Without treatment the dog will progress into a subclinical stage in which there is a recognizable antibody titer but subtle or no clinical symptoms. Over time, symptoms including decreased appetite, occasional fever, weight loss and a general loss of body condition will become apparent as the dog experiences an increasing parasite load in the chronic phase of the infection. When we consider the wide range of clinical symptoms that may be present with Babesia infection, it would be very difficult to make a diagnosis without supportive lab data. It is rare to find the parasite on blood film exam under the microscope in subclinically infected pets. Young pups and adult dogs only recently infected with the organism may have negative titers, necessitating a follow-up titer to confirm diagnosis.
Controversy abounds regarding when to treat and which medication to use.
Although not approved for general use in the United States, the drug Imidocarb dipropionate is available to veterinarians who apply to use the drug under the FDA's Compassionate Investigational New Animal Drug Exemption. In personal contacts with Dr. Doug Gorman, a veterinarian using Imidocarb to treat symptomatic and asymptomatic positive titer dogs, he reports good success with this therapy. Usually a single injection of the drug into the muscle is all that is required but occasionally a second injection may be needed at a later date if symptoms reoccur. Side effects are minimal and include local discomfort at the site of injection, drooling and occasional vomiting. It is recommended that the patient be observed in the animal hospital the day of the injection for development of any of these side effects.