A Comparative Study of the Intestinal Protozoa of Wild Monkeys and Man*

Hegner, Robert; Chu, H. J.

doi:10.1093/oxfordjournals.aje.a115270

Cited by 14 publications

(18 citation statements)

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“…Humans are probably the definitive host of this parasite even though D. fragilis trophozoites have been reported in nonhuman primates, including macaques (132,167), baboons (204), and gorillas (255).…”

Section: Dientamoeba Fragilismentioning

confidence: 99%

Clinical Significance of Enteric Protozoa in the Immunosuppressed Human Population

et al. 2009

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SUMMARY Globally, the number of immunosuppressed people increases each year, with the human immunodeficiency virus (HIV) pandemic continuing to spread unabated in many parts of the world. Immunosuppression may also occur in malnourished persons, patients undergoing chemotherapy for malignancy, and those receiving immunosuppressive therapy. Components of the immune system can be functionally or genetically abnormal as a result of acquired (e.g., caused by HIV infection, lymphoma, or high-dose steroids or other immunosuppressive medications) or congenital illnesses, with more than 120 congenital immunodeficiencies described to date that either affect humoral immunity or compromise T-cell function. All individuals affected by immunosuppression are at risk of infection by opportunistic parasites (such as the microsporidia) as well as those more commonly associated with gastrointestinal disease (such as Giardia). The outcome of infection by enteric protozoan parasites is dependent on absolute CD4+ cell counts, with lower counts being associated with more severe disease, more atypical disease, and a greater risk of disseminated disease. This review summarizes our current state of knowledge on the significance of enteric parasitic protozoa as a cause of disease in immunosuppressed persons and also provides guidance on recent advances in diagnosis and therapy for the control of these important parasites.

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Section: Dientamoeba Fragilismentioning

confidence: 99%

Clinical Significance of Enteric Protozoa in the Immunosuppressed Human Population

et al. 2009

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“…For instance, Dobell's attempt to infect macaques by rectal inoculation failed (Dobell, 1940). One possibility is that the organisms described in these reports (Hegner and Chu, 1930;Knowles and DasGupta, 1936) were misidentified and macaques are not a true host for Dientamoeba. There are several plausible explanations for Dobell's failed attempt to infect macaques.…”

Section: With Respect To Animalsmentioning

confidence: 99%

“…As few studies have explored this possibility, the role of animals remains uncertain. Hegner and Chu (1930) reported Dientamoeba infections in 2/44 wild monkeys from the Philippines. Knowles and Das Gupta (1936) detected Dientamoeba in the stools of captive macaques (1/30) using an iron haematoxylin staining technique.…”

Section: Introductionmentioning

confidence: 99%

The ambiguous life ofDientamoeba fragilis: the need to investigate current hypotheses on transmission

et al. 2011

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Dientamoeba fragilis is an inhabitant of the human bowel and is associated with gastrointestinal illness. Despite its discovery over a century ago, the details of Dientamoeba's life cycle are unclear and its mode of transmission is unknown. Several theories exist which attempt to explain how Dientamoeba may be transmitted. One theory suggests that animals are responsible for the transmission of Dientamoeba. However, reports of Dientamoeba in animals are sporadic and most are not supported by molecular evidence. Another theory suggests that Dientamoeba may be transmitted via the ova of a helminth. Given that the closest relative of Dientamoeba is transmitted via the ova of a helminth, this theory seems plausible. It has also been suggested that Dientamoeba could be transmitted directly between humans. This theory also seems plausible given that other relatives of Dientamoeba are transmitted in this way. Despite numerous investigations, Dientamoeba's mode of transmission remains unknown. This review discusses the strengths and weaknesses of theories relating to Dientamoeba's mode of transmission and, by doing so, indicates where gaps in current knowledge exist. Where information is lacking, suggestions are made as to how future research could improve our knowledge on the life cycle of Dientamoeba.

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“…Indeed, morphology has been superseded by molecular markers in the description and identification of species in some genera of amoeboid organisms, for example Entamoeba (34) and Naegleria (31). Although D. fragilis has been found in nonhuman primates, this diagnosis is based only on morphology (59,73,83). Whether these organisms represent distinct species within the genus awaits further information.…”

Section: Taxonomymentioning

confidence: 99%

Emerging from Obscurity: Biological, Clinical, and Diagnostic Aspects of Dientamoeba fragilis

2004

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Ever since its first description in 1918, Dientamoeba fragilis has struggled to gain recognition as a significant pathogen. There is little justification for this neglect, however, since there exists a growing body of case reports from numerous countries around the world that have linked this protozoal parasite to clinical manifestations such as diarrhea, abdominal pain, flatulence, and anorexia. A number of studies have even incriminated D. fragilis as a cause of irritable bowel syndrome, allergic colitis, and diarrhea in human immunodeficiency virus patients. Although D. fragilis is most commonly identified using permanently stained fecal smears, recent advances in culturing techniques are simplifying as well as improving the ability of investigators to detect this organism. However, there are limitations in the use of cultures since they cannot be performed on fecal samples that have been fixed. Significant progress has been made in the biological classification of this organism, which originally was described as an ameba. Analyses of small-subunit rRNA gene sequences have clearly demonstrated its close relationship to Histomonas, and it is now known to be a trichomonad. How the organism is transmitted remains a mystery, although there is some evidence that D. fragilis might be transmitted via the ova of the pinworm, Enterobius vermicularis. Also, it remains to be answered whether the two distinct genotypes of D. fragilis recently identified represent organisms with differing virulence

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A Comparative Study of the Intestinal Protozoa of Wild Monkeys and Man*

Cited by 14 publications

References 0 publications

Clinical Significance of Enteric Protozoa in the Immunosuppressed Human Population

Clinical Significance of Enteric Protozoa in the Immunosuppressed Human Population

The ambiguous life ofDientamoeba fragilis: the need to investigate current hypotheses on transmission

Emerging from Obscurity: Biological, Clinical, and Diagnostic Aspects of Dientamoeba fragilis

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