(CN) FW: PRO/AH/EDR Porcine reprod. & resp. syndrome - China (02)

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PRO/AH/EDR> Porcine reprod. & resp. syndrome - China (02)

Mon, 14 May 2007 08:31:21 -0400 (EDT)

 

PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME - CHINA (02)

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Sat 12 May 2007

Source: Guangxi News - Modern Life Daily [in Chinese, trans.

Dan Silver, edited]

<http://www.gxnews.com.cn/staticpages/20070512/newgx46450bf3

-1072301.shtml>

 

 

On the morning of 11 May 2007, personnel from the Nanning Municipal

Agricultural Bureau spread out to major pig-farming counties to [organize]

comprehensive pig " high fever disease " prevention and control measures

among veterinary departments at all levels, [including] strengthening

immunization supervision. [The same day], sources in relevant departments

said that pig " high fever disease " has occurred in the past several months

in Anhui, Hunan, Guangdong, Shandong, Liaoning, Jilin, and other provinces,

and has caused the deaths of more than 20 million pigs, with extremely

heavy economic losses.

 

Pig " high fever disease " has already been discovered in 8 counties

(districts) in the [Guangxi Autonomous] Region.

Among these, pig " high fever disease " is suspected to have occurred in 92

administrative villages of 10 townships in Cenxi City. The disease has been

found in 4875 pigs, with

287 deaths. Although there are no reports of disease within Nanning

Municipality at this time, earlier this year [2007] pig deaths occurred for

unknown reasons in 2 or 3 counties

(districts) in Nanning. Some medium and small pig farms and pig-raising

households had not implemented pig " high fever disease " vaccination. The

circumstances of prevention and control activities are grim.

 

On 10 May 2007, the [Guangxi] Autonomous Region People's Government

conducted thorough deployment for prevention and control work across the

Region. While demanding thorough pig " high fever disease " immunization

within about a month, it also demanded that all relevant departments carry

out supervision of pig markets and private slaughterhouses and sternly

strike against illegal sale of diseased pork and pork products. [The same

day], Nanning Municipal Government held a citywide pig " high fever disease "

prevention and control conference, stipulating that all relevant

departments at all levels make every effort toward implementing prevention

and control work for pig " high fever disease " and other serious diseases,

to guarantee personal health and public hygiene safety for the population.

 

Veterinary departments at all levels are to strengthen disease inspection

work on production sites and slaughterhouses, allowing [healthy] pigs to

market while resolutely stopping diseased pigs from entering distribution.

Those responsible for illegal purchase, sale, or processing of diseased pigs

will be severely punished according to the law.

 

Porcine " high fever disease " , an OIE (World Animal Health

Organization) notifiable disease, also called pig blue ear disease, is a

pig reproductive and respiratory viral syndrome (PRRS). It is an infectious

illness characterized by reproductive disorder, premature delivery,

miscarriage, and stillbirth, as well as abnormal breathing in piglets.

When pigs contract this disease, it not only spreads extremely fast, but

morbidity and mortality are also very high.

 

" We are reminding residents that for their own health, they should not eat

diseased pork or pork of uncertain origin! " , a staff member of the Nanning

Municipal Agricultural Bureau's Animal Husbandry Section told reporters. A

reporter observed that in Nanning's Xinzhu Road, Gucheng Road, Minzhu Road,

and other produce markets, pig " high fever disease " had not significantly

affected consumption.

Many pork retailers were nearly sold out within an hour.

 

[byline: Yuan Lu]

 

--

Communicated by:

Dan Silver

<dgsilver

 

[According to the information above, " high fever disease " , apparently

caused by PRRS virus (PRRSV), has been observed during the past several

months in more than 7 provinces of China; the official OIE notification of

9 May 2007, referred to one of them (Guandong). Nanning, referred to in the

newswire above, is the capital of the Guangxi autonomous Region, situated

in southern China, approx.160 km (100 miles) from the border with Vietnam

[see map at <http://sedac.ciesin.org/china/admin/bnd90/bnd90data.html>]

 

PRRSV (currently classified as a member of the newly established order of

_Nidovirales_, family _Arteriviridae_, genus _Arterivirus_) is now

ubiquitous throughout most of the pig-rearing areas of the world and is

believed to exist in 2 main forms -- the type 1 genotype, which

predominates in Europe and the type 2, which predominates in the USA. A

complicating factor in PRRS epidemiology has been the use of live vaccines,

some of which have caused clinical disease and become established in the

local pig population.

Such vaccines have allegedly been applied throughout the world, including

Asia.

 

Increasing data indicate that PRRSV is antigenically, genetically, and

pathologically very heterogenic. Since the mid 1990s, a more virulent form

of PRRSV has been causing high abortion and mortality rates in vaccinated

swine populations in the US. These severe outbreaks of PRRS have been

referred to as acute PRRS, atypical PRRS, hot PRRS, abortion storm, or sow

abortion and mortality syndrome.

Zimmerman et al (1997) described the criteria for the diagnosis of acute

PRRS, which include acute onset, clinical signs occurring over a 2-4 week

period, high mortality (greater than 5 percent) in sows and boars, and a

high rate of abortions (greater than 10 percent). Many of the herds

affected by acute PRRS were on a PRRS vaccination program with the available

modified live-vaccines, suggesting that the vaccine-induced antibodies

failed to neutralize the acute PRRS virus.

 

As discussed by Kijona et al (2001), several recent Danish isolates, 2

Taiwanese isolates (MD001 and FI), 2 Chinese isolates (S1 and CH1a), a

Japanese isolate (Kitasato 931), and an isolate from Guatemala (249010),

are all clustered within the North American genotype. The North American

genotype of the Danish isolates has been confirmed to be derived from the

RespPRRS vaccine that was used in Danish swine herds. The origins of the

Asian isolates with a North American genotype are not known.

 

The disease, which in China is called " high fever disease " , was initially

attributed to a mix infection of PRRS, classical swine fever, (CSF) and

porcine circovirus (PCV-2) , and probably additional agents. According to

China's last notification to the OIE, dated 9 May 2007, the causal agent of

an outbreak in Guandong is PRRSV. The report indicates that the reason for

notification is " change in epidemiology " and that the manifestation of the

disease is " sub-clinical infection " . However, the apparent case fatality

rate (20 percent) does not fit the description " sub-clinical " .

 

Clearly, more details on the PRRS virus, currently circulating in vast

areas of China and Viet Nam, are urgently needed. This should include the

exclusion of other disease agents (including avian influenza and CSF),

studies into the pathogenicity of the Chinese PRRSV and its genotyping.

Such data might indeed be anticipated soon, since the Chinese notification

(under " epidemiological

comments " ) indicates that the case is " probably caused by highly pathogenic

PRRS virus " and that " laboratory diagnosis is ongoing " .

 

Subscribers are referred to Mod.PC's commentary in ProMED-mail posting

" Porcine reprod & resp syndr - China

(Guangdong): OIE 20070512.1517 " . - Mod. AS]

 

References:

1. Zimmerman et al (1997): Results of the recent survey of the membership

of the AASP for outbreaks of sow abortion and mortality. Swine Health Prod.

5, pp 74-5.

 

2. Kijona et al (2001): Genetic variation and phylogenetic analyses of the

ORF5 gene of acute porcine reproductive and respiratory syndrome virus

isolates. Veterinary Microbiology, Vol 83 (3), pp 249-263.

 

[see also:

Porcine reprod & resp syndr - China (Guangdong): OIE

20070512.1517 Porcine reproductive & respiratory syndrome - USA (NC)

20070407.1171 Porcine reproductive & respiratory syndrome - Viet Nam: RFI

20070412.1225 Porcine reproductive & respiratory syndrome - Viet Nam (02):

OIE 20070414.

Porcine reproductive & respiratory syndrome - Viet Nam (03)

20070418.1281 Porcine reproductive & respiratory syndrome - Viet Nam (04):

OIE 20070422. Porcine reproductive & respiratory syndrome - Viet Nam (05)

20070512.1516 Undiagnosed disease, porcine - China: update (02)

20070406.1155 Undiagnosed disease, porcine - China: update

20070114.0185 2006

----

Undiagnosed disease, porcine - China (04) 20061129.3387 Undiagnosed disease,

porcine - China (03): OIE 20060924.2732]

..............................................arn/mj/jw

 

 

 

 

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