ProMed: Illness and Death in Pigs in China: Ebola-Reston??

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http://www.promedmail.org/pls/otn/f..._BACK_PAGE,F2400_P1001_PUB_MAIL_ID:1000,79809

Archive Number 20091026.3699
Published Date 26-OCT-2009
Subject PRO/AH/EDR> Porcine reprod. & resp. syndrome - China (04): update, RFI

PORCINE REPRODUCTIVE & RESPIRATORY SYNDROME - CHINA (04): UPDATE,
REQUEST FOR INFORMATION
***************************************************************************
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<http://www.isid.org>

[1]
Date: Fri 23 Oct 2009
Source: HealthMap, International Online report [in Chinese, machine
trans., summ. Rappt.AH, edited]
<http://healthmap.org/ln.php?314902&trto=en&trfr=zh&u3439>


Ministry of Agriculture: China's recent large-scale outbreak of pig
disease outbreak - not
----------------------------------------------------------------------
The China Ministry of Agriculture announced today (23 Oct 2009) that
recent reports of epidemics among pigs in the north are not true.

According to the Ministry of Agriculture, after reports of outbreaks
among pigs were published, the ministry sent teams to the area to
investigate the reports. By 20 Oct 2009, of the 31 provinces,
autonomous regions, and municipalities, 5 provinces reported
outbreaks of blue-ear disease [porcine reproductive and respiratory
syndrome - PRRS]. There were 7600 pigs with disease, and more than
7700 had been culled. The numbers of outbreaks and pigs culled are
much decreased compared to the same period last year [2008]. Other
diseases are stable.

--
Communicated by:
ProMED-mail Rapporteur Angela Huang

[The current reservations, cited above, are in disagreement with news
derived from local Chinese media, claiming that "in the North and
Northeast, the magnitude of the outbreak has been about 2 times than
what was seen in 2006". An official, firsthand notification,
preferably to the OIE, will be helpful in clearing-up the current
PRRS situation in north and northeast China.

According to China's semi-annual reports to the OIE for 2008, a total
of 91 PRRS outbreaks were recorded in 13 provinces during that year.
Cases occurred during all months, with higher incidence (64/91, 70
percent) during the 7 months April-October. The outbreaks were
reported from the following 13 provinces (in brackets, annual number
of outbreaks): Chongking (18), Anhui (1), Guangdong (27), Guangxi
(15), Guizhou (1), Hebei (2), Henan (1), Hubei (2), Hunan (5),
Jiangxi (13), Ningxia (4), Shanghai (1), Sichuan (1). - Mod.AS]

******
[2]
Date: Sun 25 Oct 2009
From: Joseph Edhlund <microasianair@yahoo.com> [edited]


China PRRS virulence - Ebola?
-----------------------------
Re- the unusual high virulence of the PRRS epizootic in China: this
is how the initial diagnostic investigation began that led to the
Ebola-Reston virus detection in Philippine swine. It might be good to
look further at other potential sources for the increased virulence.

--
Joseph Edhlund DVM
Marianas Vetcare, Barrigada
Guam
<microasianair@yahoo.com>

[Dr Edhlund's comment is valid. A reminder: between the end of 2007
and mid 2008, a sudden increase in pig mortalities was seen in the
northern Philippines. Samples from the outbreaks were sent to the
USDA Plum Island laboratory. Results showed that samples were
positive for porcine circovirus type 2 and atypical PRRS virus,
which, reportedly, was 98 percent homologous to the atypical PRRS
virus isolated in China and Viet Nam. With high morbidity and
mortality observed similar to China and Viet Nam, it was concluded
that these outbreaks were most likely caused by atypical PRRS virus.
However, the USDA Plum Island laboratory also reported to have
isolated Ebola-Reston virus from swine samples (see commentary in
ProMED-mail posting 20081220.4008).

On the other hand, according to an August 2007 Emerging Disease
Notice of APHIS (US Animal and Plant Health Inspection Services),
titled "Porcine Reproductive and Respiratory Syndrome (PRRS) in
Vietnam and China", samples of the virus from the PRRS outbreak in
Viet Nam "were being sent to an international laboratory for further
testing and characterization. In view of the need to exclude
Ebola-Reston virus, ProMED-mail remarked: "It will be interesting to
note if the samples from Viet Nam included tissues of affected
porcines; in case affirmative -- were they tested for other disease
agents in addition to the PRRS virus, and what were the results?"
(see posting 20081216.3946).

Additional requests for information on the results of tests, which
may have been performed by an international reference laboratory (the
Plum Island laboratory?) on porcine samples from Viet Nam, were
posted at later dates and are still pending. - Mod.AS]

[see also:
Porcine reprod. & resp. syndrome - China (03): virulence 20091025.3694
Porcine reprod. & resp. syndrome - China (02): North 20091024.3663
Porcine reprod. & resp. syndrome - Viet Nam (02) 20090727.2644
Porcine reprod. & resp. syndrome - Viet Nam 20090415.1431
Porcine reprod. & resp. syndrome - China: (SX) suspected 20090210.0598
2008
----
Porcine reprod. & resp. syndrome - China, Viet Nam 20070824.2773
Ebola-Reston, porcine - Philippines (05) 20081220.4008
Ebola-Reston, porcine - Philippines (04): RFI 20081216.3946
2007
----
Porcine reprod. & resp. syndrome - China (05) 20070821.2730
Porcine reprod. & resp. syndrome - China (04) 20070816.2679
Porcine reprod. & resp. syndrome - China (03): OIE 20070809.2588
Undiagnosed disease, porcine - China (16) 20070801.2486
Undiagnosed disease, porcine - China (15) 20070725.2394
Undiagnosed disease, porcine - China (14) 20070715.2275
Undiagnosed disease, porcine - China (13): Guangdong 20070628.2081
Undiagnosed disease, porcine - China (12): PRRS 20070622.2017
Undiagnosed disease, porcine - China (10) 20070612.1913
Undiagnosed disease, porcine - China (09) 20070606.1828
Undiagnosed disease, porcine - China (08): RFI 20070604.1808
Undiagnosed disease, porcine - China (07): RFI 20070530.1740
Undiagnosed disease, porcine - China (06) 20070529.1735
Undiagnosed disease, porcine - China (05) 20070525.1675
Porcine reprod. & resp. syndrome - China (02) 20070514.1533
Porcine reprod & resp syndr - China (Guangdong): OIE 20070512.1517
Undiagnosed disease, porcine - China (04) 20070509.1492
Undiagnosed disease, porcine - China (03) 20070508.1479
Undiagnosed disease, porcine - China (02): update 20070406.1155
Undiagnosed disease, porcine - China: update 20070114.0185
Porcine reproductive & respiratory syndrome - Viet Nam (09), OIE 20070801.2479
Porcine reproductive & respiratory syndrome - Viet Nam (08) 20070730.2444
Porcine reproductive & respiratory syndrome - Viet Nam (07) 20070721.2346
Porcine reproductive & respiratory syndrome - Viet Nam (06) 20070717.2293
Porcine reproductive & respiratory syndrome - Viet Nam (05) 20070512.1516
Porcine reproductive & respiratory syndrome - Viet Nam (04): OIE 20070422.1316
Porcine reproductive & respiratory syndrome - Viet Nam (03) 20070418.1281
Porcine reproductive & respiratory syndrome - Viet Nam (02): OIE 20070414.1245
Porcine reproductive & respiratory syndrome - Viet Nam: RFI 20070412.1225
2006
----
Undiagnosed disease, porcine - China (04) 20061129.3387
Undiagnosed disease, porcine - China (03): OIE 20060924.2732
Undiagnosed disease, porcine - China (02): RFI 20060908.2549
Undiagnosed disease, porcine - China (South), RFI 20060903.2508
Undiagnosed die-off, porcine - China (Jiangsu): RFI 20060412.1087]
...................................arn/mj/lm

 

[alert]

Re: ProMed: Illness and Death in Pigs in China: Ebola-Reston??

http://www.promedmail.org/pls/otn/f..._BACK_PAGE,F2400_P1001_PUB_MAIL_ID:1000,79804

Archive Number 20091025.3694
Published Date 25-OCT-2009
Subject PRO/AH/EDR> Porcine reprod. & resp. syndrome - China (03): virulence

PORCINE REPRODUCTIVE & RESPIRATORY SYNDROME - CHINA (03): VIRULENCE
***********************************************
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<http://www.isid.org>

Date: Sun 25 Oct 2009
From: Brad Chadwick <bradchadwick@netvigator.com>


The emergence of this apparently more virulent strain of PRRSV in
China is interesting. When I was working at the Tai Lung Veterinary
Laboratory of the Agriculture, Fisheries and Conservation Dept in
Hong Kong a few years ago, there was early evidence of this variant
strain emerging in the region. PRRS-associated disease was commonly
diagnosed in Hong Kong pigs by pathology and RT-PCR. When I started
there about 5 years ago, most cases typed genetically as the EU
strain or the US strain, which were the only strains described. By
the time I finished 3 years later, more and more cases failed to type
as either EU or US strain, and some differences in the pathology were
also emerging.

The typical case presentation of EU and US strains was low but steady
and with ongoing mortalities in grower pigs, with poor performance of
the herd overall. PM cases consistently showed moderate sub-lethal
interstitial pneumonia that contained the virus, which was
demonstrated by immunohistochemistry. Lymphoid depletion in bronchial
lymph nodes was probably present but debatable. Death was almost
always attributable to secondary bacterial pneumonia. The variant
cases of non-EU, non-US PRRS often showed the same findings, but some
cases also included mortality in much younger weaner pigs, with acute
haemorrhage into the lungs, severe lymphoid depletion in bronchial
lymph nodes, only early mild interstitial pneumonia, and no secondary
bacterial involvement. The cause of death appeared to be entirely
attributable to acute PRRSV infection.

Unfortunately, the cases were not followed up with definitive
sequence data and a publication because pig farms were on the way out
in Hong Kong, and the research was not considered a priority by
management. However, I believe there was enough evidence then to be
convincing of a new genetic variant of PRRSV with the potential to
emerge as a new virulent phenotype and a new wave of acute disease
with higher mortalities that would take us back to the days of "blue
ear disease." I think that is what we are now seeing in China.

--
Dr Brad Chadwick
VetPath Asia Veterinary Laboratory
Mong Kok, Kowloon
Hong Kong SAR.
<bradchadwick@netvigator.com>

[Dr Chadwick's firsthand contribution is gratefully acknowledged. It
adds valuable detail to the gradually unfolding picture of the PRRS
epizootic in China (and, apparently, Viet Nam).

ProMED-mail's subscribers have been following the evolvement of the
major PRRS epizootic in China since mid 2006 and in Viet Nam since
spring 2007. The reporting from China was initially based upon
reports and advisory articles for farmers indicating heavy economical
losses and soaring pork prices, which appeared in local media and
farmers journals, initially addressing the condition as "Pig High
Fever Disease". It appeared that the syndrome may had been affecting
the pig population in south China "during the hot and humid season"
of earlier years as well (see 20060908.2549).

Following ProMED-mail's 3 RFI's, China submitted a report to the OIE
on 14 Sep 2006, describing the syndrome as "mixed infection of
classical swine fever, porcine reproductive and respiratory syndrome
and porcine circovirus," which affected the pig industry in 6
provinces (see posting 20060924.2732). In the early summer of 2007,
the syndrome renewed its spread; on 9 May 2007, China notified the
OIE that "based on the experience of the similar epidemic (which)
occurred in 2006 in China, which was notified to the OIE on 12 Sep
2006, this case is probably caused by highly pathogenic PRRS virus.
The laboratory diagnosis is ongoing".

The 1st scientific paper on the PRRS epizootic in China, titled
"Emergence of Fatal PRRSV Variants: Unparalleled Outbreaks of
Atypical PRRS in China and Molecular Dissection of the Unique
Hallmark," was published in the June 2007 issue of PLoS (Public
Library of Science) ONE, available free at
<http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1885284>
(see posting 20070622.2017).

Among other things, the authors, Tian et al, stated that the
"unparalleled large-scale outbreaks" spread to "more than 10
provinces (autonomous cities or regions) and affected over 2 million
pigs with about 400 000 fatal cases". Furthermore, the authors
stated: "Whole-genome analysis of the isolated viruses revealed that
these PRRSV isolates are grouped into Type II and are highly
homologous to HB-1, a Chinese strain of PRRSV (96.5 percent
nucleotide identity). More importantly, we observed a unique
molecular hallmark in these viral isolates, namely a discontinuous
deletion of 30 amino acids in nonstructural protein 2 (NSP2). Taken
together, this is the 1st comprehensive report documenting the 2006
epidemic of atypical PRRS outbreak in China and identifying the 30
amino-acid deletion in NSP2, a novel determining factor for virulence
which may be implicated in the high pathogenicity of PRRSV".

In November 2008, Feng et al published their paper "Porcine
respiratory and reproductive syndrome virus variants, Viet Nam and
China, 2007" in the monthly Emerging Infectious Diseases, Volume 14 ,
Issue 11, pages 1774-1776 (available on line at
<http://www.cdc.gov/eid/content/14/11/pdfs/1774.pdf>). The abstract
says: "We characterized isolates from porcine respiratory and
reproductive syndrome virus epidemics in Viet Nam and China in 2007.
These isolates showed 99 percent identity at the genomic level.
Genetic analysis indicated that they share a discontinuous deletion
of 30 aa in nonstructural protein 2, which indicates that identical
variants emerged in Viet Nam and China," a remarkable coincidence.

According to information, gathered from various Chinese sources by
ProMED-mail's Rapporteur Dan Silver in February 2008, there were 11
approved suppliers of inactivated highly pathogenic PRRS vaccine in
China, well-scattered geographically, and one approved supplier of a
live vaccine. All inactivated vaccines were approved in 2007 under a
special measure issued by the Ministry of Agriculture (see posting
20080208.0512). - Mod.AS]