Tick prevention: cost versus benefit

Desperate in our search for status on a global stage, we Australians love punching above our weight in sport, and take pride in our lethal fauna. Snakes, sharks and crocodiles are the obvious ones but quietly killing from the sidelines are the tiny and unassuming, like Ixoides Holocyclus, the Paralysis tick. No other continent hosts this species of tick, and nowhere else is there an annual toll of thousands dead from  respiratory failure.  Sure, tick-borne Lyme Disease is insidious and debilitating but it’s not going to see you drowning in your own body fluids within days. Choosing the right preventative is an important decision that may save money, grief, or even a life.

 

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Choosing your tick control

Whether to use a tick preventative, which one, and for how long, will depend on your unique situation :

  • tick incidence and seasonality in your area. For Byron Bay, see here
  • pet lifestyle: contact with tick habitat, bathing and swimming
  • pet’s previous exposure to ticks, and possible partial or full immunity to tick venom
  • owner finances and attitude towards risk and insecticidal residues
  • need for a single flea and tick product

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Sources of information

When deciding what’s the best preventative, pet owners often seek veterinary advice. Vets have 2 sources of information for evaluating the effectiveness of tick preventatives:

.1. The information from Big Pharma

Manufacturers subject their products to scientific trials in which live ticks are put on dogs protected by these agents, then the numbers of live ticks counted each day. Registration of a ‘tick-control’ claim demands kill rates above 95%.  Just as humans vary in their ability to hold liquor, 1 in 20 ticks will remain standing, in the face of a slug of insecticide, and continue to feed.

The deficiency in these trials is their inability to replicate the huge number of environmental variables that impact on product performance, in the real world. Topical insecticides (collars, rinses and spot-ons) will behave differently on the laboratory kenneled dog, whose lifestyle will not include daily swimming, a variety of shampoos, 250g of beachsand migrating through coat each day, nor basking in UV radiation. These environmental effects may raise the failure rate from 1 in 20, to 1 in 10 ticks surviving.

The other variable that clouds interpretation of technical data is species of  tick used in the trial. This may seem an unimportant detail but  ticks vary markedly in sensitivity to insecticides. The same tick collar that’s registered to kill the Brown Dog tick for 6 months, wont protect again Paralysis tick much beyond 6 weeks! This issue is particularly important when evaluating the trials of the SKUDO ultrasonic pulse device, tested in Italy..

2. Anecdotal reports from pet owners, other vets, and our own experiences

These are less scientific and can’t be over-interpreted when there are so many unknowns. When a tick product works, killing a tick before the venom has an effect, vets never hear about it. When a tick-affected animal is brought to the clinic, however, vets have an opportunity to get the dirt on what’s not working, under real-world conditions. While the majority of such pets have received no prevention, or a product that expired weeks or months previously, those with correctly applied product can give us an idea of failure rates.

PRODUCT FAILURE

What constitutes product failure? Simply, a pet developing symptoms of tick paralysis while on a correctly applied preventative.

Given tick preventatives rarely repel, finding a tick attached to your pet may not amount to failure. It may be gravely unwell or already dead. Most products aim to kill within a short time after ticks start feeding. As it takes a couple of days before tick venom causes symptoms, this is OK. In fact, in terms of tick immunity, allowing small numbers of ticks to briefly feed, and sub-clinically expose your pet to tick venom, is ideal.

Of the tick preventative failures I see when admitting tick-affected animals, I’d guesstimate about 80% are spot-on failures, and 20% tick collar failures.

Vets and nurses are rarely surprised to hear of failure of spot-ons, whereas failure of a tick collar will usually raise an eyebrow.

With both spot-ons and collars, product failure is often associated with frequent swimming, even if the collar is removed at the beach. Tick collar failures are more likely in the 5th week of use, when nearing expiry.

Superficially, this may seem as if tick collars are 4 times more reliable than spot-ons. However, as the total number of animals treated with each preventative is unknown, this comparison can’t easily be made.  Spot-ons are also more prone to pet owner mismanagement; fortnightly is easier to get wrong than changing a collar every 6 weeks.

The industry could resolve this matter: drug manufacturers or distributors could tally the number of weeks of protection sold of each agent, in one year, and vets report on product failure (number of dogs with clinical signs of tick paralysis, while using preventative according to manufacturers instructions). Such large scale co-ordination isn’t likely any time soon. Until then you’ll have to rely on anecdotal reports from under-resourced local vets like me.

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Tick prevention options

These can be used alone, or sometimes in combination, depending on the tick load. Peak season may demand several, low season maybe just one, or none.

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1. Tick Search

If you’re religious with daily rituals, your pet’s coat is short, and you know what to look for, manually removing ticks is free, quick and non-toxic.  A thorough search can be as short as 2 minutes  or up to 45 in a Malamute.  Seasonal clipping of long coats will speed up tick searches. Dogs usually love the attention and tickle; cats will tolerate if trained.

85% of ticks attach on the head, neck or armpits of the animal with a special preference for lips, eyelids and earflaps, while the remainder can be anywhere, including down ear canals, between toes, and very rarely in oral and rectal cavities.

If you find one, remove it using your favoured technique and look for more. Before you pull it off, ensure it’s actually a tick. Vets too often see terrified and confused dogs with a nipple, injured and bleeding.

There is always the risk that one may be missed but given it’s several days before the venom will have a significant effect, if done regularly enough, you will have a second or third chance. Given the failure rates described above, all drug companies recommend daily tick searches to dodge legal responsibility in such an event.

If your pet develops symptoms of tick paralysis, even if your using a preventative, you should immediately start a search while calling the emergency vet.

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2. The ‘SKUDO’ ultrasonic pulse device

Recently marketed and sold through pet shops, proporting to repel both ticks and fleas, this is the latest electronic device to claim control of pests. Outside of our hearing range, to the tick (and the dog) it’s like a miniature, wailing, car alarm, dangling from the collar.

There’s an Italian scientific paper out there, supporting their claims, but  there are flaws in it’s recommended use for Paralysis ticks in Australia.  If you wanna believe the SKUDO claim, use it on your dog, challenge him with ticks and fleas, and report back to me.  For a more thorough critique of the Skudo Study, see here.

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3. Spot-on treatments

Unlike Advantage®, Advocate® and Revolution®, which kill fleas but not ticks, Frontline Plus® and Advantix® are the only spot-ons registered for tick control. They must be applied every 2 weeks to be effective, twice the recommended frequency of application for fleas (monthly). Concentrations of insecticide on the skin only reach tick-lethal levels after the second application.

Like the other topical preventatives below, they are vulnerable to failure under adverse environmental conditions: water, shampoos, UV and sand migrating through the coat.

The other reason for spot-on failure is pet owner compliance: not following manufacturers instructions. Given their expense, some owners stretch out the 2 week dosing to every 3-4 weeks. Effective concentrations in the skin are not reached until the second fortnightly application,  so less frequent application may never result in full tick prevention. For more information on offsetting the cosgts of spot-ons see Splitting Vials: risk minimisation.

Advantix® is highly toxic to cats and shouldn’t be used on dogs in households where the inter-species bond is strong and intimate.  See comments on toxicity below.

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4. Tick rinses

These are old-fashioned OP’s or synthetic pyrethroids, diluted and poured on your dog twice weekly, or sprayed on daily. They also kill fleas. They have some deterrent activity.  Used so infrequently for ticks these days, it’s hard to get an impression of efficacy. See comments on toxicity below.

5. Tick collars

These plastic collars, coated with powdery residue, last about 5-6 weeks (Kiltix®, Preventic®). At about $14-$18 they easily represent best bang-for-your-buck in terms of cost per week of protection. The downsides: your dog will smell like an industrial chemical for the first 2 weeks of the cycle.  See comments on toxicity below.

6. Proban®

This is an insecticidal drug, given by pill given every other day, that circulates in the bloodstream and poisons the tick when it starts sucking blood.  The dose needs to be calculated on an accurate body weight to avoid under or over dosing. If a problem arises with Proban®, it’s more usually due to toxicity to pet rather than failure to kill a tick. See comments below.

Organophosphate and synthetic pyrethroid toxicity

If the flea is considered a soldier, a Paralysis tick can be looked upon as a tank. Insecticides targeting ticks need to be stronger and in higher concentrations to be effective. This is why the OP’s continue to feature commonly in tick preventatives, despite being phased out of flea products.

This class of insecticide, together with the synthetic pyrethroids, are toxic to both host and parasite, and must be dosed to kill the tick, not the pet.  Anti-tick dose rates are right at the upper limit of dose tolerable to a healthy animal.

Caution is needed when using products in combination, or in the young, old, and liver-compromised. If you put a tick collar or rinse on your old dog or give Proban to a cat, and she goes off her food, seems groggy and lethargic or, worse still, starts twitching or vomiting, stop treatment straight away and speak with a vet.

Even if your dog or cat seems to be OK  when given these drugs, there can be hidden impacts on the liver and nervous system. If you dog develops weird neuromuscular weakness the vet can’t explain, that looks like tick paralysis but drags on for weeks, stop the Proban and rinses!

All cats are highly sensitive to toxic effects of these insecticides. The recent push of a synthetic pyrethroid into the tick prevention spot-on market has seen a climbing death toll, and calls for better warning labels and reporting of adverse events from feline practitioners around the country.

Even cats that just hang out with dogs can be fatally poisoned, which should prompt us to scrutinise our own contact with these chemicals. While humans  don’t suffer the same grooming compulsion and liver-enzyme deficiency that predisposes cats, regular contact in the home or workplace (vets, nurses) may be a long-term concern.  These insecticides may be fine when applied to an outdoor dog; intolerable on those that sleep with the kids.

This class of drugs persist in the environment, are not removed by water treatment, and are highly toxic to aquatic ecosystems. Even just brief and occasional swimming in the dam may wipe-out your entire native fish and yabbie population. If you have a fish farm you should even bring them on to the property.

All this being said, if you live in an area plagued by Paralysis ticks 6 months of the year, it becomes a process of weighing the risks of toxicity against the benefit of preventing a life-threatening episode of tick paralysis.  Vets and pet shops sell thousands of these products, and may only see a couple of problems with toxicity each year.

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Recommendation

Cat owners living in tick territory have a tough decision. The options are: tick searches; Frontline Plus® applied fortnightly (expensive and prone to failure); or Proban® (near toxic to your cat). If the cat has long hair and lives outdoors you may end up relying on immunity, which can be a dangerous thing.  Advantix is highly toxic to cats and can’t be used.

Dog owner, strapped for cash, and living in a tick prone area?  Best get a short-haired breed and rely on tick searches, collars or regular rinses.  Buy 4 ticks collars at the beginning of the tick season, and change them religiously, every 5 weeks, for peak  season. A $60 investment may save you $600 in tick paralysis treatment.

If you enjoy a close relationship with your pet, you’re offended if she reeks of an industrial chemical, or can’t cope with child’s cheek pressed close to tick collar during puppy cuddles, spots-ons may be preferable to collars and rinses. Applied fortnightly, this choice may treble the annual tick-control budget however, and they seem more vulnerable to failure.

Although Proban® is of very low toxicity to family members, by locking it away in your pet’s bloodstream, you’re essentially outsourcing any toxic impact to the animal.

If you’re a Trekkie and totally believe in technological salvation, go for the SKUDO ultrasonic device. Just make sure you know the early symptoms of tick paralysis and seek medical attention when things turn pear-shaped.

If you want to use a single agent to kill both fleas and ticks then use either Advantix® or Frontline Plus® every 2 weeks, or flea rinses twice weekly, or Proban® every other day.  Tick collars don’t seem to work well against fleas.

Holidaying in a tick area?

  • The Dangers: your dog will have little or no immunity, and family members may be unfamiliar with searching for ticks, and the symptoms of paralysis.
  • Tick preventatives need to be started before you leave home, to achieve protective levels. Two weeks for spot-ons, one week for others.
  • Ticks can wander for up 7 days in the coat, like a flea, before finding their ideal site to suck blood. This means continuing tick control for 2 weeks after returning home.

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5 Responses to “Tick prevention: cost versus benefit”

  1. jessica says:

    I’m sorry Matt but you are incorrect regarding tick prevention in cats. Currently the only approved tick prevention method for cats in Australia is Frontline Spray, applied to the cat every 3 weeks (and by applied I mean sprayed all over the cat and left to dry). Frontline Plus Spot-On, used every 2 weeks, is no longer recommended by the manufacturers for tick prevention in cats and Proban should definitely not be used. (As a side note, I have personal experience with fortnightly Frontline Spot-On use not being effective against ticks on cats).

    Please feel free to confirm what I’ve said with Merial (makers of Frontline) and the Australian Veterinary Assosciation.

  2. matt says:

    hi jess, you dont have to apologise, happy to stand corrected.

    i moved this comment to this post as its probably more appropriate here. Many this season would contend that frontline top spot and even advantix applied fortightly is also ineffective in dogs. I can think of three recent cases of tick paralysis in dogs on which owners dutifully applied these preventatives on time.

    Yes, proban is not good for cats, sometimes in the short, and always in the long term. But some owners are forced to balance risk. If their cat is a long haired, hands-off farm cat, that wont tolerate full body spray without sedation. Proban may stave off a fatal case of tick paralysis, and buy some good quality life before hepatotoxicity kicks in.

    During the 90′s cythioate/proban was more commonly used in cats and i would comment:
    I guesstimate I’ve encountered at least 20 cats recieving over the years.

    Rarely were they vet initiated.

    Many were owners who had lost a cat or suffered near fatal tick incidents and viewed it as the pragmatic answer to ‘better of two evils’ dilemma.

    I havent observed a case of proban failure in a cat.

    The only ADR was one cat that was transiently inappetant and returned to good health on discontination. There are undoubtedly more catastrophic misadventures than this, as there are for NSAIDs etc.

    This is, of course, all still anecdotal but it adds depth to the debate.

    On a side track, in terms of toxicity, advantix aint so good either. Recently i did repeated liver profiles on 2 border collies at induction of fortnightly advantix, on owners request. Female , aged 6, and male 6months, zero and 6 weeks. While the juvenile had no significant changes; the ALT increased from 32 to 154 in the older bitch. Results below.

    I could not reassure the client that, although such changes didnt represent any immediate threat to the dogs welfare, there would not be secondary pathology and/or insufficiency in the long term.

    Her last dog died of liver neoplasia after years of religious flea and tick control and she blames herself to some degree. In her case, I would agree, proban and collars should be ruled out, probably advantix, leaving only fipronyl. Given its recent failure rate, that choice may run the risk of life threatening tick paralysis.

    what to do?

    Pre advantix

    VETNOSTICS COMMENT
    No significant changes. Dr Brett Stone

    VETNOSTICS
    SERUM CHEMISTRY
    Bilirubin 2 umol/L (0-10)
    ALT 32 U/L (0-80)
    GGT < 5 U/L (0-5)
    Alkaline Phosphatase < 10 U/L (1-120)
    Protein 65 g/L (55-78)
    Albumin 37 g/L (22-36)
    Globulin 28 g/L (25-40)
    Albumin/Globulin Ratio 1.3

    Post 3 fortnightly advantix

    VETNOSTICS COMMENT
    Mild hepatopathy. Dr Brett Stone

    VETNOSTICS
    SERUM CHEMISTRY
    Bilirubin < 2 umol/L (0-10)
    ALT 154 U/L (0-80)
    GGT < 5 U/L (0-5)
    Alkaline Phosphatase 14 U/L (1-120)
    Protein 61 g/L (55-78)
    Albumin 36 g/L (22-36)
    Globulin 25 g/L (25-40)
    Albumin/Globulin Ratio 1.4

  3. Jessica says:

    Thanks so much for the extra info Matt – all VERY interesting. I had no idea how toxic some of these chemicals are, which was very naive of me. I see you have mentioned long-haired cats a few times, are they less prone to ticks attaching? If so, my persian cat is very unlucky as she’s had tick poisoning twice now (the second time she was being dosed fortnightly with Frontline Plus). She is now a strictly indoor cat.

    Someone told me that ticks can ‘float in the breeze’ so even a cat on an enclosed balcony is at risk. Does this sound plausible to you?!

    Have you ever encounted a dog or cat with tick poisoning who had been correctly dosed with Frontline Spray?

    Sorry for all the questions!

  4. matt says:

    Long haired cats present 2 problems:
    1. their coat makes manual tick searches less effective. There is simply more hair to hide amongst.
    2. The greater the coat surface area, the more topical insecticide required to acheive toxic levels throughout. Its hard to get frontline spray deep down into the coat or on skin with a thick persian.

    Both these factors will tend to make long haired cats and dogs of greater risk of tick paralysis. Ticks are part of the spider family, and they climb, or are carried on animals up into trees. They dont fly on the wind with web like other spiders, but they will drop on humans and animals from above ( personal experience with this).

    I havent encountered a frontline spray failure but, to be honest, the all over spray isnt used very commonly, so it’s hard to say.

    Sorry to hear of your loss. It understandably adds to your frustration surrounding tick prevention.

    cheers
    m

  5. Kerry Shqrman says:

    An excellent and comprehensive article that presents a balanced viewpoint on tick and flea prevention.Thanks so much for an easy to understand report. Will be book-marking for future reference.

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