Streptococcus suis: An Emerging Biothreat

Abstract

Streptococcussuis infections in pigs are often seen in major hog-producing countries. This bacterium is also a zoonotic agent affecting, for the most part, people in close contact with swine or pork by-products. The humanS. suisinfections have generally been sporadic; however, in recent years, this bacterium has strongly emerged as an important public health issue in Southeast and East Asia. Most human infections have so far been recognized to cause adult meningitis; however, a recent outbreak that occurred in Sichuan Province, China, involved a fatal disease, known as the streptococcus toxic-shock syndrome. Almost all human infections were caused by contact with diseased pigs or contaminated pork by-products, so reducing the number of virulent strains ofS. suisin hog populations is an important task in diminishing the level of risk in humanS. suisinfections. However, theS. suisstrains show various degrees of virulence, and many clinically healthy pigs may carryS. suis, some of which are avirulent and some of whichmust be virulent. Therefore, a rapid assay system to identify the virulent strains ofS. suisis urgently needed. Here, general information onS. suisis described, and the recent research progress on this bacterium is summarized.