Looking for a reference or source for the recommendation of allowing the public to pet shelter animals while they are in their cages or runs.

Last updated: 2015-07-15
Author: Dr. MC Aziz
Document type: FAQs
Topics: Shelter Design and Housing, Infectious Disease
Species: Canine, Feline

Let people pet the kittehs! Here are the reasons we think letting potential adopters touch shelter animals is a life-saver, not a threat.

Question –

I’m looking for a reference or source for the recommendation of allowing the public to pet shelter animals while they are in their cages or runs. This would be as opposed to having them behind glass enclosures because of the fear of having the public transmit disease. 

Response -

The "Scrub Top Study": Disease Transmission Risks in a Typical Shelter Adoption Ward

During consultations, Dr. Cynthia Karsten (KSMP Outreach Veterinarian) has noticed more and more shelters being designed with cats housed behind glass on the adoption floor.

Cat behind plexiglass

Recently, she was reminded of an exercise that she did when she was a veterinary student. 

Dr. Karsten rounded up the ever-willing-to-research Dr. Denae Wagner, and they visited a shelter armed with a Luminometer designed to measure ATP (adenosine triphosphate - the energy source in all living cells).  Detecting and measuring ATP is a method of determining the relative cleanliness of a surface or liquid since microbiological organisms, like bacteria, yeast and mold, all contain ATP. 

The main goal was to monitor the effectiveness of cat cage cleaning using various methods and by different staff members.  While this was great fun, in the midst of the project, the duo had another idea:  to measure the ATP of a hand that pets multiple cats vs. the scrub top of a staff member. The "Scrub Top Study" was born.

So the side project began.  Dr. Karsten started by washing her hands in a manner that most people wash their hands – nothing fancy, just the usual.  Then she proceeded to pet 3 different cats, through the cage bars, as an excited potential adopter might do.  Once she was satisfied with the affection that she had given to the cats, the Drs. measured the ATP on Dr. Karsten's hand.  It measured 66899 RLU’s (reflective light units).  See figures 1 and 2.

Collecting a sample from the hand
Figure 1
Luminometer reading: 66,899 RLU's
Figure 2

They then asked for the scrub top of a staff member who happened to walk by at the opportune time.  The measurement from her top was 2,362,640 RLU’s– more than 35 times what was on Dr. Karsten's hand. See figures 3 and 4.

Collecting a sample from a staff member's scrub top
Figure 3
Luminometer reading: 2,362,640 RLU's
Figure 4


This valuable side project supported the hypothesis that the average adopter coming into a shelter to interact with the cats is NOT a large risk factor for transmitting disease between animals. 

The ASPCA conducted a very interesting study looking at what draws people to adopt particular pets.  In this published study, they found that adopters reported that “physical appearance” is the primary motivator for choosing a dog, while “behavior with people” counted most for choosing adult cats.

From this information and the informal 'Scrub Top Study', it is clear that the benefit of allowing a potential adopter to interact with shelter cats greatly outweighs the risk that this poses.  So the bottom line and one of the most important life-saving measures that we can take is…

University of Wisconsin Shelter Medicine Program
Koret Shelter Medicine Program

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


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