You raised your cat from a helpless kitten, watching her grow into a loving and healthy companion. You love your cat with all your heart and this close companionship is good for both of you. Right? Most of the time, yes. But when infectious organisms cross the species boundary, close contact sometimes means you get more than you bargained for.
Animal diseases that are transmissible to humans – called zoonotic diseases – have been known about since ancient times. Fortunately, zoonotic diseases with fatal consequences are rare between humans and cats.
Say No to Hitchhikers
Visceral/ocular larva migrans is an important zoonotic disease of those who live close to nature, heedless of hygiene (usually, children). Its caused by roundworm larvae, transmitted to humans through contact with feces or soil contaminated by feces. Toxocara canis, the puppy variety, is usually the culprit, although Toxocara cati, carried by kittens, may also cause it. In visceral larva migrans (VLM), instead of completing their life cycle, the larvae migrate through the body, ultimately reaching the heart, liver, lungs and brain.
According to James Richards, DVM, director of the Cornell Feline Health Center, ocular larva migrans (OLM) is particularly devastating because larval migration to the eyes can cause blindness. VLM is most often seen in kids under six, says Dr. Richards, whereas OLM occurs more in older kids and young adults. Regular deworming of kittens and puppies, along with avoidance of cat feces or contaminated soil – such as might be found in a childs uncovered sandbox – are the best ways to prevent this devastating condition.
Cheyletiella, the walking dandruff mite, is occasionally transmitted to humans from infected cats. It causes red, itchy spots, is easily treated with topical medication and is easily prevented by treating the cat. Normally self-limiting in humans, Dr. Richards cautions that as long as theres an infected animal around, itll keep recurring.
Ringworm is a skin disease caused by a fungus, not a worm as the name suggests. Kittens are the most common source of human infection and children are the most likely recipients. Ringworm causes a variety of skin lesions, including round, red, scaly patches that usually respond to antifungal medication. If you only have one or two cats its not too hard to treat, comments Dr. Richards. If you have a household of cats, it can be a nightmare.
Bacteria and Viruses
Salmonella gastroenteritis – vomiting and diarrhea caused by any of the many variants of the bacteria salmonella enteritidis – is thought to be the most common zoonotic infection, but cats are not the main sources of human infection. According to Dr. Richards, recent studies show that less than one percent of pet felines carry the organism. Its usually transmitted by food contaminated by fecal material during processing, but may be directly transmitted through contact with infected feces. Proper food handling and hygiene will minimize the risks for cat owners.
Rabies, with its bizarre symptoms and deadly outcome, is perhaps the most feared zoonosis. It is spread by virus-infected saliva, usually through a bite-wound. The best ways to prevent this disease are to vaccinate your cat against rabies and avoid contact with wildlife.
Cat-scratch disease is acquired when organisms common to cats – usually the bacteria Bartonella henselae – are inoculated under the skin of humans, usually children. The lesion initially resembles an insect bite, blisters, crusts over and resolves within a few days to weeks. However, lymph nodes near the scratch may become tender and enlarged and patients may feel flu-like symptoms. More serious signs such as conjunctivitis, tonsillitis or encephalitis may also develop. The best prevention – besides playing gently – is to teach children to wash all bites, scratches or cuts as soon as they occur. Youre not treating the organisms, says Dr. Richards, but youre physically removing them when you wash them out.