Gnathostomiasis

Abstract: Human gnathostomiasis is most frequently caused by the nematode Gnathostoma spinigerum. This disease is endemic to Southeast Asia, particularly Thailand and Japan. The clinical presentation is most commonly characterized by localized, intermittent, migratory swellings of the skin and subcutaneous tissues, often in association with localized pain, pruritus, and erythema. Since this worm can migrate to deeper tissues, any organ system may become involved. Characteristically, patients with gnathostomiasis have a moderate to severe elevation of the peripheral eosinophil count, with values not uncommonly exceeding 50% of the total white blood cell count. With modern-day travel and immigration, cases of gnathostomiasis are being diagnosed with increased frequency in the United States. Because of its rarity in this country, however, gnathostomiasis often is not included in an initial differential diagnosis despite the characteristic triad of intermittent migratory swelling, a history of travel to Southeast Asia, and eosinophilia. We report a case of cutaneous gnathostomiasis diagnosed in the United States, and we present a clinical review of the English-language literature on human gnathostomiasis.

Abstract: From several gnathostome species the complete internal transcribed spacer ITS-2 ribosomal DNA (rDNA) repeat sequence and a fragment of the 5.8S rDNA were obtained by direct polymerase chain reaction cycle-sequencing and silver-staining methods. The size of the complete ITS-1 sequence in agarose gel electrophoresis was also obtained. The ITS-2 enabled the differentiation of Gnathostoma spinigerum from Thailand and Gnathostoma binucleatum from Mexico and Ecuador and confirmed the validity of the latter. Gnathostoma turgidum, Gnathostoma sp. I (=Gnathostoma procyonis sensu Almeyda-Artigas et al., 1994), and Gnathostoma sp. II (=G. turgidum sensu Foster, 1939 pro parte), all from Mexico, proved to be independent species, but Gnathostoma sp. III, also from Mexico, could not be differentiated from G. turgidum. In Mexico and Ecuador, gnathostomes involved in human infection and that had been classified as G. spinigerum belong to G. binucleatum. The 5.8S rDNA sequences of the 6 Gnathostoma species studied were identical. The results of the ITS-1 agreed with those results of ITS-2.

Abstract: As the scope of international travel expands, an increasing number of travelers are coming into contact with helminthic parasites rarely seen outside the tropics. As a result, the occurrence of Gnathostoma spinigerum infection leading to the clinical syndrome gnathostomiasis is increasing. In areas where Gnathostoma is not endemic, few clinicians are familiar with this disease. To highlight this underdiagnosed parasitic infection, we describe a case series of patients with gnathostomiasis who were treated during a 12-month period at the Hospital for Tropical Diseases, London.

Abstract: The efficacy of albendazole was investigated in 112 patients with symptomatic gnathostomiasis; 49 received 400 mg twice daily, 51 received 400 mg once daily, and 12 patients received placebo, all for 21 d. Subsequent follow-up was for 6 months. Cure (no further swelling) was seen in 93.9% and 94.1% of the treatment groups but in none of the placebo group. Additionally, reductions in eosinophil counts and in immunoglobulin G antibody were observed after treatment. Side effects were minimal. Albendazole may be an effective compound for the treatment of gnathostomiasis.