Dear Dr. Roach: My neighbour is battling cancer for the third time. The medical personnel she sees when she goes for her chemotherapy treatments are urging her to get rid of her two cats. They claim the cats are a danger to her health. Wearing gloves and a mask while cleaning litter boxes will not help. Why? What do the cats have that can hurt someone going through chemotherapy?
Cancer chemotherapy frequently causes damage to the body’s immune system. Many types of chemotherapy work against fast-growing cells, and while cancer cells are fast-growing, your neighbour’s healthy immune system cells, especially white blood cells, are also fast-growing and can be damaged by the chemotherapy. Avoiding potentially infectious agents is therefore wise advice for people going through chemo.
There are several potential infections that can be transmitted from cats to humans. The one we worry about most is probably toxoplasmosis, a protozoan infection. Toxoplasmosis is a big concern in people with HIV, but also can be an issue in people who have recurrent chemotherapy or have a more prolonged reduction in immune system function. However, toxoplasmosis can be effectively avoided by wearing gloves while changing the litter box, keeping the cats indoors and feeding them only high-quality cat food and never raw meat.
Cat bites or scratches can be very serious, especially to someone with an immune system that is less than perfect. If her cats occasionally bite or scratch, that would be a problem.
There are a few other uncommon zoonotic diseases (ones that can be transmitted from animals to humans) that might be of concern. Her cats’ veterinarian would be a useful resource to find out more. The cats should, of course, be thoroughly evaluated.
Allergies, not infection, might be the issue, but allergies are usually less of a problem during chemotherapy.
The risks from a healthy indoor cat are very small. Risks must always be balanced against the very strong feelings people have for their pets, especially at a vulnerable time. I would not recommend separating a person from her cats without very good reason, and would want to know exactly why, since it’s not clear to me in this case.
Dear Dr. Roach: I am an 80-year-old man with Type 2 diabetes. I have been told that I have a heart “prebeat,” but that I should not worry unless it becomes random and misses beats. I do not have atrial fibrillation and have passed several stress tests. I can feel a rapid heart rate, especially at night. I can usually stop it by heaving my chest. Am I at risk for a serious event?
Premature heart contractions can come from either the top chambers of the heart (premature atrial contractions) or the bottom (premature ventricular contractions). Both are common, but neither is usually the sign of serious heart disease. The fact that you have found a way to stop them suggests to me that you are more likely having premature atrial contractions, which can come in runs of multiple beats (runs of premature ventricular contractions is called ventricular tachycardia and is very serious).
Evaluation of this common concern often includes a long-term electrical study of the heart, such as wearing a Holter monitor, a 24-hour recording of every heartbeat. If that has not been done, and you remain concerned, it might be reasonable to ask your doctor about obtaining one. If you have had one, and it showed nothing serious, then you are at no increased risk above the not-insignificant risk of an 80-year-old man with diabetes.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers can email questions to ToYourGoodHealth@med.cornell.edu