Forty Years Ago, a Mysterious Outbreak Plagued Tahoe/Truckee

In the winter of 1984 and for most of 1985, North Tahoe and Truckee became the center of a medical mystery. Half of the Incline High School girls basketball team came down with a chronic flu-like illness, causing the team to forfeit the rest of its season. Then a handful of teachers at Truckee High School became so fatigued they could no longer work; the same was the case with a few teachers at North Tahoe High School. Symptoms were also seen in employees of the Hyatt Regency in Incline Village.

All the patients shared related symptoms — severe fatigue, swollen neck glands, low-grade fevers, sore throats, headaches, and enlargement of the liver and spleen. Doctors were stumped. The symptoms seemed similar to mononucleosis, but the so-called kissing disease mainly affects children and young adults, and patients improve in a matter of weeks. The average age of people with the mystery fatigue sickness, however, was 40 and it was mostly women. And they were not getting better. Many were bedridden.

Newspapers called it “a mystery disease” and “a strange form of mono.”

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Doctors Daniel Peterson and Paul Cheney began treating these patients at their Incline Village clinic, Sierra Internal Medicine. By the fall of 1985, they had diagnosed 160 patients with the unidentified illness (some accounts say it was 200 patients); at one point, they were averaging 15 new cases a week, according to a 1986 Los Angeles Times article. This was the largest group of diagnosed cases of what doctors across the U.S. were calling chronic active mono. Until then, the biggest cluster in the country had been 25 people, Peterson told a newspaper in 1985.

At first, Peterson and Cheney believed the culprit was the Epstein-Barr virus, which causes mono. EBV is a member of the herpes virus family and is transmitted principally through saliva. Around 90% of all adults are infected with EBV, but the majority either never have symptoms or recover completely. Infected individuals become lifelong carriers of EBV. However, the virus had never been known to cause an outbreak.

In 1985, a new serology test for EBV became available. Peterson and Cheney tested their patients and found that most of them had high levels of antibodies to the virus, leading them to posit that another virus had reactivated their EBV. But some patients’ tests came back negative, meaning they had never been exposed to EBV, leading the doctors to believe a new, yet undiscovered pathogen and condition was at play.

That summer, Cheney and Peterson contacted the Center for Disease Control (CDC), which sent two epidemiologists to Incline to explore the outbreak of the Tahoe mystery illness. After a month-long investigation, the pair concluded that there was not enough evidence for a mono epidemic, that they could neither prove nor disprove the relationship between the Tahoe mystery illness outbreak and EBV. The Reno-Gazette Journal published a piece titled Health Officials Dismiss Mystery Disease at Incline.

But Cheney and Peterson, who were ridiculed by some in the medical community after the CDC’s findings, were convinced something else was to blame. The sick Truckee High teachers had one thing in common — they had all gathered in the teachers’ lounge on the same day. “We couldn’t understand how you could transfer mononucleosis in a teachers lounge,” Cheney told the Sacramento Bee in 1985.

Enter Erik Johnson. A 1974 Truckee High graduate who grew up in Incline Village, Johnson had served in the army in Germany before returning home. At age 29, he became so sick that his parents had to carry him into Sierra Internal Medicine, which was located close to his father’s dental office, Johnson told Moonshine Ink.

Johnson’s tests came back negative for EBV, so Dr. Cheney asked him to be patient zero to help prove to the CDC that a new, yet undiagnosed medical condition was to blame for the outbreak. Little did Johnson know that this would be the basis for a new condition — chronic fatigue syndrome (also known as ME/CFS; the ME stands for myalgic encephalomyelitis), which was finally recognized by the CDC in 1988.

Between 2021 and 2022, approximately 1.3% of U.S. adults had chronic fatigue syndrome, according to a CDC report. That is about 3.3 million people.

“I did have chronic fatigue syndrome — an illness with no name,” Johnson said. “They [Cheney and Peterson] needed someone to substantiate it, to serve as proof this was real. When the name was developed it was to solve what myself and other EBV-negative people had.”

Johnson eventually got better on his own, which he credits to skills he learned while in the army, where he was trained in biological warfare. By the fall of 1986, patients experiencing chronic fatigue symptoms in Tahoe slowed to a trickle. The outbreak was over.

Johnson believes his sickness developed from exposure to toxic mold in Germany as well as in Tahoe; he had been in all the buildings associated with the local outbreak — Truckee High, North Tahoe High, and the Hyatt, where he had worked as a cook. At the time, this condition was called building-related illness, which later became known as sick building syndrome.

However, Johnson said that Peterson and Cheney did not subscribe to his toxic mold theory. They believed the culprit was two-fold: a yet undiscovered virus that reactivated the EBV and made it chronic, and possibly a new strain of the herpes virus for those who were EBV-negative.

The exact cause of CFS is still under debate in the scientific community.

Cheney, who moved to North Carolina a few years later, died in 2021. Peterson still practices medicine and sees patients two days a week at Sierra Internal Medicine. He is also a volunteer member of the scientific advisory board of Simmaron Research, a nonprofit in Incline that is researching treatment discovery for ME/CFS and long Covid. Peterson did not respond to Moonshine Ink’s requests for an interview.