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/!

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By Humane Pennsylvania Chief Veterinary Officer, Dr. Alicia Simoneau, DVM

Last month, something big started for pets and their caretakers in our community. Did you hear? Humane Pennsylvania’s Healthy Pets Walk-In Clinic opened its doors at the Freedom Center for Animal Life-Saving at 1801 N. 11th Street in Reading!

Humane Pennsylvania (HPA) staff had been planning the venture for quite some time, and the pandemic delayed the greatly anticipated opening of the Healthy Pets Walk-In Clinic for far too long.

The concept of the Walk-In Clinic grew out of HPA’s pioneering Healthy Pets Initiative, which provides meaningful access to veterinary care for all in need. This clinic was made possible through the visionary generosity of the Giorgi Family Foundation and Jay Rosenson, in memory of Eileen Rosenson. Their leadership is helping HPA build the best communities anywhere to be an animal or animal caretaker.

The new Freedom Center, which opened July 1, 2021, included space for the Walk-In Clinic, but it took nearly a year to come to fruition. The Walk-In Clinic features two exam rooms and a comfortable lobby at the entrance at 11th and Bern Streets.

The Walk-In Clinic adds to the continuum of access to veterinary care for Berks County and surrounding communities. Access to affordable veterinary care for every community member is central to Humane Pennsylvania’s mission. HPA has many different ways for animal caretakers to access vet care, depending on their needs: Humane Veterinary Hospitals in Reading and Lancaster, Neighborhood Pay-What-You-Can Vaccine and Microchip Clinics, and now the Healthy Pets Walk-In Clinic.

The HPA Healthy Pets Walk-In Clinic offers comprehensive preventative vaccinations, care, and advice, 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.

Humane PA’s Healthy Pets Walk-In Clinic will be open every Wednesday and Friday, from 9 am to 1 pm. The clinic is first come, first served.

Current services offered for dogs: Exam with a veterinarian ($32, required with any other service), Vaccinations ($14-15), flea and tick preventatives ($9), deworming (starting at $9), Microchip (Free, including registration, with every exam).

Current services offered for cats: Exam with a veterinarian ($32, required with any other service), Vaccinations ($14-15), flea and ear mite preventatives ($9), deworming (starting at $9), Microchip (Free, including registration, with every exam).

At this time, no sick or injured care is provided at the Healthy Pets Wilk-In Clinic. Please contact Humane Veterinary Hospitals in Reading or Lancaster or another veterinary hospital to make an appointment for sick or injured care for your pet.

Visit humanepa.org for additional hours and to see what services will be provided in the coming months.

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Preventing Heartworm Disease In Dogs

April 12th, 2022 | Posted by CCadmin1* in Animal Health | Healthy Pets | Heartworm in Dogs | Heartworm Prevention | Humane Veterinary Hospitals - (Comments Off on Preventing Heartworm Disease In Dogs)
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/!

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