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Further comments on diagnostic testing for Avian
Flu and other diseases of livestock
Letter to the editor from
Roger Breeze
CEO Centaur Science Group, a science consulting
forum,
Washington DC, USA
Formerly Director, Plum Island USA Department of Agriculture
Filed 12 Apr 06
©www.land-care.org.uk
Dear Dr Irvine,
The rapid PCR tests that USDA invented for FMD, classical swine
fever, avian influenza, Newcastle disease and others in 2000-2001
are single tests - they were designed to test one animal sample
for one pathogen at a time. Almost unbelievably, five years later,
these single tests are not yet formally recognized as the benchmarks
for disease diagnosis by veterinary regulatory authorities in North
America, Europe and the International Office of Epizootics. And
the significance of the fact that the foot and mouth and classical
swine fever tests will find infected animals 2 to 3 days before
they show clinical signs of disease seems to have escaped most animal
disease control agencies.
I recently proposed in this forum (1)
that Scotland should invest in 9 or 10 RAPID PCR machines for
avian influenza and other foreign animal and poultry disease detection
at regional labs. This machine can test over 30 samples at a time
for the same disease or for several diseases using the single PCR
tests. It was not my intention to suggest that this should be the
only national investment to drive detection and diagnosis closer
to the point of need on the farm: the March of Technology is inexorable
and we are about to see waves of new devices and test technologies
come onto the commercial market (although not the market for critical
diagnosis of the world's most dangerous livestock diseases, which
is satisfied with the technology of our grandfathers).
Specifically, I must draw attention to the imminent availability
(2006) of a test cassette format (the machine has been on the market
for some time) that will allow a sample from a single animal to
be tested by real time PCR for up to 12 disease pathogens simultaneously
in about 20 minutes (this is known as multiplex testing). This machine
is about the size of a small loaf of bread and operates when slung
over the shoulder or in a moving vehicle. It is ideally suited for
investigative use on farm or at the site of the dead swan. The
PCR tests, cassette format and device are state of the art for the
U.S. military on land, sea or air, or underwater. Later this year,
a further investment of about 300,000 pounds would provide this
mobile detection capability via staff of the 9 veterinary investigation
labs for on-farm diagnosis throughout Scotland. One might choose
a standard test cassette that detects the 12 most important
foreign livestock and poultry diseases threatening the UK or species-specific cassettes
that detect the 12 most important infections, foreign and domestic, of
swine, poultry, etc.
What's alarming about failure to deploy rapid PCR tests even to
regional diagnostic labs since 2001 is that technology has moved
on significantly while nothing was being done. The means to detect
on the farm has got even better since 2001 - it did not disappear
just because responsible officials had their heads in the sand hoping
it would go away. We cannot afford to find ourselves in 2012 still
waiting for officialdom to formally approve the technology I just
described above. Just remember when you hear scientific experts
telling you that it is not possible to detect avian influenza with
real time PCR in the regional Scottish diagnostic labs today that
the next generation of on farm test capability is now coming to
market (you will be able to buy it to detect the most dangerous
viral and bacterial biological weapons threats to people in Autumn
2006, including avian influenza H5N1) and the generation beyond
that is emerging from research laboratories.
Finally, let me apologize to the staff of the 8 SAC regional veterinary
diagnostic centers. I have been gone from Scotland almost 30 years
and didn't know where the regional vet labs were located but
my proposed locations were not far from the mark. Of course, as
a Glasgow graduate (2) I naturally assumed that
the mother city would be the epicenter.
Best Wishes,
Roger Breeze
©www.land-care.org.uk
References
1. Breeze, Roger (2006). The management of Avian
Flu H5N1: If not us, who? If not now, when?
See ANIMAL HEALTH - GENERAL - Homepage, filed 07 Apr 06,
www.land-care.org.uk Click Here to View
2. Roger Breeze got his veterinary degree
in 1968 and his PhD in 1973 from Glasgow University, Scotland. He
taught in veterinary pathology at Glasgow from 1968 to 1977.
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