Gnathostomiasis: An Emerging Imported Disease

David A.J. Moore, Janice McCroddan, Paron Dekumyoy, Peter L. Chiodini


Emerging Infectious Diseases. 2003;9(6) 

In This Article

Abstract and Introduction

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.

The ease of international travel in the 21st century has resulted in persons from Europe and other western countries traveling to distant areas of the world and returning with an increasing array of parasitic infections rarely seen in more temperate zones. One example is infection with Gnathostoma spinigerum, which is acquired by eating uncooked food infected with the larval third stage of the helminth; such foods typically include fish, shrimp, crab, crayfish, frog, or chicken. Previously, most disease related to Gnathostoma was reported from Southeast Asia, particularly Thailand and Japan, because of the dietary habits of those living there. In recent years, however, gnathostomiasis has become an increasing problem in Central and South America, most notably in Mexico (perhaps related to consumption of ceviche).[1,2] In cats and dogs, which serve as important reservoirs of infection in regions where Gnathostoma is endemic,[3] the ingested third-stage larva matures into the adult worm in approximately 6 months (Figure 1). However, because the larva cannot mature into the adult form in humans, the third-stage larva can only wander within the body of the host; clinical symptoms of gnathostomiasis then occur because of the inflammatory reaction provoked by these migrating larvae (Figure 2).

Life cycle of Gnathostoma spinigerum. Adapted from an original illustration by Sylvia Paz Diaz Camacho; available from: URL: HTML/ImageLibrary/Gnathostomiasis_il.htm

Third-stage larva of Gnathostoma spinigerum. A) whole larva; B) head. (Reproduced with the permission of Pichart Uparanukraw, Department of Parasitology, Faculty of Medicine, Chiang Mai University, Thailand.)

Traditionally the disease has been divided into cutaneous and visceral forms, depending on the site of larval migration and subsequent symptoms. Another form of gnathostomiasis, which is quite rare, includes the dangerous complication of central nervous system involvement.[4] This form is manifested by painful radiculopathy, which can lead to paraplegia, sometimes following an acute (eosinophilic) meningitic illness.

We describe a series of patients in whom G. spinigerum infection was diagnosed at the Hospital for Tropical Diseases, London; they were treated over a 12-month period. Four illustrative case histories are described in detail. This case series represents a small proportion of gnathostomiasis patients receiving medical care in the United Kingdom, in whom this uncommon parasitic infection is mostly undiagnosed.