Heartworm Awareness Month

What are Canine Heartworms?

Heartworm (Dirofilaria immitis) is a fairly large worm, up to 14 inches long that, in adulthood, lives in the heart and pulmonary arteries of an infected dog. The infection is acquired through mosquito bites, as mosquitoes readily pick up larval heartworms from infected dogs and carry them to new dogs. Some geographic areas have severe heartworm problems while other areas have very few. All 50 states have been affected by heartworm disease. In order for the parasite to establish its presence in an area, the following conditions must be met:

•   Types of mosquitoes capable of carrying larval heartworms must be present

•   The weather must be warm enough to allow heartworm larval development within the mosquito

•   There must be infected dogs (or coyotes) in the area

•   There must be vulnerable host dogs in the area

When these conditions come together, an area becomes endemic for heartworm disease.

Infecting a New Dog

When a dog is bitten by an infected mosquito, the L3 (stage capable of infecting a new dog) is not deposited directly into the dog's bloodstream. Instead, it is deposited in a tiny drop of mosquito "spit" adjacent to the mosquito bite. For transmission to occur there must be adequate humidity to prevent evaporation of this fluid droplet before the L3s can swim through the mosquito bite and into the new host.

Once safely inside the new host, the L3 will spend the next week or two developing into an L4 within the host's skin.
The L4 will live in the skin for 3 months or so until it develops to the L5 stage and is ready to enter the host's circulatory system. The L5, which is actually a young adult, migrates to the heart and out into the pulmonary arteries (if there is room) where it will mate, approximately 5 to 7 months after first entering the new host.

Signs of Heartworm disease

•   Coughing
•   Difficulty breathing
•   Sluggishness
•   Exercise intolerance
•   Loss of consciousness
•   Sudden death

Heartworm Preventions

Heartworm tests should be done before beginning treatment

•   Heartgard Plus : (Ivermectin/ Pyrantel) DOGS
o   100% protection against heartworm disease
o   Beef chewable tablets given every 4 weeks
o   Safe for pups 6 weeks of age or older
o   Given at 10x the recommended dose, was safe for invermectin-sensitive collies
o   Effective against the tissue larval stage of D.immitis for 30 days after infection which prevents development into adult heartworms
o   Not effective against existing adult heartworms

•   Sentinel : (Milbemycin oxime/lufenuron)
o   100% protection against heartworm disease in dogs Safe for pups 4 weeks of age or older(>2 lbs) and kittens 6 weeks of age or older (>1.5lbs)
o   Effective against the tissue larval stage of D.immitis for 30 days after infection which prevents development into adult heartworms
o   No adverse effects in collies
o   Provides 99% control of flea egg development for 32 days

   Revolution : (Selamectin) Dogs and Cats
o   Almost 100% effective in prevention of adult heartworms in cats and dogs
o   Administered every 30 days on the skin at the base of the neck/head
o   Safe for pups 6 weeks of age or older and kittens 8 weeks of age or older
o   NOT TO BE GIVEN TO SICK, WEAK OR UNDERWEIGHT ANIMALS


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