PMC9326084_01
(A) Direct CSF examination of case No.17 showed N. fowleri trophozoite with hyaline semi-spherical pseudopods, approximately 10-20 microm in diameter. Its cytoplasm contained many granules and vacuoles. (Courtesy of Dr. Thamrongkiat Amornvivattanakul, Aikchol Hospital) (B) Gomori's trichrome staining of the ameba trophozoite found in the patient's CSF. N. fowleri trophozoite with a single nucleus containing a large, central karyosome surrounded by halo.
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Her CSF revealed pleocytosis with a white blood cell count of 653/mm3 (neutrophils 11% and lymphocytes 89%), a red blood cell count of 688/mm3, a decreased glucose level (CSF glucose 63 mg/dL, CSF to blood glucose ratio of 0.37), an increased protein level (247 mg/dL), and numerous fast-moving amebic-like organisms with active semi-spherical pseudopodia were found by direct CSF examination ( Figure 1A , and  Supplementary Video S1 ). It had a single nucleus that contained a large central karyosome surrounded by a clear halo, similar to that of Naegleria spp. ( Figure 1B ).
Axial pre-contrast (A) and post-contrast (B) computed tomography (CT) of the brain on day 3 post-infection showed generalized edema with post-contrast leptomeningeal enhancement.
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Brain computed tomography (CT) on the first day showed unremarkable findings; however, on the third day after the onset of symptoms, generalized brain edema with uncal herniation, generalized leptomeningeal enhancement, and chronic right maxillary sinusitis were observed ( Figure 2 ).