Giardia and coccidia are single-cell intestinal parasites that produce similar symptoms. You'll need to take your pup to the vet for tests to get an accurate diagnosis and the required treatment, as the treatment for giardia is different than that for coccidia. Boarding kennels, pet stores and animal shelters are prominent sources of both parasites.
Giardia is a one-celled parasite. It infects humans and pups and exists everywhere in the world. People typically get a giardia infection when traveling, usually through drinking contaminated water. Dogs typically get it from other infected dogs: sharing drinking water with an infected dog or sniffing around dog poop can be enough for the parasite to get into a dog's system. Really stinky, watery diarrhea, sometimes greenish in color and occasionally with blood in it, is the main symptom. Some dogs may vomit, but this is rarer. It is not a life-threatening infection unless it is allowed to persist and the dog loses excessive weight. Pups with an immature immune system are more at risk, as is any dog with a compromised immune system resulting from other conditions. Many dogs don't react to the parasite and remain symptomless.
The coccidia parasitic infection tends to only affect puppies. Like the giardia parasite, the coccidia parasite is microscopic, so you can't spot it in dog poop. It is present in the adult dog population, but rarely produces symptoms. Pups tend to get the infection through close proximity to the infected poop of other dogs. As with giardia, diarrhea is the main symptom. It is sometimes copious, smelly and watery and may have traces of blood in it. However, some pets may just have slightly loose bowel movements and others have no symptoms at all.
The most effective treatment for coccidia is a course of the antiparasitic drugs ponazuril or sulfadimethoxine. Depending on the drug used, the course lasts from three to 21 days. Some pets respond quickly, but coccidia can be a quite frustrating infection to treat and some pups may require more prolonged treatment. Giardia is usually treated with an antibiotic such as metronidazole combined with an antiparasitic drug such as fenbendazole. The treatment usually lasts between five to seven days. Always take your pet to the vet the minute you suspect an infection.
Keeping your pup away from where other dogs regularly poop is a useful preventory measure. Also, don't allow your pup to drink from a water bowl shared with other dogs, or from a water source you're unsure about. If your pup has giardia, she can pass it to you. Disinfect the dog's sleeping areas and the home in general. Wash your hands thoroughly after playing with your pup, or administering her medication. Make sure kids take extra care with hygiene as well. People with a compromised immune system are at particular risk from giardia and should take great care when handling an infected pet. The coccidia infection doesn't spread to humans. However, keeping your pup's environment clean and keeping her away from other dogs' poop are the best ways of preventing her getting the infection.