A Bayesian evaluation of two dip-stick assays for the on-site diagnosis of infection in calves suspected of clinical giardiasis

Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
Veterinary Parasitology (Impact Factor: 2.46). 09/2010; 172(3-4):337-40. DOI: 10.1016/j.vetpar.2010.05.015
Source: PubMed


The objective of the present study was to evaluate two commercially available dip-stick assays for the diagnosis of Giardia infections in faecal samples from calves suspected of clinical giardiasis. The dip-stick assays provide an on-site and hence quick alternative to laboratory diagnosis. A three-test Bayesian model was used, including the test results of the Coris Giardia strip (Coris Bioconcept, Gembloux, Belgium), the Speed Giardia or BVT dip-stick (Bio Veto Test/Virbac, La Seyne sur Mer, France), and the Meridian immunofluorescence assay (IFA: Meridian Diagnostics Inc., Cincinnati, OH). In total, 421 faecal samples were examined with the three diagnostic assays between October 2008 and November 2009. Overall, the number of positive samples was markedly higher using the IFA compared to both dip-stick assays, resulting in a high sensitivity (se: 88%, with a 95% probability interval (PI) 60-99%) compared to the Coris dip-stick assay (se: 28%; PI: 16-41%) and the BVT dip-stick assay (se: 26%, PI: 16-35). The specificities of all the three assays were very high (IFA sp: 94%, PI: 90-99%; Coris sp: 92%, PI 86-98%; BVT sp: 93%, PI 88-98%). A positive diagnosis by the dip-stick assays was significantly correlated with a higher cyst excretion level, as measured by IFA. The majority (76%) of the positive samples in the present study contained less than 5000cyst per gram of faeces, even though all these animals displayed clinical symptoms of diarrhea potentially due to Giardia. The low level of cyst excretion in these samples might in part explain the poor sensitivity of both dip-stick assays. Although multiple samplings might be an option to increase the sensitivity of the dip-stick assays, the laboratory based IFA seems at current to be the best option for clinical diagnosis of Giardia in calves.

21 Reads
  • [Show abstract] [Hide abstract]
    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.
    No preview · Article · Jan 2011
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Giardiasis is a gastrointestinal disease of humans and other animals caused by species of parasitic protists of the genus Giardia. This disease is transmitted mainly via the faecal–oral route (e.g., in water or food) and is of socioeconomic importance worldwide. The accurate detection and genetic characterisation of the different species and population variants (usually referred to as assemblages and/or sub-assemblages) of Giardia are central to understanding their transmission patterns and host spectra. The present article provides a background on Giardia and giardiasis, and reviews some key techniques employed for the identification and genetic characterisation of Giardia in biological samples, the diagnosis of infection and the analysis of genetic variation within and among species of Giardia. Advances in molecular techniques provide a solid basis for investigating the systematics, population genetics, ecology and epidemiology of Giardia species and genotypes as well as the prevention and control of giardiasis.
    Full-text · Article · Mar 2014 · Biotechnology Advances
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Giardia duodenalis is a flagellate protozoan that parasitizes humans and several other mammals. Protozoan contamination has been regularly documented at important environmental sites, although most of these studies were performed at the species level. There is a lack of studies that correlate environmental contamination and clinical infections in the same region. The aim of this study is to evaluate the genetic diversity of a set of clinical and environmental samples and to use the obtained data to characterize the genetic profile of the distribution of G. duodenalis and the potential for zoonotic transmission in a metropolitan region of Brazil.
    Full-text · Article · Dec 2014 · PLoS ONE