A 37-Year-Old Migrant Worker with Diarrhea

Last updated March 9, 2015
Case Authors: 
Real name: 
Cedric W. Spak, MD
Staff Physician 
Baylor University Medical Center
David H. Spach, MD's picture
Real name: 
David H. Spach, MD
Professor of Medicine
Division of Infectious Diseases
Clinical Director, Mountain West AIDS Education and Training Center
University of Washington School of Medicine
Learning Objectives: 
  1. Recognize the microscopic appearance of Isospora belli.
  2. List appropriate therapy for intestinal isosporiasis in HIV-infected persons.

Display Group

  1. Lindsay DS, Dubey JP, Blagburn BL. Biology of Isospora spp. from humans, nonhuman primates, and domestic animals. Clin Microbiol Rev. 1997;10:19-34.
  2. Barta JR, Schrenzel MD, Carreno R, Rideout BA. The genus Atoxoplasma (Garnham 1950) as a junior objective synonym of the genus Isospora (Schneider 1881) species infecting birds and resurrection of Cystoisospora (Frenkel 1977) as the correct genus for Isospora species infecting mammals. J Parasitol. 2005 Jun;91:726-7.
  3. Sorvillo FJ, Lieb LE, Seidel J, Kerndt P, Turner J, Ash LR. Epidemiology of isosporiasis among persons with acquired immunodeficiency syndrome in Los Angeles County. Am J Trop Med Hyg. 1995;53:656-9.
  4. Centers for Disease Control and Prevention. 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults. MMWR Recomm Rep. 1992;41(RR-17):1-19.
  5. Certad G, Arenas-Pinto A, Pocaterra L, et al. Isosporiasis in Venezuelan adults infected with human immunodeficiency virus: clinical characterization. Am J Trop Med Hyg. 2003;69:217-22.
  6. Silva CV, Ferreira MS, Borges AS, Costa-Cruz JM. Intestinal parasitic infections in HIV/AIDS patients: experience at a teaching hospital in central Brazil. Scand J Infect Dis. 2005;37:211-5.
  7. DeHovitz JA, Pape JW, Boncy M, Johnson WD Jr. Clinical manifestations and therapy of Isospora belli infection in patients with the acquired immunodeficiency syndrome. N Engl J Med. 1986;315:87-90.
  8. Pape JW, Johnson WD Jr. Isospora belli infections. Prog Clin Parasitol. 1991;2:119-27.
  9. Forthal DN, Guest SS. Isospora belli enteritis in three homosexual men. Am J Trop Med Hyg. 1984;33:1060-4.
  10. Michiels JF, Hofman P, Bernard E, et al. Intestinal and extraintestinal Isospora belli infection in an AIDS patient. A second case report. Pathol Res Pract. 1994;190:1089-93; discussion 1094.
  11. Restrepo C, Macher AM, Radany EH. Disseminated extraintestinal isosporiasis in a patient with acquired immune deficiency syndrome. Am J Clin Pathol. 1987;87:536-42.
  12. Panel on Opportunistic Infections in HIV-Infected Adults and Adolescents. Guidelines for the prevention and treatment of opportunistic infections in HIV-infected adults and adolescents: recommendations from the Centers for Disease Control and Prevention, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America. Endemic mycoses plus aspergillosis: cryptococcosis. May 7, 2013.
  13. Pape JW, Verdier RI, Johnson WD Jr. Treatment and prophylaxis of Isospora belli infection in patients with the acquired immunodeficiency syndrome. N Engl J Med. 1989;320:1044-7.
  14. Bernard E, Delgiudice P, Carles M, et al. Disseminated isosporiasis in an AIDS patient. Eur J Clin Microbiol Infect Dis. 1997;16:699-701.
  15. Frenkel JK, Silva MB, Saldanha J, et al. Isospora belli infection: observation of unicellular cysts in mesenteric lymphoid tissues of a Brazilian patient with AIDS and animal inoculation. J Eukaryot Microbiol. 2003;50 Suppl:682-4.
  16. Benator DA, French AL, Beaudet LM, Levy CS, Orenstein JM. Isospora belli infection associated with acalculous cholecystitis in a patient with AIDS. Ann Intern Med. 1994;121:663-4.
  17. Ng E, Markell EK, Fleming RL, Fried M. Demonstration of Isospora belli by acid-fast stain in a patient with acquired immune deficiency syndrome. J Clin Microbiol. 1984;20:384-6.
  18. Centers for Disease Control and Prevention, Division of Parasitic Diseases. DPDx: Laboratory identification of parasites of public health concern. Isosoporiasis.
  19. Murphy SC, Hoogestraat DR, Sengupta DJ, Prentice J, Chakrapani A, Cookson BT. Molecular diagnosis of cystoisosporiasis using extended-range PCR screening. J Mol Diagn. 2011;13:359-62.
  20. Weiss LM, Perlman DC, Sherman J, Tanowitz H, Wittner M. Isospora belli infection: treatment with pyrimethamine. Ann Intern Med. 1988;109:474-5.
  21. Verdier RI, Fitzgerald DW, Johnson WD Jr, Pape JW. Trimethoprim-sulfamethoxazole compared with ciprofloxacin for treatment and prophylaxis of Isospora belli and Cyclospora cayetanensis infection in HIV-infected patients. A randomized, controlled trial. Ann Intern Med. 2000 Jun 6;132:885-8.