Ringworm Environmental Decontamination in Homes of Dogs and Cats

Date Published: 11/03/2015
Date Reviewed/Revised: 02/05/2020
This Persian cat has generalized M. canis ringworm. Photo by Dr. Carol Foil.

Dermatophytosis, commonly called ringworm, is a fungal infection of the fur and skin of dogs and cats. To treat dermatophytosis, infected dogs and cats are treated with antifungals. However, infected dogs and cats will shed fur containing dermatophyte fungal spores into the home environment.  This fur can re-infect dogs and cats and make it difficult to treat the dermatophyte infection.

A key part of treating dermatophytosis in dogs in cats is decontaminating the home. Environmental decontamination is a two-part process, and involves cleaning to removing as much hair as possible followed by disinfection to kill any remaining spores. Most homes only need to be cleaned and disinfected twice a week, although some homes with many pets may need more frequent cleaning and disinfection. Environmental decontamination is continued until all of the pets in the household have been cured of dermatophytosis.

It is important to remove as much hair as possible from the home environment because shed hairs contain infective fungal spores. Below are some tips for cleaning the home and removing pet hair after your pet has been diagnosed with dermatophytosis:

  • House any infected pets in a bathroom or other room that can be easily cleaned. Try to avoid keeping infected pets in rooms with wall-to-wall carpeting, which are harder to clean.

  • After vacuuming carpeting, immediately dispose of the vacuum bag. Wear gloves when handling the vacuum bag to avoid getting dermatophytosis.

  • Use disposable products such as electrostatic pads on hard surface floors. Avoid brooms as they are difficult to thoroughly clean and disinfect after use.

  • Launder fabrics or other soft materials to remove hair. Any water temperature and any cleaner are fine for decontaminating fabric. If possible, wash exposed materials and pet bedding separately from non-exposed materials.

  • Use duct tape or lint rollers to remove hair from upholstered furniture.

  • Although ringworm spores can be cultured from the air of homes housing infected cats, ringworm is not a respiratory disease and inhaling the spores do not pose any risk to cats, dogs, or people. No special cleaning of heating and cooling ducts is required.

If a surface has been thoroughly cleaned, many disinfectants are effective against dermatophyte spores. Below are some tips for disinfecting the home after your pet has been diagnosed with dermatophytosis:

  • Chlorine bleach, when diluted 1:10 or 1:32, has good antifungal activity and is inexpensive. Prepare fresh solutions prior to use because diluted bleach solutions can degrade over time and become less effective.

  • Multiple over-the counter disinfectant solutions are effective against dermatophytes if the surface is thoroughly cleaned and allowed to stay on the surface prior to removal. Follow label instructions for information on sufficient contact time.

Below is a guide to cleaning and disinfecting various materials from dermatophyte spores, summarized from publications by dermatologist Dr. Karen Moriello at the University of Wisconsin School of Veterinary Medicine.

Material Cleaning Step Disinfection Step
Carpeting (small area rugs) Vacuum Launder, any water temperature and cleaner is sufficient. Wash separately from nonexposed laundry.
Carpeting (wall to wall) Vacuum Professional steam cleaning
Chemical disinfection (spray with a disinfectant then rinse with a carpet shampooer after 10 minutes of contact time)
Upholstered furniture Vacuum
Lint rollers or duct tape
Professional steam cleaning
Chemical disinfection (spray with a disinfectant then rinse with a carpet shampooer after 10 minutes of contact time)
Hardwood floors Vacuum
Use disposable electrostatic wipes (Swiffer® pad)
Wash with a cleaning product safe for hardwood flooring (e.g., Murphy’s Oil Soap®)
Towels Launder twice on a long cycle (for ≥14 minutes). Any water temperature and cleaner is sufficient. Wash separately from nonexposed materials. Do not overload machine to ensure maximal agitation and remove hairs.
Cat trees, pet clothing, fabric collars, etc. Discard items and do not introduce new items until infection has been successfully treated.

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