Biliary fever is an illness of the liver affecting horses, dogs and cats. This is currently the most common infectious disease of dogs in Southern Africa. It is also known as tick bite fever or "Bosluiskoors" in Afrikaans. It is caused by a tiny parasite (Babesia canis) which is introduced into the body by a tick bite.

Feline immunodeficiency virus (FIV) is a virus that's found in domestic cats that attacks the immune system. FIV leads to increased susceptibility to infections and other disease.

Most dogs with gastroenteritis will have intermittent episodes of vomiting and diarrhea. The vomit may contain foamy, yellowish bile, especially after the stomach has been emptied. Many owners will observe dry heaving or gagging after their dog eats or drinks.