DairyPost Africa • May 2014
babesiosis and heartwater. It could be
dangerous to follow blindly the advice that
tick control can be reduced substantially
after ECF immunisation, to allow small
numbers of brown ear ticks to “boost”
the immunity produced by the vaccine.
True, small numbers of brown and blue
ticks cause negligible production losses,
but even a single bont tick can destroy an
udder quarter, and “the other three” tickborne diseases will become a significant
risk. Farmers with an effective tick control
programme should consider these risks
carefully before changing their strategy.
ECF vaccination protects against ECF
(theileriosis), but it gives no protection
against the other three diseases, or
against Corridor Disease (CD), the form of
theileriosis that develops when ticks that
have fed on buffalo pass the infection to
cattle, so the advice that these diseases
should be “treated at the same time” as
ECF vaccination is meaningless. They may
occur at any time, particularly if tick control
is reduced. Practically every buffalo carries
CD that can cause even higher mortality
than ECF itself. Buffalo shed huge numbers
of ticks so even one buffalo crossing
cattle grazings poses a big risk of CD. Its
management depends on good tick control
and drug treatment of any cases that do
occur. Farmers in “buffalo affected” areas
especially should consider carefully whether
they can use the ECF vaccine safely.
The vaccine costs “$6-10 per dose”. Where
the current risk of ECF is small, the cost
of vaccinating 100% of cattle should be
compared with that of treating the few
cases that do occur. If these are detected
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and treated early, production losses are low,
particularly in beef cattle and youngstock,
and cure rates approach 100%. With efficient
tick control the risk of ECF is rarely more than
2% - usually less even than this, and cured
cattle are strongly immune to ECF.
When the vaccine is used, every vaccinated
animal becomes a carrier of ECF, so any
brown ear ticks that feed on them can pick
up the in