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Gnathostomiasis Workup

  • Author: Germaine L Defendi, MD, MS, FAAP; Chief Editor: Russell W Steele, MD  more...
Updated: Jun 20, 2015

Laboratory Studies

The following diagnostic studies are indicated in gnathostomiasis:

CBC (complete blood count)

See the list below:

  • Eosinophilia may be present, particularly during the active phases of larval migration. Eosinophilic percentage may exceed 50% of the circulating WBCs.
  • Results may show leukocytosis.


See the list below:

  • Rarely, microscopic hematuria is present.
  • The worm may be found.


See the list below:

  • Enzyme-linked immunosorbent assay (ELISA) to detect IgG antibodies and Western blot are diagnostic tests.[12]
  • Immunoblot testing for neurologic disease has been described.[13]
  • These tests are not widely available in the United States and many other countries.

Imaging Studies

Plain radiography

See the list below:

  • Pulmonary or GI findings


See the list below:

  • CT rarely helps in localizing a soft tissue worm.
  • In CNS disease, CT may reveal evidence of intracranial hemorrhage, obstructive hydrocephalus, or meningeal inflammation.

Other Tests

Sputum examination may reveal a worm.



Surgical extraction and/or resection can rarely help through identification of larvae in skin, subcutaneous tissue, gingivae, or wounds.

Lumbar puncture is helpful to evaluate cerebral spinal fluid for evidence of neurognathosomiasis. Results show the following:

  • Pleocytosis (20-1430 WBCs, but typically < 500, with a mean of 250)
  • Eosinophilia (5-94%, with a mean of 38%)
  • Xanthochromia, some RBCs

Histologic Findings

When found, larvae are 2.5-12.5 mm by 0.4-1.2 mm. In tissue, eosinophils predominate, with the presence of fibroblasts, histiocytes, and foreign-body giant cells; this finding may suggest an eosinophilic granuloma.

In the CNS, migratory tracts may be present with perivascular infiltration of eosinophils, plasma cells, and lymphocytes. No CNS granulomas or parasite fragments are observed, a differentiating clinical finding from eosinophilic meningitis due to A cantonensis.

Contributor Information and Disclosures

Germaine L Defendi, MD, MS, FAAP Associate Clinical Professor, Department of Pediatrics, Olive View-UCLA Medical Center

Germaine L Defendi, MD, MS, FAAP is a member of the following medical societies: American Academy of Pediatrics

Disclosure: Nothing to disclose.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Chief Editor

Russell W Steele, MD Clinical Professor, Tulane University School of Medicine; Staff Physician, Ochsner Clinic Foundation

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, Southern Medical Association

Disclosure: Nothing to disclose.

Additional Contributors

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.

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