DEAR READERS: After reading several research reports on a host of petrochemical products -- from plastic water bottles and grocery bags to styrofoam cups and packing materials -- it is evident that they are pervasive and a top environmental and public health issue.

Plastics break down into small particles that become a magnet for toxic chemicals such as polycyclic aromatic hydrocarbons in polluted sea and fresh water. Plastics disintegrate into microparticles, now present in many drinking water sources, and further into nanoparticles that can pass though the gut wall and possibly cross the blood-brain barrier.

Many anthropogenic diseases, from obesity and dysbiosis to multiple sclerosis and cancer, may well be exacerbated by these kinds of petroleum products, along with the micro- and nanoparticles in the air we breathe from other sources, including coal-fired power plants, gasoline-driven vehicle exhaust and the incineration of plastic-containing garbage.

To these we should add indoor microfiber particle “dust” from synthetic carpet and upholstery materials. These also contain endocrine-disrupting flame-retardant chemicals, which contribute to the epidemic of thyroid cancer/hyperthyroidism in cats sharing our home environments. These particles also contaminate the environment via the laundry wastewater from synthetic clothing materials. Plastic-derived and other nanoparticles in the air, rain and irrigation water contaminate our food crops, seafood and livestock feed, and thus enter the food chain and much of the food we consume.

We must quickly create and expand alternative products based on eco-friendly biochemical processes such as contained biofermentation and biosynthesis, bioremediation, sustainable biofuels and other alternative energy sources, and natural clothing and other materials derived from cotton, hemp etc. that are recyclable and biodegrade into nontoxic components. Local and international efforts to recover plastic materials from all contaminated aquatic ecosystems and unsealed landfills need to be initiated for the common good.

DEAR DR. FOX: The recent letter in reference to euthanizing shelter pit bulls who have been abused and called a “dangerous tossing of the dice” is heartbreaking.

Humans are the ones who have caused the abuse, yet we don’t euthanize them, do we? This man speaks of these dogs like they are disposable. Imagine if God felt that way about us as humans. Abuse, of any kind, is a choice. It has the power to cause complete wreckage in our lives and render us, as humans, the same status as a shelter dog.

Pit bulls have gained a reputation for responding unkindly when faced with fearful or anxiety-ridden situations. As humans, don’t we do the same thing sometimes? Just like animals, we react when things happen that we don’t like or understand. When coupled with an abusive past, people may respond in a dangerous manner, rendering us “worthless” and on our way to either life in prison or a death sentence. But should all dogs, just because they are pit bulls and have displayed dangerous behavior, be euthanized?

Dangerous people exist, just as dangerous dogs do, but that’s not the problem; PEOPLE are the problem. We abuse each other and animals then get angry when they respond. Our world is crumbling all around us, and still we blame others and seek death as an option to unwanted or undesirable behavior. If death is the “best option,” then why do we still have so many shelter animals and people spending their lives in jail? -- R.R., Farmingdale, New Jersey

DEAR R.R.: Many readers will take to heart what you have written, and most, I am sure, will agree that there are no easy solutions.

We do indeed wrestle with trying to live up to the principles of justice, compassion and reverence for life. And I agree with you that many dogs, not just pit bulls, are aggressive around people and other dogs because of human influences -- improper rearing, breeding, neglect and abuse.

But is it more or less humane to incarcerate such dogs for their entire lives because they cannot be rehabilitated, often for lack of trained staff and potentially life-threatening risks to them? I know of one instance where a powerful and unstable dog being walked at a no-kill shelter broke free and killed a small dog being walked nearby, putting both dog handlers at risk in trying to pry the one dog off the other, and the subsequent emotional trauma to both handlers. Of course, better precautions could have been taken, but what to do in cases of emergency when all animals must be removed from a shelter -- as in the case of a fire or flood?

I consider the “no-kill” animal shelter movement, which justifies releasing unadoptable cats into our communities after neutering, and incarcerating unadoptable dogs for as long as they live, contrary to the ethics of compassion. It is an abdication of the responsible application of euthanasia for the common good. No-kill shelters fill up, and then where do stray and surrendered dogs and cats go? They are often abandoned to fend for themselves, but, given room at shelters, could have been easily and safely adopted.

The pro-life movement is all very well, but its consequences should not cause more suffering just to make its advocates feel good. Such limited morality undermines the fabric of a community of compassionate and responsible living. Some veterinarians and assistants working in shelters where euthanasia is practiced on a case-by-case basis have been lambasted as “animal killers,” much like Planned Parenthood centers have been threatened by anti-abortionist pro-lifers. I can sympathize with those who oppose capital punishment and who point to the evidence of not-infrequent wrongful incarceration; but as a culture, we do need to evolve and embrace a broader bioethical sensibility, as I detail in my book “Bringing Life to Ethics: Global Bioethics for a Humane Society.”

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Andrews McMeel Syndication, 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.)

Walking my dog in 84-degree weather, just three weeks after we had a blizzard here in Minnesota, we heard a few frogs singing in the swampy ponds. Dog Kota cocked her Aussie red heeler head and looked at me as to say, “So what do we do?” She was clearly not interested in listening to their timeless croaking serenades, so we resumed our walk and I told her the story about frogs someone had told me years ago.

Put frogs in a pot of hot water, and some will jump out for sure (as evidenced lately by some of the croakers fleeing the White House). But you don’t need a lid when you warm the water slowly: The frogs habituate and relax, not knowing what is happening until it is too late and they are too stupefied to jump out.

This may well be the fate of my own kind, I told Kota.

I chose not to tell her that frogs are still being dissected by high school students, because she had suffered enough in her short life before we adopted her from an animal shelter. Nor did I tell her about how deformed frogs were first discovered in Minnesota ponds by school children in 1995. Investigators later found these developmental and also reproductive problems were due to herbicides and an insect growth regulator, methoprene, which municipal authorities put in fresh water to kill mosquito larvae. But they coincidentally killed other aquatic organisms that normally consume the mosquito larvae, such as dragonfly nymphs. Fewer healthy frogs mean fewer tadpoles to consume algae, which can produce lethal toxins and could kill Kota if she drank the water.

Frogs and other amphibians are becoming extinct all around the world, yet they and other creatures play a vital role in controlling mosquitos. We have the science now to identify and correct the causes, but without the will of the public, and responsible government and corporate behavior with regard to public and environmental health, we will surely share the fate of the frogs.

That evening, I saw a TV advertisement promoting the herbicide Roundup (considered by some scientists to be a major human and environmental health hazard), to kill weeds like the dandelion -- a medicinal and most nutritious plant. Why do we harm and destroy what is good for us and the environment? The very next morning, I saw my immediate neighbor, who has two dogs, spraying the dandelions on her lawn. I should take her a copy of the warning about exposing cats and dogs to such herbicides in the Morris Animal Foundation’s new Pet Cancer Prevention Checklist brochure (morrisanimalfoundation.org).

Time to wake up before we all croak!

MERRICK DOG TREAT RECALL: HIGH THYROID HORMONE CONTENT

A voluntary recall was issued by Merrick Pet Care for certain Merrick Backcountry and Castor and Pollux brand dog treats after a consumer complaint of finding high levels of beef thyroid hormone in one of the products. The recalled products include Merrick Backcountry Great Plains Real Beef Jerky, Real Beef Sausage Cuts and Real Steak Patties, as well as Castor and Pollux Good Buddy Prime Patties Real Beef Recipe and Sausage Cuts Real Beef Recipe, all with best-before dates of May 1, 2017 through Sept. 1, 2019. The treats were distributed to pet stores and grocery stores across the United States and via online retailers. (FoodSafetyNews.com, May 24)

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Andrews McMeel Syndication, 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 READERS: Dogs with so-called atopic dermatitis suffer with a common, difficult condition. It’s characterized by intense itching, redness and papules on the skin, especially on the belly, legs, face and ears, which is often coupled with inflammation of the nasal cavity and eyes, especially in response to seasonal changes. In a small but promising study published in the British Veterinary Record in April (by C.J. Klinger and others), significant improvements were reported in dogs diagnosed with this condition who were given a high oral dose of vitamin D3. Doses started with 300 international units (IU) per 1 kilogram of body weight, increasing to 1,400 IU over a four-week period, then maintaining that high intake with close veterinary monitoring.

If your dog has been diagnosed with this condition, or has an unresolved skin issue and common causes such as mange and food allergy have been ruled out, discuss vitamin D therapy with your veterinarian. Do not treat your own dog without veterinary monitoring, because high doses of vitamin D3 can cause harm: elevating blood calcium levels, possibly causing bladder stones and even comas. A few drops of fish oil daily and a 1/2 teaspoon of local bee pollen can also benefit dogs with itchy skin conditions.

Treatment with vitamin D3 may well be safer and more effective, and will certainly be less costly, than with Novartis’ Atopica (cyclosporine) and Zoetis’ Apoquel (oclacitinib) for “itchy dogs.” The latter drug, currently widely advertised on TV, essentially shuts down the immune system, sometimes with fatal consequences, as reported earlier by one reader of my column. More cases of adverse reactions are being reported. (See Dr. Andrew Jones’ article “Apoquel Alert” at theinternetpetvet.com.)

Vitamin D3 benefits have been reported for people with this skin condition and also asthma, hypertension, congestive heart failure, cancer and dementia. Veterinarian Dr. Deva Khalsa, who has also posted reservations about using Apoquel, reports in the June/July 2018 issue of Animal Wellness Magazine that older dogs showing signs of canine cognitive dysfunction showed improvement when given a daily vitamin D3 supplement. She gives 5,000 IU daily for two months, then half that amount for maintenance, to large dogs; smaller dogs get smaller doses.

DEAR DR. FOX: We have several cats (six, the last time I counted! Ha!) all of whom are indoors all the time. Recently we had a slight cold go through the cats. Most of them had only a slight case of sneezes or light coughs for a couple days, with no effect on their behavior. Two of them, however, developed breathing issues and were visibly ill.

One cat was taken to our regular vet because it was a Friday afternoon and we were concerned about going into the weekend. I’d been reading online about cats with colds and knew they could get serious quickly. He was given an injection of antibiotics and sent on his way. There was an improvement in his mood and energy levels almost immediately, and he recovered well.

The other cat, however, began to get ill over that same weekend and it progressed rapidly. On Monday night, at 10 p.m., he was hiding under my bed and would not come to me. When I got him out, I realized he was doing some mouth-breathing and knew it was serious. After some steam treatment in the bathroom, I took him to a local emergency vet. After many hours of waiting, they prescribed an antiviral pill, an antibiotic liquid medication, and eyedrops, all of which I was supposed to give every 12 hours for 10 days.

They wanted to do a chest X-ray and insisted that he was “very sick,” but were ready to send me home without giving him his first dose of meds -- at 3 a.m., when I had no one at home to help me! Upon request, they did administer a dose but, once home, it proved nearly impossible to do myself. I got a few of the pills into him, but very little of the liquid. What I did give him upset his stomach so bad that he would retch for 15 minutes after taking it. He was so traumatized by all of this that my very affectionate and needy cat wouldn’t come near me for over a week. He did eventually recover just fine, however, and is now back to his usual lovey self.

I’ve owned cats almost all my life and never experienced cats with colds like this. Do you have any suggestions or recommendations? -- J.S., Moorhead, Minnesota

DEAR J.S.: You went through an experience familiar to those with many cats and who have an “open” policy in terms of adding a new cat, or having one or more of their cats get outdoors and contact an infected cat.

In some instances, a free-roaming cat could get onto an open deck that the house cats have access to, and leave infective material carrying one of many respiratory viruses. It is also possible that you were carrying a respiratory virus, or even a strain of influenza, and while you showed no symptoms, you infected your cats.

As you have discovered, cats do vary in their immune response to infection. The one who really became ill may have another underlying chronic viral infection, which could have impaired the immune system, making the cat unable to withstand the infective virus.

You are not the only person to complain to me about veterinarians giving no instruction as to how best to give medication to cats. This can be very difficult, often requiring an assistant to secure the cat. An alternative to stressful hospitalizations would be home visits from a vet tech or veterinary nurse/assistant, who can medicate feline patients.

Cats can be challenging patients. The more they become used to being put in a carrier and riding in the car from an early age, the easier it will be to get them to the veterinarian for routine wellness examinations and in times of emergency.

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Andrews McMeel Syndication, 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.)