Talk given to Dairy Goat Society of Australia , Qld branch 30 June 2012 about the clinical signs, testing for and control of Caprine Arthritis Encephalitis or CAE, a lentivirus disease of goats that causes arthritis, wasting, pneumonia and nervous signs. There is no vaccine and no real treatment . Author is Dr Sandra Baxendell, PSM, BVSc (Hons), PhD MANZCVSc, GCertAppSC(RurExt), GCertPSectMgt, PGDAppSc, MRurSysMan Director, Goat Veterinary Consultancies -goatvetoz goatvetoz@gmail.com Mobile 0477 813278 Skype goatvetoz http://www.goatvetoz.com.au Twitter http://www.twitter.com/goatvet @goatvet Pinterest http://pinterest.com/goatvetoz/ Facebook http://facebook.com/goatvetoz/ LinkedIn https://www.linkedin.com/in/sandrabaxendell YouTube Channel https://www.youtube.com/user/goatvetoz/ SlideShare http://www.slideshare.net/SandraBaxendell/ Also please like this Facebook page - Let's Eradicate CAE from Australian Goats https://www.facebook.com/EradicateCAEinGoat

1. Presentation on CAE or Caprine
Arthritis Encephalitis (Big Knees or
Caprine Retrovirus)
by Dr Sandra Baxendell to the Qld branch of the
DGSA on 30th June 2012
Laidley, Qld
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2. Caprine Retrovirus or CAE Virus

= a slow virus

RNA only (not DNA, but converts to DNA within
cells)

retrovirus family (like HIV-AIDS)

Subgroup Lentivirus like sheep disease Maedi
Visna (= Ovine Progressive Pneumonia)

attached to monocytes and macrophages
(types of white blood cells) but only multiply in
the later
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3. CAE virus also found in

Cells of the udder (mammary) – also that CAE
positive goats more likely to develop bacterial
mastitis

Cells of the uterus

Large numbers of viruses in inflamed brain,
spinal cord, lung, joints, and mammary gland
cells of CAE positive goats

Smaller numbers in lung, liver, spleen, lymph
nodes, lining the vessels of brain, synovium,
intestines, kidneys & thyroid
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4. Clinical Signs

Chronic Arthritis which starts as a peri-arthritis
and progresses to deformed limbs and wasting

“Hard Udder” - udder feels like a smooth stone
under the skin with only a small amount of milk
produced

Chronic interstitial pneumonia with wasting and
difficulty breathing

Nervous signs (generally in kids)
Note most goats get only 1 form
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5. CAE is worldwide in dairy goats
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6. CAE exported from developed
countries

Australian dairy goats gave CAE to
NZ

Western countries have given CAE to
Fiji, Kenya, Mexico, New Zealand
and Peru plus probably others

Africa is generally free
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7. Risks

Feeding pooled milk to all kids

Dairy goats, rarely in fibre & ferals

Age (older goats more likely to be
positive)

Large herds

Milking & kidding herds
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8. CAE Transmission

Milk and colostrum is main source of
infection

Horizontal risk low, but still possible, if not
milking or kidding

Single intra-mammary dose can transmit
CAE – milking machines?

Some via ET but not all methods

Sheep overseas have acted as carriers
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9. Handy Hints

Wash kids when catch them at birth

Keep cows colostrum (JD free) in
freezer

Milk negative does first

Elastoplast doe's teats

Induce does within 7days of due date
so kid on weekends (ask your vet)
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10. Blood Tests in General

Precision = repeatability and
variance (bias)

Accuracy = trueness
But general public just needs to ensure use a
NATA accredited laboratory
NATA= National Association of Testing
Authorities see www.nata.asn.au
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11. Blood Tests in General 2

Sensitivity – picks up levels of antibodies so
can have false negatives in early stages or if
no antibodies produced e.g. close to giving birth
or antibody production capacity is reduced

Specificity – measures the type of antigen
so can have false positives if picks up too wide
a range of antigens
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12. CAE Blood Tests

ELISA – automated, recommended

AGID -recommended, good specificity but is
generally less sensitive

PCR - picks up viral DNA, but lentiviruses are
very genetically variable so less sensitive than
ELISA . Not a screening test nor recommended

Western Blot (no protocol, research lab only)

Radio immune types (no protocol, research lab
only)
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13. Vet Labs System & CAE

The World Organisation for Animal Health
(OIE) – the former Office International des
Epizooties - AGID or ELISA are the prescribed
tests in their Terrestrial Manual (Chapter 2.7.3

Australia and NZ's Animal Health committee's
via their lab subcommittee (SCAHLS)
recommend AGID or ELISA

Australian Vet labs should be NATA
accredited and take part in proficiency tests
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14. Animal Health Committee- Subcommittee on Animal
Health Laboratory Standards (SCAHLS)

SCAHLS = reps from Australian Government, state
and territory governments, CSIRO-AAHL, veterinary
schools at universities & the private labs

SCAHLS establishes, implements and monitors
professional & technical standards by dealing with
quality assurance, skills, & the validation of new tests.

Publishes the Australian & New Zealand Standard
Diagnostic Procedures.

Runs international proficiency testing (30 labs Aust,
NZ, USA , Asia, Europe etc)
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15. Does test type matter?
Do you ask your doctor or pathology
office what blood test type you are
going to get for yourself when getting
tested for any disease/condition?
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16. CAE blood tests

Work best in herds with high virus loads

Individual goats can give false negatives if
their immune systems are reduced in
capacity. So do not test within 1 month
either side of kidding or after vaccination
or if have clinical CAE

Goats with low virus levels can become
intermittently negative
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17. So what does this mean?

Tests need to be backed up with clinical
examination of the herd by a vet

Tests need to be considered a herd, not
an individual test; i.e. don't test just the
goat you want to buy, but ensure the
whole herd it comes from has been tested

Whole herd tests need to be repeated
initially each year
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18. The Bottom Line

CAE can be eradicated from goat
herds by catching kids for a separate
new herd and then blood testing these
kids to pick up any unlucky enough to
be positive

CAE control schemes have worked
around the world
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19. CAE Control Schemes

NSW the best

WA -CAE is no longer a notifiable
disease & accreditation scheme
stopped in 2006 as goat industry was
not interested in it when it moved to
full cost recovery.

UK – run by Dairy Goat Society not
government
©

20. Successes

Smallpox and Rinderpest eradicated from
world

Bovine Pleuro-pneumonia, TB &
Brucellosis eradicated from Australian
cattle

EBL eradicated - Australian dairy cattle '12

Alpaca and Johne's Disease

Visna eradicated from Iceland
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21. Why Bother?

Consumer perceptions

Animal welfare

More mastitis, udder infections & higher SCC

Herds viral loads will increase and more health
problems then occur

Dairy goats will become the pariah of the whole
goat industry

Sheep industry concerns re MV and CAE
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22. Warning for Goat Buyers

Both NZ and UK have warnings on their
websites e.g.
http://www.allgoats.com/health.htm#How
%20often%20should%20I%20test
NZ “ Warning to New Goat Buyers
There are a number of significant diseases that can affect
goats in New Zealand, such as Johnes Disease and
Caprine Arthritis Encephalitis (CAE). If a goat displays
signs of these diseases, it can be very distressing for the
owner..............................
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23. So could CAE be eradicated from Qld and
Australia like the Dairy Cattle Industry did with a
similar slow virus (Enzootic Bovine Leucosis) ?
YES
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24. What is needed

Clear vision with awareness campaign

Commitment to control schemes in goats

Ideally survey to determine how
widespread, but how to fund a survey?

Once a high level of control, then
eradication from states and then Australia

Ideally a bulk milk test + blood tests – but
need funding for R&D to check it works?
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25. Opportunities

DOOR = Do Our Own Research

Universities with students looking for
projects & partners

Government and their agencies with
good track record in eradications if all
parts of industry supports it

Seek allies for funding - who benefits
if CAE is eradicated?
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26. Opportunity for Qld

Queensland has only 1 goat herd
quarantined for Johne's disease,
despite lots of testing

Johne's disease is not established in
Qld sheep or cattle

If Qld could also eradicate CAE, live
export of goats could benefit
©

27. Margaret Mead quote
“Never doubt that a small group of
thoughtful committed citizens can
change the world. Indeed, it is the
only thing that ever has.”
©