Types of Veterinary Disinfectants: Choosing One for Cats

For cat areas, choose a disinfectant that kills non-enveloped viruses, because that is what panleukopenia and calicivirus are. Accelerated hydrogen peroxide, potassium peroxymonosulfate and correctly diluted bleach all do, on a surface that has been cleaned first. Quaternary ammonium products ("quats") lack independent evidence against those viruses, alcohol does poorly against them, and phenol-based disinfectants are toxic to cats.

No single product does every job. The feline disinfection guidelines from the European Advisory Board on Cat Diseases (ABCD) set three priorities: the product has to work, it has to be safe for the cat, and it has to be safe for the people using it every day.

Why Cat Areas Need a Tougher Disinfectant

Shelters, catteries and hospital wards put many cats close together, often while they are stressed, so one sick cat can expose many others. The germs behind the worst outbreaks in those rooms are also some of the hardest to kill.

• Panleukopenia (feline parvovirus) is a non-enveloped virus. The ASPCA notes it can persist in the environment for more than a year and resists some common shelter disinfectants.
• Calicivirus is non-enveloped too.
• Ringworm spreads through fungal spores, and those spores need a product proven against them.

Parvovirus is the benchmark. It is the most resistant virus, so a product that kills it will likely kill most other viruses as well. At the other end, enveloped viruses such as feline leukemia virus and feline herpesvirus die fairly quickly outside the cat without any special treatment.

Disinfectant Types at a Glance

"Yes" below means the class worked in independent testing or shelter guidance when used at the label dilution, on a clean surface, for the full contact time. The product label still decides the details.

Sources: ASPCApro Shelter Disinfectant Quick Reference, ABCD feline disinfection guidelines, Traverse and Aceto (Veterinary Clinics of North America), Moriello (2015), Hurley (2005).

The Main Types, One by One

Accelerated hydrogen peroxide (AHP)

AHP products are stabilized hydrogen peroxide disinfectants made for surfaces. In the ASPCA's shelter disinfectant quick reference, AHP covers non-enveloped viruses and ringworm, is only minimally slowed by organic material, and has some detergent action. In a 2015 laboratory study by Moriello, an AHP concentrate killed both main ringworm fungi in naturally infected material with 10 minutes of contact. The Veterinary Clinics review also prefers AHP wipes over quat wipes.

AHP is not the same thing as the hydrogen peroxide sold in pharmacies. The shelter evidence in the table applies to AHP disinfectants, so don't swap one for the other.

Potassium peroxymonosulfate (PMS)

PMS is an oxidizing disinfectant. The ABCD guidelines describe it as strongly bactericidal and virucidal: it kills parvovirus with 10 minutes of exposure and reduces calicivirus. For ringworm, strength matters. In Moriello's study the stronger concentration killed the fungi and the weaker one did not, so follow the label's ringworm directions. The trade-off is corrosion of plain metals and concrete.

Peracetic acid, a related oxidizer, holds up well in dirty conditions but is corrosive too.

Bleach (sodium hypochlorite)

Bleach is broad and, in the ABCD guidelines' words, relatively safe around cats. It is one of the few chemicals that inactivates parvovirus. It also has real limits:

• It needs a clean surface, because organic material inactivates it quickly.
• It loses strength once diluted, so mix it fresh every day.
• It is caustic, corrosive and a respiratory irritant, for cats and staff alike.
• Never mix it with other products. Bleach mixed with acids releases toxic chlorine gas.

Published dilutions differ, so follow your clinic protocol and the product label. For ringworm spores, the Merck Veterinary Manual gives 1:10, while the ASPCA quick reference and Moriello's study used 1:32 after thorough pre-cleaning. For bacteria, parvoviruses and respiratory viruses, Merck gives 1:32. The ASPCA also points out that household bleach is most often 5.25%, so check the concentration on your bottle.

Contact time follows the same rule: keep the surface wet as long as the product label states. Merck and the ASPCA list 10 minutes for bleach; the Veterinary Clinics review says at least 15 minutes.

Quaternary ammonium compounds (quats)

Quats are common in clinics because they are easy to use and have some cleaning action. For panleukopenia and calicivirus, though, the evidence isn't there. The ASPCA chart answers "not according to independent published research" for non-enveloped viruses, and the ABCD guidelines say there is no evidence that quats work against parvovirus. Organic material, soap and hard water inactivate them. For ringworm, the ASPCA accepts a quat only when its label claims fungicidal activity against Trichophyton.

The ABCD guidelines conclude that quats are probably best avoided in cat environments.

Alcohols and hand sanitizers

Alcohol does poorly against non-enveloped viruses: in testing, parvovirus survived 5 minutes of alcohol exposure. Hand sanitizers don't reliably inactivate panleukopenia virus, calicivirus or ringworm spores either, so between cats, wash your hands or change gloves.

Chlorhexidine and iodine

Both belong on skin, not on cage floors. Chlorhexidine is a hand and surgical scrub, and it is ineffective against calicivirus. Iodine and iodophors are skin antiseptics; iodophors irritate less and don't stain.

Phenols

Phenol-based disinfectants are toxic to cats. The safety section below explains why.

Heat, Steam and UV

Heat is the most broad-spectrum disinfectant there is, and moist heat beats dry heat. Autoclaves sterilize instruments, and steam cleaners can treat floors, work surfaces and soft furnishings. For laundry and food bowls, the ABCD guidelines recommend washing machines and dishwashers that reach at least 60°C (140°F). Parvovirus is the catch again: it can survive 80°C (176°F) for at least an hour.

Ultraviolet-C (UV-C) devices can reduce bacteria such as Clostridium difficile in human hospital rooms, and parvoviruses appear more sensitive to UV-C than caliciviruses. They are whole-room tools: the room must already be clean, and no animals or people can be inside while the device runs.

Clean First, Then Disinfect: The Routine

The first rule is never to spray disinfectant on a dirty surface. Organic material shields germs and inactivates many disinfectants. According to Merck, washing with detergent removes up to 99% of bacteria and gets the surface ready for the disinfectant to finish the job.

With the cat out of the enclosure:

1. Tidy. Remove bedding, litter, food and visible debris. Use a squeegee rather than a broom, and tip litter deep into the bin.
2. Wash. Apply detergent and scrub from top to bottom. Scrubbing breaks up biofilm.
3. Rinse at low pressure. High-pressure rinsing throws germs into the air.
4. Remove the water. Puddles dilute the disinfectant until it stops working.
5. Disinfect. Apply the product at the label dilution and keep the surface wet for the full label contact time.
6. Rinse if needed. Some products must be rinsed before animals return, and rinsing housing and food and water bowls is always recommended.
7. Dry completely. Cats returned to wet disinfectant can get sores on or between their footpads, on the tongue and around the mouth.

A few habits make the routine work:

• Read the label. In the US, look for an EPA registration number and a kill claim for the pathogen you're worried about. Not every household bleach carries one.
• Skip buckets and rags. They carry germs from one cage to the next.
• Spot clean occupied cages. Scooping, wiping and swapping soiled bedding is less stressful for a cat that is staying.

Products That Are Unsafe Around Cats

Cats lack enough of a liver enzyme (UDP-glucuronosyl transferase) that other species use to clear phenols, the ABCD guidelines explain, so phenol-based disinfectants and many essential oils should stay out of feline environments.

• Phenols. The Veterinary Clinics review lists phenolics as toxic to animals, particularly cats and pigs.
• Pine-oil disinfectants. The ABCD guidelines report a pine-oil disinfectant case with incoordination, liver and kidney damage, and death.
• Essential oils, including tea tree oil. In ASPCA Animal Poison Control Center cases, concentrated tea tree oil caused drooling, weakness, wobbliness and tremors within 2 to 12 hours, lasting up to 3 days, and younger and smaller cats were at greater risk of serious illness. Most exposures came from people using the oil on purpose. Keep essential oils out of cat areas and off cats unless your veterinarian directs otherwise.
• Benzalkonium chloride (a quat). The ABCD guidelines list burns to skin and eyes, and mouth and esophageal ulcers in cats that licked it.
• Any disinfectant left wet. Wet floors and cage surfaces can injure paws, tongues and mouths, which is why the drying step matters.

If a cat has been exposed to a disinfectant or essential oil, call your veterinarian or a 24/7 poison line now: ASPCA Animal Poison Control Center at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661 (a fee may apply). Have the product label with you, and don't give anything at home unless you're told to.

Quick Answers

Is bleach safe to use around cats? Correctly diluted, rinsed and dried, it is one of the most useful disinfectants for cat areas. Undiluted, mixed with other products, or left wet, it is not.

Do quats kill ringworm? Only products labeled fungicidal against Trichophyton, used on a surface that was cleaned first.

What should we use after a panleukopenia case? Clean thoroughly, then use a product proven against non-enveloped viruses (AHP, PMS or correctly diluted bleach) for the full label contact time. Your veterinarian or shelter medicine team can help set the protocol for your space.

Sources

• Merck Veterinary Manual: Cleaning, Disinfection, and Sanitation in Shelter Medicine
• Addie DD et al. Disinfectant choices in veterinary practices, shelters and households: ABCD guidelines on safe and effective disinfection for feline environments. J Feline Med Surg, 2015
• ASPCApro: Shelter Disinfectant Quick Reference
• ASPCApro: Feline Panleukopenia
• Traverse M, Aceto H. Environmental Cleaning and Disinfection. Vet Clin North Am Small Anim Pract, 2015
• Moriello KA. Kennel Disinfectants for Microsporum canis and Trichophyton sp. Vet Med Int, 2015
• Hurley KF. Feline infectious disease control in shelters. Vet Clin North Am Small Anim Pract, 2005
• Ingraham A, Fleischer TM. Disinfectants in Laboratory Animal Science. Lab Anim (NY), 2003
• Khan SA et al. Concentrated tea tree oil toxicosis in dogs and cats: 443 cases (2002-2012). JAVMA, 2014
• Pet Poison Helpline: Tea Tree Oil
• ASPCA Animal Poison Control Center

This article is for general information and is not a substitute for advice from your veterinarian.