Oorsig/Review
Peculiarities of Foot and Mouth
Disease in Southern Africa and
Resulting Implications
Gavin Thomson BVSc, MSc, PhD
Background
It’s remarkable that Foot and Mouth Disease is
so widely misunderstood bearing in mind the
international importance ascribed to it. The
disease generally kills few animals and does
not cause disease in humans; yet in the wider
animal health world it is often considered the
most important disease of livestock. Part of
the explanation is that in intensive livestock
production systems such as large piggeries and
dairies, it can have devastating effects and can
destroy commercial enterprises overnight. On
the other hand, in extensive rangeland systems
its presence, certainly in much of Southern Africa,
may be difficult to detect because the disease is
so mild or even unapparent. The considerable
impact of FMD in Southern Africa relates to its
profound trade effects; parts of the world free
from FMD go to great lengths to avoid importing
what they consider risky commodities or
products.
It is important to appreciate that the FMD virus
genus (Aphthovirus) has two distinct branches or
lineages: (1) comprising the three SAT 1 types (1,
2 & 3) and (2) the so-called Eurasian serotypes –
A, O, C & Asia 1 (Fig. 1).
FMD virus family tree showing 2 dis8nct lineages
Eurasian types (O, A, C & Asia 1) –
evolved over last 500 years, mainly in
domes@c livestock, in Eurasia
SAT X
SAT X – progenitor – probably
originated in African buffalo ≈
1 000 years ago
Fig 1. FMD virus Family Tree showing 2 distinct lineages
The Eurasian lineage (molecular genetic studies
suggest) split from the progenitor SAT lineage
(maintained by African buffalo) about 500 years
ago. Since then the Eurasian types have evolved,
mainly in Eurasia, in association with cloven-
hoofed livestock. Essentially therefore, the SATs
are African buffalo viruses while the Eurasian
types are livestock viruses that originally evolved
in Eurasia, although some types – particularly O
and A – have spread far and wide since the early
19th Century. Including in Africa where they
are endemic to the northern portions of some
southern African countries such as Zambia and
Malawi.
SAT – abbreviation for ‘South African Territories’, the name given to these viruses when they were first identified by
The Pirbright Laboratoty, UK in the 1950s
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