Streptococcus suisinfections in humans: the Chinese experience and the situation in North America

Abstract

AbstractInfections caused byStreptococcus suisare considered a global problem in the swine industry. In this animal species,S. suisis associated with septicemia, meningitis, endocarditis, arthritis and, occasionally, other infections. Moreover, it is an agent of zoonosis that afflicts people in close contact with infected pigs or pork-derived products. Although sporadic cases ofS. suisinfection in humans have been reported, a large outbreak due toS. suisserotype 2 emerged in the summer of 2005 in Sichuan, China. A similar outbreak was observed in another Chinese province in 1998. Symptoms reported in these two outbreaks include high fever, malaise, nausea and vomiting, followed by nervous symptoms, subcutaneous hemorrhage, septic shock and coma in severe cases. The increased severity ofS. suisinfections in humans, such as a shorter incubation time, more rapid disease progression and higher rate of mortality, underscores the critical need to better understand the factors associated with pathogenesis ofS. suisinfection. From the 35 capsular serotypes currently known, serotype 2 is considered the most virulent and frequently isolated in both swine and humans. Here, we review the epidemiological, clinical and immunopathological features ofS. suisinfection in humans.