Giardia: A tough bug to beat!
Giardia are tiny single-celled parasites that can live in the small intestine of dogs and cats. Many animals become infected at some point in their lives, most commonly puppies, young animals, or pets with a weakened immune system. A typical sign is foul-smelling diarrhea that may be slimy or foamy. Sometimes it comes in bouts, so everything can seem normal in between. Some animals still appear surprisingly bright and active, while others lose weight, have a rumbling stomach, or seem less resilient overall.
The tricky part about Giardia is not so much one single episode, but how easily it spreads. The parasites are shed in the feces as so-called cysts. These cysts are very hardy and can survive in the environment for a long time, in some cases up to three months. This means Giardia is transmitted not only directly from animal to animal, but also via anything that comes into contact with feces: paws, fur, bowls, toys, sleeping areas, and litter trays. In multi-pet households or group settings, one small lapse is enough for the cycle to start all over again.
Treatment consists of an effective medication and strict hygiene. It’s important that the medication is given consistently and exactly as prescribed. Grooming is also important, because cysts can stick to the fur and your pet can reinfect itself while cleaning. For dogs, for example, it can be helpful during treatment to shampoo thoroughly several times and rinse under running water, especially toward the end of therapy, to remove as many cysts from the coat as possible.
The second major component is the home environment. Anything that regularly comes into contact with your pet should be cleaned as hot as possible. Blankets, pillow covers, and toys should go into the wash at at least 60°C if possible. Bowls can be cleaned well with hot water and dish soap, and many can also go in the dishwasher. Litter trays should be kept consistently clean, including thorough cleaning of the tray itself. Outdoors, please pick up feces immediately and dispose of it in sealed bags. During treatment, dogs should ideally not be allowed into the garden, because areas that have had contact with feces can be considered contaminated and cysts can persist there for a long time.
Even after successful treatment, tests can remain positive for a while because dead parasite stages may still be detectable. If the diarrhea has stopped, your pet is eating normally, and overall seems stable again, a follow-up sample is not automatically needed right away. If symptoms persist or return, a pooled stool sample collected over three days is useful, because Giardia is not shed evenly in every stool.
Giardia is considered a zoonosis, meaning humans can, in principle, become infected. In everyday practice this happens rather rarely, but households with small children or people with weakened immune systems should be especially careful.