Question: 

All of our ringworm cats are in one foster home. She has a heated garage that she keeps them in. The cats are caged separately by litter group, and are not free roaming. She is bathing them about once a week with a Clorhex/Miconazole shampoo.  However, if they are all caged together with varying stages of ringworm infection, isn't it likely that they are able to re-infect one another with spores floating around on hair and litter dust?

If a vacuum is used in the space, it is my understanding that it merely blows around more ringworm spores. Is this correct?

Answer: 

Housing littermates together should not pose a concern for re-infection if everyone is on the same treatment protocol of itraconazole and twice weekly lime sulfur dips.  We often recommend breaking litters into groups of two or three to ease crowding and help identify cure more quickly. The lime sulfur dips reduce environmental contamination by inactivating spores that are contained on damaged and shed hairs.

Regarding cleaning, the most important factor in minimizing environmental contamination is effective topical treatment.  Additionally diligent mechanical removal of dust and hair will help keep the environment clean.  Specifically, you can minimize how much the spores are stirred up by not sweeping or airing out bedding inside.  Swiffers® or other electrostatic cleaners can be used in place of sweeping.

Vacuuming should be done on carpet or rugs to pick up infectious hairs and be sure to change out the vacuum bag daily (or discard the contents outside) to prevent recontamination.  When mechanical cleaning and disinfection are in place, airborne transmission of spores is minimally significant.  After thoroughly cleaning, disinfecting with Accel® (1:16), bleach (1:32) or other effective disinfectant can be done.

Chumkee Aziz, DVM
Resident, Koret Shelter Medicine Program
Center for Companion Animal Health
UC Davis School of Veterinary Medicine

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