DEAR DR. DONOHUE: I was diagnosed with Parkinson’s disease four years ago. I have a tremor, and I am not too solid on my feet.

A family member states firmly that Parkinson’s is a mental illness and that I am no longer able to sign legal documents. If I do so, my family can step in and take my assets. She gives as an example the pope. Please explain? – F.Z.

ANSWER: Your family member is a font of misinformation.

Parkinson’s disease is a movement disorder that results when there is a dearth of the brain chemical dopamine. Dopamine transfers information from one brain cell to the next. Parkinson’s evolves when the brain areas that control movement are the sites of dopamine deficiency.

The typical Parkinson’s tremor occurs when the hands are at rest and often consists of the index finger rolling over the thumb. Tremor is only one sign of the illness. All movement slows. It takes a Parkinson’s patient an eternity to move from family room to kitchen. In addition, muscles become rigid. Furthermore, it is quite common for Parkinson’s patients to lose their balance and fall. Often the face of a patient is frozen into an expressionless stare.

Personality changes can be a part of the illness, but they are not an essential part. A few patients come down with symptoms similar to Alzheimer’s patients, but that happens to a minority and is not an integral part of the Parkinson’s picture.

Parkinson’s is not a mental illness. No one says it is.

Parkinson’s patients can sign legal documents validly. If anyone tries to take their assets, they have every right to pursue that person in court, and they will win.

The pope, although not in recent close contact with me, conducts his duties with a clear mind but an infirm body.

DEAR DR. DONOHUE: A relative is in the hospital with a kind of food poisoning called listeriosis. We are not familiar with it but understand that it is deadly. What is the outlook? – M.T.

ANSWER: Listeria is a bacterium that’s all over the place. It is in the intestinal tracts of many animals; it can be found on many foods, including raw vegetables; it might be contaminating soft cheeses, meats and poultry. It is often in unpasteurized milk.

Fever, headache, abdominal pain, nausea and diarrhea are listeria’s food poisoning symptoms, not much different from food poisoning from many other bacteria and viruses. For most people, listeria food poisoning can be successfully treated and rarely results in death.

Other kinds of listeria infections, however, are dangerous. Bloodstream infection is quite serious and must be treated on an emergency basis in order to save life. Infection of the meninges, the brain coverings, is similarly serious and must be treated aggressively and quickly. Newborns, people with a weak immune system and pregnant women are the ones most apt to fall victim to these kinds of listeria infections.

“Listeriosis” is just another way of saying “infection with the listeria germ.”

DEAR DR. DONOHUE: I throw my hands up in disgust with all the conflicting advice medicine has to offer when it comes to food. Our ancestors were not so uptight with what they ate. I am giving my family raw milk, and I believe I am doing the right thing by not tampering with a natural food. Am I doing something terrible? – C.N.

ANSWER: You are doing something that is definitely unwise.

Pasteurization of milk kills many germs and has greatly lessened diarrhea illnesses in milk drinkers, especially children. It is not tampering with milk. It heats milk to a certain temperature to kill germs “naturally” found in it.

Don’t give your family raw milk.

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.