Dear Dr. Fox:

Recently, we had a horrific experience with a rare water mold/fungus called pythiosis. It is a fungus-like organism found in standing water, such as ponds and swamps. Endemic in states bordering the Gulf of Mexico, it has been diagnosed in dogs as far north as southern Indiana.

Pythiosis was identified and confirmed in our darling 4-year-old Lab, Alice. She had gastrointestinal pythiosis, which is usually fatal because by the time one becomes aware of the problem, it's too late. We were alerted when Alice began to turn her nose up at food (which never happened before).

With the description of vomiting, constipation and lethargic behavior (which are the same signs for so many other illnesses), the veterinarians did every test imaginable. After exhausting noninvasive procedures, they recommended exploratory surgery and discovered a mass in her mesentery tissue, which was diagnosed as lymphoma. Little did we know at the time that we would be praying for it to be lymphoma.

As I'm sure you've surmised, we had to euthanize Alice, and it broke our hearts. I am writing today to inform your readers of this infectious disease, so they can take precautions to keep their pets -- and children -- from coming in contact with stagnant water. It is a growing problem in dogs and (although rare) humans.

We are relentlessly pushing our county government to test stagnant water in our neighborhood because we are confident that's where Alice contracted the disease. Not surprisingly, none of our local health officials has heard of this disease and no one knows what to do about it.

T.H., Vienna, Va.

This fungus-like disease, generally fatal to dogs, also occurs in horses (equine pythiosis), causing "kunkers" (lumpy growths on the skin, also invading the respiratory and digestive systems and bones). "Swamp cancer" is another name for it. Cases have also been reported in cattle, cats and humans. Since they are of vital ecological importance, swamps and wetlands should not be drained or treated with chemicals to eradicate this or other potentially harmful organisms. We should simply keep our distance and keep our animals out. Standing water -- if close to human habitation or recreation areas -- should be routinely checked by local health authorities. Dear Dr. Fox:

We have an 8-year-old cat, Nelly, who has a strange fetish: Whenever she encounters a plastic bag (grocery, trash, diaper), she licks it obsessively. Her housemate, Shaneequa (roughly the same age), has never done this sort of thing (nor have any of the dozen cats I've lived with over the years).

Any thoughts on why Nelly can't stop licking?

M.S., Silver Spring

Many people with cats write to me about this feline addiction to plastic. Some also lick paper money and photographs. Paper money is sized with an extract of tallow (animal fat), and photos often have an emulsion finish that contain stearates derived from animal fat, which are used to soften plastic.

Cats also like various soaps, hand and face creams, and other toiletries. These, too (unless the label declares "no animal ingredients" or "all vegetable products"), contain extracts of animal fat and other materials. I would check the label and only buy if it says "not tested on animals." If cats could read, they surely would agree with my choice!

Finally, since plastics contain phthalates and other potentially toxic petrochemicals, do not let your cat lick plastic or eat and drink out of plastic bowls.

Dear Dr. Fox:

My male beagle is 8 years old. He was having seizures, so we went to the vet and she said to just let him be. It got to a point where he was having seizures twice a week, so I tried an experiment.

We put our dog on a diet of lamb and rice. I also started putting 2 tablespoons of tuna water (which has omega-3) on the dog's food.

He hasn't had a seizure since! The vet said she can't believe it, but I told her I have the living proof -- no seizures for over 11/2 years. I hope this might help others with similar situations.

P.P., Kalamazoo, Mich.

There are many factors that can cause seizures in dogs -- from influenza and tumors to genetic defects, nutritional deficiencies and certain food ingredients.

Your discovery of a cure for your dog is worth noting. But don't overfeed the tuna -- it is high in mercury. Flaxseed oil is a safer source of omega-3 and -6 fatty acids. One teaspoon per 30 pounds of body weight daily, mixed in with the food, is good for all dogs.

Michael Fox, author of many books on animal care, welfare and rights, is a veterinarian with doctoral degrees in medicine and animal behavior. Write to him in care of United Feature Syndicate, 200 Madison Ave., New York, N.Y. 10016. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

(c) 2005, United Feature Syndicate Inc.