Giardia is a microscopic parasitic protozoan that lives in the intestines of a range of animals, including dogs (canines). It's one of the most common intestinal parasites in dogs, especially puppies. The giardia organism has two forms:
Trophozoite: This is the active form inside the host (in this case, the dog). These have a unique, 'teardrop' or 'pear' shape and move around.
Cyst: This is the hardy, protected form that is shed in the feces and can survive in the environment, potentially infecting other animals if they ingest it.
Dogs become infected with giardia when they ingest the infective cyst form of the parasite. This might happen by drinking contaminated water, eating contaminated soil, or even just through normal grooming if the fur is contaminated.
Once inside the dog's intestines, the giardia cysts transform into trophozoites, which attach to the intestinal wall to feed, multiply, and eventually form new cysts, which are then passed in the dog's feces and can potentially infect other animals.
In some dogs, giardia infection can cause diarrhea, vomiting, weight loss, poor condition, and other symptoms. However, many dogs infected with giardia do not develop any symptoms. Even if they're not showing symptoms, dogs can still shed giardia cysts and potentially spread the infection to other animals or even humans. The best way to diagnose giardia is through a fecal examination by a veterinarian, although giardia can sometimes be difficult to detect in this way.
Treatment typically involves antiprotozoal medication to kill the giardia organisms, along with good hygiene to prevent reinfection. Regularly picking up and disposing of dog feces, providing clean drinking water, and bathing the dog to remove any cysts from the fur can help prevent giardia infection and reinfection.