- "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."
-
- Last year we were told that the disease in pigs was Strep
Suis. The Chinese insisted that was the agent and they had it
all under control. This year, the same symptoms appear as last but we
are told by the Chinese to believe that the agent is Porcine Reproductive
and Respiratory Syndrome, aka Pig High Fever Disease. What are we going
to be told it is next year?
-
- There has been no mention of Avian Flu testing and that
should be the first test taken and results reported.
-
-
- PORCINE REPRODUCTIVE AND RESPIRATORY
SYNDROME - CHINA (02) ProMed Mail
- By Luan Yu Guangxi News - Modern Life Daily
- (in Chinese, trans. Dan Silver, edited)
-
- 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.
-
-
- http://www.gxnews.com.cn/staticpages/20070512/newgx46450bf3-1072301.shtml
-
-
- ProMed Mail
-
- 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.
-
- Patricia A. Doyle DVM, PhD
- Bus Admin, Tropical Agricultural Economics
- Univ of West Indies
-
- Please visit my "Emerging Diseases" message
board at:
- http://www.emergingdisease.org/phpbb/index.php
- Also my new website:
- http://drpdoyle.tripod.com/
- Zhan le Devlesa tai sastimasa
- Go with God and in Good Health
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