50
46TH
ANNUAL
CONGRESS
OF
THE
SAEVA
SKUKUZA
16-‐20
FEBRUARY
2014
Lessons learned from the current
CEM-outbreak in South Africa
Schulman, ML1* and May, CE1
1
Section of Reproduction, Faculty of Veterinary Science, University of Pretoria
Background
The first outbreak of contagious equine metritis (CEM) due to the bacterium
Taylorella equigenitalis in South Africa was recognised in April 2011 and reported to
the OIE. As a consequence, South Africa lost its CEM-free status. This outbreak
report was linked to the importation of the index case (a Warmblood stallion) from
Germany. An outbreak was initially suspected following an unofficial test breeding on
the index property in Midrand (Gauteng Province) of a Thoroughbred mare using
semen collected from the index stallion. Samples from both index animals were
confirmed positive for T. equigenitalis after the State was notified and submitted
swabs for testing to a reference laboratory in the UK. The index property was
quarantined and a traceback was instituted to identify and screen all in-contact
animals. This exercise was extended countrywide as it became apparent that indirect
venereal transmission via movement of both carrier stallions and chilled semen as
well as horizontal transmission via fomites was important in the dispersal of T.
equigenitalis from the index property. The Department of Agriculture, Forestry and
Fisheries (DAFF) introduced a mandatory nationwide Stallion Screening Programme
in June 2011 to identify carrier stallions, which was central to assessing the
prevalence of T. equigenitalis and the extent of the outbreak. Currently as of
December 2013, a total of 39 horses (36 stallions and 3 mares) have been identified
and after confirmation of their carrier status were successfully treated under
quarantine conditions. All, with the exception of three horses (North West = 2;
Western Cape = 1) were identified in Gauteng. Most positive animals have been
linked either directly or indirectly to the index premise. The role of horizontal
transmission via fomites (e.g. personnel, housing, breeding equipment) has been
central and few animals appear to have been directly infected by the venereal route.
No evide nce of classic transmission at natural cover was recognised, and the cases of
venereal transmission were apparently associated with AI using contaminated semen.
Lessons learned
1. Epidemiology
a) CEM transmission had a strong risk-association with biosecurity
b) CEM transmission had a strong risk-association with artificial breeding centres
c) CEM transmission and geographic dispersal were facilitated by artificial breeding
d) CEM transmission was facilitated by housing stallions in close proximity
e) CEM was absent in Thoroughbreds in SA despite exclusive use of naturalcovering
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