Isosporiasis Clinical Presentation

Author: Robert W Tolan Jr, MD; Chief Editor: Michael Stuart Bronze, MD more...

Updated: Jun 29, 2011

What would you like to print?

History and Physical Examination
Complications
Show All

History and Physical Examination

I belli infection is most commonly observed in immunocompromised individuals or in individuals who have recently traveled to tropical areas, in people who are institutionalized, or in persons who live in poor sanitary conditions. The incubation period ranges from 3 to 14 days. Symptoms begin approximately 1 week after ingestion of the oocysts and last 2-3 weeks, with gradual improvement. Infection in people who are immunocompromised may continue indefinitely.

Symptoms and signs may include the following:

Profuse, watery, nonbloody, offensive-smelling diarrhea, which may contain mucus
Foul-smelling flatus
Cramping abdominal pain, vomiting (nausea and vomiting are uncommon)
Malaise, anorexia, weight loss
Low-grade fever
Steatorrhea in protracted cases
Myalgias (rare)
Headache (rare)

In immunocompromised individuals with severe or long-lasting disease, dehydration may be evident. Otherwise, minimal abdominal tenderness may be present.

Complications

Severe dehydration is the most common complication and almost always occurs in patients who are very young or immunocompromised. Acalculous cholecystitis has been reported in patients with AIDS. Tissue invasion and dissemination have been reported on autopsy findings in a few patients with AIDS. Colitis in patients with AIDS has been rarely reported. Reactive arthritis is very unusual in the immunocompromised patient.

Proceed to Differential Diagnoses

Contributor Information and Disclosures

Author

Robert W Tolan Jr, MD Chief, Division of Allergy, Immunology and Infectious Diseases, The Children's Hospital at Saint Peter's University Hospital; Clinical Associate Professor of Pediatrics, Drexel University College of Medicine

Robert W Tolan Jr, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa, and Physicians for Social Responsibility

Disclosure: Novartis Honoraria Speaking and teaching

Coauthor(s)

Venkat R Minnaganti, MD Consulting Staff, Department of Medicine, Winthrop University Hospital; Clinical Instructor, Department of Internal Medicine, Division of Infectious Disease, State University of New York School of Medicine at Stony Brook

Venkat R Minnaganti, MD is a member of the following medical societies: All India Ophthalmological Society, American College of Physicians, American Medical Association, American Society for Microbiology, and Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Glenn Fennelly, MD, MPH Director, Division of Infectious Diseases, Lewis M Fraad Department of Pediatrics, Jacobi Medical Center; Clinical Associate Professor of Pediatrics, Albert Einstein College of Medicine

Glenn Fennelly, MD, MPH is a member of the following medical societies: Pediatric Infectious Diseases Society

Disclosure: Nothing to disclose.

Specialty Editor Board

Klaus-Dieter Lessnau, MD, FCCP Clinical Associate Professor of Medicine, New York University School of Medicine; Medical Director, Pulmonary Physiology Laboratory; Director of Research in Pulmonary Medicine, Department of Medicine, Section of Pulmonary Medicine, Lenox Hill Hospital

Klaus-Dieter Lessnau, MD, FCCP is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, American Medical Association, American Thoracic Society, and Society of Critical Care Medicine

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

John W King, MD Professor of Medicine, Chief, Section of Infectious Diseases, Director, Viral Therapeutics Clinics for Hepatitis, Louisiana State University Health Sciences Center; Consultant in Infectious Diseases, Overton Brooks Veterans Affairs Medical Center

John W King, MD is a member of the following medical societies: American Association for the Advancement of Science, American College of Physicians, American Federation for Medical Research, American Society for Microbiology, Association of Subspecialty Professors, Infectious Diseases Society of America, and Sigma Xi

Disclosure: emedicine $50.00 Author of chapter; MERCK None Other

Russell W Steele, MD Head, Division of Pediatric Infectious Diseases, Ochsner Children's Health Center; Clinical Professor, Department of Pediatrics, Tulane University School of Medicine

Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, and Southern Medical Association

Disclosure: Nothing to disclose.

Chief Editor

Michael Stuart Bronze, MD Professor, Stewart G Wolf Chair in Internal Medicine, Department of Medicine, University of Oklahoma Health Science Center

Michael Stuart Bronze, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Medical Association, Association of Professors of Medicine, Infectious Diseases Society of America, Oklahoma State Medical Association, and Southern Society for Clinical Investigation

Disclosure: Nothing to disclose.

References

Woodcock HM. Notes on Protozoan parasites in the excreta. BMJ. 1915;2:709..
Goodgame R. Emerging Causes of Traveler's Diarrhea: Cryptosporidium, Cyclospora, Isospora, and Microsporidia. Curr Infect Dis Rep. Feb 2003;5(1):66-73. [Medline].
Sasaki M, Tanaka A, Nishimura T, Tsujikawa T, Andoh A, Ishizuka I, et al. A case of malabsorption syndrome caused by isosporiasis in an immunocompetent patient. J Gastroenterol. Jan 2004;39(1):88-9. [Medline].
ten Hove RJ, van Lieshout L, Brienen EA, Perez MA, Verweij JJ. Real-time polymerase chain reaction for detection of Isospora belli in stool samples. Diagn Microbiol Infect Dis. Jul 2008;61(3):280-3. [Medline].
Malik S, Samantaray JC, Bagga A, Das A. Refractory isosporiasis. Indian J Pediatr. May 2005;72(5):437-9. [Medline].
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. Dec 1995;53(6):656-9. [Medline].
Rowe JS, Shah SS, Motlhagodi S, Bafana M, Tawanana E, Truong HT, et al. An epidemiologic review of enteropathogens in Gaborone, Botswana: shifting patterns of resistance in an HIV endemic region. PLoS One. Jun 2 2010;5(6):e10924. [Medline]. [Full Text].
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. Jul 10 1986;315(2):87-90. [Medline].
Limson-Pobre RN, Merrick S, Gruen D, Soave R. Use of diclazuril for the treatment of isosporiasis in patients with AIDS. Clin Infect Dis. Jan 1995;20(1):201-2. [Medline].
Fox LM, Saravolatz LD. Nitazoxanide: a new thiazolide antiparasitic agent. Clin Infect Dis. Apr 15 2005;40(8):1173-80. [Medline].
Gilles HM, Hoffman PS. Treatment of intestinal parasitic infections: a review of nitazoxanide. Trends Parasitol. Mar 2002;18(3):95-7. [Medline].

Oocyst of Isospora belli with 2 sporoblasts. From the Image Library, Division of Parasitic Diseases at the National Center for Infectious Diseases, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia.

View Table List

Read more about Isosporiasis on Medscape