BEASTS OF BURDEN
Whether your pet swims in a bowl or runs by your side, you may be getting more from him than companionship and love. Your best friend may be making you sick.
While most of us are careful not to catch something infectious from other people--whether it's by frequently washing our hands or avoiding a coworker with the flu--we may forget that the animals that share our homes could also be responsible for troublesome diseases.Fortunately, many diseases transmitted by companion animals, just like those passed along by humans, can be avoided with some extra care.
Cats can be Contagious
Toxoplasmosis, which can be transmitted by cats, may be the most troublesomeyet easiest to avoiddisease that pet owners risk contracting, and in the case of pregnant women, passing on to the fetus.Toxoplasmosis is caused by small clump-like cysts of protazoan parasite that grow in infected individuals. The cysts provoke an immune response from the body, and cause serious after-effects. The disease acquired directly from an animal is called primary toxoplasmosis, while toxoplasmosis transmitted from mother to fetus is called congenital toxoplasmosis.
"Children born with toxoplasmosis can have severe symptoms at birth, or they can show no symptoms at all," says Andrea Kovacs, M.D., associate professor of pediatrics and pathology and head of the division of infectious diseases at LAC+USC Medical Center's Department of Pediatrics.
Roughly 3,300 infants are born in the U.S. each year with congenital toxoplasmosis. Affected children can develop problems from mild visual impairment to blindness and learning disabilites to severe mental retardation. "The organism can grow in the developing fetus's brain" says Kovacs. Treatment and surveillance are essential, she explains, since the disease worsens as years go by.
The two populations most vulnerable to toxoplasmosis are infants of seronegative pregnant womenwomen who have never been exposed to the protazoaand immunocompromised individuals such as those with AIDS or undergoing chemotherapy.
Women who are seronegative before they conceive should avoid handling the litter box and can be retested for toxoplasmosis antibodies during their pregnancy. Symptoms include fever, malaise, sore throat, muscle aches, rashes and swollen glands.
Toxoplasmosis travels from cat to human in the form of small oocytes, reproductive cells that travel from the intestines of an infected animal. The oocytes form when a cat eats an infected bird, rodent or raw or undercooked household meat. They then travel to the cat's feces, which in turn decomposes in cat litter or soil.
Changing cat litter or gardening in infected soil puts humans at risk of becoming the oocytes' next host. Since oocytes are not infective until 24-48 hours after passage, daily litter box cleaning is essential. Unfortunately, oocytes can live for up to 18 months without a host, so danger of infection remains after cats have been removed from a particular area.
Adult cats do not typically show symptoms of toxoplasmosis infection, so seemingly healthy cats could still be responsible for transmitting the congenital variety of the disease. Petting a cat, though, poses little or no risk of contracting toxoplasmosis.
The simplest ways for at-risk individuals to stay away from toxoplasmosis: "Cook meats well, don't eat raw beef, and definitely get someone else to change the litter box," advises Kovacs.
Be Cautious with KittensBacteria called Rochalimaea henselae are responsible for this infection commonly called cat-scratch fever. The bacteria are usually transmitted by scratches from kittens.
"Symptoms can result from the scratch, including enlarged lymph nodes, fever and, rarely, more serious reactions such as encephalitis," Kovacs explains.The illness usually gets better on its own, yet some symptoms can persist for months after the initial infection. Doctors can help with pain medication or antibiotics, and occasionally by draining swollen lymph nodes.
Bacteria is for the BirdsPet birds, especially parrots, parakeets, lovebirds and pigeons, can transmit a disease called Psittacosis. The condition is caused by Chlamydia bacteria, and usually appears as a respiratory illness in humans, including cough, fever and chest pain. Contagious birds don't necessarily look sick, although they could develop diarrhea, conjunctivitis, or "ruffled feathers." Psittacosis in humans and birds can be treated with a course of tetracycline. The best way to avoid bringing a sick bird to your home is by purchasing feathered pets from a reputable store.
Turtles are ToxicSalmonella is one more infection to watch out for in pets, especially in turtles, says Kovacs. In some studies, more than 85 percent of turtles were infected with the salmonella bacterium. Diarrhea, cramps, fever and chills could signal infection with the salmonella bacterium, which is also responsible for many cases of food poisoning.
Children usually have a higher risk of contracting the intestinal disease due to their increased likelihood of having close contact with an infected animal.
Allergies from Animals"Any animal that's furry, fuzzy, or feathery," says Ronald Ferdman, M.D., "can potentially cause allergies." Ferdman, assistant professor of clinical pediatrics, treats allergies at Childrens Hospital Los Angeles. Nearly 35 percent of his patients, he says, react against cat or dog allergens, the tiny particles that spark allergies.
"Cats are much more common causes of allergies than dogs," says Ferdman. "Cat allergen is light, so it floats in the air, is easier to breathe in, and penetrates deeper into the lungs than dog allergen." Even after a cat is removed from a home, allergy-causing particles remain for up to nine months.
Small skin flakes called dander are usually blamed for allergic reactions, but researchers aren't yet sure of the specific source of irritating particles. "We don't know if it comes from saliva, or something excreted in skin glands, or from flaked-off skin itself," explains Ferdman. Since cats groom themselves frequently, their hair and skin can carry allergen secreted in saliva.
Common allergy symptoms include asthma, hay fever, runny nose and itchy eyes. Some people can have life-threatening asthma attacks when exposed to particular animals.
When it comes to purchasing a cat or dog, remember that there is plenty of variation between individual animals, but not necessarily between breeds. "Short or long hair, or a breed that sheds are not good predictors of how troublesome a pet will be for allergy patients," Ferdman explains.
Aside from minimizing contact with allergy-causing animals, Ferdman says allergy shots may help to ease the suffering caused by well meaning pets. Injecting the allergen rather than inhaling it makes all the difference in training the immune system to tolerate certain substances that it would otherwise react against.
Love Conquers AllA little extra care is a small price to pay to be safe from animal-borne diseases or serious allergies, compared to the enormous benefits of the human-animal bond. Companion animals can provide priceless social interaction and morea recent study in the American Journal of Cardiology found that dog owners were more likely than non-dog owners to survive the first year after a heart attack.
Good hygiene, patronizing a reputable pet dealer, and keeping a close eye on children's contact with animals all help to minimize the risk of illness. Best of all, regular visits to a veterinarian can make for healthy petsand pet ownersfor years on end.
