The severity of the infection depends on many factors including the number
of mature worms, the length of the infection, and a dog's activity level.
Cats may only have a
few mature worms or might only be infected with immature worms.
To avoid accidentally
causing mature worms to die off, a heartworm test (4Dx) is administered annually, prior to refilling your heartworm prescription.
Worms mate by joining their clitella (swollen area near the head of
a mature worm) and exchanging sperm.
Occasionally,
the mature worms (they look like spaghetti) can be found by the guardian in the cat's stool or vomit.
The treatment for heartworm disease is perilous, as we must kill all
the mature worms in the heart, which can lead to the very problem we are trying to avoid — lung compromise and extreme pain.
But even
some mature worms appear to resist the killing - effects of the drug.
Occasionally,
the mature worms can be found in the dog's stool or vomit.
Should
a mature worm move into the cat's brain the unfortunate creature might experience blindness and seizures.
«Dogs are infected with heartworms by mosquitoes, but it takes a long time for heartworm larvae to mature into adult, reproducing worms that can strangle the heart,» says Jennifer Miller, President of FOTAS, «so heartworm disease in a healthy, young dog is treatable with a course of antibiotics, which weakens
any maturing worms, followed by monthly heartworm prevention medicine, like Heartguard, which every dog in the South should be on anyway.»
After a host is infected with the tiny parasite, the developing and
maturing worm (called larvae at this point) moves freely through the system and into the connective tissue of the victim.
Mature worms are often 3 - 4 in.