:
Mystery Pig Illness in China
Outbreak of Streptococcus suis suspected
in China
In July 2005, an outbreak of unknown
etiology was reported in west China’s Sichuan Province
affecting farmers who recently slaughtered or handled sick
or dead pigs and sheep. Affected individuals presented with
rapid onset of fever, fatigue, nausea, vomiting and bleeding
under the skin. In many cases, individuals became comatose
and 20% resulted in rapid death. Human-to-human transmission
has not been reported. Additional cases are now being identified
in Hong Kong and South China’s Guangdong Province.
As of August 8, 2005, 214 cases have been reported with 39
deaths.
Laboratory testing in China reports the causative agent
as Streptococcus suis. However, prior reports of human infection
with S. suis, caused limited human cases and clinical signs
(meningitis, hearing loss) that differ from the current outbreak.
This has left international experts, including the World
Health Organization (WHO) with many questions regarding this
outbreak. Has the organism mutated to a more virulent form
or acquired a new virulence factor? Is another etiologic
agent involved or co-occurring? Is a second pathogen causing
suppression of the immune system of individuals allowing
the S. suis organism to be more opportunistic? Is there synergism
between two pathogens?
Current efforts to control this outbreak include depopulation
and burial of affected swine, and education efforts to convince
owners not to slaughter sick animals for food. Vaccination
of unaffected swine will soon be implemented.
The CFSPH has developed a fact
sheet on Streptococcosis, which provides a technical overview
of the various species of this genus and their affect on
humans and animals. To download the file, right click on
the link below and select “Save
Target As…”
 (PDF
421KB)
Please contact us at cfsph@iastate.edu if
you have any comments and questions.
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