In order to describe the biology and life cycle of Gnathostoma nematodes; and the epidemiology, clinical manifestations, diagnosis, management, and prevention of human gnathostomiasis, Internet search engines, including PubMed, Medline, Ovid, Google[R], and Google Scholar[R], were queried with the key medical subject heading (MESH) words, "infections, helminthic; Helminthiasis, gnathosomiasis, neurognathostomiasis; nematode parasites, Gnathostoma species." Case reports, case series, epidemiological investigations, and laboratory studies were reviewed; high-risk behaviors for gnathostomiasis were identified, and human cases of gnathostomiasis were stratified as cutaneous gnathostomiasis, visceral gnathostomiasis, neurognathostomiasis, and ocular gnathostomiasis.
(6) Nine patients presented with cutaneous gnathostomiasis, two with visceral (gastrointestinal) gnathostomiasis, and two with signs of neurognathostomiasis. (6) The median interval between symptom onset and treatment with albendazole (n = 12) or ivermectin (n = 1) was 3.5 months, and eight patients relapsed within a median of two months (range 1-7 months) after initial treatment.
(5) Ultimately, one or more larvae may reemerge seeking to mature in any tissue and causing cutaneous, visceral, ocular, or neurognathostomiasis, or any combination of larva migrans.
(3,12) These same mechanisms are also responsible for the four clinical manifestations of gnathostomiasis: (1) cutaneous disease with intermittent migratory swellings and, less often, subcutaneous nodules containing an L3 larva; (2) visceral (hepatic) or gastrointestinal disease; (3) neurognathostomiasis with high case fatality rates; and (4) ocular gnathostomiasis, the rarest manifestation of the larval migration.
(3) The main clinical and diagnostic imaging features of neurognathostomiasis are compared in Table 2 and are also accompanied by peripheral hypereosinophilia.
The most severe manifestation involves infection ofthe central nervous system, neurognathostomiasis. Although gnathostomiasis is endemic to Asia and Latin America, almost all neurognathostomiasis cases are reported from Thailand.
The most severe manifestation of the visceral disease is involvement of the central nervous system (CNS), i.e., neurognathostomiasis. Neurognathostomiasis has been reported only in G.
We found 24 reports describing a total of 248 patients with neurognathostomiasis published in English-language literature.
(9) delineated the clinical syndromes of neurognathostomiasis, which facilitated further prospective and retrospective case identification (10).
Most (241/248) identified cases of neurognathostomiasis reported in the English-language literature were from Thailand.