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Neurognathostomiasis is a rare but severe form of human gnathostomiasis. Diagnosis of neurognathostomiasis is made presumably by using clinical manifestations. Serologic tests for neurognathostomiasis are not widely available and limited. We studied 12 patients with diagnoses of neurognathostomiasis at Srinagarind Hospital, Khon Kaen University, Thailand. There were three types of neurognathostomiasis (five patients with intracerebral hemorrhage, one patient with subarachnoid hemorrhage, and six patients with myelitis). All patients were tested for antibodies against Gnathostoma spinigerum by an immunoblotting technique. The sensitivity and specificity of the 21-kD and 24-kD diagnostic bands were 83.3% and 100%, and 91.7% and 100%, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value for the 21-kD and 24-kD diagnostic bands were all 100%. Both diagnostic bands are a helpful diagnostic tool for neuro gnathostomiasis and show good diagnostic properties.

A 16-year-old Thai male presented with sudden onset severe epigastric and right upper quadrant pain, fever (39 degrees C), chills and malaise. He gave no history of underlying disease, migratory swelling or urticarial skin rash. He had a history of frequently eating raw pork. Physical examination revealed a soft abdomen with markedly tender hepatomegaly. His blood count showed extreme leukocytosis with hypereosinophilia. After admission he developed a non-productive cough with left sided chest pain, a chest x-ray showed a left pleural effusion. Serological findings were positive for Gnathostoma larval antigen but not Fasciola antigen. The patient recovered completely after albendazole treatment. His clinical presentation is compatible with abdominopulmonary hypereosinophilic syndrome or visceral larva gnathostomiasis. The presented case is interesting not only for physicians who work in endemic areas of gnathostomiasis but also for clinicians who work in travel medicine clinics in developed countries, to consider abdominopulmonary gnathostomiasis when patients present with the signs and symptoms of visceral larva migrans.

Gnathostomiasis is a rare nematode disease acquired by travelers to endemic areas. The most common clinical presentations are cutaneous forms; however, neurologic involvement can also occur. We present two cases of gnathostomiasis, one of them with severe neurologic complications, in Spanish travelers to Thailand and Mexico, who consumed local food and became infected.

Specific IgE antibody levels in the serum of patients with proven gnathostomiasis and in those with intermittent cutaneous migratory swelling (CMS) were determined by the enzyme-linked immunosorbent assay (ELISA) using somatic extract and excretory-secretory (ES) products of Gnathostoma spinigerum infective larvae as antigens. The third stage larval used were obtained from naturally infected eels. There was an increase in specific IgE antibody to both antigens in these patients. The mean levels of these specific IgE antibodies were significantly higher than that of the healthy control (P<0.01). Comparison between using somatic extract and ES products in the test showed, a positive result in the group of suspected patients with gnathostomiasis or CMS was significantly higher when using ES products (81.81%) than somatic extract (59.09%) as the antigens (P<0.05). However, both somatic and ES antigens cross-reacted with other parasitic sera. The overall sensitivity of the ELISA for these IgE antibodies detection were 71.87 per cent and 87.50 per cent with somatic and ES antigens, respectively. The specificity was 57.53 per cent when somatic antigen was used and increased to 69.86 per cent when ES antigen was used. The positive and negative predictive values of the test were 42.59 per cent and 82.35 per cent by using somatic antigen. Both of these values, were also increased to 56.00 per cent and 92.72 per cent by using the ES antigen. It is obvious that more potential components may be present in ES products than those in the somatic extract. The ES antigen may have to be further purified and may be suitable for evaluation of the effectiveness of chemotherapy. As such, the antibody responses to secreted products are more closely related to active infection than the anti-whole worm antibody that may persist following the death of the parasites. However, in this disease, the effect of the IgE antibody on its pathophysiology it is still not known.

Gnathostomiasis is common in Southeast Asian countries and can be found sporadically in other parts of the world mainly due to human migration. The definitive diagnosis can be given either by identification of the parasite isolated from the patient or through histologic section of the lesion. It is therefore important for pathologists to be familiar with the morphology of parasitic larvae which varies according to the levels of section-cutting so that the diagnosis will not be misled. We present three cases of gnathostomiasis with different features of parasitic morphology and compare these with the reference adult worm.

During a 4-week holiday in Thailand a 13-year-old boy from Germany briefly fell ill with diarrhoea without blood-tinged stools and fever. 5 months later oedematous, reddish swellings occurred, at first on the right upper arm, later over the right side of the chest. Especially at night these swellings were associated with severe local and generalized itching. Bilaterally the axillary lymph-nodes were hard and slightly enlarged. There was a marked eosinophilia of 56%, the white count was 22,700/microliters and the serum level of IgE was raised to 1777 IU/ml. No worm eggs or larvae were found in the stool. Enzyme-linked immunosorbent assay, using larvae of Gnathostoma spinigerum as antigen, demonstrated antibodies against this nematode. Gnathostomiasis having been diagnosed treatment was started with albendazole (200 mg twice daily for 21 days), after which the boy was symptom free. After 2 months the eosinophilia had regressed to 10%, the white cell count was normal and the antibody titre had fallen.