VCA Conewago Animal Hospital

Heartworm Disease

Heartworm disease is a very serious disease that affects both cats and dogs. If heartworms are left untreated, the disease can be fatal. The vector for the disease are infected mosquitoes, however, the disease affects cats slightly differently than dogs. In cats, the disease is more commonly referred to as H.A.R.D (Heartworm Associated Respiratory Disease). Unlike dogs which can be infected with up to several hundred heartworms, cats typically are infected with 1-4. Immature heartworms pass through vessels of the heart where most of them die causing sudden inflammation. The surviving heartworms travel to the lungs and mature causing acute inflammation. The adult heartworms in cats can live 1-2 years. Heartworm disease in cats can be difficult to diagnose, therefore it is recommended that your cat stay on year round heartworm prevention.

Heartworm disease in dogs is more easily diagnosed. However, the disease is just as serious and just as fatal if left untreated. Heartworms in dogs differ in cats in that they spend the majority of their adult life in the right side of the heart and in the major blood vessels that connect the heart to the lungs. Heartworms can affect dogs in a number of ways. Typically, dogs show no distinctive signs of heartworm disease, therefore it is highly recommended to have your dog tested annually for heartworm disease. The most common sign of infection is a cough. Heartworms can block major vessels resulting in a fluid accumulation in the abdomen called ascites. In rare cases, some dogs may experience sudden death due to heart failure from the large number of worms that a dog may be infected with.

The most effective and economical way to protect your pet from heartworm disease is to have an annual screening done on your animal for the disease, and keep your pet on a once monthly topical or chewable heartworm preventative.

Heartworms disease is transmitted through mosquitoes. When a mosquito bites an infected animal, it ingests very small heartworm larvae called microfilariae. That mosquito then becomes the means of transfer or vector for the disease. When the infected mosquito bites another animal, the heartworm larvae enter the blood stream of the animal and mature.


Specialty Care

Sometimes sick or injured pets need the care of a veterinary medical specialist. When that happens, VCA specialty hospitals work closely with the general practitioner veterinarians who refer cases to us in order to provide seamless veterinary care to your pet. When your pet is facing any kind of serious illness or injury, our specialty referral hospitals will provide the compassionate and expert care your beloved pet needs.

Our goal is to make sure that when you and your pet are in need that you have access to board certified specialists who are up to date on the very latest developments in their field. In our state of the art hospitals, our specialists also have access to the most sophisticated diagnostic and treatment tools and techniques from ultrasonography and endoscopy to CAT scans and even MRI.

As part of the VCA family, we have over 83 specialty hospitals across the US and Canada which provide referral specialty care, so there may be one near you. Our specialized services include: behavior, cardiology, critical care, dentistry, dermatology, integrative medicine, internal medicine, neurology, oncology, ophthalmology, radiology, rehabilitation, reproduction, and surgery.

Find a VCA Specialty Care Animal Hospital near you:


See all VCA Animal Hospitals >


Emergency Care

IN CASE OF AN EMERGENCY DURING NORMAL BUSINESS HOURS:  Please call us immediately at 717-632-4425

IN CASE OF AN EMERGENCY AFTER NORMAL BUSINESS HOURS:  Please call one of the following emergency hospitals immediately.

Animal Emergency & Referral Center of York (Open 24 hours)
1640 South Queen Street
York, PA 17403

Central Carroll Animal Emergency (Open 7pm-7am & weekends)
1030 Baltimore Blvd., Ste 180
Westminster, MD 21157