American Kennel Club Toy Breeds
What is heartworm?
It's an infection by a type of roundworm that literally wraps spaghetti-like strands of worms around the heart.
This can cause blood clots in the lung, liver failure or heart attack. It's often fatal. Even if successfully treated, a dog can suffer permanent organ damage.
How do dogs get heartworm?
The only way is when a dog is bitten by an infected mosquito.
Once your dog is bitten, it will take about seven months for the larvae to mature into adult heartworms.
Since it isn't contagious, your dog can't get it from another dog - only from a mosquito.
What are the symptoms of heartworm?
Symptoms may be as mild as a soft cough and an unwillingness to exercise.
Owners may not realize treatment is needed until more severe symptoms appear. Those include bloated appearance from retaining fluids, abnormal lung sounds, and loss of consciousness from restricted flow of blood to the brain.
How is heartworm diagnosed?
A veterinarian can diagnose it with blood tests.
Note, even if you use a preventive, 99% of veterinarians will want to test your dog each year during his regular checkup. This is standard medical practice and well worth it. No medication is always effective, and your dog could vomit the pill outside your view.
How is it prevented?
You must give your dog a pill every month; that means every month even during the Winter. Your vet will test your dog for heartworm before recommending a preventive.
There's some old wives tales that dogs don't get heartworm when its cold outdoors and mosquitoes aren't present. Why would you risk your dog's health?
Moreover, all the popular heartworm medications also protect against other intestinal worms such as roundworms, whipworms, or tapeworms.
I used to use Heartgard Plus, which has been the gold standard, but now am using a newer medication called Iverhart Plus which has the same main ingredient but is about $10 a box cheaper. A six month supply should be $40-60 depending on where you buy it.
Both medications offer the same guarantee - if you use them and your dog develops heartworm, they will pay for his treatment. Heartgard Plus is a beef flavored tablet while Iverhart is a pork flavored one. My dog has chowed down both without any problem.
WARNING: Any one medication may trigger an allergic reaction in any one dog. Always have a responsible person present for several hours after your dog is given any new medication. Contact your vet immediately if your dog acts strangely or shows symptoms such as swelling or breathing distress.
WARNING: Several years ago there was a preventive called ProHeart 6 that had to be injected by a veterinarian and offered protection for six months.
Unfortunately, it also resulted in serious adverse effects or deaths in thousands of dogs and was recalled at the direction of the the Food and Drug Administration (FDA).
The manufacturer is now reintroducing the medicine which supposedly has been reformulated but still has to be given by injection from a veterinarian. Beware. Some veterinarians may advocate this drug because it's a profit center for them. You can't buy it at a pet store or online. They have to inject it.
For me, once a medicine has unintentionally killed dogs and been pulled off the market at FDA direction, you're pretty much dead in my book.
Do the preventives work?
but. There are lawsuits and an FDA complaint pending
about Heartgard Plus alleging that the product has been advertised
as 100% effective when the reality is that it's 95% or so effective.
The less than total effectiveness is probably true of any medication
you use. For scientific details, read the following:
Increase the odds for your dog by making sure he swallows the medication and avoid exposing him to mosquitoes. That means reduce the times he is outdoors at dawn and dusk when mosquitoes are most prevalent. Real veterinary-school studies have shown that dogs who live outdoors are more likely to be infected. All it takes is one mosquito.
How is it treated and how much does treatment cost?
You may have heard that heartworm is expensive to treat, and it may be.
Dogs are given an injection of a drug called Immiticide. It’s an arsenic-based product that kills the adult heartworms in four to six weeks after two or three injections.
Before the drug is given, there will need a full work-up including blood tests, X-ray and exam. With about $300-400 for total shots, this could cost as much as $1000, depending on where you live and how much your vet charges.
After treatment, your dog will need to be restrained from activity, and for several weeks, you'll probably only be allowed to take him out for potty breaks. His confinement must be implemented if the treatment is going to be fully effective.
Are there alternative treatments?
You may find Internet references to a 'slow kill' method. In that method, dogs are given given an antibiotic for a couple of weeks and then treated with Heartgard or Iverhart every two weeks for up to six months.
This is gentler for the dogs and less expensive for the owners than the standard treatment above. The drawback is that the heartworms can continue damaging your dog's heart and other organs while the treatment is ongoing. I would not expect many vets to use this method and probably only for dogs with a mild (Stage 1) infection and under two years of age.
In the most severe cases, surgery may be the only option. A vet opens up the major heart artery and mechanically removes the worms. It's risky and even those dogs that survive the surgery may suffer some degree of organ damage.
Other treatments such as those labeled holistic or natural are not substantiated by any studies. Ask your vet.
Heartworms are deadly. The treatment is painful for your dog and expensive for you. Prevention, prevention, prevention.