Myxobolus sp., Another Opportunistic Parasite in Immunosuppressed Patients?

Abstract

During a study of intestinal parasitic infections in human immunodeficiency virus-positive patients, a parasite belonging to the phylum Myxozoa, recently described from human samples, was identified in one sample. When this parasite was stained by the modified Ziehl-Neelsen staining method, the features of the spores were identified: they were pyriform in shape, had thick walls, and had one suture and two polar capsules, with each one having four or five coils. The suture and two polar capsules were observed with the chromotrope-modified stain. The number of stools passed was more than 30 per day, but oocysts of Isospora belli were also found. Upon reexamination of some formalin-or merthiolate-iodine-formaldehyde-preserved samples an identical parasite was found in another sample from a patient presenting with diarrhea. Strongyloides stercoralis larvae and eggs of Hymenolepis nana and Ascaris lumbricoides were also found in this sample. Given that both patients were also infected with other pathogens that cause diarrhea, the possible pathogenic role of this parasite could not be established. The probable route of infection also could not be established.

Application of an aqueous acid-fast staining technique to detect pathogens of aquatic species

“…Mature spores stain weakly with hematoxylin and eosin, but are strongly acid-fast (Gardiner et al 1998). Myxozoan fish parasites have been found in human fecal samples (McClelland et al 1997, Boreham et al 1998, Moncada et al 2001. Moncada et al (2001) reported spores belonging to the genus Myxobolus based on morphology visible by light microscopy, but only in specimens stained by acidfast techniques.…”

Myxozoan genera: definition and notes on taxonomy, life-cycle terminology and pathogenic species

“…Developmental stages and unassigned spores were surprisingly found in inflammatory lesions of hepatic ducts in ducks (Lowenstine et al 2002). There have been also repeated findings of Myxobolus spores in the faeces of humans suffering from intestinal disorders or infected with the HIV virus (e.g., Boreham et al 1998, Moncada et al 2001, Hessen and Zamzame 2004. These reports led Canning and Okamura (2004) to postulate that myxozoans may under certain conditions become opportunistic parasites of homeothermic vertebrates.…”

The first finding of myxosporean development from plasmodia to spores in terrestrial mammals: Soricimyxum fegati gen. et sp. n. (Myxozoa) from Sorex araneus (Soricomorpha)

“…In stool samples of humans examined for gastrointestinal disorders, spores of the genera Myxobolus Bütschli, 1822 and Henneguya Thélohan, 1892 were found and it was presumed that they were parasites of consumed fish (McClelland et al 1997, Boreham et al 1998. In another case (Moncada et al 2001), it was speculated that the Myxobolus spores found in the stool might have been the result of an opportunistic infection of an HIVinfected patient.…”