Gnathostomiasis Workup

Updated: Apr 26, 2018
  • Author: Germaine L Defendi, MD, MS, FAAP; Chief Editor: Russell W Steele, MD  more...
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Laboratory Studies

The following diagnostic studies are indicated in gnathostomiasis:

CBC (complete blood count)

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  • 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.


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  • Rarely, microscopic hematuria is present.

  • The worm may be found.


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  • Enzyme-linked immunosorbent assay (ELISA) to detect IgG antibodies and Western blot are diagnostic tests. [13]

  • Immunoblot testing for neurologic disease has been described. [14]

  • These tests are not widely available in the United States and many other countries.


Imaging Studies

Plain radiography

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  • Pulmonary or GI findings


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  • 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.