They give you joy. They give you loyalty. They give you sloppy kisses.
But before you allow Fido or Fluffy to climb into bed with you at night, as an increasing number of Americans are doing, know that they can also give you something else: a variety of diseases known as zoonoses.
A University of California-Davis veterinary professor has penned an article for a scientific journal showing that people who allow their pets to lick them, give them "kisses" or sleep with them are at risk for zoonoses. The conditions can range from mundane to life-threatening.
Bruno Chomel and his co-author, Ben Sun, emphasize that pets provide many health benefits, including stress relief, and the authors stop short of recommending that people abstain from smooching their pooches. But in reviewing reports from several countries, they argue that such interactions carry some risk, particularly among infants and people whose immune systems have been weakened by disease, chemotherapy or other medicines.
"The risk is not huge. But the trend is that more and more people are sharing their environments with pets, allowing them in their beds, kissing them like crazy," Chomel said in an interview. "They need to know that a risk does exist" from bacteria that live in the mouths of felines and canines.
In their article, to be published in next month's edition of the journal Emerging Infectious Diseases, Chomel and Sun note that pets are becoming increasingly popular in urban households and "have conquered our bedrooms."
According to a recent survey by the American Pet Products Association, nearly half of pet dogs and 62 percent of cats sleep with their human companions.
Among the bacterial, parasitic and viral conditions they might bring with them are plague, cat-scratch disease and Staphylococcus infections, Chomel and Sun report.
The researchers reviewed literature about diseases transmitted from animals to humans. In Japan, a study found evidence of zoonoses in pet owners who kissed their animals regularly, but not in those who abstained, according to the paper. Some of these bugs cause mild symptoms, but others can morph into daunting illnesses, such as meningitis.
In the United States, the most common parasitic zoonoses associated with dogs are caused by hookworms and roundworms, which in humans can cause gastrointestinal symptoms, anemia and other conditions. Pasteurella multocida, an infection commonly caused by pet licks, can cause conditions ranging from mild respiratory symptoms to endocarditis, which inflammation of the inside lining of the heart chambers and heart valves.
None of those risks, however, keep Lesley and David Kirrene from doting on their pets.
The Kirrenes, who live in east Sacramento, Calif., share their bed every night with Austin, a 60-pound Australian shepherd, and a portly tabby, Sammy. Their other pooch, Reba, has no interest in joining them.
Until recently, David Kirrene had adamantly opposed the sleeping arrangements.
"To me, it just seemed like a sanitary thing. Animals in the bed? Would you start smelling like an animal?"
But Kirrene has changed his tune. Austin is his running partner, after all, and helps keep everyone warm on cold winter nights, he said. "Now I call him up on the bed," he said.
The Realtor and his spouse are less keen on engaging in full-on smooches with their pets.
"I'll allow a little kiss on the face," Lesley Kirrene said, but she knows where to draw the line.
Lesley Kirrene works at the Sacramento office of the Society for Prevention of Cruelty to Animals, which holds an annual fund-raiser that features a "kissing contest" involving animals and their owners, and some participants go overboard in the name of competition.
"Sometimes it's truly embarrassing," she said. "It's really hard to watch."
Chomel advises against such behavior.
Those who do choose to share bed and lip space with animals can avoid disease transmission by hand washing, tooth brushing, regular veterinary care and good overall hygiene, he said.
"I am a pet lover, but my pets have never been in my bed," said Chomel.