Basic HTML Version
SPRING 2014 ISSUE
EQUINE MATTERS
8
VETERINARY ADVANCES
3. Apply 2-3 layers of rolled cotton
wool to the limb, for padding
and
further protection.
Recent
advances
within
the veterinary industry
One of the most significant advances in the
equine veterinary industry in recent years
isn't an exciting new surgical procedure, it
is not an amazing new piece of equipment
or a revolutionary drug appearing on the
market, but it is a simple laboratory test
called PCR analysis.
PCR stands for Polymerase Chain Reaction
and is a biochemical procedure which helps
us look for pieces, or sequences of DNA.
PCR analysis can pick up tiny pieces of this
material and whether it is viable or not
(i.e. alive or dead); the analysis procedure
replicates it to produce measurable quantities
for reliable detection and identification.
Although PCR was developed 30 years
ago, its application in equine medicine
to look for disease has only recently
become readily available to all vets in
general practice.
In the human medical field it is used to look
for hereditary diseases and for paternity
testing. It is also used in forensics to look
for DNA at a crime scene or on a murder
weapon. It was indeed PCR analysis that
recently found horsemeat in our burgers.
We don't use PCR for such exciting
newsworthy matters in the equine veterinary
world but we use it for rapid disease
identification.
PCR analysis has helped us to identify
pathogens (bacteria, viruses etc) very quickly,
often in less than 48 hours. It also helps us to
identify if a horse is excreting the pathogen
and whether it could be infectious.
PCR can be used to identify a number of infections such as those causing respiratory infection
(1) and Lawsonia intracellularis (2)
Graham Hunter BVM&S GPCert(EqP) CertEP CertAVP(ESO) MRCVS,
Ardene House Veterinary Practice
Veterinary surgeon
Graham Hunter
XLVets Equine practice
Ardene House
Veterinary Practice
Paralytic Herpes (EHV-1)
The equine herpesvirus can behave like
cold sores in people, i.e. it can hide and
sit in a latent form. The virus sits hidden
in large numbers of horses but can
reactivate under periods of stress. EHV-1
can cause paralytic herpes where the
nerves of the spinal cord are attacked.
Six significant UK outbreaks have
occurred in the past 14 months and
all have involved PCR testing of the
cerebrospinal fluid giving a rapid
diagnosis and control of the spread of
this often fatal disease.
Strangles
PCR testing on swabs or washes can
very accurately and rapidly detect the
bacteria Streptococcus equi, the highly
infectious cause of strangles. The faster
the diagnosis is made the quicker isolation
can be undertaken, biosecurity measures
can be implemented to limit the spread of
the disease and reduce the number of
horses affected.
'Rattles'
Bronchopneumonia in foals can be
caused by Rhodococcus equi and is
often called rattles or summer pneumonia.
It is difficult to treat and often requires a
prolonged course of multiple antibiotics.
The speed of diagnosis in these cases
is often a crucial factor in the success
of treatment. A rapid negative result
is also important so that excessive
use of inappropriate antibiotics does
not occur.
Examples of diseases where we
use PCR testing:
PCR testing is considerably faster
and more accurate than traditional
culture techniques and has helped
us diagnose and control some of the
most important equine infectious
diseases we have in the UK.
1
2
(Photos courtesy of Celia Marr, Rossdales Veterinary Surgeons)