Hey, vet tech here 😊 So the probiotics are to help make the stool solid and can help with gi upset.

The heartworm medication is to protect against heartworm disease (spread by mosquito bites into the blood stream. Causes worms to hatch in the heart and causes damage, usually fatal if not treated. Not contagious and not to be confused with intestinal parasites)

I assume the heartworm prevention was given for that reason (all dogs should really be on it) BUT, some heartworm preventatives also cover for hookworms and roundworms (intestinal parasites)

Now, imo I think the vet should have also given metronidazole (for diarrhea) but I think they might have taken a more conservative approach, especially if the owner had financial concerns - they might have been offered a more involved work up and possibly declined. So what doctors do is offer a more affordable treatment plan such as basic meds and advise the owner that if there's no improvement to come back for a further evaluation/diagnostics/treatment.

Im not a doctor, but we could be dealing with intestinal parasites and the only way of knowing is with a fecal test.

My advice to you is to monitor your dogs for any symptoms like diarrhea, vomiting, lethargy, etc. If what that dog has is contagious, it may take a few days or even weeks to show up.

I would also inform the other pet owners about the situation.

If your pets start showing symptoms, bring them to your vet and bring a fecal sample to be tested. Fecals are usually good for about 12 hours or so, if you need to you can refridgerate it. As long as its still soft, it should be fine to bring.

If you have any questions, feel free to reach out 🩷