China?s Streptococcus suis Outbreak Update

August 23, 2005 — (ed. Rika Jolie)
  [ES]

As of Sunday August 21st, 38 people have died and 204 have been infected in China's southwestern Sichuan province as a result of exposure to a deadly strain of Streptococcus suis serotype 2. According to an article in the official Xinhua News Agency, China's ministries of health and agriculture indicated that the outbreak was under control in the Sichuan province. Additional cases, however, have been reported in Guangdong province and Hong Kong. There has been no reported incidence of human to human transmission with all cases to date having had direct contact with either raw pork or pigs. Properly cooked pork poses no health risk to humans. Chinese state media have reported that vaccine has been shipped to Sichuan province to vaccinate pigs.

A number of organizations, including the World Health Organization (WHO) and the UN's Food and Agriculture Organization (FAO), have questioned whether S. suis is the only etiologic agent responsible for the current outbreak. A recent AP article reported by CNN.com stated that Dr. Marcelo Gottschalk at the University of Montreal's S. suis reference laboratory expressed an interest in receiving some samples from the Chinese outbreak for further identification. In the same article, Dr. Juan Lubroth, an animal health official with FAO in Rome, also questioned the clinical presentation being reported in the recent outbreak. "One explanation is you have additional problems and it's not just Streptococcus suis that's causing it" he says.

Although rare, such outbreaks in humans have been previously reported in China. According to a report appearing in ProMED from Dr. Chi Wai Leung, a similar outbreak occurred in 1998 in Jiangsu province resulting in 14 human deaths. This outbreak also involved Streptococcus suis Type 2 exposure resulting from contact with sick or dead pigs. As in the current outbreak, the distribution of cases was geographically scattered and mortality rates varied from 11% - 81%. The highest mortality rates were reported among cases in which the patients developed streptococcal toxic shock syndrome (STSS). The cases in the current outbreak are being classified in one of four categories: 1) ordinary (milder febrile illness with no shock or meningitis), 2) STSS (with high mortality), 3) meningitis (with high incidence of deafness), and 4) mixed type (with both STSS and meningitis and high mortality). The ProMED article supplies a number of references which may be of interest.

Sources: http://edition.cnn.com/2005/HEALTH/08/03/china.pigdisease.ap/index.html
http://edition.cnn.com/2005/HEALTH/08/17/china.pigdisease.ap/
http://www.promedmail.org PRO/AH/EDR> Streptococcus suis, porcine, human - China (15)