Published Date: 2007-07-26 13:00:07
Subject: PRO/AH/EDR> Streptococcus suis, human, porcine & PRRS - Viet Nam
Archive Number: 20070726.2403
STREPTOCOCCUS SUIS, HUMAN, PORCINE AND PORCINE REPRODUCTIVE AND
RESPIRATORY SYNDROME - VIET NAM
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Tue 24 Jul 2007
Source: ChinaView, Xinhua News Agency report [edited]
A pig disease in Viet Nam that has sickened 42 people and killed 2
has the government calling for speedier investigations and urgent
measures to control the bacteria, the nation's agriculture minister said.
Cao Duc Phat told health officials at a meeting that initial
assessments showed the disease caused by _Streptococcus suis_
bacteria had spread in the country, the Viet Nam Agriculture
newspaper reported on Tuesday [24 Jul 2007].
"Since the disease involving _Streptococcus suis_ bacteria is
directly related to human health and the development of the husbandry
sector, we need to act urgently, without any delay," Phat was quoted
as saying at the Monday [23 Jul 2007] meeting.
The bacteria came to light recently in the country of 85 million
people after 22 people in the northern provinces became infected,
followed by 20 in the southern region.
Animal health authorities nationwide should increase disease
surveillance, work out treatment measures for pigs, and publish
information to raise public awareness, Phat said.
He urged officials to check if there were any links between the
porcine reproductive and respiratory syndrome (PRRS) virus, also
known as Lelystad virus that has infected more than 27 000 pigs in
the central region, and the _Streptococcus suis_ bacteria.
People can be infected after coming into direct contact either by
hand or eating pork from a sick pig, Nguyen Hong Ha, deputy head of
the National Institute for Infectious and Tropical Diseases, said in
a Voice of Viet Nam radio broadcast.
The bacteria causes rapid internal haemorrhage and high fever and can
[progress to] meningitis, septicaemia, and endocarditis in the next
stage leading to death or deafness if the victim survives.
On Monday [23 Jul 2007], Minister Phat said the PRRS, also known as
"blue ear disease," had been spreading fast in the central provinces
of Quang Nam, Quang Ngai, and Danang city partly because officials
were unable to stop trading and transport of pigs.
[The article above brings the number of human infections with _S.
suis_ in Viet Nam to 42, adding 20 cases in the south to the 22
cases, with 2 mortalities, described earlier from the north
As to the question raised by Viet Nam's Minister of Agriculture on
possible links between pig-origin _S. suis_ infections in humans and
PRRS (porcine reproductive and respiratory syndrome) in pigs:
In its initial report on the emerging porcine disease (which later,
in 2007, was attributed to PRRS), sent to the OIE (World Organization
for Animal Health) on 14 Sep 2006 (see ProMED-mail 20060924.2732),
China included data on the results obtained from 582 collected
samples from affected pigs. While most of them were positive for
PRRS, CSF (classical swine fever), and PCV-2 (porcine circovirus),
(only) 6 samples were found positive for _Streptococcus suis_. This
is a rather low infection rate, since _S. suis_ is known to be
carried asymptomatically by many pigs (see
However, more virulent strains can cause serious disease in pigs,
mainly in suckling pigs (polyarthritis or peracute meningitis and
septicemia) and in recently weaned and growing pigs (meningitis, with
high mortality rates). In addition, _S. suis_ sometimes causes
pneumonia, endocarditis, myocarditis, or abortions in adult pigs.
PRRS virus is known to have immunosuppressive effect, which might
enhance clinical manifestation of latent _S. suis_ infections (in
pigs). There is also some experimental evidence of a possible link
between PRRS virus and _S. suis_: the incidence of isolation of _S.
suis_ and PRRSV was found to be higher in dually inoculated pigs.
PRRSV-induced suppression of pulmonary intravascular macrophage
function was suggested as a possible explanation for the
PRRSV-associated increased susceptibility to _S. suis_ infection (see
Numerous cases of _S. suis_ in humans have been reported from China
during the 2nd half of 2005, killing at least 38 people (see
ProMED-mail 20060411.1082). It is not known if PRRS was, at that
time, as prevalent in China as it is now. Since mid-2006, a
wide-scale epizootic of highly pathogenic PRRS has been reportedly
spreading throughout China. A new _S. suis_ case, affecting a
49-year-old male living in Bao'an District of Shenzhen City, was
reported by Xinhuanet news agency yesterday (25 Jul 2007; article (in
Chinese) available at
Thanawongnuwech R, Brown GB, Halbur PG, Roth JA, Royer RL, Thacker
BJ: Pathogenesis of porcine reproductive and respiratory syndrome
virus-induced increase in susceptibility to _Streptococcus suis_
infection. Vet Pathol. 2000 Mar; 37(2): 143-52 (full article available at
Data from China and Viet Nam on the possible impact of PRRS upon _S.
suis_ in pigs (and, consequently, upon public health), or the denial
of such impact, will be helpful. - Mods.AS/MPP
A map of Viet Nam, with provinces, is available at
<http://www.angelfire.com/co/hongnam/vnmap.html>. - CopyEd.MJ]