Giardiasis: Modern Concepts in Control and Management

Thompson, R.C.A.

doi:10.1159/000113306

Cited by 14 publications

(11 citation statements)

References 81 publications

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“…; most of these can be attributed to deficiencies in the filtration process (THOMPSON, 2004;KARANIS et al, 2007;BALDURSSON;KARANIS, 2011;EFSTRATIOU et al, 2017). Cattle has already been considered as a source of water contamination; however, there is little evidence that these animals are the main source of waterborne outbreaks, and that contamination with sanitary effluent from domestic sources is the most likely source (THOMPSON, 2004;SMITH et al, 2006;THOMPSON, 2008). Livestock and rainfall in poorly filtered catchment areas favor the occurrence of outbreaks, especially in areas where environmental concentrations of these protozoans are higher (RISEBRO et al, 2007;PLUTZER et al, 2010a).…”

Section: Cryptosporidium and Giardia: Waterborne Organisms And Their mentioning

confidence: 99%

Waterborne Giardia and Cryptosporidium: contamination of human drinking water by sewage and cattle feces

Toledo

Martins

Freire

2017

SCA

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Water is an important vehicle for pathogens such as Cryptosporidium spp. and Giardia duodenalis. In fact, these organisms are responsible for almost 58% and 38% of the waterborne outbreaks reported in ~60 years. Characteristics related to the environmental phase of these protozoa and the different types of hosts are important factors related to environmental contamination. In cryptosporidiosis and giardiasis, outbreaks caused by waterborne pathogens are identified as major risk factors for contamination of water resources by untreated sewage and the entrainment of cattle feces in rainwater. Further, this review covers taxonomic, biologic, and epidemiologic aspects such as prevalence, risk factors, and molecular characterization of these protozoa observed in humans and cattle in order to elucidate the role of these hosts in environmental pollution, and consequently, as a source of infection for susceptible humans, especially in rural areas. Alternative water resources such as wells and springs are used without water treatment and potability monitoring. Epidemiological data are useful, but insufficient to characterize the source of infection, thereby requiring the use of appropriate molecular methods for subtyping the protozoa detected in environmental and feces samples as well as for assessing public health risk. Key words: Sanitation. Giardia duodenalis. Cryptosporidium parvum. Zoonosis. Rural areas. Molecular characterization. ResumoA água é um importante veículo de transmissão de patógenos, entre eles Cryptosporidium spp e Giardia duodenalis, respectivamente responsáveis por 58% e 38% dos surtos de veiculação hídrica registrados em cerca de 60 anos. Características relacionadas às fases ambientais destes protozoários e a grande quantidade de hospedeiros são importantes fatores relacionados à contaminação ambiental. Em surtos de criptosporidiose e giardíase por veiculação hídrica são apontados como principais fatores de risco a contaminação dos mananciais, utilizados para a dessedentação humana, por esgoto não tratado e o desague de fezes de animais devido ao carreamento por água da chuva. Além destes fatores, esta revisão aborda aspectos taxonômicos, biológicos e epidemiológicos, como prevalência, fatores de risco e caracterização molecular destes protozoários em humanos e bovinos como forma de elucidar a importância destes hospedeiros na contaminação ambiental e, consequentemente, como fonte de infecção para humanos suscetíveis, especialmente em áreas rurais. Nestas áreas são frequentemente utilizadas fontes alternativas de abastecimento de água, como poços e nascentes, sem tratamento e monitoramento de potabilidade. Dados epidemiológicos auxiliam, porém não são suficientes para caracterizar fontes de infecção, sendo necessário o uso de adequadas ferramentas de caracterização molecular para subtipagem de protozoários identificados em fezes e amostras ambientais e avaliação do risco de saúde pública.

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Section: Cryptosporidium and Giardia: Waterborne Organisms And Their mentioning

confidence: 99%

Waterborne Giardia and Cryptosporidium: contamination of human drinking water by sewage and cattle feces

Toledo

Martins

Freire

2017

SCA

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“…The clinical impact of Giardia is the greatest in children, particularly in developing countries or disadvantaged communities where poor hygiene and the proximity of animal reservoirs sustain environmental contamination leading to a high frequency of transmission and the establishment of chronic infections (Thompson, 2008). In such situations, nutrition may be suboptimal, exacerbating the impact of Giardia infections that contribute to poor growth and development (failure to thrive) in early childhood, zinc and iron deficiency, poor cognitive function, and failure to thrive (growth retardation) as well as predispose to the development of allergic diseases (Berkman et al, 2002 andreviewed in Savioli et al, 2006;Thompson, 2008.…”

Section: Giardiamentioning

confidence: 99%

“…Drugs are not the answer as studies have shown that once drug pressure is removed without concurrent improvements in hygiene and sanitation, reinfection rapidly occurs (Thompson et al, 2001;Thompson, 2008). Long-term freedom from infection requires education in terms of basic hygiene, but without improvement in sanitation it is difficult to see how the impact of enteric parasite infections can be improved.…”

Section: Control and Future Trendsmentioning

confidence: 99%

Foodborne, enteric, non apicomplexan unicellular parasites

Thompson

2015

Foodborne Parasites in the Food Supply Web

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“…In non-fatal cases of diarrhea, particularly chronic infections diarrhea has been strongly correlated with growth retardation and yet good health is a precondition for society to develop. (Prado et al ., 2005; Thompson, 2008; Tumwine et al ., 2003)…”

Section: Introductionmentioning

confidence: 99%

Occurrence ofCryptosporidium hominisin cattle bordering the Lake Mburo National Park in Kiruhura district, Western Uganda

Witto

Kankya

Kazibwe

et al. 2019

Preprint

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BackgroundCryptosporidium is an emerging opportunistic zoonotic pathogen that causes diarrheal illness in a wide range of hosts including livestock and humans. Globally there is exponential increase in livestock production to meet the worlds’ demand for animal protein as well as for financial reasons. However, there is raised concern of the public health threat due to contamination of the environment by livestock waste carrying zoonotic pathogens such as Cryptosporidium. This study set out to establish the prevalence of Cryptosporidium as well as the circulating genotypes in order to elucidate the potential role of cattle in the spread of human cryptosporidiosis. We collected rectal coprological samples from 363 cattle in 11 households in Kiruhura district, Southwestern Uganda. The samples were screened for presence of Cryptosporidium oocysts using the phenol auramine staining method followed by fluorescent microscopy. DNA was then extracted from the microscopy positive samples and the COWP gene amplified using PCR. Amplified gene products were sequenced and subjected to phylogenetic analysis.ResultsThe overall animal level prevalence of Cryptosporidium was 7.7% (95% CI: 5.1-10.9), and herd level prevalence was 33.3% (95% CI: 18.5-52.2). We found a statistically significant difference (p=0.02) between infection in bulls as compared to cows. There was however no significant difference in the prevalence among the different cattle breeds sampled, with the following prevalence’s observed in Crosses 9.2%, Ankole 5.7%, Friesian 7.1%, and Boran 2.8% respectively. The COWP gene was successfully amplified from 20 of the 28 microscopy positive samples. All the sequenced DNA amplicons were confirmed to be C. hominis, with 98%-100% identity to sequences in the GenBank. C. hominis was the only genotype isolated from this study, further asserting that cattle could be a potential high risk source of human cryptosporidiosis.ConclusionThis study represents the first time naturally occurring C. hominis has been isolated from cattle in Uganda. This further provides evidence of cattle possibly being biological reservoirs for C. hominis and cattle could be a potential high risk source of human cryptosporidiosis.

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Giardiasis: Modern Concepts in Control and Management

Cited by 14 publications

References 81 publications

Waterborne Giardia and Cryptosporidium: contamination of human drinking water by sewage and cattle feces

Waterborne Giardia and Cryptosporidium: contamination of human drinking water by sewage and cattle feces

Foodborne, enteric, non apicomplexan unicellular parasites

Occurrence ofCryptosporidium hominisin cattle bordering the Lake Mburo National Park in Kiruhura district, Western Uganda

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