Chytridiomycosis, a disease caused by chytrid fungi, has caused the extinction of 90 species of frogs and other amphibians over the past 50 years, according to researchers from a number of worldwide universities.

The pathogen has caused huge losses of 501 species of amphibians, including the 90 extinctions and 124 other species whose populations have declined by more than 90 percent, according to a report by an international group of scientists published in the March 29 edition of the journal Science (“Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity”). See also “Amphibian ‘apocalypse’ caused by most destructive pathogen ever” (National Geographic, March 28).

The highly contagious fungus eats away the amphibians’ skin. Unable to properly respire, they die from cardiac arrest. Amphibians that are resistant to it become carriers, making it nearly impossible to eradicate.

In my opinion, and from a One Health veterinary perspective, this disease is a symptom of frog and salamander immune system dysfunction, enabling this fungus to spread rapidly under the facilitative influence of the lucrative world trade in exotic pets. Amphibians are extremely popular as pets, but some owners later release the animals, having lost interest, or the animals escape and infect indigenous species.

Their immune and reproductive systems have been damaged by agricultural petrochemical insecticides. These and other chemicals are in the rain, acidified with carbon dioxide from the burning of fossil fuels, that falls ever more unpredictably on wetlands and jungle habitats. The documented disappearance of insects due to similar human causes means many insectivorous amphibians are malnourished or starving. The bats of North America dying from white nose fungal disease are casualties of similar causes.

These losses mean the web of life in many ecosystems, the natural biodiversity, is being destroyed. In the absence of adequate biodiversity controls — namely bats, toads and frogs — harmful insects, such as mosquitoes and ticks, proliferate.

The declining quality of air, water and habitats around the world must be addressed, along with climate change, for our own sakes as well as the frogs and salamanders.

Ironically, an unrelated drug-resistant fungus, Candida auris, is now infecting people around the world. The drug resistance found in several strains has been linked with the global application of fungicides to various crops. (“A mysterious infection, spanning the globe in a climate of secrecy,” New York Times, April 7). Remember: “As ye sow, so shall ye reap.”

Dear Dr Fox: I have a wonderful and loving 12-year-old Weimaraner, who unfortunately has many fatty tumors on his body. Our veterinarian indicated that this is a common problem with this breed of dogs. Is there anything I could have done to prevent these tumors from developing? Is it too late to correct the problem now? — V.B., Palm Beach County, Florida

Dear V.B.: These fatty growths, called lipomas, are not cancerous, but they can become numerous and large in certain breeds. They can require surgical removal when they cause discomfort, interfere with the dog’s range of motion and mobility, or become ulcerated or infected.

There are various theories as to why dogs develop these tumors, including genetic/breed susceptibility, metabolic syndrome with too much starch in the diet, neutering and lack of regular physical activity.

Pending a pre-surgical risk evaluation, your dog may be in good enough condition for surgery. But if none of the growths are causing any discomfort, and it is only for cosmetic reasons, I would not accept the risk of surgical removal considering your dog’s age.

How owner personality affects pet health: Research shows that pets and their owners become more similar over time, and the finding could be used to improve animal welfare and veterinary care, write professors Paul McGreevy and Pauleen Bennett. Owner personality affects how pets are treated and how frequently they receive veterinary care.

“Each clinical case must now be understood in the context of the human background baggage that enters the consultation room,” they write. (The Conversation, March 25)

Visit Dr. Fox’s website at DrFoxOneHealth.com.