DEAR DR. FOX: In at least one past column, you strongly discouraged using Frontline on dogs and Advantage on cats because of the risk of cancer. I also vaguely recall that these products came out or became popular in the late 1980s.

We started using these medications at our veterinarian's recommendation beginning in the '80s. Since then, both of our dogs were diagnosed with terminal cancer at ages 12 and 13, as were two of our three cats at age 10. The last one was recently diagnosed. We have another cat, 11, who doesn't get this treatment because she never goes outside; therefore, she is the only one not to contract cancer. The other two cats have gone outside on a 20-foot rope attached to our garage, and we check them regularly. The dogs went out on a rope to do their business and were walked on a leash.

None of our previous dogs and cats ever had these products -- and they never had cancer. Our dogs lived to 14, 16 and 17. One cat lived to 19; the other two died at young ages when we were young and naive about letting them loose outside.

Could you cite a study that documented this phenomenon? -- D.A.R., Reston, Virginia

DEAR D.A.R.: Cancers that are not caused by viruses or specifically identified carcinogens such as asbestos have complex causes. Some of those causes include genetic and epigenetic susceptibility, coupled with environmental triggers including radiation, consumption of DNA-damaging food and water contaminants, and exposure to various chemicals. Furthermore, some chemicals, like dioxins, are more toxic in minute doses over a long time period. While in the body, chemicals can break down into metabolic byproducts that can be damaging, and they can combine with other chemicals to be more harmful than when tested alone.

Since it can be extremely difficult and costly to confirm that one synthetic petrochemical or other compound is safe, it is common sense and good preventive medicine to invoke the precautionary principle, which calls for greater vigilance and never using any such products of the Age of Chemistry without accepting the potential risks, which generally outweigh the benefits.

Read more on this subject -- which your experiences certainly support -- on my website, DrFoxVet.net. You can also read about the related risks to humans and companion animals from exposure to the chemicals released unwittingly into the environment that end up inside other life forms.

DEAR DR. FOX: I never hesitate to email you when I disagree with your views regarding trap-neuter-release, so I felt it only appropriate that I do the same when I agree with you on an animal-related issue. Your column supporting the reintroduction of cougars and wolves in areas where they once thrived was "spot on" -- as the Brits say.

Obviously, as you note, such efforts need to be carefully controlled, but they are definitely doable. The cougars are making their way back east of their own accord anyway. There are definitely wilderness places where wolves and cougars could be re-established in limited numbers. There are plenty of deer (and coyotes) available to sustain the wolves and cougars, and the deer population would not be endangered by the reintroduction of such predators.

In urban and suburban areas, wolves and cougars could not coexist with humans, but in large, sparsely populated rural and forested areas, such reintroduction could work. We already coexist with a growing black bear population. I applaud your position on this issue. -- T.R.S., Olney, Maryland

DEAR T.R.S.: There does seem to be a groundswell of public support for "rewilding" of deer as well as wolf and American lion prey-rich habitats. This would benefit from encouraging natural recolonization and would help establish viable populations of these large predators.

I am currently reading Dan Flores' remarkable book "Coyote America: A Natural and Supernatural History," which I highly recommend for all readers who are concerned about the future of wildlife and their environments in North America. Readers will be engaged immediately by the historical, cultural and ecological insights Flores provides with scintillating wit and wisdom. He raises a significant point that effective municipal control of free-roaming dogs across the United States has reduced competition over food resources for the opportunistic, relatively omnivorous and highly adaptive coyote. The coyote has also benefited from America's decades-long extermination of wolves and lions. While some 500,000 of these incredible desert song dogs are killed annually -- including around 80,000 at taxpayers' expense by USDA Wildlife Services for the livestock industry -- they outwit their human adversaries at every turn and are in every state and ever more suburbs and urban environments. Their resilience calls for greater respect and understanding, as advocated by Flores and projectcoyote.org.

The coyote challenges us to find peaceful ways of coexistence for the good of all and to appreciate the presence of a native carnivore who provides significant ecological benefits to healthy ecosystems -- including our own backyards and communities.

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

Visit Dr. Fox's website at DrFoxVet.net.)

DEAR DR. FOX: I recently read your column about how the reader's cat's kidneys might be damaged, and I wanted to tell you about an illness my 2-year-old cat had, called tularemia, or "rabbit fever."

Like the cat described in the column, my cat ran a high fever, lost all desire to eat or drink, stopped grooming himself and would hardly move around at all. He also developed swollen glands in his neck. The first vet I took him to assumed it was an infection, maybe from a bite (since our cat is an outdoor cat) and prescribed antibiotics and administered fluids in the office. My cat didn't get any better; he actually got worse. It wasn't until a couple days later that a second vet examined him and asked if my cat kills and eats rabbits -- the answer was an absolute yes. The vet said she had seen only one other case of tularemia, but it requires a special antibiotic, which she administered by injection three days in a row and then had us give in liquid form after that for a week.

Over the course of three days, our cat's temperature went from 107 to 104 to normal, and his appetite returned (and became voracious). Over a period of about 10 days, he made a full recovery!

I just wanted to tell you about this, in case it would help anyone else; it was almost a miracle that the second vet we saw even recognized the illness for what it was and knew how to treat it. -- T.B.B., St. Louis

DEAR T.B.B.: This disease is more prevalent in some states than others, and veterinarians are on the alert in areas of greater prevalence, especially since this is a disease that people can also contract. With climate change, it is likely to become more prevalent. In your case, it is a warning to not let cats roam free and kill wildlife.

DEAR DR. FOX: I have an 11-year-old schnauzer, Beau, who has survived two episodes of pancreatitis. I am a widow, and he is my baby and companion.

For the last seven years, I have had him on Natural Choice venison food. Once in a while, I cook for him fish (tilapia) with quinoa and green beans. He likes both foods. For snacks, I give three little pieces of banana and three little pieces of apples. For years, I have given him a capsule of omega-3 oil, as recommended by the vet.

For about two years, I have noticed some masses on his body: two about the size of a small orange, and the other about the size of a lemon. I take him to the vet every year for his annual checkup, and the vet told me the masses are not malignant and that they are typical of schnauzers. I have noticed, though, that he cannot climb onto my bed as he used to, so I have to carry him to my bed; he gets out of bed with no problem. Also, when he climbs the stairs, he is not as fast as he used to be. I am concerned that the masses are impeding his movement.

Please let me know what I can do about these masses. I love Beau with all my heart, and I want him to live for many more years. -- P.P., Fairfax, Virginia

DEAR P.P.: These are probably fatty tumors called lipomas, which are common in older dogs. They grow and grow, but they do not spread to the internal organs. Once they become large enough to interfere with the dog's freedom of movement, it is time to consider surgery under a general anesthetic if the dog is otherwise healthy. Discuss this with your veterinarian, who may refer you to a soft-tissue veterinary surgical specialist. This is the step we took with one of our older dogs; she had a new lease on life after successful removal of a large lipoma in her groin.

You dog may have arthritis. There are supplements like Cosequin and Nordic Naturals fish oil for dogs that can help, along with regular massage as per my book, "The Healing Touch for Dogs."

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

Visit Dr. Fox's website at DrFoxVet.net.)

DEAR DR. FOX: My 4-year-old English cocker spaniel has significant folds on the lower side of her mouth. About six months ago, she began leaving dark spots on the furniture, our clothes and the bed. These spots were coming from her mouth, where something seems to gather in the folds. I try to clean her mouth once or twice a day with MalAcetic wipes (suggested by the vet), and my groomer says to use witch hazel on a gauze pad. This has become a chronic problem. I try to keep this part of her face clipped closely. But I would love to figure out how to stop it instead of just treating it.

Do you think a change in diet would help? I am at a loss, and I am wearing out my washing machine! Could I get the residue analyzed to see what it actually is? -- L.B., Vero Beach, Florida

DEAR L.B.: There are bacteria and fungi that live normally on a dog's skin and oral cavity, and when established as a balanced population, like a well-managed garden, help keep the skin and gums healthy and prevent injurious organisms from becoming established. Some of these microflora can produce porphyrin compounds that stain and cause the problems you are facing. Your poor dog probably hates the smell of her stain-making drool.

The stain (pigment) can come not only from some of these microorganisms, but also from artificial dyes in pet foods, some of which are known carcinogens and should be banned.

Did the attending veterinarian closely evaluate your dog's oral health, including teeth and gums? That is a first consideration. I would try PetzLife's oral gel for dogs and my home-prepared diet and treats (posted on my website, DrFoxVet.net) or a dye-free dog food -- I like Sojo's freeze-dried dog foods.

Witch hazel wipes are good, but change to doing it twice daily for three days and then repeating after a three-day break. Your dog may benefit from a vitamin A supplement or Nordic Natural's cod liver oil for dogs, since cocker spaniels can develop a stinky skin condition (seborrhea) and they require more of this vitamin in their diets.

DOGS CAN DETECT POTENTIAL BACTERIAL INFECTIONS

A springer spaniel named Angus is trained to detect Clostridium difficile (C-diff) in the environment, and he'll soon be working full time, allowing staff at Vancouver General Hospital to do targeted disinfection. Angus' success rate is between 95 and 100 percent, and his brother, Dodger, will be trained next, says dog trainer Teresa Zurberg.

DEAR DR. FOX: We had a cat who suddenly started biting around age 4. He would get a wild look in his eye and rush and bite. I took him to the vet after he attacked my daughter. The vet asked if he was a jumper, and suggested an X-ray. It turns out he had a pinched a nerve in his spine. A very short course of steroids and muscle relaxants did the trick. -- D.W., Albany, New York

DEAR D.W.: You are most fortunate to have taken your cat to such a vigilant veterinarian, who must have suspected a pain-trigger for this behavior during the initial physical examination, one sign being hyperesthesia or hypersensitivity along the back. As a preventive measure, a daily massage as per my book, "The Healing Touch for Cats," could help prevent recurrence.

APPRECIATION OF ANIMALS USED IN BIOMEDICAL RESEARCH

Lisa G. Portnoy, DVM, DACLAM, Animal Care Program director National Institute of Health Clinical Center in Bethesda, Maryland, sent me this announcement:

"The Animal Research Advisory Committee members and the IC Animal Program Directors decided to commemorate the exceptional efforts and contributions made by the animal care staff and research animals to the mission of the NIH and the many health advances that have been supported. The commemoration will be a bronze plaque affixed to a granite boulder to be placed on the south side of the Clinical Center. The boulder will be a quiet spot with two benches along with discrete landscaping elements. The plaque will read: 'With recognition and gratitude to the research animals and the NIH animal care and use community that have contributed to exceptional biomedical research advances. Presented by the Animal Research Advisory Committee.'"

I empathize with both the animals and those involved in their care and pray for the day when there will be more alternatives to using live animals in biomedical research and greater integration of clinical studies of animals already ill as we move toward a better application of the One Health concept and preventive health care for all.

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

Visit Dr. Fox's website at DrFoxVet.net.)