Giardia in Pets and Farm Animals, and Their Zoonotic Potential

Abstract

Although the protozoan parasite Giardia duodenalis is worldwide recognized as an important cause of gastro-intestinal disease in human patients, the relevance as a pathogen in production and pet animals and the zoonotic potential of animals were prone to more debate. Since long, clinical disease has been associated with giardiasis in companion animals, but over the last few years, an increasing amount of data also confirmed the clinical and subclinical relevance of infection in production animals. Next to the clinical relevance, animal giardiasis was studied from a public health point of view, as the parasite was implicated in a large number of waterborne outbreaks, and at least part of these outbreaks were thought to be due to animal contamination of water supplies. Especially livestock and to a lesser extent wildlife have been considered as potential reservoirs for this waterborne transmission. Furthermore, pet animals have been associated with direct transmission of giardiasis to human patients, especially in endemic settings. Molecular epidemiological research over the last two decades did provide a better insight in the zoonotic transmission pathways, although many questions still remain. In this chapter, the current knowledge on clinical relevance of giardiasis in production and pet animals is reviewed, along with the diagnosis, the treatment, the control of infection and the zoonotic potential of animal giardiasis.