NZDA H&W 198 WEB

The pathologist at work: Jim used ear plugs in his nose and a surgical mask to help
make the stench more bearable
two biopsy samples each of nose,
lung, hoof, kidney and liver tissue.
This was getting more like CSI than
NZDA!
So the next day we went early,
armed with rubber gloves, surgical
masks, scalpel and labelled sample
bottles (all provided by Sam), hoping
the cold, still conditions would
keep the smell down. I took the
external samples first, which was
fairly straightforward, but the next
step wasn’t for the faint-hearted.
Remember, the animal was diseased
and had been lying dead in the open
for two days. A pair of ear-plugs
served as nose-plugs, and a surgical
mask helped too.
I gutted the animal and took the
internal organ samples. The liver and
kidney appeared healthy but the lungs
had been destroyed by Ray’s bullet.
The lower intestine and bowel was
dry, transparent and definitely not
right. Back at Tekapo we repackaged
the samples – some “as-is” (i.e., dry)
and others in formalin – then packed
all of them into ice and sent them off
to MPI (initially to Dunedin, then
to the Wallaceville Animal Health
Laboratory, Upper Hutt). Their initial
testing confirmed orf virus (the
sheep strain of parapoxvirus), which
causes “scabby mouth” or contagious
ecthyma (see sidebar).
After I got home to the Hutt
Valley, I dropped in to the
Wallaceville lab to catch up on the
case over a coffee with Tom Rawdon.
He is part of a team who investigate
suspected exotic, new or emerging
animal diseases and pests in stock
and wildlife. He said this was a case
of interest as mouth lesions can also
be a sign of certain exotic diseases
such as foot-and-mouth.
Also, it appeared to be the
first case of scabby mouth in
tahr officially reported since
the 1960s.
The Animal Surveillance
and Investigation team
can be contacted via their
freephone number (0800
80 99 66) and if you see
anything suspicious they
would rather hear from you
than not, to discuss any
concerns and work up a plan
of action. People dealing
with animals during their
daily work (farmers, vets,
pest controllers) or recreation
(hunters, anglers, trampers)
are the eyes and ears of
animal disease surveillance.
This is extremely important
to ensure animal health
issues can be detected and
acted on promptly. It also
underpins NZ’s trade in
animal commodities, by
the transparent and timely
reporting of our animal
health status.
The MPI team is always
interested in hearing about
any new or unusual animal
health issues, especially if
more than one animal is
involved.
So the roar of 2017
turned out to be one of the most
interesting in years. It highlighted
the fact that killing an animal is
only one component of hunting.
Keen observation skills and
knowledge of animal health and
habits are also important. Hunters
are conservationists at heart, and it
Extract from the MPI report:
… Thickened skin lesions were present on
the face, affecting especially the mouth
and base of horns, and multiple sites in
the lower limbs. The horn base had similar
proliferative changes, while the horns
were in very poor condition with pieces
broken off or generally eroded, dull and
flaking. Photographs were reviewed by
the Incursion Investigator and it was
determined that the presentation was not
consistent with that of foot-and-mouth
disease, but aligned with either a parapox
or papillomatous condition.
… Fresh and fixed skin and visceral tissue
samples showed no significant lesions in
the liver, kidney or lung. The face and lower
limb lesions consisted of an excessively
folded and attenuated epidermal layer
which exhibited marked hyperkeratosis.
In areas the dermis contained many
lymphocytes and plasma cells, and
in places there were large pustules
composed of degenerate neutrophils. No
viral inclusion bodies were seen. Findings
were consistent with contagious pustular
dermatitis (Orf, contagious ecthyma)
caused by parapoxvirus.
Molecular testing excluded the presence
of exotic poxviruses (orthopox, capriprox
and leporipox), and confirmed the
presence of ovine parapox (orf virus).
The tahr had been shot in an area next to
farmland with sheep, indicating a potential
pathway for an environmental source of
parapox. No further cases were identified.
Although outbreaks of parapoxvirus in
young tahr have been documented in
the Southern Alps, this was an isolated
incident in an adult exhibiting stunted
growth (given its estimated age from the
horn length). In previous outbreaks adults
were not affected, indicating a degree
of age-acquired immunity. Possibly
the individual reported here was more
susceptible to severe or chronic infection,
given its stunted growth.
… The samples have proved very useful for
further work, given the rarity of the case.
The MPI laboratory team will carry out full
genome sequencing of the parapoxvirus
detected here. The work will also enable
detailed comparisons of the virus with
deer, sheep and chamois parapox viruses.
is in our own best interests to assist
government departments like DOC
and MPI in order to manage the
health of our game animals. We all
commented that helping with this
unusual case made us feel good, and
it would not stop us tahr hunting
again. Neither should it discourage
you!
NZ Hunting & Wildlife 198 - Spring 2017
47