Human gnathostomiasis - A systematic review and analysis of the literature

Human gnathostomiasis is a foodborne zoonotic nematode infection caused by the larval stage of Gnathostoma species. Although historically reported predominantly from Asia and America, cases are increasingly identified in previously non-endemic regions. The heterogeneous clinical presentation and diagnostic challenges likely contribute to underrecognition of the global disease burden. Current evidence is largely derived from case reports and case series, with a notable lack of prospective studies. To better delineate the epidemiological distribution and clinical characteristics of human gnathostomiasis, we systematically reviewed and analyzed the available literature. Most cases are reported from Asia and the Americas, with Thailand, Japan, and Mexico accounting for the highest numbers. Clinical manifestations are predominantly larva migrans syndromes, including cutaneous involvement (83.6% of cases), followed by neurological (7.7%), ocular (3.5%), and visceral (2.3%) presentations. Long-term sequelae are uncommon overall but occur frequently in ocular (51.8%) and neurological (32.2%) disease, the latter also being associated with a substantial case-fatality rate (33.9%). Diagnosis is based on exposure risk, most commonly consumption of raw fish (70.7%), as well as laboratory findings such as eosinophilia, positive serology, and, when feasible, histopathological confirmation. Treatment primarily relies on anthelmintic treatment with albendazole and/or ivermectin and, if feasible, surgical removal of larvae. Treatment success is highest with albendazole plus ivermectin combination therapy (86.7%) compared to monotherapy with albendazole (73.5%) or ivermectin (56.7%).