leaving it like a car stuck in high gear.

The team's research found that at about three years into the condition, cytokine levels drop off and the immune system begins to show signs of exhaustion, says Hornig.

She says understanding the course of the illness and how it changes over time should help researchers find effective treatments, she said.

"Early diagnosis may provide unique opportunities for treatment that likely differ from those that would be appropriate in later phases of the illness," she said.

The researchers say they now have "unequivocal evidence of immunological dysfunction" in CFS patients. They also have good evidence that the disease has distinct stages, which means there could one day be distinct treatments for each stage.

Earlier this month, the Institute of Medicine sought to redefine CFS by choosing five main symptoms as criteria for diagnosis.

They also urged that the condition be renamed Systemic Exertion Intolerance Disease, to reflect that symptoms worsen after exertion.

Their findings so far should come as relief to chronic fatigue syndrome sufferers who have long tried to convince others their symptoms are real. There remains no medical test for the condition, leaving many to dismiss the illness as simply low-grade depression or general malaise.

But the 400,000 patients in Canada with the illness have long described persistent and profound fatigue that makes even the simple of activities such as washing the dishes an exhausting chore. They also noted the condition makes concentrating difficult and leads to headaches and muscle pain.

Trying times

During the most trying times of her illness, Scheiderman says that she couldn't do simple math because she couldn't remember "numbers long enough to add them together."

Now, on a "good day," she says she needs to rest after reading for just 10 to 15 minutes. And standing for five minutes requires between 10 minutes to an hour of rest before she can attempt another activity.

Schneiderman says the condition forces her to plan out her day meticulously.

"I have to do it in bite-sized pieces … if it is a day I have to get groceries, I have to make sure there is absolutely nothing else on my schedule so it takes a lot of planning," she said.

But she says the findings from the Columbia University study gives her hope for the future, and she believes it may be a "watershed" moment.

"Having an understanding of what is wrong makes a big difference and it gives me a way to target my own recovery," she said.

"It is amazing … there a lot (of) bright people working really hard … so we can really move this disease forward in its understanding and treatments."