So - what exactly is Giardia? Giardia is sometimes confused with "worms" because they invade the gastrointestinal tract and can cause diarrhea. Giardia is a one-celled parasitic species classified as a protozoa.
How do dogs get Giardia? A dog becomes infected with Giardia when it swallows the cyst stage of the parasite. Once inside the dog's intestine, the cyst goes through several stages of maturation. Eventually, the dog passes infective cysts in the stool. These cysts lie in the environment and can infect other dogs. Giardia may also be transmitted through drinking infected water. Most streams and lakes in Colorado are infected with Giardia.
How did we diagnose Giardia in these puppies? At Care Animal Hospital we perform two different tests on fresh stool to try and identify giardial cysts. One is called a fecal centrifugation test, where the feces are spun in a specially designed centrifuge machine using a specific kind of liquid to help separate the cysts. The coverslip sitting on the centrifuge tube is placed on a slide and the sample scanned under the microscope looking for cysts.
Recently we obtained another type of test known as an ELISA test - which looks for some of the markers on the outside of the giardial cysts and reacts with a color change.
Both tests miss about 15% of the positive dogs, but they miss a different 15% so using both tests together helps us to be over 90% sure that the dog is infected if we get a positive ELISA test or we identify the cysts under the microscope
How is giardiasis treated? The typical drug used to kill Giardia is metronidazole (flagyl), an antibiotic that is either a tablet or we can create a liquid for smaller animals. It is normally given for 8 days (two times a day) to treat giardiasis. Other drugs are also used if diarrhea and dehydration occur. If Metronidazole is not effective, other medications may be recommended.
Can humans become infected with Giardia? Giardia can cause diarrhea in humans. If your dog is diagnosed with giardiasis, environmental disinfection is important. We recommend thoroughly cleaning the pet's living and sleeping areas and then allowing the areas to dry out for several days before reintroducing pets. One cup of bleach in 1 gallon of water is effective in killing the cysts.
Are dogs with giardial cysts always sick? Most dogs that are infected with Giardia do not have diarrhea or any other signs of illness. When the dysts are found in the stool of a dog without diarrhea, many times we consider them transient and sometimes do not treat these dogs. However, as Rambo and Pinball taught us, in puppies and debilitated adult dogs, Giardia may cause severe, watery diarrhea that may be fatal.
We are happy to report that Rambo and Pinball are currently doing very well.
