Prevalence, molecular typing and risk factor analysis for Giardia duodenalis infections in dogs in a central London rescue shelter

Department of Veterinary Clinical Sciences, Royal Veterinary College, Hawkshead Lane, Hertfordshire AL9 7TA, UK.
Veterinary Parasitology (Impact Factor: 2.46). 09/2010; 172(3-4):341-6. DOI: 10.1016/j.vetpar.2010.05.010
Source: PubMed


A cross-sectional survey to investigate canine infections with Giardia duodenalis was undertaken at a central London rescue shelter between October 2006 and March 2007. The objectives of the study were to (i) estimate the prevalence of infection in dogs admitted to a London dog shelter using a commercially available ELISA-based test kit; (ii) identify the relative importance of potential dog level risk factors for infection; and (iii) identify the occurrence of different G. duodenalis assemblages present in this population in order to identify presence of any potentially zoonotic assemblages. A faecal sample was collected from each dog entering the shelter within 1 day of arrival. Each sample was tested for the presence of parasite cyst wall protein using the Giardia SNAP test kit (Idexx Laboratories). Samples were graded for faecal consistency on a standard scale and data on age, breed, categorized breed group, sex and neutered status were collected for each dog. Associations between infection status and each dog level variable were investigated using univariable and multivariable logistic regression. Selected G. duodenalis-positive samples were genotyped using previously described primers targeting the 18S rDNA gene and the beta-giardin gene. Samples from a total of 878 dogs were collected and the true prevalence found to be 21.0% (95% CI 16.7-25.4%). In the present study, the odds of infection decreased with increasing age (adjusted odds ratio 0.66, 95% CI 0.54-0.80, p<0.0001) and was increased for Rottweilers (adjusted odds ratio 2.12, 95% CI 1.03-4.34, p=0.04). Of the 51 samples selected for genotyping, 41 samples yielded a good amplification at one or both of the targeted genes, demonstrating the occurrence of mainly dog-specific assemblages C and D. The potentially zoonotic assemblage A and a mixed template C/D were found in two individual dogs. The results of the present study illustrate the high prevalence of G. duodenalis in shelter dogs. Although predominantly infected with dog-specific assemblages, the identification of assemblage A suggests that appropriate precautions should be taken to minimize the risk of transmission to staff.

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    • "The predominance of dog-specific assemblages C and D over zoonotic assemblages A and B in canine Giardia isolates exists not only in South Eastern Europe but also in other countries worldwide. The occurrence of non-zoonotic assemblages C or D was 100 % at the SSU rRNA and 93.3 % at the bg locus in England (Upjohn et al. 2010), 98.7 % at the SSU rRNA, 97.3 % at the bg and 100 % at the gdh and tpi loci in Canada (McDowall et al. 2011), 88.6 % at the SSU rRNA locus in the USA (Johansen 2013) and 96.2 % at the SSU rRNA locus in Trinidad and Tobago (Mark-Carew et al. 2013). In general, assemblage D outweighed assemblage C in most studies on canine Giardia assemblages including the present study. "
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