Just Ask the Expert: Will chlorhexidine kill ringworm?

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Q: My rescue group has recently had a serious outbreak of ringworm stemming from our local humane society. We were told to have our fosters disinfect their homes with chlorhexidine. Is this is a successful method of ridding the environment of ringworm spores. If it is, how effective is it?

A:

The short answer

Chlorhexidine alone will not provide reliable sanitation to remove ringworm from your foster homes. Fortunately, addressing ringworm contamination in homes can be very successful with some time and effort. Below are the steps that I recommend for each foster home with ringworm.

Step-by-step guide

Dispose of any items exposed to the affected cats or kittens that cannot be washed or easily disinfected such as toys, scratching pads, etc.

Wash any bedding that can be laundered on the longest cycle twice. Dry as normal. No special detergents are needed.

Vacuum all exposed areas to remove fur and any other large debris.

Once the visible debris is cleared, disinfect all other surfaces such as tile, laminate flooring, counter surfaces, crates, etc. Cleaned with either a 1:10 dilution of bleach or Rescue, an accelerated hydrogen peroxide disinfectant. Rescue is more user-friendly and comes in both spray bottles and wipes. The vacuum bristles and washing machine also need to be cleaned and wiped down with disinfectant before future use.

Since hardwood floors and furniture usually can't be disinfected without causing damage to the finish, clean wood surfaces and areas with a Swiffer WetJet or a similar product. This effectively removes ringworm spores.

Use hot water extraction to decontaminate carpets and upholstery. If renting a device for hot water extraction is not feasible, washing the fabric twice with carpet shampoo is an alternative.

As a final precaution, the environment can be cultured just as you would for diagnosis of ringworm in an animal. The ideal way to obtain a sample for culture is by wiping any exposed surfaces with a Swiffer mop or similar product and then bringing in a swatch of the disposable cleaning surface for culture.

Thankfully, it's uncommon for healthy adult cats to acquire ringworm infection from a contaminated environment alone. But the above steps should help protect against any future transmission in the home.

Erin Doyle, DVM, DABVP, is the vice president of the Associate of Shelter Veterinarians and the lead veterinarian of Shelter Veterinary Services at the Animal Rescue League of Boston.