Giardia can lurk in melting snow. Feces that has been sitting around in the snow becomes dilute as snow melts and can often end up on the paws of your dog, who then might lick his paws and the parasite enters the body.
A more widely known common cause of Giardia in dogs, is drinking from a lake, pond or stream that contains trace amounts of animal feces. The feces contains a cyst that enters the gastrointestinal track and then changes into protoza.
Coccidia is a similar parasite infection that affects the intestinal track, only it is caused by eating feces directly.
Symptoms of Giardia in dogs is are not always obvious, but they may include diarrhea, vomiting and weight loss.
Symptoms of Coccidia may include a cough, diarrhea, loss of appetite and dehydration. Coccidiosis, the disease caused by Coccidia is very serious disease for puppies.
Prevention is the best remedy for both of these parasites. Always pick up your dogs feces and dispose of it properly and be very aware of what your dog picks up when he is outside. Also, make sure your dog always has plenty of fresh clean water to drink and do not allow him to drink from ponds or puddles.
It's a good idea to take a stool sample to the vet if you have any concerns about your dog with either of these parasites.