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| Ticks are a major cause of morbidity and mortality (illness and death), and they're out in force again this year. |
Tick
season is well and truly here. The potential negative impact of the paralysis
tick cannot be underestimated: not only is the paralysis tick responsible for
hundreds, if not thousands of deaths along the East Coast of Australia, it also
causes significant suffering.
Dr
Rob Webster is a veterinary specialist and director of the Animal Emergency
Service in South East Queensland, aka tick central. He has seen more cases of
tick paralysis that any vet I know, often at the more severe end of the spectrum.
Tick
paralysis is preventable, but Dr Webster and colleagues argue that everyone –
veterinarians, nurses and pet owners – need to be more proactive about giving
ticks the flick.
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| Dr Rob Webster and patient. |
How commonly does
your clinic treat tick paralysis?
We
have four emergency vet practices in South-East QLD and each of them treats
2-10 primary accession cases of tick paralysis each day from September to
January. We have mechanical ventilation capability at each of the hospitals and
usually there is at least one patient receiving mechanical ventilation at all
times during ‘tick season’. We have had up to 5 patients being ventilated at
the same time. We had a significant decrease in tick patient numbers in 2015,
and fortunately it looks like the trend will continue this year.
Why can ticks present
such a diagnostic challenge?
Tick
cases are challenging because of the multi-systemic effects, which may develop
before paralysis, and the difficulty in confirming the diagnosis.
Tick
paralysis patients may present with disorders of the gastro-intestinal system
(vomiting/regurgitation/gagging/choking), the respiratory system (pneumonia,
upper airway obstruction), and the neuromuscular system
(ataxia/paresis/paralysis). These signs are often mild on initial presentation
and don’t prompt the clinician to think immediately of tick paralysis.
I
think most of the PR and professional problems ticks cause for vets occur
because the disease goes from difficult to diagnose to very easy, when the
patient becomes paralysed. Owners may make the diagnosis at home themselves
when they find a tick after a trip to the vet, or even worse take the pet to
another vet where the tick is found straight-away. This makes the vet appear
unprofessional: How difficult can it be to find a tick?
I
think the most important thing vets can do is continually emphasise to clients
that it is impossible to consistently find all ticks in a pets coat. We need to
put the onus back on owners to use tick prevention.
You work in an
emergency clinic that sees emergency as well as referral cases of tick
paralysis. How severe can it get?
Patch
was a young Dalmatian with grade 4D tick paralysis who had cardiac arrest
during treatment. He was ventilated for 120 hours, recovered with persistent
neurological deficits and took 6 months to walk again.
Tick
paralysis is horrible. I have no doubt it is the leading cause of preventable
deaths in pets on the East Coast of Australia, it costs owners a heap of money,
leads to frequent board complaints, and contributes to professional burn-out
amongst veterinary staff who dread ‘tick season’.
Let’s
eliminate it!!
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| Someone in this photo is contemplating a treat! |
What are the
potential secondary and long term problems associated with tick paralysis?
The
most important secondary problem is aspiration pneumonia. The high prevalence
of this complication in dogs with tick paralysis, makes the condition much more
challenging to treat. If dogs didn’t aspirate the condition would be much
easier to treat and more predictable in outcome. Pure NMJ paralysis patients
are also much easier to ventilate in severe cases. I think the predominant
difference between dogs and cats with tick paralysis is the prevalence of
pneumonia (dogs>>cats), and consequently cats have a much higher survival
probability in early stages.
Figure1. Histological lung section from a healthy control
dog. (H&E; Bar = 140 μm.)
Histological lung section a dog euthanased due
to tick paralysis showing severe neutrophilic bronchopneumonia with evidence of
aspiration pneumonia. In addition to prominent exudation of neutrophils in
alveoli and airways, there is extensive necrosis with obliteration of
bronchioles accompanied by numerous bacterial colonies. (H&E; Bar = 140 μm.)
From: Webster, Mackie et al Aust Vet J 2013;91:306–311
Long
term problems are not well documented. There is a chance of sudden cardiac
events (purportedly due to prolonged Q-T interval), during the weeks after the
discharge from hospital.
Some owners
report that working dogs are never quite the same after tick paralysis, lower
energy levels and never quite as athletic; but no studies have been performed
into this aspect of the disease.
Have newer tick
products made a noticeable impact on the incidence of tick paralysis? Why do
you think this is?
There
has been a significant reduction in tick patient numbers (dogs) at my practice
in 2015, and this trend is continuing in 2016. Anecdotally, every other practitioner
I’ve spoken with reports the same thing. I believe that the availability of
effective prevention has been key in the reduction of case numbers. Not only
does [Bravecto] work but more clients are using it.
What can
veterinarians do to reduce the incidence of tick paralysis cases?
Talk
to every client about the severity of tick paralysis, and the high prevalence
in certain geographical regions. ‘Tick paralysis’ doesn’t describe the
suffering and pain caused by this disease. Explain in detail the suffering it
causes, the high cost of treatment, and the fact that dogs die by suffocating
on their own vomit.
Sell
Bravecto (or alternate effective prevention) to every client with a dog in tick
areas. Point out that almost every veterinarian uses an isoxazoline on his or
her dog.
We
need to put the responsibility for tick prevention back on the client. We
stress over tick patients, we suffer with them, we agonise about the decisions
we make in their management (when there are often no good decisions to make).
We often discount the bill- not charging for our time and angst, which impacts
all aspects of our lives. We need to be able to say to clients: ‘You can
prevent this. If your pet develops tick paralysis I will do my best, but this
is a severe disease, and it could kill your pet. Treatment is expensive. Don’t
neglect to use prevention then complain later’.
Vets
need to paint a picture of paralysis ticks as the Grim Reaper. Keep him at bay
by using prevention.
Thank you Dr Webster. Professor Richard Malik is another veterinarian calling for more action on the tick prevention front. You can read his article in The Conversation here.
Declaration: Dr
Webster is promoting the product Bravecto, but there are alternative tick
preventatives available. Please consult your veterinarian for specific advice.
