Heartworm Disease

Heartworms are carried by mosquitoes. The mosquito bites a dog with heartworms and ingests baby heartworms along with a blood meal.

The mosquito flies around doing its thing while the babies grown up into "L3" larvae. They are like pre-teens.
Now, when an affected mosquito bites your pet, some of these L3 larvae find their way into your pet's body.
They wander around a bit and become adolescent heartworms in about 3 months.
They enter the blood stream and hang around for about 6 to 8 weeks.
Finally, they find their way to the heart and become adult worms.
Once there, they mature, mate, and have babies.
Unfortunately, in 6 months to several years they will cause heart failure.

Heartworm Detection

The best outcome results when a heartworm test is performed before symptoms are present.
When symptoms of heart failure are present, the prognosis is much worse.

Treating is problematic. If the worms are killed, they fall right into the lungs usually causing a fatal pulmonary embolism.
Heartworms have to be killed slowly so the immune system can destroy them without causing large pieces of worms to be pumped into the lungs. This is usually done by giving them a organic arsenic type of drug. It does not have a high safety margin and can be toxic to the dog.
Before being treated a series of tests must be run to determine the degree or stage of infection. This cost alone is in excess of $200.
The treatment protocol is dependent on the stage of infection. Costs are variable but $500 is not uncommon.

Compared to treatment prevention is cheap and easy!
Heartgard Plus is a monthly chewable treat that will prevent heartworms.
It is very safe and comes in three sizes.
It should be given all year long.
Heartworm tests are recommended every 2 years, if prevention is given for 12 months of the year. If any months are missed, then heartworm tests should be done annually.