Objective To investigate control options for contagious ecthyma (scabb
y mouth) in Australian sheep exported live to the Middle East. Design
Prevalence, vaccination and modelling studies. Procedure One hundred a
nd forty weaner sheep (less than 1 year old) on each of 106 farms in W
estern Australia (WA) and 18 farm groups of adult wethers received at
a WA commercial feedlot were examined for lesions of scabby mouth. She
ep on a total of 26 farms in 3 States were divided into treatment and
control groups for the vaccination study. A simple deterministic compa
rtmental model was developed to establish which parameters had the gre
ater effect on disease prevalence. Results The proportion of farms wit
h evidence of scabby mouth in weaner sheep was 23.6% and, on those far
ms with the disease, the overall prevalence was 6.1%. At the feedlot,
4 out of 18 farm groups had 5 or more sheep with lesions on arrival. T
he overall prevalence in the 4 diseased groups was 5.2%. Sheep vaccina
ted on farm before trucking to the feedlot had a lower prevalence of s
cabby mouth at the end of simulated shipping than controls. The main d
eterminant of scabby mouth prevalence was the proportion of sheep immu
ne to the disease. Conclusion A program of vaccination for scabby mout
h will reduce the prevalence of disease during live export. However, u
sing current technology it is not possible to deliver shipments of she
ep to the Middle East that are guaranteed completely free of scabby mo
uth.