Heartworm infection risk is highest during spring and summer (specifically April through early fall) when warmer temperatures, increased rainfall, and mosquito activity peak. While warmer months present the highest risk of transmission, heartworms can be a year-round concern in many regions, particularly in warmer climates.

What time of year are dogs most likely to get heartworm?

In most parts of the country, exposure risk is greatest during the warm months of summer and early fall.

Is there a heartworm season?

There's No Season for Heartworms - American Heartworm Society.

Do dogs really need heartworm medicine every month?

Because heartworms must be eliminated before they reach this adult stage, it is extremely important that heartworm preventives be administered strictly on schedule (monthly for oral and topical products and every 6 months or 12 months for the injectable).

Where are dogs most likely to get heartworm?

Are heartworms more common in certain areas of the United States? Heartworms have been found in all 50 states, although certain areas have a higher risk of heartworm than others. Some very high-risk areas include large regions, such as near the Atlantic and Gulf coasts, and along river tributaries.

So Your Dog Has Heartworms, What Now?

What are the first signs of heartworms in dogs?

The first signs of heartworms in dogs are often subtle, including a mild, persistent cough (sometimes a "goose honk" sound), lethargy or reluctance to exercise, fatigue after activity, decreased appetite, and weight loss, but many dogs show no symptoms in early stages, making regular vet testing crucial. These initial signs develop as worms grow and damage the heart and lungs, leading to more severe issues like heart failure or respiratory distress as the infection progresses.
 

How common is heartworm in dogs really?

April is heartworm awareness month. Despite being a common parasite that affects around 1 in every 200 dogs each year, many owners still don't know a great deal about the disease and the effects that it can have on their furbaby.

How to naturally prevent heartworms in dogs?

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.

What is the controversy with HeartGard?

The Heartgard controversy centers on allegations that its maker, Merial, falsely advertised the drug as 100% effective, despite internal knowledge and FDA warnings (circa 2009) that its efficacy was closer to 95%, especially as heartworm resistance emerged; lawsuits claimed this deception led to dogs contracting heartworms, causing severe illness, while a whistleblower suit alleged cover-ups and improper data handling by Merial, though the company maintained product safety.
 

Is it better to prevent heartworm than treat it?

Heartworm is a progressive, life-threatening disease. The earlier it is detected and treated, the better the chances that your pet will recover and have less complications. Dogs: As with most medical problems, it is much better to prevent heartworm infection than to treat it.

What states are worst for heartworms?

North America can carry heartworms. WHERE THE WORMS ARE WORST. The TOP 5 states are: Mississippi, Louisiana, South Carolina, Arkansas, and Alabama.

What temperature kills heartworms?

The temperature cannot drop below 57°F during this time frame or either the mosquito will die or the development of the heartworm will stop.

What is the safest heartworm prevention for dogs?

The safest heartworm prevention for dogs involves FDA-approved medications like Heartgard Plus, Interceptor Plus, and Revolution, with the best choice depending on your dog's specific needs, age, and health; Heartgard (ivermectin) is often cited as very safe, even for sensitive breeds like Collies at recommended doses, while Interceptor (milbemycin) is also a good, safer alternative, and Revolution (selamectin) is another gentle option, but always consult your vet to avoid issues with specific sensitivities (like ivermectin in some collies) and to ensure year-round protection. 

Can you skip heartworm in winter?

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.

Where is heartworm most common?

In the United States, heartworm disease is most common along the Atlantic and Gulf coasts from the Gulf of Mexico to New Jersey and along the Mississippi River and its major tributaries, but it has been reported in dogs in all 50 states.

What are the first signs of heartworm?

Early heartworm symptoms in dogs are subtle, often missed, and include a mild, persistent cough, lethargy or exercise intolerance, and unusual fatigue after activity, while later signs involve significant weight loss, trouble breathing, or a swollen abdomen, emphasizing the need for prevention and regular testing.

Does apple cider vinegar help with heartworms in dogs?

Enzymes in apple cider vinegar are thought to have a beneficial effect against worms as the coating of the worm becomes weak and they then lose their grip on the intestinal wall. Spray the vinegar directly on the food; if your pup does not like the smell or taste, mix it in a bowl of wet food.

What can I give my dog instead of Heartgard?

The chicken-flavored chewable monthly preventative, Interceptor Plus, is a popular alternative to the better-known Heartgard anti-heartworm medication. The main ingredient is Milbemycin Oxime which is anthelminthic.

What happens if I give my dog heartworm medicine and they have heartworms?

Monthly preventatives are labeled and proven to kill baby heartworms, but they will not kill the adult heartworms that are living in your dog's heart. So while it may kill the baby heartworms and prevent more adults, you're allowing the adult heartworms that are already in there to continue causing more damage.

How long can a dog survive with heartworms?

How long can a dog live with heartworms? Dogs are able to live for years with this parasite, however, their condition will continuously worsen. It's a dangerous disease overall, which is why some people have even described untreated heartworms as the “slow kill.”

Does Australia have heartworm?

Most heartworm cases are documented in tropical/subtropical areas of Australia, but they can be found anywhere. Tasmania is not considered to be heartworm-endemic. Approximately 90% of heartworm cases reported to Zoetis in recent years were from Queensland and approximately 10% were from other states.

What state has the most heartworms in dogs?

The leading states for heartworm incidence continue to be those around the lower Mississippi Delta, which has a climate where mosquitos thrive along with the presence of untreated dogs and wildlife that can carry infection.

How do dead heartworms leave a dog's body?

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.

---