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Fleas, Ticks, & Heartworm Disease


Information and Prevention


As veterinarians, one of the most common skin conditions we see in California is Fleas. What often makes this condition challenging to treat is the perception by many pet owners that their pets simply “do not have fleas.”

FACT: if your pet goes outside, and is not receiving regular monthly flea prev­ention, it will get fleas! This is the reality of living here, in a tropical climate, with feral cats in abundance outdoors everywhere. They are a constant source of environmental contamination, shedding dozens of eggs every day, which grow up to become adult fleas, ready to jump on any furry passerby. Every dog that goes outside, even for a brief walk, is exposed to fleas. Even indoor-only cats can get fleas because we bring the flea eggs and larva in on our feet, shoes, and clothing.

Unfortunately, despite our best efforts to inform and educate, there is still a certain stigma associated with fleas, and those who don’t know the facts think that their pet having fleas means they are “unclean” in some way. Some people even think that their dog can “catch” fleas from another dog. This is simply not true. Fleas do not jump from one animal to another. Rather, they live everywhere outdoors–in the grass, dirt, under trees, bushes, houses, and your lanai. Fleas propagate in moist areas that are not too hot, not too cold, not too wet, and not too dry. This describes almost every­where in California! Weather extremes kill the flea eggs, which is why some parts of the country do not have fleas, or only have them seasonally. Unfortunately, the climate here is ideal for flea maturation during all months of the year, and in order for our pets to be flea-free, they need to be treated with a flea control product year around.


Ticks are common parasites that can be found anywhere, from the deep woods to urban parks. And each year, thousands of dogs become infected with serious diseases transmitted by a number of different ticks, like ehrlichiosis, Lyme disease, anaplasmosis and others. Generally known as a vector-borne disease, the risks they pose to your dog can be minimized with preventive measures (topical medications, tick collars, etc.) and annual check-ups include vector-borne disease screening. This is especially important, as symptoms of vector-borne disease are often vague and difficult to recognize. Because of this, many pet owners don’t know their dog is suffering from a debilitating tick disease until it’s too late.

Heartworm Disease

Heartworm Disease is transmitted when mosquitoes carrying microscopic heartworm larvae bite your pet’s skin, allowing the larvae to enter through the bite wound and into your pet’s blood. Over several months, the worms migrate to the vital blood vessels of the heart and lungs where they can grow to be the size of spaghetti. These large worms live in the heart and pulmonary artery where they cause considerable damage including damage to the liver and kidneys.

There are no early signs of heartworm infection. By the time that you notice any symptoms (coughing, difficulty breathing, loss of energy) your pet may be in respiratory distress due to severe lung inflammation. This may also lead to heart failure. Fortunately, there is a simple blood test to see if your pet has been exposed to heartworm disease. If the test is negative, your pet can be started on a once-a-month heartworm preventative. This medication will kill any heartworm larvae that may have entered your pet’s bloodstream within the past month and prevent future infection.

If your pet tests positive for heartworm disease, treatment can last from four to six months, during which time your pet is given a series of injections to kill the worms. Your animal will need to be crate-confined for approximately eight weeks. The killing of the heartworms can cause severe side effects and so it is critical that your pet remain quiet and inactive during the entire treatment process.

While we live in an area that is less conducive to the development of infective heartworm larvae, San Diego County has seen several hundred documented cases of heartworm disease since 2001. We have seen five positive cases here at our clinic just in the past year. There are a number of factors that contribute to your pets’ risk of becoming infected with heartworm disease including travel, lifestyle, exposure to water sources, and the amount of time spent outdoors. Since California is composed of many different micro­climates, there are opportunities for traveling animals to become infected. Therefore, it is critical that owners who choose to travel, camp, and hike with their pet are aware of this increased risk.


There are numerous commercial products available these days for prevention of fleas, ticks, and heartworm disease, as well as several combination products on the market, and it can get very confusing! Unfortunately, there is not a single product that covers all three parasites, so you will likely need to use at least TWO different products if you need to protect your pet from fleas, ticks, and heartworms.

Contact Us

San Diego Pet Hospital


7368 Broadway Lemon Grove, CA 91945

Clinic Hours

Mon-Fri: 8 am -6 pm
Sat 8am-5 pm closed Sunday