DEAR DR. FOX: Every time I see an ad for covered litter boxes, I worry about the poor cats that are forced to use them. The ads state these covered boxes provide “privacy,” which is ridiculous since animals are not embarrassed about relieving themselves. What is your opinion? – D.Z., Fairfax, Va.

DEAR D.Z.: This design is a real problem when owners don’t keep the litter meticulously replenished soon after it is soiled. Cats prone to respiratory infections often have to use poor-quality, dusty litter.

As for the privacy issue: Cats do need privacy, and some, feeling more vulnerable than others when needing to evacuate, become house soilers (especially if the litter box is in a noisy, high-traffic part of the home). Many stop being house soilers when the litter box cover is removed, which supports your point.

DEAR DR. FOX: The last time I took our 8-year-old German shepherd to his regular vet, his bloodshot eyes were dismissed and I forgot to mention he had a runny nose. Nevertheless, Max was given all of his shots. A few weeks later, we took him on a hiking trip, and when we got home he was breathing heavy. Then, in a matter of weeks, Max was dead from lung cancer. Is it possible that too many shots compromised his immune system? – B.T., Saratoga Springs, NY

DEAR B.T.: Cancer is a complex disease, some forms of which have multiple causes. It is too simplistic to put all the blame on your dog’s history of being over-vaccinated. One of the rules of vaccinating is never to vaccinate an animal showing the slightest signs of illness, such as red eyes and a runny nose. In my opinion, Max was already fighting the undiagnosed cancer, and the revaccination simply pushed him over the edge.

Send questions to Dr. Michael Fox, care of United Features Syndicate, 200 Madison Ave., New York, NY