Occurrence and molecular epidemiology of Giardia duodenalis infection in dog populations in eastern Spain

Abstract

BackgroundGiardia duodenalis is one of the most common enteric parasites in domestic animals including dogs. Young animals are more prone to the infection, with clinical manifestations ranging from asymptomatic to acute or chronic diarrhoea. Dogs are primarily infected by canine-specific (C-D) assemblages of G. duodenalis. However, zoonotic assemblages A and B have been increasingly documented in canine isolates, raising the question of whether and to which extent dogs can act as natural reservoirs of human giardiosis.MethodsIn this cross-sectional epidemiological survey we assessed the molecular diversity of G. duodenalis in dogs in the province of Castellón, Eastern Spain. A total of 348 individual faecal samples from sheltered (n = 218), breeding (n = 24), hunting (n = 68), shepherd (n = 24), and pet (n = 14) dogs were collected between 2014 and 2016. Detection of G. duodenalis cysts in faecal material was carried out by direct fluorescence microscopy as a screening test, whereas a qPCR targeting the small subunit ribosomal RNA gene of the parasite was subsequently used as a confirmatory method.ResultsGiardia duodenalis was detected in 36.5% (95% CI: 31.6–41.7%) of dogs. No significant differences in prevalence rates could be demonstrated among dogs according to their sex and geographical origin, but breeding (45.8%; 95% CI: 27.9–64.9%) and sheltered (40.4%; 95% CI: 34.1–47.0%) dogs harboured significantly higher proportions of G. duodenalis. Multi-locus sequence-based genotyping of the glutamate dehydrogenase and β-giardin genes of G. duodenalis allowed the characterization of 35 canine isolates that were unambiguously assigned to assemblages A (14.3%), B (22.9%), C (5.7%), and D (37.1%). A number of inter-assemblage mixed infections including A + B (11.4%), A + D (2.9%), and A + B + D (5.7%) were also identified.ConclusionsData presented here are strongly indicative of high infection pressures in kennelled animals. Zoonotic sub-assemblages AII, BIII, and BIV were responsible for a considerable proportion of the G. duodenalis infections detected, but very few of the genotypes identified have been previously documented in Spanish human populations. Although possible, zoonotic transmission between dogs and humans seems an infrequent event in this Spanish region.Electronic supplementary materialThe online version of this article (10.1186/s12917-018-1353-z) contains supplementary material, which is available to authorized users.

Occurrence and genotypes of Cryptosporidium spp., Giardia duodenalis, and Blastocystis sp. in household, shelter, breeding, and pet market dogs in Guangzhou, southern China

“…transmission to humans, therefore, posed a limited risk to humans. This is consistent with the findings reported in dog populations in eastern Spain, where most of the genotypes identified seemed to be primarily transmitted within canine cycles 24 .…”

“…This finding is comparable to the prevalences in Poland (2.0% for G. duodenalis) 41 , India (3.0% for G. duodenalis) 42 , the United States (2.0% and 3.8% for Cryptosporidium) 43,44 , China (3.8% and 4.9% for Cryptosporidium) 10,14 , Italy (3.3% for Cryptosporidium) 9 , Australia (2.5% for Blastocystis) 29 , Brazil (2.6% for Blastocystis) 31 , and France (3.4% for Blastocystis) 20 . However, higher prevalences of 21% of Cryptosporidium from Japan, 36.5% of G. duodenalis from Spain, and 37.5% of Blastocystis from Colombia were also previously found in dogs 22,24,33 . Aside from geographical considerations, many factors can contribute to this difference in the prevalence, including a dog's age, origin, health status, and examination methods used.…”

Giardia duodenalis in small animals and their owners in Germany: A pilot study

“…Sequence typing was successful in only 6/13 canine samples, although an effort was made to type at four different marker genes. Expectedly, the most successful PCR method in the present study was at the multicopy SSUrDNA gene locus compared to the typing attempts at the singly gene copy loci tpi, bg and gdh as reported previously (Adell‐Aledon et al, ; Gil et al, ). Low parasite numbers in the analysed faecal samples likely contributed to this low typing success.…”

Giardia is the most prevalent parasitic infection in dogs and cats with diarrhea in the city of Medellín, Colombia

“…Recent molecular methods have classified Giardia organisms into assemblages that tend to be species-specific, suggesting low potential zoonotic threat. In people, assemblage clusters place them into A/B assemblages, dogs have C/D assemblages and cats have assemblages F (Adell-Aledón et al, 2018;Raza et al, 2018). However, questions remain as the amount of crossover between people and dogs and cats and what conditions promote this zoonotic transmission, since assemblages A/B have been found in dogs and cats (Adell-Aledón et al, 2018;Raza et al, 2018).…”

“…In people, assemblage clusters place them into A/B assemblages, dogs have C/D assemblages and cats have assemblages F (Adell-Aledón et al, 2018;Raza et al, 2018). However, questions remain as the amount of crossover between people and dogs and cats and what conditions promote this zoonotic transmission, since assemblages A/B have been found in dogs and cats (Adell-Aledón et al, 2018;Raza et al, 2018). When contrasting our results with two previous studies in dogs from the Medellin area (Caraballo et al, 2007;Sierra-Cifuentes et al, 2015), their results were strikingly similar in spite of the limited number of animals examined.…”