Slightly neglected dog with contagious health issues?

Is there any recourse for sitters when a sitters dogs health is adversely affected because of interaction with a client’s dog?

Background: I recently accepted a last-minute week-long booking and attended my meet and greet(Sunday). During the meet and greet no health concerns were mentioned by the owner despite some obviously thick (aged)scabbing, hair loss, and lumps/bumps on the dog’s neck, behind the ears, elbows, haunches, belly, anus, top of the tail. The owner only mentioned some potential ear irritation and provided drops. I did not inquire further as I put my trust in the clients to let me know if there are health concerns of any kind that are relevant to my assignment. Most people provide more information than is necessary. I have seen dogs with some alarming-looking conditions that were actually harmless so I try not to judge. My first night with the dog I noticed some constant licking and occasional scratching during the evening times but didn’t think too much of it as all dogs do it to some degree, right?

I got prior approval to introduce my pup who is an ESA. He is a 10-month-old pup who LOVES dogs. He actually comes to my dog friendly workplace and whenever possible joins me during my rover assignments. Him and this other dog hit it off and spent a couple of evenings wrestling, playing together (Monday, Tuesday). By Wednesday both myself and several coworkers had noticed a marked increase in aggressive grooming, scratching, licking. He is current on flea meds but I of course did a spot check. He is a medium/short hair dog (terrier) with blonde/light tan coloring making flea detection a breeze. I am fairly certain this is not a flea issue. I ran a comb through the other dog and did not see obvious sign of fleas. I will say the own requested I not take their dog on walks because of flea problems they had previously experienced while walking their dog in the neighborhood.

It is now Thursday morning and I have found some fresh rashes and redness on my dogs’ legs/belly, I assume are arising from the constant scratching. I spend a lot of time with my dog as he comes to work and goes most places with me. I know where/how he spends his time and I know how many scratches is typical for him throughout the day. In the 6 months I have had him we have met many dogs and visited many places and up until now, not had any incidents. From food to exercise to places he visits there is not much I can point my finger at as a possible cause other than the flaming arrow pointed at the dog that is my current assignment.

I called the rover hotline, no help. I reached out the owner who mentioned possible food allergies, so no help. It is obvious from the conditions the dog is living in that ... (more)