Waterborne and Environmentally-Borne Giardiasis

Robertson, Lucy J.; Lim, Yvonne Ai Lian

doi:10.1007/978-3-7091-0198-8_3

Cited by 7 publications

(3 citation statements)

References 189 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been proposed that the routine water treatment practices usually employ concentrations of chlorine able to inactivate only bacterial and viral pathogens, but not Giardia cysts [ 25 – 26 ]. Thus, adequate control of giardiasis, particularly in Amazon region requires the improvement of drinking water quality and reduction of environmental contamination with feces [ 27 ]. Despite the high prevalence of giardiasis and its health impact worldwide, large-scale interventions—as those implemented for STH control—are lacking in developing countries.…”

Section: Resultsmentioning

confidence: 99%

Spatial and Molecular Epidemiology of Giardia intestinalis Deep in the Amazon, Brazil

et al. 2016

View full text Add to dashboard Cite

BackgroundCurrent control policies for intestinal parasitosis focuses on soil-transmitted helminths, being ineffective against Giardia intestinalis, a highly prevalent protozoon that impacts children’s nutritional status in developing countries. The objective of this study was to explore spatial and molecular epidemiology of Giardia intestinalis in children of Amerindian descent in the Brazilian Amazon.Methodology/Principal FindingsA cross sectional survey was performed in the Brazilian Amazon with 433 children aged 1 to 14 years. Fecal samples were processed through parasitological techniques and molecular characterization. Prevalence of G. intestinalis infection was 16.9% (73/433), reaching 22.2% (35/158) among children aged 2–5 years, and a wide distribution throughout the city with some hot spots. Positivity-rate was similar among children living in distinct socioeconomic strata (48/280 [17.1%] and 19/116 [16.4%] below and above the poverty line, respectively). Sequencing of the β-giardin gene revealed 52.2% (n = 12) of assemblage A and 47.8% (n = 11) of assemblage B with high haplotype diversity for the latter. The isolates clustered into two well-supported G. intestinalis clades. A total of 38 haplotypes were obtained, with the following subassemblages distribution: 5.3% (n = 2) AII, 26.3% (n = 10) AIII, 7.9% (n = 3) BIII, and 60.5% (n = 23) new B genotypes not previously described.Conclusions/SignificanceGiardia intestinalis infection presents a high prevalence rate among Amerindian descended children living in Santa Isabel do Rio Negro/Amazon. The wide distribution observed in a small city suggests the presence of multiple sources of infection, which could be related to environmental contamination with feces, possibly of human and animal origin, highlighting the need of improving sanitation, safe water supply and access to diagnosis and adequate treatment of infections.

show abstract

Section: Resultsmentioning

confidence: 99%

Spatial and Molecular Epidemiology of Giardia intestinalis Deep in the Amazon, Brazil

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Despite protozoa detection rates of 71.36% (142/199 water samples), there were fundamental disparities between the association of bacterial pathogens and protozoal oocysts in water column samples and exploratory variables included in this study (e.g., E. coli concentration MPN/100 ml, E. coli phylotype, faecal age, rainfall, water flow etc.). These observations may be influenced by contrasting kinetics and/or settling velocity deposition through sedimentation (Searcy et al, 2005 ) for the two microbial types and the contrasting sizes of individual protozoal (oo)cysts (≥5 μm) (Robertson & Lim, 2011 ; Ryan & Xiao, 2014 ) and generic E. coli cells (1–2 μm). Alternatively, low concentrations in faecal samples (Moriarty et al, 2008 ) and inability to grow outside hosts, predation of (oo)cysts by ciliated protozoan species (Siqueira‐Castro et al, 2016 ) or effect of ambient sunlight (Ahmed et al, 2023 ; King et al, 2008 ) on oocysts may also influence these disparities.…”

Section: Discussionmentioning

confidence: 99%

Population structure and pathogen interaction of Escherichia coli in freshwater: Implications of land‐use for water quality and public health in Aotearoa New Zealand

Cookson,

Devane,

Marshall

et al. 2024

Environ Microbiol Rep

View full text Add to dashboard Cite

Freshwater samples (n = 199) were obtained from 41 sites with contrasting land‐uses (avian, low impact, dairy, urban, sheep and beef, and mixed sheep, beef and dairy) and the E. coli phylotype of 3980 isolates (20 per water sample enrichment) was determined. Eight phylotypes were identified with B1 (48.04%), B2 (14.87%) and A (14.79%) the most abundant. Escherichia marmotae (n = 22), and Escherichia ruysiae (n = 1), were rare (0.68%) suggesting that these environmental strains are unlikely to confound water quality assessments. Phylotypes A and B1 were overrepresented in dairy and urban sites (p < 0.0001), whilst B2 were overrepresented in low impact sites (p < 0.0001). Pathogens ((Salmonella, Campylobacter, Cryptosporidium or Giardia) and the presence of diarrhoeagenic E. coli‐associated genes (stx and eae) were detected in 89.9% (179/199) samples, including 80.5% (33/41) of samples with putative non‐recent faecal inputs. Quantitative PCR to detect microbial source tracking targets from human, ruminant and avian contamination were concordant with land‐use type and E. coli phylotype abundance. This study demonstrated that a potential recreational health risk remains where pathogens occurred in water samples with low E. coli concentration, potential non‐recent faecal sources, low impact sites and where human, ruminant and avian faecal sources were absent.

show abstract

“…A recent review reported that, of the 199 global outbreaks caused by protozoa during the period 2004-2010, 70 (35%) were caused by Giardia (Baldursson and Karanis, 2011). The majority of these outbreaks were reported from North America, UK, and Asia (Robertson and Lim, 2014); this is likely the result of better detection and monitoring systems rather than epidemiological differences in various parts of the world. Outbreaks can be large, as was the case of the Bergen (Norway) outbreak of 2004, with a total of 1300 laboratory confirmed cases (Nygård et al, 2006).…”

Section: Transmission Routesmentioning

confidence: 99%