Molecular Analysis of Household Transmission ofGiardia lambliain a Region of High Endemicity in Peru

Abstract

Background Giardia lamblia is ubiquitous in multiple communities of non-industrialized nations. Genotypes A1, A2, and B (Nash groups 1, 2, and 3, respectively) are found in humans, while genotypes C and D are typically found in dogs. However Genotypes A and B have occasionally been identified in dogs. Methods Fecal Giardia isolates from 22 families and their dogs, living in Pampas de San Juan, were collected over seven weeks in 2002 and six weeks in 2003. Samples were genotyped, followed by sequencing and haplotyping of many of these isolates, using loci on chromosomes 3 and 5. Results Human infections were all caused by isolates of genotypes A2 and B. Human co-infections with Genotypes A2 and B were common, and the reassortment pattern of different subtypes of A2 isolates supports prior observations suggesting recombination among Genotype A2 isolates. All dogs had genotypes C and/or D with one exception of a dog with a mixed B/D genotype infection. Conclusions In a highly endemic region where infected dogs and humans constantly commingle, different genotypes of Giardia are almost always found in dogs and humans, suggesting that zoonotic transmission is very uncommon.

Prevalence and molecular genotypic characterization of Giardia duodenalis isolates from Iranian patients (Fars province)

“…However, it was in contrast to some other studies showing the predominance of assemblage B from Australia (6), Bangladesh (42), Belgium (43), England (44), Nicaragua (45), and Philippine (46). In this study, subtyping analysis showed that all the 32 assemblage A isolates were identical to sub-genotype AII that has also been shown in Australia (6), Brazil (37), Iran (38), Nicaragua (45) and Peru (47). …”

Giardia duodenalis genotypes among schoolchildren and their families and pets in urban and rural areas of Sinaloa, Mexico

“…Although G. duodenalis isolated from dogs typically belong to C or D genotypes, A and B also have been identified in the regions with high endemic areas of genotypes A and B, such as in Argentina [21], Brazil [42], Peru [48], and Mexico [18,[38][39][40]. Sharing of the same G. duodenalis genotype between dogs and their owners has been reported [49].…”

Subclinical Giardia in dogs: a veterinary conundrum relevant to human infection

“…For example, G. duodenalis genotypes A and B have been detected in some studies from dogs, but the canine specific genotypes (C and D) tend to dominate [11]. With regard to canine giardiasis, some studies suggest that transmission between dogs and humans may be uncommon [12,13], but other studies have indicated that in particular situations dogs may act as reservoirs for human infection [14]. Although a few studies report occurrence of assemblage C and D in human samples [15], it seems likely that these represent carriage rather than infection with these genotypes.…”