INCLINE VILLAGE, Nev. — Sandy Schmidt, 42, came down with the mysterious illness soon after she ran a marathon in San Francisco last July. She got better before becoming sick again this spring, forcing her to quit her job as a business office manager. Running even one mile now would "put me in bed for a day and a half," she said.
Schmidt is among 160 residents of Lake Tahoe's North Shore who have been diagnosed by two local physicians since the winter of 1985 as having a chronic flu-like illness in a medical puzzle that has assumed national proportions.
Most of the victims are well-educated, previously healthy, about 40 years old and are more likely to be women than men. Their complaints also are similar: severe fatigue, recurrent colds and difficulties with memory and concentration. About half of them have enlarged lymph nodes in their neck and almost all have abnormal blood tests, suggesting that a common viral infection may be involved.
Drs. Peter R. Cheney and Daniel L. Peterson believe the explanation may be a chronic version of the familiar Epstein-Barr virus, which causes mononucleosis. But the so-called "kissing disease" affects primarily children and young adults, albeit the short-lived symptoms are not unlike those being seen here.
If they are right, solving the puzzle of this cluster of illnesses may have wide repercussions. Perhaps tens of thousands of Americans throughout the country with chronic lethargy have been similarly diagnosed in recent years as suffering from chronic infection with the Epstein-Barr virus. And many of them have joined support groups or sought unproven treatments with antiviral or other drugs.
But there is sharp disagreement over whether the Epstein-Barr virus explains more than a handful of cases of chronic illness nationwide--or any of the cases in this area. Indeed one Incline Village physician has accused the two doctors who have been making the local diagnoses of "perpetrating a hoax."
And last fall, two investigators from the federal Centers for Disease Control spent several weeks here looking into the mystery. They concluded last week that they could "neither prove nor disprove" the relationship between the Tahoe illnesses and the Epstein-Barr virus.
That finding was immediately questioned by Dr. Paul R. Cheney, one of the two doctors who has been treating the patients. He said the investigation was too narrow and has been overtaken by subsequent developments.
"Something unusual happened there," agreed Dr. Anthony Komaroff, chief of general medicine at the Brigham and Women's Hospital at Harvard Medical School. He is collaborating with Cheney in an ongoing research study. "It is not all fabrication or hysteria or misinterpretation. I have guesses, but it is still a mystery."
The Tahoe cases are puzzling because the mononucleosis virus, which spreads through the saliva, is not easily transmitted and has never been known to cause an epidemic. (The Lake Tahoe illnesses are not related to an outbreak of a respiratory virus in Los Angeles last winter that affected some nursing home residents.)
Conceivably, a new strain of the virus has developed. Or another infectious agent may be the culprit, and the Epstein-Barr virus may not even be responsible.
The fact is, doctors cannot even agree how to define this infection, recognize it and treat it.
Better Blood Tests
The current controversy is likely to continue until better blood tests are developed--perhaps in the next several years--because the current tests often give ambiguous results. Since 1968, the Epstein-Barr virus has been linked to mononucleosis, whose symptoms include fever, sore throat and enlargement of the lymph nodes and spleen. It usually runs its course in several weeks.
By the age of 60, four-fifths of Americans have had an infection with the virus, often through contaminated eating and drinking utensils. But the vast majority either never had symptoms to begin with or recovered completely. Infected individuals become lifelong carriers of the Epstein-Barr virus.
Like other members of the herpes virus family, this virus can be periodically reactivated, for unknown reasons, leading to, for example, some forms of nose and throat cancer, Burkitt's lymphoma, a tumor of the lymph glands that is common in Africa and a variety of severe illnesses in patients with abnormal immune systems.
When Cheney and his partner, Dr. Daniel L. Peterson, both internal medicine specialists, saw their first patients with severe fatigue in the winter of 1985, they were "not all that impressed," Cheney recalled. They thought the patients would recover quickly, without requiring special laboratory investigations or treatments. But every couple weeks, they saw a few more cases.
By May and June, many of the first patients were still not better, and the doctors were diagnosing up to 15 new cases a week, including 10 cases among teachers at one high school and five cases among teachers at another.