Published Date: 2005-07-26 23:50:00
Subject: PRO/AH/EDR> Undiagnosed deaths - China (Sichuan)(05): Strep. suis susp.
Archive Number: 20050726.2169
UNDIAGNOSED DEATHS - CHINA (SICHUAN) (05):STREPTOCOCCUS SUIS SUSPECTED
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Date: Wed, 27 Wed 2005
From: ProMED-mail <email@example.com>
Source: The Standard (China) [edited]
Pig disease responsible for 24 deaths is identified
A highly pathogenic pig disease responsible for 24 human deaths in Sichuan
province has been identified by mainland authorities a month after the
first admission to hospital.
The health and agriculture ministries have confirmed that the patients
contracted swine _Streptococcus suis_ type 2 bacteria through slaughtering
or handling infected pigs, but there is no sign of human to human transmission.
According to the Ministry of Health, as of noon Tue, 26 Jul 2005, the total
number of people affected was 117.
5 of the reports were laboratory confirmed cases. Among the patients, 24
died and 5 were discharged. That translates into a near 25 percent death
rate, compared with about 17 percent for SARS and 33 percent for bird flu.
Bob Dietz, a spokesman for the WHO's Western Pacific region in Manila, is
concerned about the high death rate. "We grew accustomed to SARS and avian
influenza, which have very high mortality rates, but [a near] 25 percent is
uncomfortably high." He said the WHO has offered assistance to China if
A provincial disease-control center bacteria expert said more studies are
needed to find out if the high death rate is due to a virulent form of the
bacteria after mutation, or because the cases were not treated in time.
Secretary of the Sichuan Provincial Communist Party Committee Zhang
Xuezhong reassured the public that the infection has been brought under
control. "Pork from the infected areas is banned from export. This swine
streptococcus bacterium does not transmit among humans, and only people
with open wounds who come into contact with sick pigs can catch it. So
there is no need to panic."
He pledged to continue studying how to prevent further human infections of
the pig disease, adding that the production of vaccines has been sped up
and testing can start in a week.
According to revised figures by the SAR government, 9 people have been
infected with the pig disease since 2004, with 1 death. A government source
said it is considering including the disease in the notification system.
Exports of pork products from the most affected cities of Ziyang and
Neijiang were banned Mon, 25 Jul 2005.
Date: Tue, 26 Jul 2005
The following abstract, published in a Chinese paper in 2002, may add some
background, indicating that serious infections with _Streptococcus suis_
have been recorded in the past in China.
Zhang X , Ding J, & Qin H: Clinical analysis of 22 cases of the disease
contracted both by man and pigs with swine streptococcus Infections.
(Chinese) Journal of Tropical Medicine, 2, 2002; 2:361-63.
Objective: To further prevent and control the contraction of the disease
both by man and pigs with swine streptococcus infections by analysis [of]
the clinical manifestation of the disease.
Methods: Reviewing analysis was made of 22 case of the disease contracted
both by man and pigs with Swine streptococcus infections.
Results: Of the 22 cases: 5 cases which were ordinary type were cured; 10
cases were meningitis 2 type, 8 of which were cured and 2 of which
improved; AND 7 cases were toxicosis shock syndrome (TTS) 2 type , none of
which was able to avoid death. The total mortality was 31.8 percent.
Conclusion: At the time the disease was widely epidemic and worsened
rapidly , quite a number of people and pigs contracted the disease. It has
not been reported before. This report is based on the analysis of the
clinical documents. Our aim is to arouse effective measures to be taken to
prevent and cure the disease.
[The total number of cases is now 117 with 24 deaths. As noted as of
earlier today, 26 Jul 2005, 5 of the patients have been said to have
confirmed _S. suis_ type 2.
The abstract implies that an outbreak of human (and swine) infections
occurred but the exact details of the length of time that the cases were
found is not given. In Kay's paper on _S. suis_ in Hong Kong published in
1995 (1), the authors mention a "small outbreak" of 38 cases between 1981
and 1983. These cases, indeed most cases including the cases occurring now,
tend to present in the summer months. The 1981-83 cases appear to have
occurred following the importation of "10 000 live pigs per day from
neighboring China in hot and crowded conditions." Small clusters, therefore,
appear to have occurred before but not to this degree and generally linked to
meningitis due to this organism (2).
A carrier prevalence study was reported from Germany (3) to assess the
amount of culture-positive throats among workers in swine slaughterhouses
and processing plants. 7 of 132 workers (5.3 percent) were found to have
positive throats cultures with no colonization in control individuals.
Kay and colleagues (1) present a cogent discussion on the classification of
_S. suis_. Based on analysis of porcine streptococcal strains in the 1950s
and 1960s that were ungroupable using the Lancefield typing sera,
serogroups R, S and T were designated for these porcine strains. The S
capsular strain became referred to as _S. suis_ type 1 and the R capsular
strain as type 2. Although almost 30 capsular types have been now
characterized, type 2 _S. suis_ remains the most relevant serotype in
porcine and human infection (as here).
Although the governmental official states that risk of infection is only
present with open wounds, Kay's study (1) reported that only 20 percent of
patients were noted to have sustained minor cuts or burns before symptoms
occurred. Finding that many patients had no history of any injury, the
authors speculate that respiratory or oral routes may be important.
1. Kay R, Cheng AF, Tse CY: _Streptococcus suis_ infection in Hong Kong. Q
J Med 1995; 88:39-47.
2. Chau PY, Huang CY, Kay R: _Streptococcus suis_ meningitis: an important
underdiagnosed disease in Hong Kong. Med J Aust 1983; 1:414-17.
3. Strangmann E, Froleke H, Kohse KP: Septic shock caused by _Streptococcus
suis_: case report and investigation of a risk group. Int J Hyg Environ
Health 2002; 205:385-92. - Mod. LL]