Leptospirosis

Leptospirosis is often spread through wildlife, so veterinarians used to think of it as a more rural disease, Jones said. That’s not the case anymore, though it’s hard to tell where exactly a dog might get it since the disease is transmitted through urine, he said.

When dog diseases can affect humans, they’re extra worrisome for society, Jones said, noting that it can cause liver and kidney failure in both humans and animals. In fact, it could even lead to infected humans needing a kidney transplant, he said.

The American Veterinary Medical Association (AMVA) says that the signs of leptospirosis vary from dog to dog, but could include fever, vomiting, thirst, jaundice, and either frequent urination or lack of urination. It also notes that, if treated early, dogs can recover. However, Dr. Richard Baumgartner of Atlantic Veterinary Hospital in New Jersey notes that recovery could take months, and some dogs might never fully recover.

Ringworm

Named for the pattern the disease makes and not because it’s an actual worm, ringworm is a fungus that affects a dog’s skin. While it is contagious, isn’t necessarily seen in many dogs these days.

“Most of the time a healthy dog isn’t going to get ringworm,” Baumgartner said, noting that it’s more often seen in puppies and older dogs who already have other health issues. Jones said it’s most often seen in shelter settings.