Four species of Gnathostoma have been documented in Vietnam: G. spinigerum, G. hispidum, G. doloresi, and G. vietnamicum. The only species known to infect humans is G. spinigerum. Infections in animals have been reported in Vietnam since 1914. Recently, reports have revealed a high prevalence among pigs (24.1%), eels (11%), and dogs (4.3%). The first human infection was reported in 1963. Based mainly on findings of larvae from tissue, the number of reported human cases was still low, until 1999 (4 cases). Since 1999, however, more than 600 cases from different cities of south Vietnam have been diagnosed based on clinical symptoms and signs, eosinophilia and ELISA at the Department of Parasitology, School of Medicine, University of Pharmacy and Medicine, Ho Chi Minh City. Larvae were founded in tissue, or from the intestinal lumen, of 14 cases. The main clinical manifestation was subcutaneous swelling with or without eruption. In addition to improving recognition of this, until now, neglected infection and diagnostic abilities, the environmental, cultural, social and dietary changes may be responsible for the increasing number of cases. Immunoblot and IgG subclass antibodies should be used for more sensitive screening or more specific confirmation in human cases. The infection status in animal and fish are under ongoing evaluation. Based on the extend of human and animal infection, appropriate interventions will be needed in the future. (Houdenur, 1938) and in Saigon in 1965 (Hoa et al, 1965). G. hispidum was found in pigs in 1911 in Hue (Railliet and Henri, 1914). Among pigs slaughtered in Chanh Hung, Saigon, in 1965, the prevalence G. hispidum was 30-40%, with a high intensity of 10-20 parasites per host. The highest intensity was 42 mature parasites and many larvae in the layer muscle of the stomach (Hoa et al, 1965). G. doloresi has also been found in pigs but with lower prevalence (1%) (Hoa et al, 1965). In Saigon, 1965, Hoa reported a new species of Gnathostoma found in the kidneys of otters (Lutra elioti ) and named it G. vietnamicum (Hoa, 1965). In humans. Although four species of Gnathostoma have been found in animals, human gnathostomiasis was considered a rare disease. The first human case was due to G. spinigerum, described in 1965, in a boy from Tay Ninh, with a migrating tumor on his head (Hoa et al, 1965). More than 20 years later, no more human cases have been reported. RECENT STUDIES ON GNATHOSTOMA IN ANIMALS AND FRESHWATER FISH A survey on Gnathostoma hispidum in 5,935 pigs raised in southern provinces from 1983-1993 showed an average prevalence of 24.1%. Kien Giang and Ca Correspondence: Le Thi Xuan, Department of Parasitology, School of Medicine, University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam. INTRODUCTION At least ten species of Gnathostoma have been registered in the world. Among them, four species, G. spinigerum, G. hispidum, G. doloresi, and G. nipponicum, have been identified as etiologic agents of human gnathostomiasis (Miyazaki, 1991). In Vietnam, G. spinigerum, G. hispidum, G. doloresi, and G. vietnamicum have been documented in the literature (Hoa et al, 1965). However, only G. spinigerum is known to be responsible for human cases (Xuan and Rojekittikhun, 2000). HISTORICAL REVIEW ON GNATHOSTOMIASIS IN VIETNAM Gnathostomiasis has been reported in Vietnam since the early 20 century. In animals. G. spinigerum was found in the stomach of a tiger from the national zoo, in 1914 (Railliet and Henri, 1914). It was recovered from domestic cats in northern Vietnam (in 1938) SOUTHEAST ASIAN J TROP MED PUBLIC HEALTH 98 Vol 35 (Suppl 1) 2004 meningitis. Among 654 positive cases, there were 381 males (58.3%) and 273 females (41.7%), two thirds of them were 20-49 years of age (range 3-72). The common manifestation was cutaneous, with 417 cases (63.8%). Visceral manifestations were found in 96 cases (14.7%). Most of them had cerebral or meningeal signs (79 cases, 12.1%). There were 141 cases (21.6%) without specific anatomical manifestations (Table 1). Most of the cases (411/446, 92.2%) had increased eosinophil >5% (from 6 to 75%), of total peripheral white blood cells. Eosinophilia was suggested for the diagnosis of visceral diseases especially for cases without cutaneous manifestations. There were 32 cases with skin signs but no increase in eosinophil (8.8%). In 14 parasitologically-confirmed cases, larvae were found: from the skin (10; 7 with spontaneously exiting larvae, 3 by skin biopsy), removal by eye surgery (2 cases: 1 with a larva in the vitreous cavity, and 1 in the anterior chamber), removal by gastro-intestinal endoscopy (1 from the stomach and 1 from the colon). All 14 causative agents found were G. spinigerum.