JOHNS HOPKINS
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Department of Pathology
600 N. Wolfe Street / Baltimore MD 21287-7093
(410) 955-5077 / FAX (410) 614-8087
Diviision of Medical Microbiology
THE JOHNS HOPKINS MICROBIOLOGY NEWSLETTER Vol. 25, No. 22
Tuesday, November 21, 2006
A. Provided by Sharon Wallace, Division of Outbreak Investigation, Maryland Department
of Health and Mental Hygiene.
There aren’t any outbreaks available at this time.
B. The Johns Hopkins Hospital, Department of Pathology, Information provided by,
Andrea Subhawong, M.D.
Clinical presentation: A 38 year old male with HIV diagnosed in 1996 was non-compliant with
HAART therapy and antimicrobial prophylaxis (last CD4 count 51, undetectable viral load), and
had a history of chronic diarrhea, HSV proctitis, Pneumocystis pneumonia, cryptococcal
meningitis, esophageal candidiasis, MAI cervical lymphadenitis, shigellosis, and MRSA axillary
cellulitis. He has been followed at JHH for several years with known microsporidial diarrhea,
with failure to take albendazole. He now presents with several weeks of worsened diarrhea and
acute renal failure with severe metabolic derangements (potassium 2.6, creatinine 3.9, calcium
6.6, and bicarbonate 10). Many Cryptosporidium spp. oocysts were noted by trichrome and acid
fast stains on stool O&P smears. Microsporidia were seen as well.
Cryptosporidiosis
Background: Cryptosporidium parvum and C. hominis are intracellular protozoan parasites that
infects digestive and respiratory tract epithelial cells of vertebrates. Human infection is usually
caused by drinking water contaminated by the feces of animals, but can also occur from direct
contact with infected animals. Prior to the AIDS epidemic, Cryptosporidium spp. were known to
cause a self-limited diarrheal illness in children and travelers. However, in the clinical setting of
advanced AIDS, Cryptosporidium spp. have become a frequent cause of serious intestinal
infections. In fact, detection of Cryptosporidium spp. in patients of unknown immune status
should prompt specific HIV testing. Waterborne transmission is a major problem because the
oocysts are resistant to chlorination. The incidence of cryptosporidiosis in North American AIDS
patients is estimated at 16% to 33%. In developing countries, 55% of AIDS patients are infected.
Clinical presentation: Patients usually present with watery diarrhea, at times with severe
dehydration, malabsorptive syndromes, electrolyte derangements, and weight loss. Dull
abdominal pain with bloating is common, and can be accompanied by nausea and vomiting,
anorexia, and low grade fever.
Diagnosis: The homogenous, red-staining, spherical oocysts (4-6 microns in diameter) can be
identified in fecal smear acid fast stains. Enzyme immunoassays for antigen detection also exist,
but the sensitivity of this approach is a point of contention. Diagnosis also can be made in
hematoxylin and eosin-stained tissue biopsy sections by identifying the tiny oocysts on the villi
epicellular surfaces lining epithelial cells.
Therapy: Albendazole, paromomycin, atovaquone, nitazoxanide, and azithromycin can be used,
with only temporary effects, along with supportive treatment using loperamide and tincture of
opium. The severity of symptoms in AIDS patients correlates with lower CD4 cell counts;
therefore, the use of antiretroviral therapy and concomitant increase in CD4 count may help
resolve symptoms.
References
1. Pensa E, Borum M. The AIDS Reader. 10(6):347-358, 2000.
2. Gelb A, Miller S. AIDS and gastroenterology. Am J Gastroenterol. 1986;81:619-622.
3. Wyatt SH, Fishman EK. The acute abdomen in individuals with AIDS. Radiol Clin North Am.
1994;32:1023-1043.
4. Garone MA, Winston BJ, Lewis JH. Cryptosporidiosis and the stomach. Am J Gastroenterol.
1986;81:465-470.
5. Ramratnam B, Flanigan TP. Cryptosporidiosis in persons with HIV infection. Postgrad Med J.
1997;73:713-716.
6. Flanigan T, Whalen C, Turner J, et al. Cryptosporidium infection and CD4 counts. Ann Intern
Med. 1992;15:840-842.