Join Club

Healthy Paws: Intestinal Parasites

Healthy Paws

Editor’s Note: Healthy Paws is a new column sponsored and written by the owners of Clarendon Animal Care, a full-service, general practice veterinary clinic. The clinic is located 3000 10th Street N., Suite B. and can be reached at 703-997-9776.

Most of you have likely brought a stool sample in to your pet’s annual veterinary visit, perhaps wondering in the back of your mind why it’s necessary to check a stool sample on an annual basis, especially if you have a cat or dog that spends minimal time outdoors.

Roundworms, hookworms, Giardia and coccidia are the most common intestinal parasites in our geographical region, and all but coccidia also have the potential to be zoonotic — transmissible to human beings — thus deserving special attention.

Roundworms, most specifically Toxocara canis (in dogs) and Toxocara gati (in cats), were found to be present in 1/79 (1.2%) of dogs and 1/26 (3.82%) of cats in Arlington County. Infection can occur via ingestion of infective eggs, in utero transmission (dogs only), or transmammary transmission, which is why it is seen so commonly in puppies and kittens. Infection can cause pot-bellied appearance, failure to thrive, and gastrointestinal signs; puppies infected in utero are most likely to be severely sick. Roundworm eggs are often found in soil, including houseplant potting soil (a source of infection for indoor-only cats). Children, with their propensity to put things in their mouths, are most at risk for zoonotic infection. Due to the complicated migration of roundworm throughout the body tissues upon ingestion in an inappropriate host, symptoms in humans can include visceral larva migrans and ocular larva migrans. Ocular larva migrans is a cause of retinal damage and partial blindness in children and can be mistaken for the more severe disease, retinoblastoma (cancer), resulting in an unnecessary removal of the eye.

Hookworms (Ancylostoma species.), found in 2.21% of dogs and 0.51% of cats in Arlington County, are transmitted via ingestion of infected eggs, as well as transmammary transmission; the larval stages of hookworm also have the ability to penetrate intact skin to infect their host. Hookworms suck blood from the wall of the intestinal tract and can lead to severe anemia and even death in young puppies; older dogs may show diarrhea as the primary sign. Hookworms are most often contracted by humans when they directly penetrate the skin, leading to cutaneous larva migrans.

Giardia, a protozoan parasite, is a common cause of intestinal symptoms in cats and dogs — primarily diarrhea, and less commonly vomiting, inappetence, or weight loss. According to the CAPC, 15.6% of dogs and 10.3% of cats with compatible symptoms tested positive for Giardia, though there are distinct regional differences, with infection being more common in some areas than others. Giardia is the most common intestinal parasite of humans in the U.S., causing similar gastrointestinal signs to those seen in our pets, such as diarrhea, bloating and cramping. Transmission in both humans and dogs results from ingestion of cysts shed in the feces of infected animals, typically from contaminated water. Fortunately, Giardia subspecies are quite species-specific so transmission between humans and pets is uncommon in healthy individuals. Children, elderly, or otherwise immune-deficient individuals are most at risk for transmission from an infected pet.

Coccidia (Isospora species), another protozoan parasite, though not thought to be zoonotic, is a common intestinal parasite, especially in puppies and kittens who do not have fully developed immune systems. It is also more common in pets from intense breeding, hoarding and shelter situations as it is very hardy in the environment. The most recent prevalence data from CAPC showed that Coccida was present in approximately 3% of dogs and cats in Pennsylvania (the closest state with prevalence data).

In general, pet-to-human transmission of roundworms, hookworms and Giardia can be minimized by removing feces from the environment on a daily basis and hand-washing after any potential contamination. Once in the environment, it is extremely difficult to decontaminate the environment; however, if stools are picked up immediately there is little chance of transmission to other pets and/or humans. It is also important to dispose of feces with the municipal waste, as it otherwise has the potential to contaminate water sources.

Other intestinal parasites found less commonly in our pets include whipworms (dogs), tapeworms, stomach worms, Toxoplasma (cats), and Strongyloides. In addition to your pet’s veterinarian, the Companion Animal Parasite Council is a fantastic resource for all things parasite-related.

The views and opinions expressed in the column are those of the author and do not necessarily reflect the views of

Recent Stories

Good Friday evening, Arlington. Today we published articles that were read a total of 17124 times… so far. 📈 Top stories The following are the most-read articles for today —…

A march against drugs drew a large crowd of parents and community members to Wakefield High School, where a student died this week.

Arlington County police responded to an unusual incident on Route 50 this afternoon. It happened around 1 p.m. at the intersection with Park Drive, near the Arlington Forest Shopping Center…

Building a new home should be a rewarding and memorable experience. That’s why a custom-built home requires personalized service! Here’s your chance to learn everything you need to know about…

The Arlington-Aachen High School exchange is returning this summer and currently accepting applicants.

The sister-city partnership started in 1993 by the Arlington Sister Cities Association, which seeks to promote Arlington’s international profile through a variety of exchanges in education, commerce, culture and the arts. The exchange, scheduled June 17th to July 4th, includes a two-week homestay in Aachen plus three days in Berlin. Knowledge of the German language is not required for the trip.

Former participants have this to say:

_”The Aachen exchange was an eye-opening experience where I was fully immersed in the life of a German student. I loved biking through the countryside to Belgium, having gelato and picnics in the town square, and hanging out with my German host student’s friends. My first time out of the country, the Aachen exchange taught me to keep an open mind, because you never know what could be a life changing experience.” – Kelly M._

Read More

Submit your own Announcement here.

Learn about the new assessment of Arlington’s urban tree canopy and the many ecological and social benefits trees provide. Staff from the Green Infrastructure Center (GIC) will share study results and compare canopy cover for different areas of Arlington.The webinar will include assessments of ecosystem services such as stormwater mitigation, air quality, carbon uptake, and urban heat islands. For background on Arlington trees see the “Tree Benefits: Growing Arlington’s Urban Forest” presentation at

Please register in advance to assure your place at the webinar,

About the Arlington County Civic Federation: The Arlington County Civic Federation (“ACCF”) is a not-for-profit corporation which provides a forum for civic groups to discuss, debate, inform, advocate and provide oversight on important community issues, on a non-partisan basis. Its members include over ninety civic groups representing a broad cross-section of the community. Communications, resolutions and feedback are regularly provided to the Arlington County Government.

The next meeting is on Tuesday, February 21,2023 at 7 pm. This meeting is open to the public and will be hybrid, in-person and virtually through Zoom. Part of the agenda will be a discussion and vote on a resolution “To Restore Public Confidence in Arlington County’s Governance”. For more information on ACCF and this meeting, go to

Read More

Submit your own Announcement here.

Valentine Pop-Up at George Mason University

Valentine gifts for someone special or for yourself are here at George Mason University from noon -4pm on February 14, 2023. Satisfy your sweet tooth with Kingsbury Chocolates, find a handmade bag from Karina Gaull, pick up treats from Village

Standup Comedy Showcase Starring Matt Ruby (Comedy Central)

Dead Horse Comedy Productions brings together top comedians from the DMV and beyond for a live standup comedy show!

Matt Ruby, Headliner

Matt Ruby is a comedian, writer, and filmmaker from New York City. His comedy has been filmed by


Subscribe to our mailing list