This excellent article was originally published in the Pasadena Star-News. Apple Valley Vets is extremely grateful to Dr Dunavan for granting us permission to use it on our website blog. Please be sure to read the additional comments following the article.

Pet-associated ailments stalk animal owners

By Dr. Clare Panosian Dunavan, David Geffen School of Medicine at UCLA

Posted: 12/02/2009 04:47:06 PM PST

Every morning precisely between 5:35 and 5:45 a.m., I awake to the excited snuffles, wags and barks of two starving spaniels. (Yep, they barely scraped through obedience school, but they sure know how to tell time). 

As they prance through the house in search of kibble and dental treats and I groggily follow, I sometimes think: Egad! Will this go on for the rest of our lives? 

God willing, yes. Despite lost sleep and other sacrifices, my husband and I consider ourselves richly repaid by the affection our pets give. In other words, we're hooked. 

OK, so much for the dewy-eyed paean, now to a darker truth. What else do companion animals sometimes give their owners? 

Like it or not, the answer is: downright nasty bugs. 

This paradox first hit me at age 8 when, thanks to a friend, I acquired a miniature turtle. I was desperate to raise the baby terrapin, but my plan cut no ice with my meticulous mother. 

"Eek! Get that thing out of here. It's loaded with salmonella!" were the first words out of her mouth upon finding its slightly murky oasis on our bathroom counter. Thus ended a beautiful relationship. 

But my awareness of pet-associated infections dawned anew as a third-year medical student. That's when I met the patient I will forever remember as "the man who slept with his dog." 

First let me set the stage. By the time he arrived at my Midwest medical center, the middle-aged handyman - who had been feverish for months - had lost so much weight his ribs jutted through his ragged T-shirt. My resident decided (the handyman) must have cancer, or - "if he's lucky," he grunted in knowing tones - "a whacked-out thyroid gland." 

Both diagnoses were plausible, but for once, the resident was wrong. Several days after admission, our new patient's blood grew tiny bacteria. He had brucellosis, aka "undulant fever," a malady usually contracted from farm animals. His case was textbook except for one detail: 

The colonies on the agar plate were the rare species Brucella canis. 

"He got brucellosis from a dog!" my resident exclaimed upon hearing the news. "Go back and ask him more questions." 

Dutifully, I complied. 

"Sure, I'm around dogs, Miss," the man drawled. "I bunk with one." I was aghast. 

Today, I'm more sympathetic. I also know the old-timer (who pulled through his illness, thanks to potent antibiotics) is far from alone in cherishing his pet. In recent years, it seems, our country's appetite for animal companionship just won't quit. 

Currently, more than 50 percent of U.S. households have at least one pet, with AVMA data indicating a 16 percent rise in the total population of dogs and cats from 1996 to 2001. 

And that's just a piece of the landscape. Thanks to a booming undercover trade, no one can say how many exotic companion animals - from pythons to parrots to giant Gambian rats - American homes now hold. 

Needless to say, the laundry list of infections that can pass from these critters to us is more than one column can cover. So here are a few highlights. 

The most common bacterial infections linked to pet ownership? 

Hands down: Salmonella and another intestinal bug called Campylobacter, accounting for more than 200,000 cases of pet-associated human gastroenteritis per year. Many animals, including cats and dogs, harbor Campylobacter; salmonella also abounds in chicks, ducklings, turtles and iguanas. 

The most common fungal skin infection? 

Ringworm ("cutaneous dermatophytosis," if you like medicalese) from dogs and cats afflicts roughly 2 million Americans each year. Experts believe cats are more infectious than dogs; even perfectly normal-appearing felines may transmit this pesky blight. 

And, speaking of tabbies who occasionally have hissy fits, yes, Virginia, there really is something called cat scratch disease. Exposure to young cats or cats with fleas is the leading risk factor for CSD, which starts with a minor scab or ulcer, followed by swelling of nearby lymph nodes. Although the infectious agent (a bacteria called Bartonella) is susceptible to several antibiotics, many sufferers recover with no specific treatment. 

Final question for budding medical detectives: How many pet parasites that (sometimes) infect humans can you name in 15 seconds? 

Hmmm. For starters, my list includes Toxoplasma, Toxocara, Echinococcus, and Giarda. More about these in future columns. 

In parting, perhaps it's time for a true confession. Do my husband and I share our bed with quadrupeds? Er, yes - although they snooze atop a special coverlet. 

More notably, even my mom is now a doggie convert. She may not sleep with our little guys, but she's fine with an occasional kiss. So are we. 

Dr. Clare Panosian Dunavan is an infectious disease specialist and a professor of medicine at the David Geffen School of Medicine at UCLA.

Additional comments:

The concept of “One Medicine” deals with all of the complex medical issues of the inter-relationships between animals and people. Dr Dunavan, an expert in human infectious diseases, correctly points out that pet ownership is not without risk to the owner, but she understands that the bond between our pets and us is very important and powerful.

Serendipitously, she chose to write about Toxoplasma (please refer to our previous blog), Toxocara (roundworms), Echinococcus (a type of tapeworm), and Giardia (an intestinal single cell parasite). Although we don’t see Echinococcus, we do see other kinds of tapeworm which can cause problems in people. All of these parasites are preventable or treatable if we find them in time.

While we can never claim to be able to prevent all of the possible risks to us implicit in pet ownership, with vigilance we can minimize the potential for harm to our pets and to us. We have tried to stress that an annual physical examination is at least as important as a routine vaccination or heartworm medication. Dr Dunavan’s article clearly reinforces the argument.