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Sarcosporidiosis Workup

  • Author: Edward Charbek, MD; Chief Editor: Mark R Wallace, MD, FACP, FIDSA  more...
Updated: Oct 07, 2015

Laboratory Studies

In intestinal Sarcocystis infection, sporulated sporocysts in freshly voided stool can be found via a flotation technique. Sporocysts contain 4 sporozoites. Kato thick smear is a newly applied technique that is used to examine a larger fecal sample and that utilizes cellophane as a slip cover. In one study, Kato thick smear was found to be highly sensitive, identifying 21 of 22 sarcocyst-infected stool samples, while direct smear identified only 1 of the 22 infected samples.[15]

CBC count usually reveals eosinophilia.[16] In cases of sarcosporidiosis with accompanying myositis, creatine kinase levels may be elevated.

Polymerase chain reaction (PCR) techniques can be used to exclude Toxoplasma gondii infection.

Indirect immunofluorescent antibody test are genus-specific but not widely available.

A muscle biopsy may be useful in detecting myositis.

Toxoplasma and Sarcocystis organisms are periodic acid-Schiff (PAS)–positive; trypanosomes are PAS-negative.


Imaging Studies

Radiographs of the involved extremity may identify calcified cysts of Taenia solium (ie, cysticercosis)

CT scan or MRI of the extremities may demonstrate the cysts of sarcosporidiosis, which can grow to 5 cm in diameter.



Excisional biopsy in the area of the painful muscle swelling can be performed for diagnostic purposes but is not needed therapeutically.[2, 16]


Histologic Findings

Intact sarcocysts observed in muscle are not associated with inflammation. The sarcocysts are septate and rather large (ie, 11 µm X 350 µm), and they can have a thick, radially striated wall. Seven distinct histopathologic types have been described.[17] The tissue form is PAS-positive. After the sarcocysts disintegrate, inflammatory cells can be observed, including lymphocytes and neutrophils and an intense eosinophilic infiltrate surrounding the muscle cyst. Localized vasculitis and fibrosis of the muscle is apparent.[18]

Contributor Information and Disclosures

Edward Charbek, MD Fellow in Pulmonary/Critical Care Medicine, St Louis University Hospital

Disclosure: Nothing to disclose.


Nirav Patel, MD Assistant Professor of Internal Medicine, Division of Infectious Diseases, Allergy and Immunology and Division of Pulmonary, Critical Care, and Sleep Medicine, St Louis University School of Medicine; Interim Chief Medical Officer, Director of Antibiotic Stewardship, Infection Control Officer, St Louis University Hospital

Nirav Patel, MD is a member of the following medical societies: American Medical Association, Infectious Diseases Society of America, Missouri State Medical Association, Society for Healthcare Epidemiology of America, Society of Critical Care Medicine, Infectious Diseases Society of St Louis, St Louis Metropolitan Medical Society

Disclosure: Nothing to disclose.

Specialty Editor Board

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

Disclosure: Received salary from Medscape for employment. for: Medscape.

Joseph F John, Jr, MD, FACP, FIDSA, FSHEA Clinical Professor of Medicine, Molecular Genetics and Microbiology, Medical University of South Carolina College of Medicine; Associate Chief of Staff for Education, Ralph H Johnson Veterans Affairs Medical Center

Joseph F John, Jr, MD, FACP, FIDSA, FSHEA is a member of the following medical societies: Charleston County Medical Association, Infectious Diseases Society of America, South Carolina Infectious Diseases Society

Disclosure: Nothing to disclose.

Chief Editor

Mark R Wallace, MD, FACP, FIDSA Clinical Professor of Medicine, Florida State University College of Medicine; Clinical Professor of Medicine, University of Central Florida College of Medicine

Mark R Wallace, MD, FACP, FIDSA is a member of the following medical societies: American College of Physicians, American Medical Association, American Society for Microbiology, Infectious Diseases Society of America, International AIDS Society, Florida Infectious Diseases Society

Disclosure: Nothing to disclose.

Additional Contributors

Raphael J Kiel, MD Associate Professor of Medicine, Wayne State University School of Medicine; Associate Professor of Medicine, Oakland University William Beaumont School of Medicine; Consulting Staff, Infectious Diseases Division, William Beaumont Hospital; Consulting Staff, Infectious Diseases Division Providence Hospital

Raphael J Kiel, MD is a member of the following medical societies: American College of Physicians-American Society of Internal Medicine, American Geriatrics Society

Disclosure: Nothing to disclose.

Nicholas R Ondrasik, DO Resident Physician, Department of Internal Medicine, Tripler Army Medical Center

Nicholas R Ondrasik, DO is a member of the following medical societies: American Medical Association, American Osteopathic Association, Christian Medical and Dental Associations, Association of Military Osteopathic Physicians and Surgeons

Disclosure: Nothing to disclose.

Gunther Hsue, MD Consulting Staff, Department of Infectious Diseases, Chief, Multi-Specialty Clinic, Tripler Army Medical Center

Gunther Hsue, MD is a member of the following medical societies: American College of Physicians, Infectious Diseases Society of America, Armed Forces Infectious Diseases Society

Disclosure: Nothing to disclose.


Kenneth C Earhart, MD Deputy Head, Disease Surveillance Program, United States Naval Medical Research Unit #3

Kenneth C Earhart, MD is a member of the following medical societies: American College of Physicians, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, and Undersea and Hyperbaric Medical Society

Disclosure: Nothing to disclose.

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