Check Up with Blum: Giardia and Leptospirosis in Chicago

August 29, 2017

Welcome back to our monthly blog series, Check Up with Blum! Each month, we are discussing a topic about canine health that affects your Chicago pet! Join us as we cover these topics with Blum Animal Hospital’s co-owner Dr. Natalie Marks, and learn about how you can help keep your best friend healthy and happy in the big city!

This month, we are talking about Giardia and Leptospirosis—two very communicable illnesses for your dog that are common in Chicago. Read on to learn more about these two diseases and how you can help prevent them in your pet!

First, let’s discuss Giardia—what is it and what does it do to a dog’s body?

Dr. Marks states that Giardia is a protozoan one-celled parasite of dogs, and it is incredibly common in Chicago. This parasite attaches itself to the intestinal wall and causes temporary damage to this organ.  Although an infected dog can be asymptomatic (show no signs at all), most dogs will develop acute (sudden-onset) foul-smelling diarrhea. Dogs with Giardia have stool that can range from soft to watery, often has a greenish-tinge to it, and occasionally contains blood and/or mucus.  Vomiting can occur in some cases as well.  In chronic cases (over 3 weeks of infection), dogs can have gradual weight loss, lethargy, or a fever.

How does a dog become infected with Giardia?

A dog becomes infected with Giardia when it swallows the “cyst” stage of the parasite according to Dr. Marks.  There are two stages to the parasite’s life cycle and this is the only infectious stage.  These cysts are found in contaminated feces from another animal or in contaminated water sources.  This is one reason Dr. Marks strongly recommend picking up dog feces immediately after defecation to help decrease the likelihood of transmission around the city.

Are some dogs more susceptible to becoming infected with Giardia based on age, breed, or other factors?

According to Dr. Marks, almost 50% of puppies will be exposed to and develop an infection with Giardia in the early months of life.  It is most commonly seen in environments with dense populations, such as kennels, pet stores, animal shelters, dog parks, and dog beaches. While the presence of Giardia cysts in an adult dog without diarrhea is typically a transient finding (the parasite is moving through without causing infection), adult debilitated dogs or immunosuppressed patients can develop this disease and have severe, watery diarrhea.

How is Giardia treated?

Dr. Marks states that Giardiasis (infection with Giardia) is treated most commonly with either of these medications: fenbendazole (Panacur) or metronidazole (Flagyl).  Treatment varies from 3-10 days depending on the severity of infection and the patient’s overall health.  Bathing is also strongly recommended on the last day, focusing under the tail, hind limbs, face, and paws.  Giardia is a sticky parasite and likes to cling to hair coats, which puts the patient at risk for reinfection if he or she grooms excessively.  A recheck of the dog’s stool sample is required in 2 to 4 weeks.

Can a dog have lasting side effects after being diagnosed and treated for Giardia?

Giardia is typically a short-lived disease, and most patients have no permanent changes to the intestines or general health after treatment according to Dr. Marks. If, however, an adult dog develops recurrent Giardia with associated diarrhea or vomiting, further investigation is needed to look for an underlying primary cause of immune suppression.

What is the best way to prevent Giardia in your dog?

The best way to prevent Giardia is through avoidance of feces in the environment and standing water sources.  Dr. Marks suggests bringing your own water source and collapsible water bowl to parks and beaches.  Avoid storefront water bowls and alleys.  Wipe your dog’s feet when coming in from outside with baby wipes to lessen contamination.

Now, let’s discuss Leptospirosis. What is this disease, and what does it do to a dog’s body?

Dr. Marks defines Leptospirosis is a spirochete bacterium that causes disease worldwide.  Recently,  Chicago has had an uptick of this disease in the dog population in the city.  The bacteria, once in the body, takes up residence in the liver and/or kidneys.  While some dogs develop an infection with very mild clinical signs, most start to show disease through vomiting, diarrhea, lack of appetite, weakness and/or depression.  As the disease progresses, dogs may have a fever, pale mucus membranes, fast heart rate, low platelet count (clotting cells), and in severe cases, this disease can be fatal.

How does a dog become infected with Leptospirosis?

According to Dr. Marks, a dog becomes infected with Leptospirosis through many routes, including ingestion of contaminated water, bite wounds, direct contact with infected urine, or ingestion of infected tissues (rodents, etc.) 

Are some dogs more susceptible to becoming infected with Leptospirosis based on age, breed, or other factors?

Dr. Marks states that this disease really does not discriminate based on age or any other factors. Leptospirosis can develop in most mammals, including dogs of any breed, any age, and any gender.

How is Leptospirosis treated?

Leptospirosis treatment depends on the severity of infection.  However, most dogs with this infection require IV fluid therapy to replace loss of fluid from vomiting and diarrhea.  Anti-vomiting medications and antacids are used to calm down the stomach.  Antibiotics are essential to therapy – Ampicillin or Doxycycline are the choice antibiotics for treatment according to Dr. Marks.  Supportive care for the liver and kidney can also be initiated depending on the dog’s health status.  In severe cases of kidney disease, patients may be placed on temporary dialysis. 

Are there any lasting side effects of having been diagnosed and treated for Leptospirosis?

Dr. Marks states that Leptospirosis caught early can be treated and cured without permanent organ change to the liver and kidney.  With early recognition and appropriate treatment, the survival rate for dogs is approximately 80%.  However, in severe cases or cases diagnosed in the latter stages of the disease, patients can be left with permanent liver and/or kidney disease, impacting longevity and quality of life.

 What is the best way to prevent Leptospirosis in your dog?

Dr. Marks suggests that the best ways to prevent Leptospirosis are through similar avoidance techniques as mentioned with Giardia and also vaccination.  There is a four-strain vaccine available (although there are more than 20 strains of Leptospirosis identified) and this should be a discussion with your veterinarian at your dog’s annual exam. It always important to remember that while a vaccination will lessen the severity and intensity of disease, no vaccine will prevent disease in all patients.   Rodent control in the environment and removing any sources of standing water are also incredibly important to preventing Leptospirosis.

Now that we know what Giardia and Leptospirosis do to our pets, it is important to know this—can humans get Giardia and Leptospirosis from their dog?

Yes. Dr. Marks emphasizes that this is a very important concept to be aware of as a dog owner in Chicago.  Giardia and Leptospirosis are considered zoonotic parasites, meaning that the parasite can transmit from dog to human.

Giardia transmission to humans from dogs happens typically through fecal-oral route and poor hygiene.  If a dog in the household is diagnosed with Giardia, environmental disinfection and good handwashing is essential to prevent accidental spread to humans.   People diagnosed with an immunodeficiency, such as cancer, AIDS, or autoimmune disease, should use extreme care, especially when handling stools or administering medication to their pets. To disinfect the environment, use a chlorine bleach at 1:32 or 1:16 dilution (1 to 2 cups of bleach per gallon of water).  Test the affected surface first before using.  Lysol is also effective in killing cysts.  Giardia is also very susceptible to drying, so you should try to keep the environment (your pet’s living and sleeping areas) as dry as possible.

Leptospirosis transmission to humans from dogs typically is associated with contact with the dog’s infected urine.  Humans living with dogs who are suspected or confirmed to have Leptospirosis should always wear gloves when handling urinary accidents and follow frequent handwashing protocols.  Leptospirosis is not contagious after 24 hours of antibiotic therapy.   However, you should clean and disinfect areas in your home where urinary accidents have occurred with the same bleach protocol mentioned in the previous paragraph.

While Giardia and Leptospirosis are unpleasant, they are a part of life in Chicago for pet owners, and it is important to know what to look for and how to keep your dog safe. Follow these guidelines laid out by Dr. Marks, and both you and your pup can stay healthy!


Thank you to Dr. Natalie Marks at Blum Animal Hospital for her insight into Giardia and Leptospirosis. We appreciate her hard work in making sure that every Chicago pet has the best life possible!

Blum Animal Hospital is located at 3219 N. Clark Street and has been caring for Chicago’s pets since 1952. They have been accredited by the American Animal Hospital Association (AAHA) since 1972. To learn more about Blum, their Fear Free certification and the calming techniques they use, check out their website!

Windy City Paws is a Chicago dog walker and petsitter committed to providing helpful information to Chicago dog owners through its blog.

Written for Windy City Paws by Lauren Baud