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Outbreaks of FMD in Europe 1951-1990
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FMD outbreaks were numerous throughout Europe for most of the first half of the 20th
century. However, as a result of advances in the large-scale production of vaccine it
was possible to begin mass annual vaccination campaigns in the 1950s and 60s.
Some countries which had never vaccinated (e.g., United Kingdom, Ireland), or had given
up vaccination a long time ago (Denmark), began to control FMD through importation
control, slaughter and zoosanitary measures.
Mass annual prophylactic vaccination was very successful in totally eliminating European
outbreaks by 1990. The banning of importation of bone-in beef from non-FMD-free states
in 1978 assisted these FMD eradication policies.
Historically, the original source of FMDV for vaccine production was clinically
derived material, such as infected cattle tongues (Vallée
et al., 1926). In 1951 a new technique was described for the production
of FMDV on an industrial scale in tongue explants (Frenkel,
1951). It was FMD vaccine made in this system that was used in The
Netherlands in the first of the highly successful mass annual prophylactic
vaccination campaigns to be carried out in Europe. The advantages of this
production system were its simplicity, low cost and the fact that adaptation
of the virus to the culture system was not required.
A significant development in FMDV antigen production was the transition
to tissue culture methods for virus growth. Initially, small scale production
in roller bottles using primary calf kidney cells was instigated in Italy
(Ubertini et al., 1963).
However, following the introduction in 1964 of a continuous cell line
(BHK21), derived from baby hamster kidney fibroblasts, that supported
the growth of FMDV (Stoker and
MacPherson, 1964), this system gained wide acceptance in FMDV vaccine
production. A significant scale-up in production capacity was achieved
with the advent of technology which exploited the ability of BHK21 cells
to grow in an anchorage independent manner in deep suspension culture
(Capstick et al., 1965). Subsequently,
a variety of monolayer systems was devised for anchorage-dependent cultures,
to increase culture vessel surface area and thus productivity (Spier
and Whiteside, 1976; Girard
et al., 1980).
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