All dogs should be on one of the many effective monthly preventives from April through December after a negative blood test in order to prevent this deadly mosquito transmitted disease. Infected dogs must be treated before safely taking prevention. Risk of treatment complications and death increases markedly as the disease becomes more progressive and severe. Cats acquire the disease in the same manner. Diagnosis in cats is difficult and may be confused with asthma, allergic bronchitis, or lung worms. Because there is no safe or effective treatment for felines, any cat exposed to mosquitoes should take monthly prevention; topical formulations are available that eliminate the need for pills.