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The veterinarians at VOTS are dedicated to keeping your fur baby healthy and happy. Our practice is set up to help prevent diseases and parasites in dogs and cats.

Let’s face it, our fur babies sometimes eat grass, lick puddles, kiss strange pets and even eat poop. This exposes them to many diseases; some are deadly. Even our “homebodies” are exposed by our clothing, mosquitoes, quick visits outside or chewing a houseplant.

This blog will focus on one very common problem: heartworms. Heartworm disease is very complex, but it is easy to prevent. My goal is to present a “Cliff Notes” rundown of heartworm disease and our recommendations for pet parents.

The Infection:
Heartworms are transferred from a positive dog to a negative dog or cat via mosquitos. (Yes, cats do get heartworm disease)! The mosquito takes a blood meal from the positive dog, and with that blood meal comes microscopic baby heartworms. They are called L-1 (the “L” stands for larva). While in the mosquito’s mouth, the baby heartworms go through two molts (L-1 to L-2 and then to L-3) in which they are “activated” like a seed that has been placed in soil and water). This occurs over an eight day period. Every time the infected mosquito bites another dog, she injects saliva into the skin and with that saliva comes a few of the “activated” baby heartworms (L-3). Over the next four months those worms migrate through the tissues and then blood vessels toward the heart where they molt two more times into adults worm (L-3 to L-4 and finally to the adult form L-5). The dog or cat’s body tries to reject the worms resulting in massive inflammation. (Think of how a splinter under your skin causes inflammation… but this is in your fur baby’s heart!)

Once the worms attach themselves to the big vessels of the heart, they cause significant damage. They grow to lengths of 5 to 12 inches, and there are around 5 to 25 worms present. The presence of the worms in the heart and large vessels blocks blood flow to the lungs and the inflammation causes heart failure.

Detection:
A heartworm test must be performed to detect the presence of ADULT worms. A very small blood sample is taken to run this test, and we have the results in ten minutes. Here are some important facts about all heartworm tests:

• Only dogs can be tested accurately, as cat heartworm disease is extremely difficult to detect.

• Sadly cats are usually diagnosed after they have died from the disease… you may have heard of “sudden death” syndrome in cats. Some of these are from unprevented and undetected heartworm disease.

• Heartworms younger than 6 months cannot be detected in dogs. Remember that the process takes four to six months from the day of infection to the presence of ADULT worms.

• The test in dogs is very accurate, but again, if the heartworms are younger than six months, the test will not show positive.

Treatment:
Treating heartworms (killing the adult heartworms in the heart) is a three month process and must be performed by a full service hospital. Preliminary bloodwork, radiographs and ultrasounds are performed to evaluate the extent of damage the heartworms have inflicted. During the first month, the pup gets an antibiotic called doxycycline and a medication to kill the microfilaria (baby heartworms L-1) in the blood. Then there are three injections given deep into the muscles of the back over a two month period. The injections are very painful and the pain lasts weeks, often requiring pain medication. For those two months, the patient must be kept confined in a small space and kept calm. As the adult heartworms die, they decompose inside the heart and blood vessels and the body’s white blood cells very slowly eat the dying worms. If a piece of this worm breaks off, the blood flowing by will send the piece to the brain or lungs and a life-threatening stroke or embolus will result. Keeping the patient’s heart rate slow is important to avoid such complications.

The treatment of heartworms is very complex, expensive, painful and long. The damage they cause is permanent. Bottom line: THE BEST TREATMENT IS PREVENTION.

Prevention:
Preventing heartworms in both dogs and cats is easy, inexpensive and very effective. It just requires consistency. The biggest failure of oral and topical preventatives is forgetting to administer the medication. So many times I have to tell pet parents that their dog tested positive for heartworms. At first they usually say, just give him/her a dewormer. Then reality checks in- heartworms are not like intestinal worms (see above). I hear explanations like: “I have heartworm meds at home, I just forgot to give it.” This devastates me. The product doesn’t work in the package; it has to be administered as directed.

Types of Prevention:
I have thirty-five years of experience in preventative medicine for pets; these are my recommendations:

Monthly oral preventatives like Iverheart, Sentinel, Simperica Trio, etc. are only in the body for a few hours. They work by killing the early infective stages of the worms (L-3 and L-4). They will not work on the adult worm, L-5. Technically the medication “deworms” the fur baby every month of the early, very susceptible stages of heartworms. It is important to note that heartworm preventatives ALSO prevent the intestinal parasites: roundworms and hookworms. These are VERY common intestinal worms that cause chronic diarrhea and intestinal damage. You and your children can get hookworms and round worms, but not heartworms.

There is a fantastic topical heartworm preventative for cats called Senergy. It prevents heartworms, intestinal worms AND fleas, ticks and mites. It is applied to the back of the head and the medication is actually absorbed by the skin into the body. It is a monthly application.

Finally, we offer a ONCE YEARLY injectable heartworm preventative called ProHeart12 that prevents heartworms, roundworms and hookworms for 12 months! It has been around for over 25 years and is extremely safe and effective. NOW it is a very affordable “ONE AND DONE” solution for those pet parents that forget to give the monthly pill. The only requirement is that you pet be twelve months or older. (A growing puppy will “out-grow” the dose).

Final Thoughts:
Heartworm disease is devastating yet VERY preventable. Pet parents with busy schedules often forget to give the monthly preventative, exposing their dogs to heartworm infestation. Statistics show only 15% of pet parents give monthly preventatives on time and all year round, thus increasing the risk of a breakthrough infestation of heartworm disease. 90% of dogs that test positive in our clinics have owners that had purchased a few heartworm pills but forgot to get more. As you can see, consistency is key… so VOTS encourages our pet parents to set monthly reminders on their phones and/or calendars, purchase a year supply when budget allows, or sign up for our preventative subscription service where your medication is routinely sent to your home.

If you want the easiest and best protection for your dog, then ProHeart 12 is your answer. This once yearly injection protects your dog from heartworms, hookworms and roundworms for an entire year. Please note that ProHeart12 can only be used in full grown dogs (usually those over 12 months of age) and like all heartworm preventatives, ProHeart12 cannot be started unless a current negative heartworm test is performed.

Thanks for reading our Pet Parents Blog! We hope this information empowers you to make informed decisions about your pet’s health. Please visit our resource center for more tips and educational tools.