Dear Christopher Cat: Our new foster cat brought ringworm into the house, and now most of us – cats and humans – have it, too. Our veterinarian prescribed medication and a special shampoo and dip for the cats, and she instructed us to clean the house well. We’re vacuuming daily. Should we also rent a carpet shampooer?
Christopher Responds: Despite its name, ringworm isn’t a worm at all, but a fungal infection. Most cats with ringworm have patchy hair loss, but a carrier’s coat can appear normal.
Ringworm spores persist in the environment, making eradication difficult. So a successful outcome requires treatment of all pets and scrupulous cleaning of the home.
To kill ringworm spores, clean and disinfect solid surfaces. Launder bedding and other fabric, small area rugs and soft articles. Vacuum upholstered furniture and drapes, and discard the vacuum cleaner bag. Press duct tape to furniture to remove any hair the vacuum missed.
Clean hardwood and tile floors with a damp, disposable cloth, such as a Swiffer pad. Avoid brooms, which are difficult to decontaminate.
Carpeting should be vacuumed to remove all hair and cleaned to eliminate the ringworm spores. A recent study compared commercial hot water extraction cleaning to carpet shampooing once or twice, with or without a 10-minute pre-treatment with disinfectant.
Commercial hot water extraction, sometimes called steam cleaning, worked best. Shampooing once was least effective. Pre-treating with disinfectant helped but frequently discolored the carpet.
Replace all furnace filters, which trap ringworm spores, so it isn’t necessary to clean your air ducts.
Your job will be easier if you restrict your cats to a room you can clean quickly, such as a bathroom, until your veterinarian confirms that the ringworm is gone.