Keeping up with heartworm prevention year round isn't just a summer task — it's a 12-month commitment that could save your dog's life. Many Australian pet owners assume mosquito activity drops enough in cooler months to justify a break, but even one missed dose of heartworm medication for dogs can open a dangerous window of infection. Here's why consistency matters and what you can do to stay on track.
How Heartworm Spreads in Australia
Heartworm disease is transmitted by mosquitoes. When an infected mosquito bites your dog, it deposits microscopic larvae beneath the skin. Over roughly six months those larvae migrate to the heart and pulmonary arteries, where they mature into worms that can reach 30 cm in length.
Australia's warm, humid climate — particularly along the eastern seaboard from Far North Queensland down to Sydney and beyond — means mosquitoes can be active well outside the traditional "summer" window. In tropical regions like Darwin and Cairns, mosquitoes breed virtually all year. Even in Melbourne and Adelaide, mild autumn and spring nights can sustain enough mosquito activity to pose a real threat.
Why Skipping Even One Month Is Risky
Monthly heartworm preventatives work retroactively. Each dose eliminates larvae that entered your dog's body during the previous 30 days. If you miss a dose, any larvae deposited during that unprotected period can develop beyond the stage the medication targets.
Once larvae mature past a certain point, standard monthly treatments can no longer kill them. The immature worms continue growing silently, and by the time symptoms appear — coughing, fatigue, weight loss — the disease may already be advanced and difficult to manage.
In short, a single missed month doesn't just leave a 30-day gap. It can set the stage for an infection that takes months to detect and far longer to address.
The Case for Year-Round Protection
Providing heartworm prevention all year round eliminates the guesswork about when mosquitoes are active in your area. Climate patterns are shifting, and unseasonably warm weeks in the middle of winter are becoming more common across southern Australia.
Year-round dosing also helps you build a reliable routine. It's much easier to give a preventative on the same date every month than to remember when to start and stop a seasonal schedule. Many pet owners who take a winter break simply forget to restart in spring — and that delay is when infections happen.
Quick tip: Set a recurring calendar reminder on your phone for the same day each month. Pair it with another habit — like a monthly weigh-in or nail trim — so it becomes second nature.
Consistent protection also means your dog's flea, tick, and worm prevention stays aligned. Many combination products cover multiple parasites in a single treatment, so keeping to a regular schedule protects against more than just heartworm.
Choosing the Right Heartworm Medication for Your Dog
Heartworm medication for dogs comes in several forms: monthly chewables, topical spot-ons, and longer-lasting injectable options administered by a vet. The best choice depends on your dog's size, temperament, and lifestyle.
Monthly chewables are popular because most dogs treat them like a snack. Brands like Heartgard have been trusted by Australian pet owners for decades and make compliance straightforward. Spot-on treatments suit dogs that are fussy eaters, while annual or six-monthly injections can be ideal for owners who worry about remembering monthly doses.
Whichever format you choose, the key is sticking to the recommended schedule without gaps. A product only works if it's administered on time, every time.
Simple Ways to Stay on Schedule
Consistency is the single most important factor in heartworm prevention. Here are a few practical strategies:
- Buy in bulk. Purchasing a 6- or 12-month pack means you always have the next dose ready and you're less likely to run out unexpectedly.
- Use a dosing diary. A simple chart on the fridge lets everyone in the household see when the last dose was given.
- Link it to payday. Tying the dose to a recurring date you already remember — like the 1st of the month or your pay cycle — reduces the chance of forgetting.
- Keep a spare dose. If you travel or board your dog, pack an extra dose so nothing gets missed while you're away from home.
Staying organised with your dog's parasite control doesn't need to be complicated. Browse our full range of flea, tick, and worm treatments for dogs to find a product and schedule that fits your routine.
Frequently Asked Questions
What happens if I miss one month of heartworm prevention?
A single missed dose creates a window where larvae can develop beyond the stage that monthly treatments eliminate. If your dog was bitten by an infected mosquito during that gap, the larvae may mature into adult heartworms over the following months. Restarting the medication won't reverse development that has already occurred.
Do dogs in cooler parts of Australia still need heartworm prevention in winter?
Yes. While mosquito numbers drop in cooler regions during winter, they don't disappear entirely — especially during mild spells. Because each dose works retroactively to clear larvae from the previous month, maintaining coverage through winter ensures there are no unprotected gaps heading into spring.
Can I use a flea and tick product that also covers heartworm?
Several combination products protect against fleas, ticks, intestinal worms, and heartworm in a single monthly treatment. These all-in-one options can simplify your parasite prevention routine significantly. Check the product label or description to confirm heartworm is included in the coverage.
Protecting your dog from heartworm is one of the simplest and most impactful things you can do as a pet owner. If you're unsure which product suits your dog best, have a quick chat with your vet, then head to our dog flea, tick, and worm collection to stock up and keep your prevention schedule on track all year long.