DEAR DR. DONOHUE: My daughter is a freshman in college. It is the first time she has ever been away from home. I have been called by the university’s doctor, who says she has infectious mononucleosis but not a bad case of it. He has her resting and sees her daily. How did she catch it? Should we bring her home? What medicines are used for it? – R.T.

ANSWER: Infectious mononucleosis, or mono, is all but a universal infection, with 90 percent of adults having evidence of previous infection even if they have no recollection of it. It often strikes in early childhood, and children younger than 5 usually do not develop any symptoms. Another peak of infection occurs between the ages of 15 and 24, and when infected then, symptoms are frequent. It’s a viral infection, and the virus is the Epstein-Barr virus.

Fever, sore throat and enlarged lymph nodes, particularly those in the neck, are its most common signs. The infected are drained of energy and often complain of muscle aches. The spleen and liver frequently enlarge.

The virus is usually transferred by saliva, and it’s usually a transferral from one who is not sick. The virus remains in saliva for a long time after an infection.

There is no medicine for mono. Initially, most want to stay in bed, but they can gauge their activities by how they feel. Many feel well in two to three weeks, but fatigue can last for months.

If your daughter says she is doing OK and since the doctor sees her daily – attention most mono patients do not get – she can stay put. If she feels too tired to fend for herself, then she should come home.

DEAR DR. DONOHUE: I am a 68-year-old female who belongs to an HMO. In 2003, my gynecologist said I should have a colonoscopy.

My primary-care doctor says the fecal blood test he does yearly is a sufficient test for colon cancer, and he refuses to authorize a colonoscopy.

Am I supposed to die from colon cancer? Do I report him to the American Medical Association? Should I ask for another doctor? – S.W.

ANSWER: Expert health committees recommend that everyone should have a colonoscopy at age 50.

The stool test for blood is not an adequate substitute. Getting another doctor is a good idea. Reporting the doctor to the AMA is not a good idea. The AMA has no power over HMOs. Writing to the chief executive office of the HMO would be worthwhile. If the HMO believes it is saving money by denying colonoscopies to its clients, it is sadly mistaken. It is much more costly for it to pay for the treatment of colon cancer than it is to pay for prevention of colon cancer.

DEAR DR. DONOHUE: In 1982, I was diagnosed as having sarcoidosis. They prescribed medicine for me, but I never took it. Recently, I saw a doctor because I am having shortness of breath. I would appreciate any information on how this disease affects you. – E.R.

ANSWER: Even though the name is unfamiliar, sarcoidosis is not a rare disease. Its cause has eluded detection. Its trademark pathology is heaps of dead cells called granulomas, which can be found in many organs but most often in the lungs and lymph nodes. The most common symptoms are cough and shortness of breath.

Many patients have a complete resolution of symptoms in, at most, three years. Others have a degree of organ impairment, but the illness stabilizes.