Giardia is a microscopic parasite that causes the diarrheal illness known as giardiasis. Giardia (also known as Giardia intestinalis, Giardia lamblia, or Giardia duodenalis) is found on surfaces or in soil, food, or water that has been contaminated with feces (poop) from infected humans or animals.

Giardia is protected by an outer shell that allows it to survive outside the body for long periods of time and makes it tolerant to chlorine disinfection. While the parasite can be spread in different ways, water (drinking water and recreational water) is the most common method of transmission.

Giardia intestinalis (aka: G.duodenalis, G.lamblia) is a common, microscopic (intestinal) parasite that commonly affects humans, dogs, and cats.

Common signs and symptoms of Giardia infection (in both humans and pets) are diarrhea, gas, abdominal discomfort, nausea, and vomiting. However, it is possible to be infected and have no signs or symptoms of illness.

How is Giardia spread?

Anything that comes into contact with feces (poop) from infected humans or animals can become contaminated with the Giardia parasite. People and animals become infected when they swallow the parasite. It is not possible to become infected through contact with blood.

How does my dog or cat get infected with Giardia?

Your dog or cat might get infected by:

• Being in contact with infected feces (poop) from another dog or cat
• Rolling and playing in contaminated soil
• Licking its body after contact with a contaminated surface (for example, a dirty litter box or dog cage or crate)
• Drinking water from a contaminated creek, pond, or other body of water

Young pets, like puppies and kittens, have a higher risk of infection than adult dogs and cats.

How do I protect myself if my dog or cat has a Giardia infection?

The risk of acquiring Giardia infection from your dog or cat is small. However, there are some steps you can take to minimize your exposure to Giardia if you have dogs or cats:

• Wear gloves when gardening to reduce the risk of coming into contact with infected feces (poop) or soil.
• Clean household surfaces regularly.
• Clean and disinfect areas that your pet has access to—as well as items like toys, bedding, and water and food bowls—regularly.
• Wash hands frequently and properly:
  • Wet your hands with clean, running water (warm or cold) and apply soap.
  • Rub your hands together to make a lather and scrub them well; be sure to scrub the backs of your hands, between your fingers, and under your nails.
  • Continue rubbing your hands for at least 20 seconds.
  • Rinse your hands well under running water.
  • Dry your hands using a clean towel or air dry them.

If my pet has a Giardia infection, how do I clean and disinfect my house?

Giardia is hard to completely eliminate from the environment, but there are things you can do to decrease the risk of your pets’ reinfection and of human infection.

• Hard surfaces (for example: cement and tile floors, crates, tables, trash cans, etc.)
  • Cleaning
    • Wear gloves.
    • Remove feces and discard in a plastic bag.
    • Clean and scrub surfaces using soap. Rinse surface thoroughly until no obvious visible contamination is present.
  • Disinfection
    • Wear gloves.
    • Disinfect according to manufacturer guidelines using one of the following:
      • Quaternary ammonium compound products (QATS), which are found in some household cleaning products; the active ingredient may be listed as alkyl dimethyl ammonium chloride.
      • Bleach mixed with water (3/4 cup of bleach to 1 gallon of water)
    • Follow product instructions, ensuring the product stays in contact with the surface for the recommended amount of time.
    • Rinse with clean water.
• Carpet / Upholstered Furniture
  • Cleaning
    • Wear gloves.
    • If feces are on a carpet or upholstered furniture, remove them with absorbent material (for example, double layered paper towels).
    • Place and discard the feces in a plastic bag.
    • Clean the contaminated area with regular detergent or carpet cleaning agent.
    • Allow carpet or upholstered furniture to fully dry.
  • Disinfection
    • Wear gloves.
    • Steam clean the area at 158ºF for 5 minutes or 212ºF for 1 minute.
    • QATS are found in some carpet cleaning products and can also be used after cleaning to disinfect. Read the product labels for specifications, and follow all instructions.
• Other items (toys, clothing, pet bed, etc.)
  • Household items should be cleaned and disinfected daily while a dog or cat is being treated for Giardia infection.
  • Dishwasher
    • Dishwasher-safe toys and water and food bowls can be disinfected in a dishwasher that has a dry cycle or a final rinse that exceeds one of the following:
      • 113ºF for 20 minutes
      • 122ºF for 5 minutes
      • 162ºF for 1 minute
      • If a dishwasher is not available, submerge dishwasher-safe items in boiling water for at least 1 minute (at elevations above 6,500 feet, boil for 3 minutes).
  • Washer and Dryer
    • Clothing, some pet items (for example, bedding and cloth toys) and linens (sheets and towels) can be washed in the washing machine and then heat-dried on the highest heat setting for 30 minutes.
    • If a clothes dryer is not available, allow clothes to thoroughly air dry under direct sunlight.

How do I reduce the amount of Giardia in my yard or outdoor environment?

Giardia is hard to completely eliminate from the environment, but there are things you can do to help decrease the risk of pet reinfection and of human infection. Please remember that despite your best efforts to clean the environment, Giardia can persist in outdoor spaces and pet reinfection is possible.

• Wear gloves when handling feces.
• Remove feces promptly and put them in a plastic bag.
• Limit access to common outdoor spaces, where possible, if pets have diarrhea or are being treated for Giardia.
• Eliminate any source of standing water (for example, puddles, containers with water, and fountains that are not in use).
• Do not attempt to use bleach or QATS in your soil or grass area, as they will be ineffective.
• Do not allow any new animals, especially young ones, to enter the yard or other outdoor space until advised by your veterinarian.

How long does Giardia survive in the environment?

• In the soil
  • In cold temperatures (around 4ºC/39.2ºF), Giardia can survive for approximately 7 weeks (49 days).
  • At room temperature (around 25ºC/77ºF), Giardia can survive for approximately 1 week (7 days).
• Dry vs. moist surface or environment
  • In a dry, warm environment that experiences direct sunlight, Giardia can survive for only a few days.
  • In a moist, cool environment, Giardia can survive for up to several weeks.
• Water
  • In water temperatures below 10ºC/50ºF (for example, lake water or puddle water during the winter, refrigerated water), Giardia can survive for 1–3 months.
  • In water temperatures above 10ºC/50ºF (for example, river water during the fall, tap water, and puddles during the summer), Giardia can survive for less time than in colder temperatures. For example, in water above 37ºC/98.6ºF, Giardia can survive less than 4 days.

How often and for how long should I clean and disinfect my home after my dog or cat is diagnosed with Giardia infection?

• Clean and disinfect potentially contaminated items (toys, water bowls and food bowls, pet bedding, floors, dog crates, linens, towels, litter box, etc.) regularly for as long as your pet is sick.
• If your pet is taking medication, clean and disinfect frequently (daily if possible) until a few days after the last dose of medication is given.
• Giardia survival depends on many factors, so we recommend that you consult your veterinarian for further advice.

How do I prevent my dog or cat from getting re-infected, or sickening my other pets, during treatment?

• If you have other dogs or cats, make sure you tell your veterinarian even if they are not showing signs of diarrhea. Other pets may also be put on medicine depending on the situation. Even animals showing no signs of Giardia infection could be infected and shedding Giardia into the environment.
• Bathe all household pets with pet shampoo following medical treatment to ensure no fecal residue is in the pet’s coat.
• Clean dogs’ and cats’ environment (holding areas, floors, crate, etc.) and wash water bowls daily with soap and water.
• Limit your dog’s access to untreated surface water (creeks, ponds, lakes) to avoid re-infecting your animal and contaminating the water which could make other animals sick.

How do I treat my pet for Giardia infection?

• If your pet has persistent diarrhea, seek veterinary care. Diarrhea has different causes and could result in dehydration or other serious complications.
• Diagnosis and treatment of Giardia infection must be done by a licensed veterinarian.
• No approved over-the-counter treatment is available for Giardia infection.
• Giardia can be passed in stool intermittently, and an animal may appear healthy or without signs of disease before it stops passing Giardia. Repeated fecal tests may be necessary.
• Follow your veterinarian’s recommendations, and take your pet to all follow-up appointments.