Ticks


The BTHG would like to thank Merial Animal Health Ltd, the makers of Frontline, for giving permission to use photographs from their publication “Under the Microscope – A Guide to Canine & Feline Ectoparasites”.



The Tick Life Cycle.


Ticks are mainly found in areas of rough grazing, e.g. moorlands and heaths, and in woodlands but they are also known to occur in parks and gardens.


With the prospects of warmer, more settled weather during spring and early summer there is the opportunity to go further afield when walking our dogs. The possibility that such walks may be over tick-infested land, and knowing that whenever the situation arises, the Bedlington will indulge in its passion for rooting around in hedge bottoms and ditches, the possibility that they may be infected is increased.


There are several species of ticks that may affect dogs, the most common of which are the Sheep Tick, the Hedgehog Tick and the Dog Tick. Surprisingly, it is the Sheep Tick that is seen most frequently on dogs.


Each of these three species of tick has a 3-year (3 host) life cycle.  In order to progress through each stage of its life cycle (larva, nymph, adult and sexually mature adult), the tick must take a feed of blood from a warm-blooded animal.

 

Our concern is that this feed of blood may be from the dog …… or its owner.




Life Cycle of a 3 Host Tick



Ticks (adults, larvae and nymphs) are temporary parasites and only spend a relatively short period of time feeding on their host (a few days each year) – this is the parasitic stage. During the inter-parasitic stage the ticks lie dormant in the damp, humid conditions found in the decaying debris at the base of the plants.


As the temperature rises in the spring, newly emerged adults migrate upwards to the tips of the grass leaves and ‘quest’ for a host animal (from our point of view, the dog). Once on the host, they attach themselves by means of their mouthparts and gorge themselves with blood. Although mating can occur on the ground, it usually takes place on the host within a short time after feeding.  Once fertilised, the female ticks subsequently feed for about 14 days and become engorged with blood after which they will drop to the ground and commence to lay from 1000 - 10000 eggs before dying.  The male adult ticks die relatively quickly.

 

Although a tick problem can occur at any time throughout the warmer months of the year, it is generally recognised that the main period of activity is in late spring (the so-called ‘spring rise’ - March-June) with a smaller, but still significant peak of activity in late summer (the so-called ‘autumn rise’ - August-November).  In Britain the “questing behaviour” begins with the “spring feeding” ticks when the mean day-night temperature exceeds 10º and ends with the “autumn feeders” when the temperature drops below 10º. The warmer, drier conditions in mid-summer tend to restrict the ‘questing activity’ of ticks.




 




                                          An Adult Tick                                       Engorged Adult Female Ticks



Under suitable conditions the eggs hatch into larvae. These larvae attach to a host and feed for 2-12 days before falling to the ground to metamorphose into nymphs that, in turn, attach to a host and feed for 3-10 days. The nymphs then detach and fall to the ground where they change into adult ticks and the life cycle begins again – the start of a new generation of ticks.




A Tick Larva



Ticks normally, but not exclusively, adhere to the underside of the dog, particularly the areas between the legs and the body, e.g. the groin, or around the muzzle, ears and neck. Owners should develop the habit of regularly examining their dogs whenever they have been exercising in areas where there may be a tick problem. Unfortunately, with the exception of adult females, which may be up to 1 cm in length when fully engorged, ticks are not always easy to find - larvae (“pepper ticks”) are less than 1 mm in length and nymphs are less than 2 mm in length.  Incidentally, adult male ticks are only 2-3 mm long.


Initially they may be mistaken for warts but on closer examination the legs can be seen underneath the body next to the skin.


The effects that ticks may have on their host are associated with the way in which they feed. In order to feed, the tick bites through the host’s skin and ‘injects’ saliva containing, amongst other things, an anticoagulant to prevent the blood from clotting whilst it is being ingested. Micro-organisms may also be injected. The physical penetration of the skin and the injection of saliva may cause a localised skin reaction at the attachment site, i.e. swelling and irritation. The dog may inadvertently rub/scratch the affected area and dislodge the tick, usually resulting in the mouthparts being left in the skin. These act as a ‘foreign body’ and often result in infection and the development of an abscess or an ulcer. It is advisable to remove any detached mouthparts and if necessary your veterinary surgeon should be consulted.



Physical Removal of Ticks.


Left to their own devises, ticks will drop off of their own accord once they have finished their blood meal. This often takes as long as 10-14 days. However, most owners will prefer to remove the ticks before this happens.


In the normal course of events the effects of a tick bite are not serious providing care is taken when removing the tick to ensure that the mouth parts are not left embedded in the skin or to squeeze the tick so that the gut contents, including micro-organisms, are injected into the dog because this could result in the development of an ulcer/abscess or possible infection with disease-causing micro-organisms ingested by the tick during a previous blood feed.


a.   Carefully slide the points of thin-tipped tweezers. between the tick and the skin and’ grasp’  the tick as close to the skin as possible. Take care not to grip the body of the tick


b.   Pull firmly but gently away from the skin with an even pressure. Avoid any twisting. This should remove the tick with the mouthparts intact.


c.   Ideally, the ‘wound’ should then be treated with a skin antiseptic.


Various proprietary ‘tick hooks’ and forceps can be purchased to aid the removal of ticks and your veterinary surgeon will be able to demonstrate their use.


Methods such as the application of petroleum jelly, using a hot match, etc, are sometimes advocated by those ‘in the know’. However, these techniques are not to be recommended. They rarely work and can aggravate problems.



The use of Pharmaceutical Products.


Although the manual removal of a small number of adult ticks is a practical proposition providing care is taken, removal of larvae and nymphs is a different matter and can be problematic because of their small size. Moreover, removal of ticks from such places as the eyelids, nose, etc can be difficult, not least because of the need to adequately restrain the dog.


There are pharmaceutical products, available through the veterinary profession, that can be used to treat affected dogs or, more importantly, to prevent infestation. Currently, there are various types of veterinary product licensed for the control of ticks, i.e. spot-on preparations, sprays and an acaricidal collar. Your veterinary surgeon will be able to advise on the suitability of different products.


Note:-


For the Pet Travel Scheme (Pet Passport), dogs travelling back to the UK from an approved country must be treated for ticks using a treatment licensed for use against ticks and which has a marketing authorisation in the country of use. An acaricidal collar is not acceptable. Full details of the Pet Travel Scheme can be obtained from the local Animal Health Divisional Office or on the DEFRA website at: www.gov.uk/take-pet-abroad



Warning - Zoonoses (diseases of animals that can affect people).


Ticks may be infected with micro-organisms that may cause illness in humans if they are bitten by an infected tick. Lyme disease, caused by a bacterium, is the most common tick-transmitted zoonose to be encountered. Your GP should be consulted if you experience flu-like symptoms + a pink-red circular ‘spot’ with and inflamed ‘border’ at the site of the tick bite.  




Summary of Report.

on

The Prevalence, distribution and risk associated with tick infestation of dogs

In Great Britain



A report on research into the incidence of tick infestations in dogs has recently been produced by the University of Bristol's Veterinary Parasitology Group and published in the Journal Medical and Veterinary Entomology.


The main findings were:


1.  It was found that the average frequency of tick infestation in all dogs examined between March and October was nearly 15% .  The results suggest that the risk of tick infestation is far higher in dogs than was previously thought. This has serious implications for the incidence of tick-borne diseases and is a timely reminder of the vital importance of tick treatment in pets.


2.  Over 72% of the ticks were identified as sheep ticks and nearly 22% were hedgehog ticks. However, 5 cases of the European meadow tick were also found in West Wales and south-eastern England.   This is a tick species previously only found in continental Europe and there is concern that this particular species of tick is becoming established in Britain.  In Europe, this tick is responsible for transmitting a form of babesiosis and scientists have warned that this and other new strains of disease may be introduced from the continent. The presence of this “new” species is thought to be a likely result of increased animal and human movements around the world, as well as the changing climate.  


3.  Gundog, terrier and pastoral breeds were more likely to carry ticks, as were non-neutered  dogs


4.  Dogs with shorter hair were less likely to have ticks.


5.  Dogs were most likely to carry a tick in June and least likely in March.



There are many tick-borne diseases which can have a devastating impact on pets, livestock and humans and it is hoped that this research will remind pet owners of their duty towards their animals' health and welfare.


This is a timely reminder of the vital importance of tick treatment for pets both in this country and when travelling abroad. It is a particularly important message as we approach the summer when owners should be treating their animals at regular intervals.



Note:


The BVA Animal Welfare Foundation's leaflet on 'Taking your pets abroad' outlines the main diseases likely to be encountered abroad and how to avoid them.  This can be downloaded from:


www.bva-awf.org.uk  


Click on the “Pet Care Advice” tab, then on the “Pet Travel” box.  Click on “Taking your pets abroad.pdf” to read/download the leaflet.


Use of an approved form of Tick treatment is a compulsory part of the Pet Travel Scheme, in order to reduce the likelihood of exotic ticks entering the UK.  Consult with DEFRA if you are considering taking your dog abroad.






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