Eliminating standing water close to your home that could serve as mosquito breeding grounds is also recommended. Finally, natural repellents such as Neem oil and CedarCide may help diminish the chances that pets will be bitten by infected mosquitoes; however, Neem oil products should be used with caution in cats.
Reducing the Risk
Take your dog for regular veterinary visits and blood tests to allow for early diagnosis. The sooner it's diagnosed, the less likely the infection will turn into disease. Limit your dog's exposure to mosquitoes. They can be controlled naturally with citrus oils, cedar oils, and diatomaceous earth.
Signs of Heartworm Disease in Dogs
Right now, heartworm disease can only be prevented through the regular and appropriate use of preventive medications, which are prescribed by your veterinarian.
Heartworm infection is almost 100% preventable in dogs and cats. There are several FDA-approved heartworm preventives available in a variety of formulations. Your veterinarian can recommend the best method of prevention based upon your pet's risk factors and lifestyle.
(CN) – A federal class action claims the makers of a popular heartworm medicine have ignored 7 years of warnings from the FDA and jeopardized the lives of thousands of dogs by continuing to misrepresent the drug as “100 percent effective.” The class claims Merial misrepresented its HeartGard Plus medication because ...
10 Best Heartworm Medications for Dogs in 2025 [Vet-Recommended]
Ivermectin is a safe and effective medication that prevents a variety of parasitic infections in dogs, including heartworm infections. When used as a monthly parasite preventative, the risk of side effects is very low. Side effects and medication interactions are more common with high doses of ivermectin.
Not all dogs with heartworm disease develop caval syndrome. However, if left untreated, heartworm disease will progress and damage the dog's heart, lungs, liver, and kidneys, eventually causing death.
As they break up, they are carried to the lungs, where they lodge in the small blood vessels and are eventually reabsorbed by the body. This resorption can take several weeks to months, and most post-treatment complications are caused by these fragments of dead heartworms.
Although there are fewer mosquitoes in the winter, there is still a risk that your pet could get heartworms if you stop giving heartworm prevention medication during this season. That's one reason veterinarians strongly recommend pets receive heartworm prevention medication year-round.
Heartworms are transmitted from one dog to another by mosquitoes, which pick up the tiny microfilariae when they bite an infected dog. The microfilariae develop in the mosquito and are transmitted when the infected mosquito bites another dog.
Also bring a fresh stool sample for them to check for the presence of worms. Finding microscopic intestinal worm eggs in the stool is the most common way to diagnose worms in dogs. Heartworms are diagnosed with a blood test, an X-ray of the chest, or an ultrasound of the heart.
Find The Best Natural Dog Dewormer
Factors affecting the level of risk of heartworm infection include the climate (temperature, humidity), the species of mosquitoes in the area, presence of mosquito breeding areas, and presence of animal “reservoirs” (such as infected dogs, foxes or coyotes).
However, Heartgard Plus Chewables cannot prevent the development of the adult stage. Use with caution for collies and other herding dog breeds. These breeds have been known to have adverse reactions to ivermectin at elevated dose levels.
Certainly, drug-free strategies can help reduce the risk of heartworm transmission to a dog or cat. Because heartworms are spread by mosquitoes, keeping pets indoors overnight and avoiding walks at dusk or dawn when mosquitoes may be feeding can help prevent exposure to mosquitoes that could be carrying heartworms.
Approximately 1 in 500 cats nationwide test positive for heartworms each year. Heartworm rates are higher in Texas, Mississippi, Alabama and Louisiana, where 1 in 200 cats tested positive (see Louisiana-specific news release).
Simparica Trio Chewable Tablet for Dogs is our vets' pick for the best flea, tick, and heartworm prevention for dogs.
Some breeds of dog (e.g., collies, sheepdogs, and collie- or sheepdog-crosses) are more sensitive to ivermectin than others. This is typically due to a genetic mutation (MDR1) that makes them less able to tolerate high doses of ivermectin and other medications.
" Heartworm preventives do not kill adult heartworms. Giving a heartworm preventive to a dog infected with adult heartworms may be harmful or deadly. If microfilariae are in the dog's bloodstream, the preventive may cause the microfilariae to suddenly die, triggering a shock-like reaction and possibly death.
Common indicators of heartworm infection are as follows:
The short answer to “Can I get heartworm medicine without a vet?” is no. Preventative medication to kill immature heartworm larvae will require a prescription from a veterinarian for several reasons. The Federal Food and Drug Administration regulates all medications, including heartworm preventatives for pets.
Both products are safe for dogs when following directions and have been approved by the FDA to treat and prevent flea and tick infestations. While Simparica was trialed and not approved, Nexgard has not yet been evaluated for use in breeding, pregnant, or lactating dogs.