Heartworm

This is a somewhat controversial disease in Melbourne. Should I prevent it or not worry about it? We will explain how the disease works, the pros and cons of prevention, and encourage clients to let us know whether they want to prevent this disease or not. It is a complicated disease that needs to be prevented, because it is hard to cure once infected.

WHAT IS HEARTWORM:
This is a parasite which lives in the heart. It is transferred from dog to dog by mosquitoes. Once infected, after 1 month the worm actually changes to a stage that the treatments no longer kill. Hence there is only about a month's time frame in which we can kill new infections. For proper heartworm prevention, we need to use a monthly treatment, and never miss! This is the big difference between heartworm and normal intestinal worms. Normal intestinal worms will be killed by intestinal worm tablets no matter how old the worms are. It doesn't really matter if regular intestinal worm treatments are missed. It does matter if routine heartworm tablets are missed. Fortunately there is a yearly prevention that can be given in the form of an injection. This injection lasts 1 year, hence all new infections are killed.

WHAT DOES HEARTWORM DO TO MY DOG:
The young worms introduced via mosquitoes circulate the blood stream until they become adults at 6 months, lodging in the heart and lungs. It usually takes about 2 years to actually start showing signs of heart disease, but at this stage it's very difficult to cure. Left untreated heartworm is often fatal.

DO I NEED TO PREVENT HEARTWORM IN MELBOURNE:
Many clients have told me they've had dogs all their lives and never prevented heartworm and their dogs have never got heartworm. In Melbourne I expect this to be the case. Heartworm in Melbourne is rare. Only a few dogs get infected each year in Melbourne, whereas in Queensland and the Northern Territory heartworm is a very prevalent disease and one would be unwise not to be on prevention up there.

Hence the takehome message on heartworm is:

	In Melbourne this is a low risk disease
	If infected and not treated it is usually fatal
	For owners deciding they want prevention, diligence is required, whether using monthly treatments or yearly.

Hence in Melbourne heartworm prevention is a slightly tricky one for our “risk-reward” ratio of medicating our pets. The chance of getting heartworm is low, but very nasty for the few that do. Personally I treated my own dog until about 11 years old, then stopped, as Burnese Mountain dogs are not long lived dogs. So I recommend treating young and middle aged dogs but ask my clients to consider stopping prevention in their very latter years. Ultimately the choice is yours.