|
FMD Control Policies
|
|
Crucial to any FMD control programme is the prevention of entry of animals or animal
products that may introduce the virus. For FMD-free countries in particular it is
important to ensure that imported livestock and their products originate from sources
with similar FMD status. Trade in live animals would not be allowed between FMD-free
countries and endemic countries
Veterinary administrations should consider as potential sources of imported FMDV:
• Domestic and wild ruminants and pigs
• Semen of ruminants and pigs
• Embryos/ova of ruminants and pigs
• Fresh meat of domestic and wild pigs and ruminants
• Meat products of domestic and wild pigs and ruminants not processed to ensure destruction of FMDV
• Products of animal origin destined for human consumption, animal feed or for industrial use
• Products of animal origin destined for pharmaceutical use
• Non-sterile biological products
Importation controls must be assessed by country of origin, but some general rules are
possible, and are discussed in the Office International des Epizooties (OIE) Animal
Health Codes and, for the EU, in Directive 90/423:
For importation of live susceptible animals
From FMD free/nonvaccinating countries: an International Animal
Health Certificate is required which attests that the animal was free
of clinical signs of FMD on shipment day, and had lived in an FMD free
zone for the previous three months.
From FMD free/vaccinating countries: an additional requirement
is seronegativity when animals are imported to nonvaccinating countries,
and possibly a negative probang sample from ruminants. Serum antibody
positive ruminants must be considered as potentially convalescent and
therefore possible FMDV carriers.
From FMD infected countries: additional requirements are absence
of FMD from the neighbourhood of the exporting farm; isolation for 30
days prior to quarantine; negativity in diagnostic serology and probang
virus isolation assays; quarantine for 30 days prior to transport and
negativity in diagnostic tests at the end of quarantine; absence of FMD
from the surrounding area of the quarantine station, and no contact with
sources of infection during transport from quarantine.
The current serological assays that are established and recognised for international
trade purposes cannot discriminate between post-vaccinal and convalescent serum antibody
against FMDV. There are two serotype-specific serological assays, described as
'Prescribed' tests by the OIE, which can be used for the detection of serum antibody to
FMDV in traded animals following infection or vaccination. However, neither the virus
neutralisation test nor the liquid-phase (blocking) ELISA will differentiate between
convalescent animals (and therefore potential FMDV carriers if ruminants) and vaccinated
animals.
At present, therefore, any animal which is seropositive for FMD has to be considered a
potential carrier of FMDV and its importation constitutes an unacceptable risk of
introducing the virus into a country. The greatest risk of introduction of FMD is
associated with the importation of live animals in which the disease is mild or
inapparent (sheep and goats for example), or in convalescent carrier cattle.
Several assays are currently under development for the differentiation of post-vaccinal
from convalescent serum antibody. Such assays would have the potential to allow trade in
vaccinated animals between countries of similar FMD status, and assist in epidemiological
surveillance in vaccinating countries, allowing the movement of unexposed animals out of
'emergency' vaccination zones.
For importation of animal products
For germ plasm, similar International Animal Health Certificate should attest that the
animal from which germ plasm is derived was free of FMD and kept in a similar fashion to
that required for live animal importation.
For meat, an International Sanitary Certificate is required which attests that the meat
has come from animals kept and slaughtered in a similar fashion to that required for
live animal importation. In addition, if vaccination is practised in the exporting
country, then deboning and maturation of the carcass may be required, and the major
lymphatic organs must be removed. Meat exported by FMD infected regions must be
processed to ensure destruction of the virus.
There are similar requirements for the importation of milk/milk products/blood/hides/wool
/trophies, and again an International Sanitary Certificate should accompany such imports.
Waste food from aircraft and ships must be destroyed to prevent contact between pigs and
potentially infected meat, and as an additional measure to limit the spread of any future
outbreak, all waste food produced domestically should be heat treated before feeding to
pigs.
Deboning and carcass maturation
• Remove all major lymphatic organs
• Allow carcass to mature at above 2°C for a minimum period of 24 hours following slaughter
• Test pH of carcass in middle of the longissimus dorsi muscle in each half carcass; this must be below pH 6.0.
• Debone
|
