Trends in Parasitology
OpinionSubclinical Giardia in dogs: a veterinary conundrum relevant to human infection
Section snippets
Giardia duodenalis and world domination
Giardia duodenalis is one of the most common intestinal protozoan infections reported globally; in 1996 the World Health Organization (WHO) estimated that ∼200 million people have symptomatic giardiasis in Africa, Asia, and Latin America, with around 0.5 million new cases annually [1]. Although infection with Giardia usually presents as diarrheal disease, often together with other gastrointestinal symptoms such as nausea, vomiting, and weight loss, the symptom spectrum is very broad, from acute
Dogs and inhabitants of developing countries: high exposure to a contaminated environment
High prevalence rates of different intestinal parasites, with Giardia often being one of the most common, have been found in dogs all over the world 14, 18, 19. This may be biased in societies in which deworming dogs is a standard routine, thereby reducing the prevalence of other commonly detected intestinal parasites such as Toxocara canis [20]. High occurrence of intestinal parasites in dogs is probably largely a consequence of the scavenging behavior of canines, in which coprophagia or close
Giardiasis versus Giardia carriers
When a host ingests infectious Giardia cysts, disease development is dependent on interactions between trophozoites and the host intestine [38]. Based on in vitro and in vivo studies of human cell interactions, these have been shown to include disruption of the small intestinal epithelial barrier, breakdown and/or rearrangement of proteins responsible for cell–cell contact (tight and adherence junctional proteins), and breakdown of the protective intestinal mucus layer [39]. Although the
Protozoa as commensals – where does Giardia stand?
The past two decades have seen an increasing awareness of the importance of commensal microorganisms (microbiota) that inhabit different mammalian organs. Intestinal bacteria outnumber host cells by 10:1, and are important in maintaining homeostasis of a healthy gut and have key functions in immunomodulation and nutrient utilization [45]. Harmless commensal bacteria also compete with potential pathogens, thus providing a protective effect [46].
So far microbiome research has largely focused on
In the veterinary clinic: diagnosis and treatment options
There are several ways to diagnose giardiasis and to detect subclinical carriage (Table 1). Microscopy of direct fecal smears, fecal flotation with centrifugation, and different rapid tests may be performed at the general veterinary clinic. Analysis of three fecal samples from alternating days is generally recommended owing to variable cyst excretion. Test sensitivity varies depending on the method used and the experience of the personnel performing the analysis [59]. At a specialized
Concluding remarks and future perspectives
Frequent detection of Giardia cysts, DNA, or antigen in feces of humans and other animals indicates that this protozoan often takes up residence in the intestines – but evidence increasingly indicates that this residency is not always pathogenic. The close association between people and ‘man's best friend’ – together with similarities in the spectrum of symptoms seen when Giardia establishes in each of them – suggest that some aspects of one host–protozoan relationship may be reflected in the
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Cited by (44)
Factors associated with Giardia infection in dogs in southern Ontario, Canada
2023, Veterinary Parasitology: Regional Studies and ReportsSurvey of U.S. based veterinarians’ knowledge, perceptions and practices about canine giardiasis
2022, Veterinary Parasitology: Regional Studies and ReportsCitation Excerpt :These qualitative tests can be performed in-clinic and/or in diagnostic labs run by universities or commercial entities. Other tests that may provide quantitative information includes immunofluorescence microscopic tests and PCR that are performed at diagnostic parasitology labs (Tysnes et al., 2014). The choice of confirmatory test used likely varies with the diagnostic skills of individual veterinarians, practice policies, test availability in-clinic and time availability.
Giardia duodenalis in a clinically healthy population of captive zoo chimpanzees: Rapid antigen testing, diagnostic real-time PCR and faecal microbiota profiling
2022, International Journal for Parasitology: Parasites and WildlifeCitation Excerpt :This finding, however, was not supported if DNA based diagnostic real-time PCR was used, or separating the samples based on burden based on real-time PCR Ct-values. Such results add to the conundrum surrounding the asymptomatic G. duodenalis infections and complex pathogenesis (Robertson et al., 2010; Tysnes et al., 2014; Fekete et al., 2020). By design our investigation lacks information on chimpanzee identities, and thus individual host factors contributing to the G. duodenalis infection.
Evaluation for associations amongst Giardia duodenalis assemblages and diarrhea in dogs
2021, Veterinary ParasitologyGeneralized cutaneous urticaria associated with Giardia infection in a five-month old puppy
2021, Veterinary Parasitology: Regional Studies and Reports