DEAR DR. DONOHUE: My husband has hepatitis C. He has no recollection of ever being sick, and even now he feels fine.

How is this illness treated? How did he get it? What precautions should we take? Can I catch it through sexual relations? We know nothing about it and would appreciate any information. – K.L.

ANSWER: Hepatitis C is a common infection. On this continent, 4 million are infected, and each year more than 35,000 new cases are diagnosed.

Most of the infected do not know they are infected. They have no symptoms. The discovery of infection is made when their blood is checked for some completely unrelated reason.

Of the infected, 85 percent stay infected for life, and of those, around 20 percent develop liver cirrhosis in 20 years.

Self-injection with contaminated needles is one route of transmission. Between 2 percent and 7 percent of infected pregnant women pass it to their infants before or during birth. Sexual relations are not a common means of spread. The risk of transmission from an infected to an uninfected partner is 0.6 percent annually – at most. Having had a blood transfusion before 1992 (the year the hepatitis C blood test was put in use) was another way the virus was passed. Many never know how they caught it.

No special precautions are needed in the home. You should not, however, share razors, toothbrushes or nail clippers.

Two treatments are available, and both employ two drugs. One is Pegasys with ribavirin, and the other is PEG-Intron with ribavirin.

Hepatitis in all its forms is a major public-health problem. Answers to readers’ questions can be found in the new hepatitis report. 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 $4.50 U.S./$6.50 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: I am 55 and have had diabetes for 15 years. My doctor has put me on high blood pressure medicine, even though I don’t have high blood pressure. Why? – K.J.

ANSWER: Diabetes often leads to kidney damage, and frequently it goes undetected until irreversible damage has occurred.

You had a urine examination at your doctor’s office, right? I am confident that your doctor found tiny amounts of protein in it, so tiny they could not be discovered on a routine urinalysis. When even small amounts of protein are in a diabetic patient’s urine, it is a sign that the disease has begun its assault on the kidneys.

In such a situation it is almost routine to put diabetics on a blood pressure medicine called an ACE inhibitor. ACE inhibitors protect diabetics’ kidneys even when their blood pressure is normal.

You have to confirm with your doctor what is only my guess.

DEAR DR. DONOHUE: I am 73 and one of seven siblings. An older sister had a shunt implanted in her brain because she had normal pressure hydrocephalus, something I read about for the first time in your column. I find myself exhibiting some of the same signs I noticed in her when she was in her early 70s.

If I am on the same path as my sister, do you have any advice on how I might slow its progression? Would eating a diet heavy in fish be a contributing factor? – V.H.

ANSWER: Normal pressure hydrocephalus is an illness that, in some respects, looks like Alzheimer’s disease. People with it slowly lose their capacity to think straight and to learn. Additionally, they walk awkwardly and often lose bladder control.

Eating a diet heavy in fish plays no part at all in causing normal pressure hydrocephalus – and neither does heredity. The fact that your sister has it does not put you at risk of getting it.

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.