By Dr. Alicia Simoneau, Humane Pennsylvania Chief Veterinary Officer
April is National Heartworm Awareness Month! To make sure all dogs are protected from this serious disease, Dr. Simoneau has provided some valuable information for you and your pets.
A pervasive, serious medical condition, heartworm disease affects more than 1 million dogs in the U.S. every year. The disease can cause irreparable organ damage, but it can be both treated and prevented. Cats and ferrets may also be affected by heartworms, but usually not to the same extent as dogs.
What Causes Heartworms?
Heartworm disease is caused by an internal blood parasite, Dirofilaria immitis. Adult heartworms produce a pre-larval stage of the parasite, called microfilaria, which is passed from one dog to another by mosquitos.
How Does Heartworm Disease Spread and Develop?
In geographic areas where mosquitos thrive year-round, heartworm disease remains endemic. Heartworms are diagnosed nationwide, but the Southeastern states harbor mosquitos that carry heartworm. Dogs are frequently taken from the south to the northeast, and people take their pets on vacation.
When a mosquito has a blood meal from a dog that has adult heartworms, the microfilaria is taken in by the mosquito and undergoes transformation to a larval stage, which can now be a source of infection for another dog. This larval stage parasite is injected from the mosquito to another dog with the next blood meal the mosquito takes.
Inside the canine host, the larval stage parasite matures into the adult stage. If not prevented by medication, the worms continue developing. As the parasite molts in the dog, it migrates through its tissue and travels into the bloodstream. The parasite finds the heart and blood vessels to the lungs, where it stays permanently lodged and is now a mature adult. The process from the larval stage to the adult stage takes about 7 months, and adult heartworms can live for 5 to 7 years.
Untreated heartworm disease results in congestive heart failure in the dog. However, the heartworm infection causes scar tissue and severe inflammation to develop even before the end-stage disease. These effects can occur as early as 7 to 12 months after a dog is bitten by an infective mosquito.
How Can Heartworms Be Prevented?
The larval stages are susceptible to medication known as heartworm preventative, which kills them and prevents them from developing into adult worms. Heartworm preventatives work to kill the heartworm larva in the dog’s tissues the day they are given. The aim is to prevent the current infection from advancing, i.e., prevent the parasite larva from developing into adults.
Heartworm preventatives do not have lasting effects, however. They clear larval heartworm infections once every 30 days. As such, they must be administered to the dog every 30 days.
It is recommended to work with a vet to get a dog on a testing schedule and give medication that kills the
larval stage of the heartworm before it has the chance to mature into an adult worm and cause excessive damage.
Screening tests look for antigens that are produced by adult female heartworms. The heartworm doesn’t make the antigen the test is looking for until the heartworm is mature, and maturity occurs 7 months after an infective mosquito transmits the larval stage of heartworm via a blood meal. This is why puppies don’t need a heartworm test to start the medication that kills the larval stage.
There is no way of knowing if immature worms exist, so testing is recommended 4 to 7 months after exposure. In young dogs at higher risk, testing twice in the first year is recommended. For adult dogs that are given year-round heartworm preventative monthly, or for other lower-risk patients that are given the preventative yearly, testing is often the recommendation.
How Is Heartworm Disease in Dogs Treated?
Once a dog is diagnosed with adult heartworms, the treatment is a year-long process. A series of oral and injectable medications are administered under the observation and guidance of a veterinarian, and stringent exercise restriction is necessary for many months.
Once the active infection is cleared, the dead adult heartworms continue to break down and be removed by the dog’s body. Scar tissue will always remain in the dog’s lung vessels and heart.
The Bottom Line
This internal blood parasite has life-threatening consequences for dogs — and those who consider them to be a family member — and it is prevalent in the United States. Heartworm disease in dogs is much easier to prevent than treat, so it is imperative to work with a veterinarian to develop a heartworm prevention plan specific to your dog to keep them healthy and happy.
Schedule an appointment and develop a heartworm prevention plan by visiting https://hvhospitals.org/contact-us/!
Thursday, February 23, 2024, is World Spay Day, and 
pets will prevent future costly issues such as uterine infections, cancers, and behavioral problems. For more information or to make an appointment, please visit our website: 
infection among other things. After her vet check, it was recommended to adopt her out as hospice care. I decided to adopt her knowing I might not have her for long. Sadly, she passed away four months later, but I made sure she spent the last few months of her life happy and loved.
One September morning a cat was abandoned at the shelter. We scanned the cat and found out she was adopted from our organization 15 years ago. She was frail and extremely underweight. Her name was Rapunzel but I called her Princess Thumbs because she was a polydactyl cat. After getting her blood work done it turned out that she had hyperthyroidism and needed to be on medication and a special diet. After doing some research about the disease, I adopted her. I was not sure of the outcome since she was so thin and I had no idea how long she was in this condition but I was determined to try. Unfortunately, her illness was too far gone, but she did give me two wonderful weeks. She was truly an amazing cat. I miss you, my crunchy princess.
surrendered for meowing too much. Her name was Marigold. She was super sweet and did indeed “talk” a lot, which made me love her even more. After getting blood work done for her, results showed that she had hyperthyroidism. I was a little nervous because I was worried I would lose her too. I still decided to adopt her and give her a chance. Well, she is now a happy cat that “talks too much” if her bowl is empty. She will hop after you like a rabbit making sure you hear her loud and clear.
During our annual 12 Days of Adoptions event during the holidays, the majority of the cats at the shelter were finding homes. There was one cat I was hoping would find her furever home since she had been overlooked for 8 months. Her name was Karma, an adorable Orange and white cat with the cutest “RBF” squishy face. Karma had a few medical issues. She was FIV+, had an old ankle injury that made her limp, and experienced bladder issues which would require a special diet and medication for life. When Christmas Eve and the last day of the adoption special arrived, I told Karma “It’s time to go home”. It’s been two months since she came home and I’m so happy I made that decision. Her health has since improved and she couldn’t be happier in her new home.
I don’t like to admit it, but as an independent rescuer for decades, I became judgmental of people who struggled to give basic care to their pets. When I met pet owners who did not match my level of pet care, it was easy for me to immediately deem them as uncaring and irresponsible without knowing any further details! However, when I started working professionally in animal welfare, I met people who had the same empathy for the animals, but with far less resources. They were rescuing outside kittens, helping injured strays or inheriting pets from friends/family that can no longer care for them and sometimes, they need a little help. 
turn, leaves more space at the shelter for the animals that really need a safe place, vet care and possibly a new family (or are reunited!). 
benefit from our organization’s enrollment in a food program that provides the same brand and type of food to everyone. Ongoing participation in this program results in a win-win situation:
Many refer to me as a “crazy cat lady,” but I don’t mind. I have spent more than 20 years advocating for the rights of and implementing humane management of free-roaming/community/feral cats in Berks County. I took care of 29 inside cats for four years and have volunteered in animal rescue for my entire life.
Although your cat still exhibits some wildness about them, rest assured that they are dependent on you to provide healthy food, adequate shelter, proper stimulation, and an annual veterinary exam to keep them in tip-top shape.
the first non-profit walk-in animal clinic in the region. The 
vaccinations. Guinea pigs can’t help us pay for our work. All those things require people. And without people, we’re nothing.
without an appointment — and it’s designed to serve more community members at an affordable price point of only 60% of normal veterinary hospital rates.
owners happen because the pets are microchipped and registered with up-to-date contact information.
Each microchip has a unique number, an ID number of sorts, that needs to be registered with the pet owner’s name, address, and phone number. It is important to ensure a chip is registered and information is kept up to date.