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Aphthovirus Genome Map
FMDV Isolates and Location
Identifing Infectious Source
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The study of the epidemiology of FMD virus has been significantly developed using
nucleotide sequencing to identify individual strains of virus.
A consequence of the high mutation rate of FMD virus is that strains of virus with a
common origin quickly diverge in sequence as they replicate and spread into new areas.
A short sequence of the gene coding for the VP1 protein of the virus is used to compare
strains of FMD virus. The greater the number of differences, the greater the distance
between the strains in space and time. Conversely, strains with identical sequences must
have had a common, more recent, origin. This has been particularly useful in identifying
some outbreaks as being due to the use of improperly inactivated vaccines.
Tracing and identification of a disease source can be performed by analysis and comparison
of sequence data. This technique has also demonstrated that FMD isolates fall into specific
genetic groups ('topotypes'), each characteristic of the world region in which they
occur.
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