Published Date: 2006-04-11 23:50:00
Subject: PRO/AH> Streptococcus suis, porcine, human, 2005 - China (Sichuan)
Archive Number: 20060411.1082

STREPTOCOCCUS SUIS, PORCINE, HUMAN, 2005 - CHINA (Sichuan)
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Date: Tue, 11 Apr 2006
From: ProMED-mail <promed@promedmail.org>
Source: Boston.com [edited]
<http://www.boston.com/news/world/asia/articles/2006/04/11/report_ties_38_deaths_in_china_to_swine/>

A dangerous infection that pigs can pass to people took an unusually
fatal form in 2005 and killed 38 people in China, scientists reported
yesterday, 10 Apr 2006.
All but one of the people killed by _Streptococcus suis_ in Jul and
Aug 2005 died of streptococcal toxic shock syndrome [see comment
below - Mod.LL], the Chinese scientists said. This severe type of
immune reaction had never been seen in _S. suis_ infections. Anyone
who is diagnosed with toxic shock syndrome and who has been around
pigs should be checked for _S. suis_ infections, other specialists
said. The researchers, led by George Gao of the Chinese Academy of
Sciences in Beijing, said 2005's outbreak, which affected 204 people,
mostly in Sichuan province, was not unique.
"Retrospectively, we found that this outbreak was very similar to an
earlier outbreak in Jiangsu Province, China, in 1998," they wrote in
their report, published in the open-access Public Library of Science
Medicine journal, found on the Internet at
<http://dx.doi.org/10.1371/journal.pmed.0030151>. In the 1998
outbreak, 14 of the 25 people infected died.
It is not clear if the streptococcus that caused the disease in pigs
and in people had mutated into a form that causes new symptoms, the
researchers said. Only 198 people had been known to have been
infected before 2005's outbreak, and only about 10 percent of them
died. Gao's report was the first to share details of the 2005
outbreak.
"In the fatal human cases, the disease started with acute illness,
malaise, fever, headache, diarrhea, rapidly developing hyperpyrexia
[very high fever], hypotension [low blood pressure], and a decline of
pulse pressure," the scientists wrote. Rash was common and the
sickest patients fell into a coma and suffered failure of multiple
organs."
The scientists said genetic examination showed the bacteria have
evolved slightly, but it is not clear if the mutations are
responsible for the severe new symptoms. Usually, toxic shock
syndrome is caused by different bacteria [Group A streptococci and
staphylococci - Mod.LL]
It does not appear that the bacteria can be passed from human to
human, meaning there is little likelihood of a human epidemic. But
_S. suis_ is common in pigs worldwide, the researchers noted.
"_S. suis_ infection is of major economic and veterinary importance
in the farming world," Dr. Shiranee Sriskandan and Dr. Joshua Slater
of the Imperial College Faculty of Medicine and Hammersmith Hospital
in London wrote in a commentary
[Byline: Maggie Fox]
--
ProMED-mail
<promed@promedmail.org>
[The citation, Tang J, Wang C, Feng Y, et al: Streptococcal toxic
shock syndrome caused by Streptococcus suis serotype 2. PLoS Medicine
2006;3:e151, is available at the URL in the posting. The abstract is
below:
"Background:
_Streptococcus suis_ serotype 2 (_S. suis_ 2, SS2) is a major
zoonotic pathogen that causes only sporadic cases of meningitis and
sepsis in humans. Most if not all cases of streptococcal toxic shock
syndrome (STSS) that have been well-documented to date were
associated with the non-SS2 group A streptococcus (GAS). However, a
recent large-scale outbreak of SS2 in Sichuan Province, China,
appeared to be caused by more invasive deep-tissue infection with
STSS, characterized by acute high fever, vascular collapse,
hypotension, shock, and multiple organ failure.
Methods and Findings:
We investigated this outbreak of SS2 infections in both human and
pigs, which took place from Jul to Aug 2005, through clinical
observation and laboratory experiments. Clinical and pathological
characterization of the human patients revealed the hallmarks of
typical STSS, which to date had only been associated with GAS
infection. Retrospectively, we found that this outbreak was very
similar to an earlier outbreak in Jiangsu Province, China, in 1998.
We isolated and analyzed 37 bacterial strains from human specimens
and 8 from pig specimens of the recent outbreak, as well as 3 human
isolates and 2 pig isolates from the 1998 outbreak we had kept in our
laboratory. The bacterial isolates were examined using light
microscopy observation, pig infection experiments, multiplex-PCR
assay, as well as restriction fragment length polymorphisms (RFLP)
and multiple sequence alignment analyses. Multiple lines of evidence
confirmed that highly virulent strains of SS2 were the causative
agents of both outbreaks.
Conclusions:
We report, to our knowledge for the first time, 2 outbreaks of STSS
caused by SS2, a non-GAS streptococcus. The 2005 outbreak was
associated with 38 deaths out of 204 documented human cases; the 1998
outbreak with 14 deaths out of 25 reported human cases. Most of the
fatal cases were characterized by STSS; some of them by meningitis or
severe septicemia. The molecular mechanisms underlying these human
STSS outbreaks in human beings remain unclear and an objective for
further study."
Tang and colleagues provide the most detailed description of the
streptococcal toxic shock-like syndrome (STSLS) associated with the
outbreak of _S. suis._ Sriskandan and Slater in a corresponding
perspective make this differentiation since by consensus STSS is due
to group A streptococci only (1) and is related to superantigen
production (which was not found in the S. suis_ isolates). The exact
virulence factor or factors in the _S. suis_ strains was not
elucidated. Of note, almost all of the fatal cases in the outbreak
(37 of 38) presented with the STSLS which was only present in 22 of
166 survivors. Most of these had meningitis.
1. The Working Group on Severe Streptococcal Infections: Defining
the group A streptococcal toxic shock syndrome. Rationale and
consensus definition. JAMA 1993;269:390-91. - Mod.LL]

See Also

2005
----
Streptococcus suis, porcine, human - China (20) 20051024.3099
Streptococcus suis, porcine, human - China (19): OIE 20050911.2690
Streptococcus suis, porcine, human - China (18) 20050825.2510
Streptococcus suis, porcine, human - China (17) 20050822.2471
Streptococcus suis, porcine, human - China (16): background 20050819.2436
Streptococcus suis, porcine, human - China (15) 20050818.2417
Streptococcus suis, porcine, human - China (14) 20050817.2409
Streptococcus suis, porcine, human - China (13) 20050816.2399
Streptococcus suis, porcine, human - China (12) 20050814.2381
Streptococcus suis, porcine, human - China (11) 20050811.2347
Streptococcus suis, porcine, human - China (10) 20050808.2311
Streptococcus suis, porcine, human - China (09): OIE 20050807.2296
Streptococcus suis, porcine, human - China (08): OIE 20050805.2285
Streptococcus suis, porcine, human - China (07) 20050804.2271
Streptococcus suis, porcine, human - China (06) 20050804.2266
Streptococcus suis, porcine, human - China (05) 20050803.2262
Streptococcus suis, porcine, human - China (04) 20050803.2250
Streptococcus suis, porcine, human - China (03) 20050802.2246
Streptococcus suis, porcine, human - China (02) 20050801.2238
Streptococcus suis, porcine, human - China 20050730.2217
Streptococcus suis, human - China (Hong Kong) 20050728.2196
Streptococcus suis, porcine, human - China (Sichuan)(02) 20050728.2194
Streptococcus suis, porcine, human - China (Sichuan) 20050727.2179
Undiagnosed deaths - China (Sichuan)(05): Strep. suis susp. 20050726.2169
Undiagnosed deaths - China (Sichuan)(04): Strep. suis susp. 20050726.2160
Undiagnosed deaths - China (Sichuan) (03) 20050725.2153
Undiagnosed deaths - China (Sichuan) (02) 20050724.2139
Undiagnosed deaths - China (Sichuan): RFI 20050724.2131
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