Today we continue our discussion from last week about how standing water can make your dog sick. There is a second concern which is actually more common than last week’s topic. This one is called Giardia. Here’s what you need to know.
Giardia is an intestinal parasite. In dogs, the most common clinical sign of giardia is soft, greasy, rancid-smelling diarrhea that may contain excessive mucus. The majority of dogs infected with Giardia, however, do not have diarrhea, vomiting or any other signs of illness.
A dog becomes infected with Giardia when it ingests the parasite in the cyst stage. Giardia can be transmitted directly via cysts shed by an infected animal but, more commonly, there is indirect transmission via contaminated water. In susceptible dogs, once the cyst passes into the dog’s intestines it attaches to the intestinal wall to feed. If sufficient numbers are present, clinical signs develop reflecting damage to the intestinal wall.
The most common clinical sign of giardia in dogs is sudden-onset foul-smelling diarrhea. The stool may range from soft to watery, often has a greenish tinge to it, occasionally contains blood, and tends to contain excess mucus. Vomiting may occur in some cases. Signs may persist for several weeks and the dog may lose weight and condition. Diarrhea may be intermittent. Most dogs do not have a fever, but they may be less active.
Giardia is treated using a combination of medication, plus cleaning and disinfection the dog’s environment, plus bathing the dog to prevent reinfection. The prognosis is good in most cases. Weakened and senior dogs, and those with incompetent immune systems are at increased risk for complications, including death.
Giardia can cause diarrhea in humans. It can potentially be passed from dogs to humans, but contaminated municipal water supplies are responsible for more outbreaks. Human-to-human transmission is also possible. Regardless of the risk to humans, if your dog is diagnosed with Giardia, environmental disinfection and good personal hygiene are important to prevent accidental spread to humans as well as other animals in the household. In particular, people with compromised immune systems should use extreme care, especially when handling feces or after administering medications.