DEAR DR. DONOHUE: I would like to know more about hepatitis C. I know sex, childbirth and sharing hypodermic needles with drug users can pass it on. Can a person contract it from using the same toilet as an infected person or from using such a person’s cups or dishes? – D.S.

Hepatitis C is anything but a seldom-seen illness. Around 4 million Americans have it.

The initial illness – acute hepatitis – brings symptoms like fatigue, nausea and vomiting. Rarely does it cause yellowing of the skin and whites of the eyes. Most get over the acute sickness in a short time. In fact, the largest number of infected people never have a single day of illness and never know that they are infected. The virus, however, stays in the body for life in many and can continue to wreak havoc in the liver. Twenty years down the road, around one-fifth of those infected will have developed liver cirrhosis, and some will have come down with liver cancer.

The chief route of viral transmission in North America is sharing of contaminated needles for illicit drug injection. Having multiple sex partners is another important route of infection. However, transmission from an infected marital partner to a spouse is possible but not common. Medical personnel can catch the illness through an accidental needle stick from an infected person. Infected mothers can transmit it to their babies. Blood transfusions, once a great contributor to spread, rarely pass the illness now that all blood is checked for the virus. And there is a category of people whose source of infection is not known.

The illness is not picked up from toilet seats. Using cups, plates or eating utensils of an infected person doesn’t spread it. Neither does kissing or hugging an infected person. It is not wise, however, to share things that might have blood on them — for instance, razors or toothbrushes. Hepatitis C is treatable but not always curable. The medicines are interferon and ribavirin.

The pamphlet on all the hepatitis viruses explains the illnesses they cause and their treatments. Readers can obtain a copy by writing: Dr. Donohue – No. 503, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6.75 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: At age 28 and midway through taking infertility treatment, I developed blood clots in my left leg and had to stop all treatments. After many tests, I was told I had protein S deficiency. I was told it is hereditary. I am 34 now and have not had any more blood clots. My mother, 64, developed a blood clot last year, and she was diagnosed with the deficiency too. What can you tell us about it? – J.C.

Protein S (the “S” comes from Seattle, the place where it was discovered) is a blood protein that acts as a blood thinner. From time to time, the body does crazy things. It might form clots when it shouldn’t. We have mechanisms to deal with those mistakes. One of them is protein S, which blocks formation of unneeded clots. People who have too little of the protein can form a clot in a vein. The danger of such clot formation depends on how great is the deficiency. The deficiency is inherited.

You have had only one clot. Your mother had a clot late in life. Neither of you is at high risk of forming another one. If you do, then usually, you’d have to take a blood thinner.

DEAR DR. DONOHUE: Will you assure my mother that it is OK to take the anxiety medicine her doctors recommend? She thinks it is a weakness to use such medicine. When she takes it, she is happy. When she doesn’t, she is miserable. – M.M.

Anxiety prepares us to fight or flee when danger arises. Constant anxiety is not normal. It takes its toll on the heart, on blood pressure, on the digestive tract and on just about all organs. It does not come from a moral weakness. It comes from a mix-up in the production of brain-messenger chemicals. Medicine can correct such an imbalance, and your mom should not hesitate to use it.

DEAR DR. DONOHUE: I have sleep apnea and use a CPAP machine. Does the inflow of pressurized air have a negative effect on my lungs? Since I exhale against pressure, does this put a strain on my heart and impede my ability to get rid of carbon dioxide? – J.L.

Sleep apnea consists of no-breathing (apnea) episodes during sleep. Because of those episodes, blood oxygen falls and sets the stage for high blood pressure, heartbeat abnormalities, constant fatigue and the possibility of heart failure. CPAP – continuous positive airway pressure – is a device that delivers air under pressure to the nose so that it can pass through obstructions in the throat that prevent its entrance into the lungs. The device doesn’t affect the lungs negatively, doesn’t strain the heart and doesn’t impede your ability to exhale carbon dioxide.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from