Heartworm disease in dogs is caused by long slender worms that live in the right ventricle  of the heart and pulmonary artery.  The worms are spread from dog to dog  by mosquitoes.

     The adult female heartworm produces larvae called microfilaria that circulate in the blood.  The mosquito ingests the larva from an infected dog and then carries it to another dog.  The larvae stay under the skin of the dog for about three months.  Then they travel to the heart where they become mature heartworms in about three more months.  It takes six months before the adult heartworms are producing larvae that can be found circulating in the blood.

     The symptoms of heartworm disease vary  depending on how many worms there are, the location of the worms, the length of time of infection, and the individual response of the infected dog.  If the heartworms are present in sufficient numbers, they can cause congestive heart failure by blocking or decreasing blood flow through the heart.  Some of the signs of heartworm disease are coughing, fluid buildup causing a bloated appearance, decreased appetite, weight loss, tiredness, and even death.  Your dog  may show any one of these signs or all of them depending on the severity of the disease.  If your dog has only a few heartworms he may not show any of these symptoms.

     There are several laboratory tests to detect heartworms during routine  examination.  Examination of your dog's blood for heartworms should be done every six months.  Usually an occult heartworm exam is done with the annual exam, and a microfilarial exam is done with the semiannual exam.

     Heartworm disease can be prevented by administration of a prescribed preventative medication (We recommend Heartgard, Interceptor, and Sentinel).  These medications must be given in the prescribed manner continuously for the rest of your dog's life.  These medications may only legally be prescribed within twelve months of the last heartworm test.  If this medication is given to a dog with heartworms,  it could have a severe and potentially life threatening reaction.  Puppies should start on heartworm preventative as soon as possible.  This is usually at 6 to 8 weeks.  As your puppy grows, the dosage of medication will be increased.  Your puppy's weight should be checked every month.

    Please call if you have any further questions about heartworms.