Giardiasis (Dogs/Cats)
The incubation period is > 10 days. Giardiasis infections in animals are often clinically asymptomatic. Clinical symptoms depend on pre-existing intestinal damage and the animal’s immune status. Poor housing conditions and a carbohydrate-rich diet also promote infection. Thus, giardiasis is a multifactorial disease. Giardiasis primarily affects young animals and manifests as acute, but more commonly as chronic, catarrhal, intermittent diarrhea. The feces are thin and mushy to watery, often containing increased amounts of mucus and fat (steatorrhea). An infection can lead to chronic, intermittent diarrhea, particularly in young animals or those kept in poor housing conditions. These animals exhibit malabsorption syndrome characterized by a shaggy coat, chronic weight loss, occasional vomiting, and apathy. The animals shed large quantities of infectious cysts. Giardia infections induce immunity in immunocompetent animals, which completely or partially eliminates the pathogen population. However, adult dogs and cats can also be chronic carriers without becoming ill themselves.
Treatment is often difficult because asymptomatic chronic carriers go undetected and, in some cases, resistance to the antiparasitic drugs used exists. Treatment is particularly problematic in group housing settings with poor hygiene, as reinfection occurs repeatedly even after successful treatment with antiparasitic drugs.
Why are Giardia so persistent?
Giardia owe their tenacity to their protective shell, which they need to infect other living beings (including dogs, cats, and humans). Giardia encase themselves in this protective shell and are excreted in feces. This shell protects them from environmental factors for days to weeks until they are ingested by a new host, primarily through feces, contaminated water, or food.
Giardia duodenalis is a single-celled small-intestine parasite with a two-phase life cycle: vegetative trophozoites colonize the proximal small intestine and multiply there by binary fission, while environmentally resistant cysts are excreted in feces and represent the infectious, persistent form. Transmission occurs via the fecal-oral route through ingestion of cysts via feces, contaminated water, or food.
Dogs and cats predominantly harbor host-adapted genotypes (assemblage C and D in dogs, assemblage F in cats); the zoonotic potential of these genotypes is low, although assemblage A—which also occurs in humans—is occasionally detected. Infections are often subclinical; clinically, giardiasis manifests primarily in young animals as chronic, intermittent, often mucoid diarrhea with malabsorption.
Since the pathogen is frequently present even in clinically asymptomatic chronic carriers, a positive result must be evaluated in a clinical context. Cyst and antigen detection in feces are available for diagnosis.
The Fassisi® tests GiarDia, GiaCPE, CryGiDia, and Triple, as well as the multiplex variants Fassisi® GiaCPE MPX, CryGiDia MPX, and Triple MPX, detect Giardia duodenalis in the feces of dogs and cats; depending on the variant, they also detect other diarrhea-related parameters (Clostridium perfringens enterotoxin, Cryptosporidium parvum, or parvovirus and coronavirus).
The technical information is documented on the sources page.
