Heartworm

Canine heartworm is a dangerous disease, which has spread to virtually all parts of the United States. It is spread by mosquitoes; thus, areas heavily populated by these insects are at greater risk.

•        What is Heartworm?

o       Parasite that lives in the blood of a dog’s heart and adjacent blood vessels.

o       Adult heartworms living in a dog’s heart produce offspring called microfilaria that circulate in the infected dog’s blood.

o       It can take 3 months for the heartworm to reach a mature length of 9-14 inches.

o       At this time the female heartworm begins to produce microfilaria.

o       It takes about 6 months from the time the dog is bitten by an infected mosquito until adult worms produce microfilaria.

o       In some cases, up to 200 worms can be found in the heart.

•        Symptoms

o       difficulty breathing

o       coughing

o       lack of stamina

o       weight loss

o       rough hair coat

o       In many cases, these are advanced symptoms. Some dogs do not appear to have symptoms in the early stages.

o       If not detected & controlled with proper treatment, heartworms can lead to congestive heart failure and death.

•        Prevention (Also see next bullet point)

o       Heartworm disease is easy to prevent if you follow precautionary measures.

o       Take pup to vet early and talk to them about which medications are right for your dog.

o       Follow medication’s directions and you won’t be concerned with this dangerous disease.

o       Some medication available

§        once a day chewable (Filarabits)

§        once a month chewable (Heartgard, Advantix)

§        6 month injectable (ProHeart6)

§        mosquito repellant that does not contain DEET

•        Diagnostic Testing and Preventative Medication

o       Highly effective diagnostic testing and preventative medications have been developed.

o       It is necessary to have a heartworm test prior to using a preventative medication if the dog is over 4 months.

o       Severe or fatal reactions may occur if they are given to dogs with heartworm disease, or may create diagnostic confusion at a later date.

o       Testing is usually done in the spring (March-April) when mosquitoes develop.

o       A small amount of blood is necessary for a heartworm test, which is very accurate in detecting the disease.

o       If the dog tests negative, he/she is put on preventative medication from April-December.

o       The preventative medication kills the immature larvae before they become adults. It does not kill the adult heartworms.

•        New Medication Available

o       Heartworm treatment should be much safer for dogs now that a new medication, Immiticide, is available to veterinarians.

o       This medication has fewer side effects and kills a higher percentage of heartworms than Caparsolate.

o       When the heartworms are killed by medications, a danger of embolism results if the dead worms block the flow of blood to the lungs.

o       This is a common cause of death during a heartworm treatment.

o       This risk still exists with Immiticide, but to a much lesser extent, due to differences in the timing of heartworm deaths.

o       Immiticide does not appear to damage the liver or kidneys.

o       Following treatment, complete rest is needed.

Excitement and exercise should be avoided for at least a month, followed by gradual return to normal activity.