Genotyping ofGiardia duodenalisisolates in asymptomatic children attending daycare centre: evidence of high risk for anthroponotic transmission

Abstract

Giardia duodenalis is a common intestinal parasite infecting children attending daycare centres. This study aimed to verify Giardia occurrence and the genotypes of isolates infecting children aged 0-6 years and workers at a daycare centre in the state of São Paulo, Brazil. The families of children who tested positive for Giardia, were asked to provide stool samples from household members and their dogs. Samples (123 children, 14 centre employees, 44 household members, 19 children after treatment, and 20 dogs) were examined for intestinal parasites using concentration methods. DNA extracted from all samples was submitted for polymerase chain reaction (PCR) testing and the amplicons generated were used for multilocus sequence typing of beta-giardin (bg), triose phosphate isomerase (tpi) and glutamate dehydrogenase (gdh) genes. Giardia was detected in 15·9% and 28·6% of the 220 samples by microscopy and PCR, respectively. Analysis of sequences retrieved from 29 isolates revealed both assemblages A (31%) and B (69%). Sub-assemblages AII, BIII and BIV were identified and the alignment of the bg, gdh and tpi sequences revealed the presence of some single nucleotide polymorphisms, especially in assemblage B sequences. The higher predominance of assemblage B and the identification of the AII type support the view that anthroponotic transmission appears to be an important route of transmission in environments that concentrate children at an age when poor hygiene practices make them more vulnerable to such infection.

Prevalence of intestinal parasites, with emphasis on the molecular epidemiology of Giardia duodenalis and Blastocystis sp., in the Paranaguá Bay, Brazil: a community survey

“…Interestingly, the presence of assemblage A, but not assemblage B, has been described in a few epidemiological surveys targeting clinical patients in the State of São Paulo [72], and paediatric populations [73] and people from disadvantaged communities seeking medical care [74] in Rio de Janeiro. In contrast, assemblage B was more prevalently found in asymptomatic children attending a day-care centre in the State of São Paulo [75]. It should be noted that direct comparison of genotyping results and drawing of conclusions from these investigations should be made with caution because of the intrinsic differences in targeted population, sample size, sampling and diagnostic procedures, molecular tools, and marker (s) investigated.…”

Intestinal protozoa in diarrheic children in an Egyptian rural area: Role of water contamination and other possible risk factors

“…Close contact of children in day care centers favors anthroponotic transmission of most enteric protozoa unless good hygiene is practiced [40,41] . Lack of significant association with protozoal infection in the present study suggests that person to person spread plays a limited role compared to waterborne transmission.…”

Distribution of Giardia duodenalis Assemblages by PCR-RFLP of β-Giardin Gene in Cuban Children

“…18,19 Children are the more prone to developing symptoms in this parasitic infection, in part due to their immunological status, as is the first time to get contact with this parasite. 20 Differences in symptomatic and asymptomatic Giardia- infected children have been attributed to several factors; genetic characteristics of this parasite have been one of the most explored factors. 6 In the present study, the β-giardin gene was used to molecularly characterize G. duodenalis isolates.…”