Parasite Prevention
May is National Parasite Prevention Month!
Dr. Kobi Johnson of BoosterPet answers some frequently asked questions to help keep your pets - and the rest of your family - as comfortable and protected as possible.
Regional Parasites
Q. Which parasites are most common in the Puget Sound area? Do we have Heartworm Disease here?
The most common parasites west of the Cascades are fleas, ticks, and intestinal parasites such as roundworm, hookworm, and giardia. Living in a moist, temperate area with dense pet and wildlife populations creates a hospitable environment where these parasites can flourish. Though Heartworm Disease is less common in the Pacific Northwest, it’s gaining traction here: in 2020, Washington State reported 733 positives cases of Heartworm in dogs, up from 466 cases in 2019. As of April 2021, 183 cases have already been reported.
Because parasites live partially in the environment and partially in or on our pets, it’s important to consider both the environmental and societal conditions that allow certain parasites to thrive, such as climate, moisture, migration, population density, pet density, and presence of rodents and wildlife.
We recommend www.petsandparasites.org and www.capcvet.org which, among other resources, both have an interactive map that details parasite risk based on species, parasite and location.
Heartworm
Q. What is Heartworm Disease and how is it transmitted?
Heartworm Disease is caused by the parasite Dirofilaria immitis, a worm which lives and matures in the heart, lungs and related blood vessels. Heartworms, when fully grown, are up to 12 inches long and the average number of worms in an infected dog is 15. It can take up to seven months from the time the parasite is introduced for a worm to fully mature.
Heartworm is a mosquito-borne illness; a mosquito that bites an infected animal has the potential to then infect the next animal that it bites. Heartworm Disease transmits the same way as many of the world’s most damaging diseases, including Malaria, Dengue Fever, and Yellow Fever.
Q. I’ve heard that Heartworm Disease is not really present in Washington State. Is that true?
Unfortunately, Heartworm Disease is firmly rooted in Washington State. The below graphic demonstrates the spread of Heartworm Disease to this area over time. Though historically considered a disease endemic to warm, moist areas of the country where mosquitos thrive, global climate shifts, natural disasters, and canine migration though rescue efforts have pushed this problem farther North and West. Heartworm Disease is now being diagnosed in Washington in dogs with no travel history outside of Washington state. The below graphic depicts, courtesy of www.heartwormsociety.org, the spread of Heartworm Disease across the country over time:
Specific to Washington State, www.capcvet.org provides the following map, placing Peirce, King, Snohomish, and Skagit counties in the med-high risk range:
Q. What are the signs and symptoms of a Heartworm infection?
Heartworm symptoms generally do not appear until there has been significant damage to the body. Symptoms include coughing, exercise intolerance and difficulty breathing. Heartworm Disease can be fatal.
Q. Is Heartworm treatable?
Heartworm is diagnosed and treated through a series of tests, oral and injectable medications over a period of two to the three months depending on the severity of the infection. Many pets require sedation and/or hospitalization over the course of treatment. Unlike intestinal parasites, which are expelled in feces when a pet is being treated, adult heartworms travel to the lungs during treatment, where they lodge in small blood vessels and decompose over a period of months. For this reason, pets receiving Heartworm treatment must have reduced activity and excitability due to the treatment’s strain on the heart and lungs.
Q. Can cats get Heartworm Disease, too?
Yes, but Heartworm Disease in cats looks very different than in dogs. Infected cats may only harbor one or two worms and those worms may never reach full maturity due to the feline immune system. However, just one juvenile heartworm can cause breathing difficulties in cats. Heartworm Disease is more difficult to diagnose in cats and there are currently no approved treatments for Heartworm Disease in cats.
For additional resources regarding Heartworm, especially the prevalence of Heartworm Disease in cats, check out www.heartwormsociety.org.
Intestinal Parasites
Q. What are the most common types of intestinal parasites?
The most common types of intestinal parasites are worms known as roundworm, hookworm, whipworm and tapeworm and protozoa, known as Giardia and coccidia.
Q. What are the signs and symptoms of an intestinal parasitic infection?
Worms and protozoa have similar gastrointestinal symptoms, such as vomiting, diarrhea, bloating, and inappetence. Intestinal parasites are sometimes found in pets with no clinic symptoms. You may see both roundworms (long, thin white worms) and tapeworms (short, rice-grain like segments) in feces. Giardia is invisible to the naked eye.
Q. How are intestinal parasites transmitted?
Most intestinal parasites transmit via the fecal-oral route. Intestinal parasites shed in the feces of an infected animal and these parasites tend to be very stable in the outside environment – and therefore remain active in the feces, soil, and groundwater long enough for transmission to occur – which happens when another animal mouths, sniffs, licks, or consumes the affected feces, soil, or water. This is why pets can often reinfect themselves with intestinal parasites, and why it’s important to pick up feces immediately and preventing your pet from consuming puddle or lake water.
Q. I’ve heard tapeworms are transmitted differently and are more common in cats – why is that?
Tapeworms are often transmitted to cats through the ingestion of an infected flea. First, an immature flea ingests a tapeworm egg, which continues to develop as the flea matures. Then, as cats groom themselves, either routinely or in response to a flea bite, they may inadvertently ingest a flea and thus acquire a tapeworm infection. Therefore, by using monthly flea prevention, you are also preventing most tapeworm infections.
Q. Can dogs get tapeworms by eating cat feces?
No, tapeworms need an intermediate host, similar to Heartworm Disease and mosquitos. Dogs can acquire tapeworms through flea ingestion, but it is less common because they don’t groom themselves as thoroughly. Both cats and dogs can also acquire tapeworms through rodent ingestion, because they act as another intermediary host. If you have a cat or dog that hunts rodents, we would recommend regularly testing for tapeworm infections.
Q. Why are puppies and kittens so susceptible to parasites?
Puppies and kittens are often born with intestinal parasites that are passed down from their mother. The stress of pregnancy awakens dormant parasitic larvae in mothers, and these parasites transfer to puppies and kittens either before they are born, or when they are nursing. We recommend regular deworming and parasite prevention as soon as they are old enough.
Fleas
Q. What are the signs and symptoms of a flea infestation?
Signs include itchiness, especially around the neck, ears and tail; flea dirt (small specks of black dust that turn red when wet), and frequent skin rashes or infections. Fleas and flea eggs are perceptible to the naked eye, though they are adept hiders and difficult to spot.
Q. I’ve heard pets can have an allergy to flea bites – is that true?
Yes, and it is referred to as Flea Allergy Dermatitis (FAD). Just one flea bite can cause an allergic reaction that begins a cycle of extreme itchiness, skin trauma, and infection. Many pets – humans – will experience some form all flea allergy symptoms which makes flea prevention even more important.
Q. My pet is on a flea preventative but is still really itchy. Could it be other types of allergies?
It could be, yes. An itchy pet is often a bit of a mystery, with many possible explanations, the most common being environmental, food or FAD. Diagnosing an itchy pet requires some trial and error, and the first thing your veterinarian is likely to suspect is fleas. Having your pet on regular flea prevention will ensure their year-round comfort but also make diagnosing and treating them a swifter process.
Q. I clean my house regularly. Shouldn’t this take care of any flea problems?
Having a flea or parasite problem is not indicative of a dirty home. It simply means you live in an area that is favorable to parasites. It has far more to do with the landscape, climate, and pet population density than the cleanliness of your home.
Ticks
Q. Ticks don’t seem prevalent West of the Cascades, or in Washington State in general. Is this true?
Historically, yes, especially compared with other parts of the country. However, veterinary clinics are reporting an increase in the number of cases they are seeing. Though tick bites may be last on your list of things to look out for, many flea preventatives include tick protection, making it easier to keep your pet comfortable and avoid tick borne diseases.
Lyme Disease is the most famous tick-borne illness, but more common in Washington state is Anaplasmosis, Rocky Mountain spotted fever, Babesiosis, and Tularemia.
Q. What are the signs and symptoms of a tick bite?
Tick bites rarely cause the signature bullseye's bite mark seen in humans. Your pet may be itchy at the spot of insertion or you may feel the tick when petting or brushing them. If you and your pet ventures in thick brush or woody areas, it’s a good idea to do a tick check. Ticks found on your pet should be removed by a veterinary professional whenever possible. There are diagnostics tests that look for certain tick-borne diseases, though a disease may not be detectable directly after a bite. It may be recommended to place your pet on a medication to prevent a tick-borne illness from taking hold if a tick bite is known or suspected.
Parasite Prevention
Q. What forms of protection are there against parasites?
It is possible to prevent infestations of almost every parasite we’ve discussed here, and it is easier than ever with numerous prevention products on the market. The best place to start is by talking to a veterinarian regarding your pet’s lifestyle, environment, and habits. Other things to consider are whether your pet prefers oral, wearable or topical medications, and if they are suited for injections. Some products last for up to three months, while most will only last for one month, so you and your family’s schedule will play a role in acquiring and administering these products. Additionally, your pet’s parasite prevention needs may vary throughout their lifetime based on travel.
Typically, the most comprehensive product you can afford will provide the most protection, and sometimes using more than one product may be necessary. Parasite prevention products - especially those recommended or prescribed by veterinarians - are designed to be safe for your pet when used properly. Note that Heartworm Disease prevention is available only through a prescription with your veterinarian.
Q. Are there any pet parasites that can transfer to humans?
Many, actually! Fleas, ticks, and intestinal parasites can all transfer to humans. There are even a handful of human Heartworm cases. Diseases that can transfer from animals to humans are zoonotic, and one of the objectives of veterinary medicine is to prevent the spread of these diseases through comprehensive prevention for your pet.
Q. My pet is senior and indoor only. Do I still need to worry about parasite prevention?
It’s true that a pet’s age, lifestyle, and whole health picture will affect their susceptibility to parasites and need for prevention. However, a dog or cat that rarely leaves the house is not immune to parasites. Fleas, for example, live in our homes and it takes just two fleas to create an infestation. Intestinal parasites get tracked in on our shoes and then transmitted when your pet nibbles a treat off the floor. And mosquitos definitely find their way into our homes; in fact, the Heartworm Society reports that one in five cats that test positive for heartworm are indoor-only cats.