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AFRICAN SWINE FEVER - RUSSIA (13): (STAVROPOL) UPDATE, REVIEW
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A ProMED-mail post
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Date: Mon 16 Nov 2009
Source: Rosbalt Information Agency [in Russian, trans. Corr.ATS, edited]
<http://www.rosbalt.ru/2009/11/16/689242.html>
The swine populations are being culled in the
village of Bogdanovka in Stepnsovsky district and
in the farmstead Novoivanovsky of Kursky district
[Stavropol krai (territory)]. The press service
of the territory's governor has informed
"Rosbalt" that these measures are being taken
because of cases of African swine fever. The
virus was detected in the pork brought from
Novoivanovsky to Bogdanovka. Quarantine measures
are now being implemented in both settlements.
The sick animal had been bought from North
Ossetia. The attorney's office is carrying out an
investigation around this incident. The governor
of the territory announced that those who are
found violating veterinary rules will not be
reimbursed for culled animals and even criminal
charges might be applied upon malicious rule
breakers. As a reminder, an outbreak of ASF was
registered in North Ossetia in November.
Quarantine measures are also in place in Rostov
oblast and Kalimikia because of ASF outbreaks during this Fall (2009).
--
Communicated by:
ProMED-RUS
<promed-rus@promedmail.org>
[Stavropol krai (territory) can be located on the map at
<http://en.wikipedia.org/wiki/File:Map_of_Russia_-_Stavropol_Krai_(2008-03).svg>.
The HealthMap/ProMED-mail interactive map of Russia is available at
<http://healthmap.org/r/00-T>.
Russia has submitted to the OIE its 10th
follow-up report on ASF on 19 Nov 2009, notifying
2 new outbreaks in domestic pig holdings in 2
hamlets, Antonov and Troytsky in the Rostov
region. The current Russian epizootic started 26
Sep 2009, so far involving 26 outbreaks. See,
including map with the 26 outbreaks in domestic
and wild swine, at
<http://www.oie.int/wahis/public.php?page=event_summary&reportid=8462>.
The recent outbreaks in Georgia and the
subsequent spread of the disease to Armenia,
Azerbaijan, and Russia are of great concern to
the growing pig industry in many eastern European
countries. The situation has been further
complicated and control options made more
difficult by the spread of the disease into the
local wild boar populations. Further west- or
eastward spread could adversely affect the pig
sector in many countries. For instance, the pig
industry in the Ukraine is an important growing
agricultural sector with massive foreign
investments into large-scale pig farming. The
presence of wild boar could lead to spread of ASF
to Moldova, Romania, Hungary, Slovakia, Poland, or Belarus.
The 1st spread of ASF outside Africa was to
Portugal in 1957 as a result of waste from
airline flights being fed to pigs near Lisbon
airport. Although this incursion of disease was
eradicated, a further outbreak occurred in 1960
in Lisbon and ASF then spread to Spain and
remained endemic in the Iberian peninsula until the mid 1990s.
Outbreaks of ASF were reported subsequently in a
number of other European countries, including
Malta (1978), Italy (1967, 1980), France (1964,
1967, 1977), Belgium (1985), and The Netherlands
in 1986. The disease was eradicated from each of
these countries but in Sardinia it has remained
endemic since its introduction in 1982. In Spain,
the final 5 years of the eradication programme
alone were estimated to have cost USD 92 million;
the disease was eventually eradicated in 1994.
Cuba, in 1971, was the 1st country in the
Caribbean region to report infection with ASF,
and the virus was believed to have been
introduced from Spain. ASF was further reported
in the late 1970s in several Caribbean island
countries: Cuba (1978, date of last occurrence
1980), Dominican Republic (1978, date of last
occurrence 1981), and Haiti (1979, date of last
occurrence 1984). ASF was reported in Brazil in
1978 and was probably introduced from Spain or
Portugal through food waste carried by
transcontinental flights and/or animal products
imported by tourists. The date of the last reported occurrence was 1981.
An updated review, "African swine fever: how can
global spread be prevented?" was published on 27
Sep 2009 in Phil. Trans. R. Soc. B 2009 364,
2683-2696. The review was authored by scientists
from leading institutions in UK, France,
Australia, and Kenya (S Costard, B Wieland, W de
Glanville, F Jori, R Rowlands, W Vosloo, F Roger, DU Pfeiffer, and LK Dixon).
The following 2 final chapters of the review,
nos. 7 and 8, may be found useful by subscribers.
7. Vaccine development
----------------------
There is currently no vaccine available for ASFV,
although there is no doubt that this is feasible.
Protection can be achieved by inoculation of pigs
with low-virulence isolates obtained by passage
in tissue culture or by deletion of genes
involved in virulence, as well as low-virulence
isolates from the field (Lewis et al. 2000;
Leitao et al. 2001; Boinas et al. 2004).
The mechanism of protection involves
cell-mediated immunity, since depletion of CD8þ T
cells abrogates protection (Oura et al. 2005;
Denyer et al. 2006). A role for antibodies in
protection is also suggested since passive
transfer of antibodies from immune pigs conferred
partial protection to lethal challenge (Onisk et
al. 1994). In experiments using recombinant
proteins, partial protection was achieved using a
combination of 2 proteins, p54 and p30, as well
as with recombinant CD2-like protein
(Ruiz-Gonzalvo et al. 1996; Gomez-Puertas et al.
1998). The failure to achieve complete protection
in these experiments may be because of the
delivery method of the antigens and/or because
more or different antigens are required to confer protection.
Further research is required to develop effective
vaccines. Identification of ASFV genes involved
in virulence and in evasion of the host's immune
response (for review see Dixon et al. 2008) makes
the development of rationally attenuated vaccines
through sequential deletion of these genes
realistic. However, extensive testing of the
safety of such vaccines is required before their
use in the field. An alternative safer approach
would involve the development of defective
non-replicating ASFV vaccines. These approaches
have the advantage that many antigens are
expressed and no prior knowledge of which are
protective is required; however, high containment
facilities are required for vaccine production.
Alternative approaches based on expression of
protective antigens are feasible but first
require identification of those antigens. The
development of high-throughput methods for
constructing recombinant viral vectors opens a
route for global analysis of the protective
potential of all ASFV-expressed genes. One
concern about the use of ASFV vaccines is the
genetic diversity of strains circulating in some
countries. Recent experiments have demonstrated
cross-protection between different genotypes and
therefore it may be possible to develop vaccines,
which can cross-protect against infection with
several genotypes. Moreover, in some regions
isolates of just one genotype are circulating.
These include countries in West and central
Africa (genotype I), the large endemic region
including Malawi and Zambia (genotype VIII) and
the Caucasus and Russia (genotype II).
8. Preventing global spread
---------------------------
The review of the current situation in endemic
regions, including insights gained through
molecular epidemiology and lessons learnt from
past outbreaks in non-endemic areas, highlight
the complexity of ASF epidemiology. To combat ASF
globally, surveillance and control need to be managed at 3 levels:
(i) locally at points of occurrence;
(ii) at regional level in endemic and adjoining areas; and
(iii) globally by preventing transboundary and
transcontinental spread through animal movement and products.
In the absence of an effective vaccine, direct
and indirect pig-to-pig transmission and contact
with wildlife reservoirs need to be limited in
endemic areas to reduce disease burden.
Increasing early detection would also improve the
chances of disease control measures making them
more effective. International agencies and donors
should promote local capacity development,
research activities including risk assessment,
and regional coordination of emerging swine
disease surveillance including ASF. For the
implementation of control programmes in endemic
or epidemic areas, tools for rapid detection
would allow a timely diagnosis and ensure
involvement at the local level in control.
Lateral flow devices for detecting virus antigens
have been used successfully in the global
rinderpest eradication programme and have the
potential for use in ASFV control. Other
technologies including pen-side PCR tests could
be used, although the equipment required may be more expensive.
Capacity building is also required to improve the
ability of regional and national laboratories to
confirm suspicious cases and to assist surveillance activities.
For local control in countries with a large
small-scale pig-holder population, educational
programmes to increase disease awareness and
improved access to animal health services are
required. In countries where the disease is
endemic, where most pig owners are poor
smallholders and where veterinary services lack
resources to achieve compliance with regulations,
the involvement of farmers is essential in the
development of control strategies that will be
applied effectively. In order to eradicate the
disease in endemic areas, the role of wildlife
reservoirs needs to be further investigated,
including wild suids in Africa and wild boar in
Sardinia and in the Caucasus. The distribution of
_Ornithodoros_ species in the Caucasus region and
their capacity to act as vectors for ASFV also needs to be investigated.
The feasibility of creating ASF-free zones within
an endemic area was shown in South Africa and
should serve as an example for localized disease
eradication and prevention that will benefit
trade, and thereby generate incentives for
producers to support large-scale eradication
programmes. Achieving ASF freedom is only
realistic when all stakeholders perceive clear
benefits from such a status and therefore are
likely to comply with the necessary prevention
and control measures. Effective communication and
involvement of all stakeholders at each stage of
the process together with the support of national
and international veterinary authorities is
pivotal to the success of such programmes.
To prevent the spread of ASF at global level
through movement of livestock, countries are
advised to follow international standards as
outlined by the World Organization for Animal
Health OIE. Strict regulations regarding animal
by-products have proven effective in many
developed countries and are critical given the
high tenacity of the virus in meat products and
in the environment. This has also been recognized
by many developing countries. For example,
following FMD outbreaks, the Philippines
implemented an effective policy incorporating
quarantine and control of waste food from ships and planes.
Comprehensive risk assessments are needed for all
currently free countries with pig production
relevant to farmers livelihoods in order to
identify which introduction pathways are most
important and inform-targeted or risk-based
surveillance strategies. Risk assessments are
also needed in endemic countries to identify the
main mechanisms for spread in the pig production
chain and thus target control measures
effectively. Data required for such risk
assessments include density and geographical
distribution of susceptible animal species --
including feral and wild pigs -- and any relevant
arthropod vectors, as well as the structure of
the pig production and marketing sector at
national and regional level. The effectiveness of
surveillance systems, early warning and early
response capacity, existing policies for
test-and-slaughter, and other preventive measures
need to be assessed. The level of international
cooperation, political, commercial, and
tourism-related links are also important, as are
the level of economic development and other
issues such as cultural and religious events that
may influence trade patterns. Data indicating
potential sources of infection (such as, ASF
prevalence in export countries) should take into
account the under-reporting of ASF outbreaks in
endemic countries, in some cases associated with
the economic development level of a country or political factors.
Lessons learnt from previous outbreaks and from
outbreaks of similar diseases such as CSF in many
countries worldwide should be considered when
designing control programmes. Improved
effectiveness of control also includes the need
for continued research aimed at the development
of an effective vaccine, since this may well have
to be used together with other prevention and
control measures in endemically affected countries.
For the references, and for the other 6 chapters
of the Review, subscribers are referred to the original paper, available at
<http://rstb.royalsocietypublishing.org/content/364/1530/2683.abstract>
(abstract free; full article upon subscription). - Mod.AS]
[see also:
African swine fever - Russia (12): (RO) update 20091110.3897
African swine fever - Russia (11): (LN, RO) OIE, FAO 20091027.3720
African swine fever - Russia (10): (KV), susp., RFI 20091020.3611
African swine fever - Russia (09): (KL), Ukraine avoids 20091017.3569
African swine fever - Russia (07): (DA, RO) 20091009.3494
African swine fever - Russia (06): (DA), OIE 20090926.3371
African swine fever - Russia (05): (RO) 20090410.1376
African swine fever - Russia (04): (STA) 20090328.1203
African swine fever - Russia (03): (STA) 20090319.1102
African swine fever - Russia (02): (STA,KDA) 20090117.0192
African swine fever - Russia: (STA) 20090113.0139
2008
----
African swine fever - Russia (10): (KDA, IN), OIE, (STA) 20081114.3596
African swine fever - Russia (09): (STA), clarification 20081104.3475
African swine fever - Russia (08): (STA), stamping out 20081030.3418
African swine fever - Russia (07): (Stavropol) OIE 20081025.3372
2007
----
African swine fever - Georgia, Armenia: FAO 20071004.3275
African swine fever - Armenia (05) 20071231.4195
African swine fever - Armenia (04): (Ararat) 20071213.4013
African swine fever - Armenia (03) 20071021.3430
African swine fever - Georgia, Armenia: FAO 20071004.3275
African swine fever - Armenia (02) 20070922.3150
African swine fever - Georgia (11): SDC mission report 20070920.3131
African swine fever - Georgia (10): Abkhazia Auton. Rep. 20070821.2737
African swine fever - Georgia (09): OIE 20070820.2724
African swine fever - Georgia (08) 20070817.2689
African swine fever - Georgia (07): EC/FAO/OIE 20070627.2066
African swine fever - Georgia (06) 20070615.1954
African swine fever - Georgia (05) 20070611.1901
African swine fever - Georgia (04): FAO 20070610.1891
African swine fever - Georgia (03): genotype 20070609.1886
African swine fever - Georgia (02): OIE 20070608.1860
African swine fever - Georgia: OIE 20070607.1845]
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