Stages of Heartworm Infection in a Canine
A mosquito bites an infected dog, gets microfilariae from its blood which grow into larvae within two to three weeks. Miniature worms migrate to the mosquito's mouth and are deposited onto your dog's skin when the mosquito bites it.
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Stage 1
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Larvae dig into the skin, grow for three to four months, migrate out of the tissue to burrow through a lung blood vessel and enter the blood stream, beginning the pre-patent period when blood tests can detect them.
Stage 2
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Larvae settle in the lower lung lobe arteries, multiply and migrate into the heart's right side. Worms become adults within about six months from the time they enter your dog and can grow from 4 to 14 inches long.
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Stage 3
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If both male and female worms are present, they mate and produce more microfilariae. Depending on the number of worms, damage to blood vessels, heart, and lungs begins.
Stage 4
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Heartworms can live five to seven years, continuing to multiply, if they do not kill your dog first.
Symptoms Stages
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No symptoms in Stage 1. Stage 2 has minimal symptoms. Stage 3 symptoms include coughing, fatigue and difficulty breathing. Stage 4 is organ damage. Stage 5 is critical symptoms including shock and death.
Prevention
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Only routine heartworm medications can prevent heartworms. No natural wormers are effective for heartworm prevention or treatment.
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References
Resources
- Photo Credit Image by Flickr.com, courtesy of Jose Roberto V. Moraes
