Haemobartonella infection is the most common cause of anemia in cats resulting in a syndrome called haemobartonellosis. Based on genetic studies, it is now known that there are actually 2 distinct species that have been reclassified into a new group of bacteria. Mycoplasma haemofelis and M. haemominutum are the proposed names; M. haemofelis is the most likely to make cats extremely ill. It is suspected, but not proven that fleas transmit the organisms between cats. There is currently no universally effective treatment for the disease. Currently used drugs have documented side effects and are difficult to administer for owners since they are given orally for many days. Imidocarb dipropionate is a drug that has been shown to be effective for the treatment of haemobartonellosis in naturally infected cats. The drug was shown to be 100% safe in 10 experimentally treated cats. If effective, this drug would be a much more convenient for owners since it is given only twice by injection. The objectives of this study are to determine whether fleas transmit M. haemofelis and M. haemominutum and whether imidocarb injections eliminate infection.