11 Vibrio parahaemolyticus—Seafood Safety and Associations with Higher Organisms Firdausi Qadri, Nandini Roy Chowdhury, Yoshifumi Takeda, and G. Balakrish Nair 11.1. INTRODUCTION Vibrio parahaemolyticus, a halophilic seafood-borne pathogen, is one of the 12 known pathogenic species of the genus Vibrio. The halophile is one of the major bacterial causes of food-borne illness that affects people who consume raw or improperly cooked seafood. This bacterium was first identified from the intestinal contents of a victim of food poisoning who had consumed half-dried sardines called “shirasu”, in Japan. Fujino (1951) reported the discovery of this pathogenic bacterium at the 25th Annual Meeting of the Japanese Associ- ation for Infectious Diseases in 1951. Since then, V. parahaemolyticus has been recognized as the cause of sporadic cases of gastroenteritis predominantly in coastal areas of the world, especially Japan, where consumption of inadequately cooked seafood is common. The past few years have witnessed V. parahaemolyticus surface as a major public health threat follow- ing the emergence of clones in Asia, which have acquired pandemic potential (Matsumoto et al., 2000). The pandemic caused by V. parahaemolyticus is the first of its kind with the first pandemic serotype being detected in Taiwan and Indonesia in 1995 (Okuda et al., 1997). Since then, numerous outbreaks of V. parahaemolyticus caused by the pandemic serotypes have been reported from various countries extending from Japan to the American continent. 11.2. THE ORGANISM V. parahaemolyticus is a Gram-negative marine bacterium. This bacterium can exist free living or attached to submerged, inert, and animate surfaces, such as particulate matter, zoo- plankton, fish, and shellfish. Therefore, V. parahaemolyticus is a common microflora of marine and estuarine environments. In laboratory, V. parahaemolyticus is commonly isolated from Firdausi Qadri and G. Balakrish Nair • International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR, B), Dhaka, Bangladesh. Nandini Roy Chowdhury • Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York 11794, USA. Yoshifumi Takeda • Jissen Women’s University, Hino, Tokyo, Japan. Oceans and Health: Pathogens in the Marine Environment. Edited by Belkin and Colwell, Springer, New York, 2005. 277