Recognition and laboratory characteristics of an atypical oocyst of Cryptosporidium

Staining blindly: an update on coloring techniques for fecal smears in parasitology: a scoping review

Dye application for parasite highlighting in the Ova and Parasite exam is a common practice in parasitology diagnosis. Methods: A scoping review investigated how staining solutions interact with parasite structures. After screening 1334 papers, 35 met eligibility criteria. Results: Differentiating background from foreground in the fecal smear under light microscopy is the core of the research on this topic. Refractivity, unevenness of staining, size and temperature were explored to enhance staining protocols. Cryptosporidium spp. and Microsporidia were the main studied species. Conclusion: Studies on diagnostic efficacy outperform those that elucidate the physical-chemical interaction between dyes and parasites. An alternative approach involves technicians using computational tools to reduce subjectivity in fecal smear interpretation, deviating from conventional methods.

Diarrhea caused by a Cyanobacterium-like organism

Seven cases of watery diarrhea of explosive onset, three of them ending within two weeks, are discussed. The cause of diarrhea is believed to be the presence of an organism called Cyanobacteriumlike organism. These are non-refractile, spherical bodies, 8-9 micrometers in diameter, which take on a faint to deep pink color after modified kinyoun acid-fast staining. Risk factors such as travel to and from warm regions, and water as a possible source of infection are briefly discussed.

Cryptosporidiosis

Before 1982, only eight case reports of human cryptosporidiosis and fewer than 30 papers on Cryptosporidium spp. appeared in the biomedical literature. At that time, cryptosporidiosis was thought to be an infrequent infection in animals and rarely an opportunistic infection in humans. The concept of Cryptosporidium spp. as pathogens has changed dramatically within the past 8 years because of improved diagnostic techniques, increased awareness within the biomedical community, and the development of basic research programs in numerous laboratories. Presently, greater than 1,000 publications including over 400 case reports in the biomedical literature address Cryptosporidium spp. and cryptosporidiosis. Cryptosporidium parvum is now thought to be one of the three most common enteropathogens causing diarrheal illness in humans worldwide, especially in developing countries. It is likely that cryptosporidiosis was previously included in the 25 to 35% of diarrheal illness with unknown etiology. Because of the severity and length of diarrheal illness and because no effective therapy has been identified, cryptosporidiosis is one of the most ominous infections associated with AIDS. The role of C. parvum as an enteropathogen is well established; documentation of its role as a cause of hepatobiliary and respiratory diseases is now appearing in the literature. Our present understanding of the natural history, epidemiology, biology, and immunology of Cryptosporidium spp. as well as the clinical features, pathogenicity, and treatment of cryptosporidiosis are reviewed here.

ACP Broadsheet 128: June 1991. Laboratory methods for diagnosing cryptosporidiosis

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Alga associated with diarrhea in patients with acquired immunodeficiency syndrome and in travelers

Spherical bodies resembling coccidian oocysts and measuring 8.0 to 9.0 microns in diameter were seen in the stools of eight persons with explosive, watery diarrhea. Seven had recently traveled to tropical countries, mostly in the Caribbean, and four had acquired immunodeficiency syndrome. The structures were easily discernible in wet mounts by light microscopy and contained variable numbers of granular inclusions, but were refractory to, or stained partially with, 12 commonly used laboratory stains. Electron microscopy revealed an outer fibrillar coat, a thin cell wall, granules, and organelles which were not surrounded by membranes. One type of organelle was similar to the thylakoid photosynthesizing organelles of blue-green algae (cyanobacteria). These findings indicate that the bodies may be a species of blue-green algae.

New mouse models for chronic Cryptosporidium infection in immunodeficient hosts

Cryptosporidium sp. causes fulminant diarrhea and chronic infection in immunocompromised, particularly human immunodeficiency virus-infected, persons. The lack of in vitro cultivation and a suitable animal model has limited development of effective treatment. We describe two new mouse models of chronic symptomatic cryptosporidiosis in adult athymic mice and in T-cell subset-depleted mice. A progressive infection, fatal within 4 months, occurred in most adult athymic mice; a few developed stable infections. Symptoms included dehydration, weight loss, intermittent diarrhea, and jaundice. Pathologic abnormalities and organisms localized in the intestine in stable infections but involved the hepatobiliary tree and pancreas in others. Lymphoid cells from histocompatible, Cryptosporidium sp.-immune mice cured infected nude mice. Identical infections occurred in neonatally infected BALB/c mice treated with anti-CD4 monoclonal antibodies alone or also with anti-CD8 monoclonal antibodies; the mice were cured when the monoclonal antibody treatments were stopped. These models will be useful in definition of the immune defects that permit chronic cryptosporidiosis to develop and in assessment of treatment modalities.

Cryptosporidium infection in Oregon public health clinic patients 1985-88: the value of statewide laboratory surveillance

To evaluate the utility of statewide laboratory Cryptosporidium surveillance, we screened stools from all 5,256 patients evaluated at local health departments for parasitic disease from January 1985 through June 1988. Fifty-seven patients (1.1 percent) were found to have Cryptosporidium. Seasonal peaks in positivity were observed in the spring, summer, and early autumn months. In children, younger age was associated with higher positivity rate of cryptosporidiosis. As a result of these surveillance efforts, Oregon's first known outbreak of cryptosporidiosis was detected and investigated during 1988. Twenty-five persons were infected, including children, parents, and staff associated with two day care centers. The cost of routine screening for Cryptosporidium was $1.13 per specimen in our laboratory, and we consider it useful.

Epidemiological aspects of human cryptosporidiosis

The coccidian protozoan parasiteCryptosporidiumhas been described in many host species since its discovery in the early part of the century, but it remained obscure until the recognition by veterinary workers in the 1970s of its importance as a cause of scours in young livestock animals [1–4].