Life without a Host Cell: What is Cryptosporidium ?

Clode, Peta L.; Koh, Wan Hon; Thompson, R.C.A.

doi:10.1016/j.pt.2015.08.005

Cited by 56 publications

(54 citation statements)

References 63 publications

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“…Cryptosporidium is an apicomplexan protozoan infecting the gastrointestinal tract of animals and humans, whose phylogenetic placement and life cycle biology are still being interrogated (1). Infection occurs via fecal-oral transmission upon ingestion of oocysts.…”

Section: Discussionmentioning

confidence: 99%

“…Infection occurs via fecal-oral transmission upon ingestion of oocysts. Each oocyst releases four sporozoites that develop into trophozoites in the gut (1). The trophozoites engage the apical side of the intestinal epithelium and fuse their plasma membrane with the host cell's membrane, forming a parasitophorous vacu-ole.…”

Section: Discussionmentioning

confidence: 99%

“…The trophozoites engage the apical side of the intestinal epithelium and fuse their plasma membrane with the host cell's membrane, forming a parasitophorous vacu-ole. Encapsulated trophozoites then absorb the content of the parasitized cells using a specialized feeder organelle (1). Multiplication of trophozoites via asexual replication is followed by development of micro-and macrogametes.…”

Section: Discussionmentioning

confidence: 99%

“…Multiplication of trophozoites via asexual replication is followed by development of micro-and macrogametes. These fuse to give rise to diploid oocysts that are directly infective upon release in the environment via defecation (1).…”

Section: Discussionmentioning

confidence: 99%

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The Brief Case: Cryptosporidiosis in a Severely Immunocompromised HIV Patient

Rossi

Couturier

2016

J Clin Microbiol

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A 52-year-old male with AIDS was admitted to the University of Utah Hospital with chronic (Ͼ3-month duration) watery diarrhea. The patient had been diagnosed with HIV infection 3 years prior to admission but had been noncompliant with antiviral therapy since primary diagnosis. Three months prior to admission (at the time of the diarrhea onset), his CD4 ϩ cell count was critically low (6 cells/l), he had an elevated viral load (ϳ54,000 copies/ml), and he was displaying rapid deterioration of overall health. The patient also suffered from multiple other known viral complications attributable to his severe immunosuppression, including chronic cytomegalovirus (CMV) retinitis and recurrent anogenital lesions caused by herpes simplex virus 2 (HSV-2).The patient was severely malnourished and hypokalemic at admission (potassium level, Ͻ1.6 mmol/liter). The stools (Ͼ20 per day) were nonbloody and devoid of mucus, and inflammation was indicated by the presence of lactoferrin in the stool. Routine stool cultures were negative for Shigella, Salmonella, Campylobacter, Yersinia, Aeromonas, Plesiomonas, and Vibrio. Shiga-like-toxin-producing Escherichia coli was not detected by antigen detection, and Clostridium difficile was not detected by real-time PCR. CMV colitis was excluded on the basis of negative results for immunohistochemical staining of colonoscopy-obtained biopsy samples. A single microscopic examination of stool for ova and protozoal parasites (O&P detection), consisting of a concentrated wet-mount preparation, a trichrome stain, a modified trichrome stain, and a modified acid-fast (MAF) stain, gave negative results for gastrointestinal parasites and microsporidia. The result for fecal antigen detection for Cryptosporidium was also negative. Additional testing with a multiplex real-time PCR panel for Entamoeba histolytica, Giardia, Cryptosporidium parvum/Cryptosporidium hominis, Dientamoeba fragilis, and Cyclospora cayetanensis gave a positive result for the presence of Cryptosporidium DNA. This result was discrepant with those for both antigen detection and microscopy but was repeatedly confirmed and eventually verified by sequencing of the amplicon.To investigate this discrepancy and attempt to provide a clinical clarification of the test results, the MAF-stained slide was reexamined for the presence of Cryptosporidium oocysts. No oocysts were seen upon review. Two additional slide preparations from the original specimen were stained and examined and revealed rare oocysts with characteristic fuchsia staining, size (5-m diameter), and morphology consistent with this protozoan (Fig. 1). Several "ghost cells" were also seen on the slides. The antigen test was repeated, and the results were negative in duplicate. The report for the MAF stain was corrected, and the physicians were consulted such that the management of cryptosporidiosis was incorporated into the long-term care of the patient. DISCUSSIONCryptosporidium is an apicomplexan protozoan infecting the gastrointestinal tract of animals and humans, whose phylo...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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The Brief Case: Cryptosporidiosis in a Severely Immunocompromised HIV Patient

Rossi

Couturier

2016

J Clin Microbiol

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“…However, recent phylogenetic studies have shown closer proximity of Cryptosporidium with gregarine protozoan than with coccidia, because they have a feeding organelle and absence of apicoplast, which allowed their reclassification in the Gregarinomorphea class, Cryptogregaria subclass (KOH et al, 2013(KOH et al, , 2014CAVALIER-SMITH, 2014;HUANG et al, 2014;CLODE et al, 2015;ALDEYARBI;RYAN et al, 2016).…”

Section: Cryptosporidium: Taxonomic and Biological Aspectsmentioning

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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Protozoan Parasites

Mehlhorn¹

2016

Animal Parasites

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Life without a Host Cell: What is Cryptosporidium ?

Cited by 56 publications

References 63 publications

The Brief Case: Cryptosporidiosis in a Severely Immunocompromised HIV Patient

The Brief Case: Cryptosporidiosis in a Severely Immunocompromised HIV Patient

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

Protozoan Parasites

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