Two Papers by Toni Bunnell PhD
This article is based on a paper originally published in the Journal of the American Holistic Veterinary Medical Association, July 2000, Vol. 19, No.2, pp 29-31.
As a researcher with a doctorate in polecat behaviour (Mustela putorius) behaviour, I have become very involved over the past four years with the rehabilitation of wild hedgehogs in the York area. I now take the majority of animals taken to the York RSPCA animal home by members of the public. In the current year (2000) this has amounted to over 70 animals to date, the situation being exacerbated by recent extensive flooding in York and the countryside, resulting in the evacuation of the animal home by the army and fire rescue services.
As I am solely responsible for the care of each hedgehog, from the day it arrives to the day it is released into the wild, I have a unique opportunity to collect detailed data without any break in continuity. The lack of opportunity to collect data on a daily basis inevitably occurs in animal homes when different staff are involved in day-to-day care. Over the past three years I have collected data on nearly 200 hedgehogs, including frequency of particular diseases and injuries found in animals presenting for treatment. Current success rates stand at 85%, nestlings being easier to progress to release status compared with juveniles.
Of the many types of ailments affecting hedgehogs, ringworm and sarcoptic mange were variously present amongst young and adult animals alike. Ringworm is a fungal infection and is fairly common in hedgehogs where the immune system is compromised. Hedgehog ringworm (Trichophyton erinacei) often presents as crusting of the skin layer on the rim of the circular orbicularis muscle, the 'ring' of muscle that contracts enabling the hedgehog to curl up into a ball. Crusting is also often found on the face where it starts on the nose. Veterinary treatment typically consists of oral administration of grisovin (25-30 mg/kg orally every 24 hours), which can be sprinkled onto food. The treatment is generally effective but slow to take effect, with accompanying increased susceptibility to pathogen invasion during this time.
Sarcoptic mange, a skin disease produced by the sarcoptid mite (also responsible for scabies in humans) presents as crusting and surface skin lesions as the mite tunnels into the skin. Some of the symptoms are similar to those seen with ringworm infestation. Mange can also result in heavy spine loss and subsequent increased vulnerability of the hedgehog to predators. Treatment typically consists of weekly subcutaneous injections of ivermectin (0.4 mg/kg) over a period of three weeks or more, in an attempt to eliminate all stages of the life cycle (mites, larvae and eggs). Both sarcoptic mange and ringworm may be accompanied by appetite loss, reduced food assimilation from the alimentary canal, and a general decrease in health status of the animal.
Te Tree antiseptic cream is commonly used in Australia for the treatment of scabies in humans. As the same mite is responsible for both scabies and sarcoptic mange, I decided to try Tea Tree cream on affected hedgehogs. After dripping cream onto the affected area, a noticeable improvement was evident within 24 hours, with new spines appearing on previously bald areas affected by mange, and new skin growing on areas previously covered by the lesions associated with ringworm. This treatment was repeated three or four times, depending on the severity of the infestation. New spines continued to grow in hedgehogs affected by mange and ringworm respectively. This treatment had now been used successfully with eight hedgehogs. In each instance veterinary treatment was not necessary, weight gain increased, and no return of either skin disease occurred.
Tea Tree antiseptic cream is harmless, relatively cheap, and easily obtainable from most health food shops. The use of the cream in these circumstances is preferable to standard treatment as it is more effective, and also less stressful to the hedgehog which does not require any injections.
I would like to express thanks to Keith Warner (MRCVS) a veterinary surgeon at the Minster Veterinary Practice in York, England, and Dr Huw Griffiths, Department of Geography, University of Hull, for invaluable help and discussion of this work.
Brockie R.E. The hedgehog mange mite Caparinia tripilis, in New Zealand. N.Z..Vet.J. 22: 243-247, 1974b.
Keymer I.F., Gibson E.A. & Reynolds D.J., Zoonoses and other findings in hedgehogs (Erinaceus europaeus): a survey of mortality and review of the literature, The Veterinary Record, March 16: 245-249,1991.
The Mammal Society, The state of British mammals, The Mammal Society: 1-4, 1999.
Reeve, N., Hedgehogs, T. & A. D. Poyser Limited, London: 1-313, 1994.
Robinson I. & Routh A., Veterinary care of the hedgehog. In Practice, (March):128-137, 1999.
Smith, J.M.B., Diseases of hedgehogs, Vet. Bull. 38: 425-430, 1968.
N.B. Since this paper was published the general consensus of opinion regarding treatment of tick infestation in hedgehogs has changed. It is now (2009) no longer always considered safe to use Frontline spray, particularly when a hedgehog has breathing difficulties. Also, it is considered to be dangerous to the hedgehog to apply oil to ticks. While, this method undoubtedly works, by blocking the breathing holes of the tick, it is also purported to cause the ticks to empty their gut contents into the hedgehog, which will include any pathogens. This could have a damaging effect on the hedgehog.
The hedgehog tick: Ixodes Hexagonus
The commonest form of tick to be found on the European hedgehog is Ixodes Hexagonus (Morris 1977, Stocker 1987, Keymer et al 1991, Reeve 1994, Sykes et al 1995). A tick is an arachnid and an ectoparasite. It appears light grey in colour, darkening as it fills with blood, and falls off the hedgehog's body when fully engorged. Ticks are found attached all over the body, most commonly behind the ears, round the neck and at points along the underside where the spines are replaced by soft hair. Smith (1968) comments that almost every wild hedgehog caught is infected with one or more ticks. I have not found this to be the case, the majority of sick hedgehogs presenting for care at my sanctuary being totally devoid of ticks (Bunnell unpubl.). However, the appearance of ticks on a hedgehog does appear to be symptomatic of disease or injury, the number indicating the state of health of the animal. On one occasion I removed 199 ticks from a juvenile which subsequently died a week later.
Typical veterinary treatment for ticks is Frontline spray (Fipronil 0.25% w/v). This product is licensed for treatment and prevention of flea infestation with cats and dogs, and for the treatment and control of ticks in dogs, and is generally accepted as a safe treatment for flea and tick infestation in hedgehogs. However, hedgehogs, especially those experiencing breathing difficulties, appear to be particularly susceptible to sprayed substances, and their condition often appears to worsen following treatment. Possibly, the tendency of the hedgehog to curl up into a ball increases the amount of insecticide inhaled.
Also, certain new flea powders containing 1% permethrin as their active agent have been proven to be harmful, and indeed fatal, to hedgehogs despite the fact that there would seem to be no absorption by the skin (The Mammal Society, 1985B). This would seem to suggest that insecticides might have different effects on different species. I would suggest that the treatment of tick infestation in hedgehogs with medication licensed for use only with dogs and cats be avoided.
In addition, Frontline does not always kill all the ticks. As each tick removes a considerable amount of blood from a hedgehog it is paramount that they are removed as soon as possible from any animal presenting for treatment to help prevent anaemia. Another reason for speedy removal of ticks is that they transmit disease, in particular those caused by viruses.
Method and Materials
An effective, but harmless, method for removing ticks from a hedgehog is to simply pour an oil, suitable for use with human babies, as close as possible to the head of the tick(s). The breathing holes of the tick are situated close to its mouth parts and a layer of oil blocks them immediately, ensuring death shortly afterwards. The ticks that fail to fall off can then be removed carefully using forceps.
I have used this method on countless occasions and have found it to be totally effective in ensuring removal of the tick Ixodes hexagonus. The use of oil is also preferable when removal of ticks by forceps is not practicable owing to either the small size of the ticks or their position on the body of the hedgehog, that is, vulnerable areas such as the eyes. An alternative to oil used on the skin of human babies is diluted lavender oil. This has the added advantage of encouraging fleas (Archaeopsylla erinacei) to leave the hedgehog, where overburdening with fleas is a problem. However, care must be taken if it means that fleas leaving one infested hedgehog are able to immediately infest other animals receiving care in the vicinity.
This technique for speedy and safe removal of the hedgehog tick (Ixodes hexagonus) is highly recommended as it is effective, non - toxic, time - saving and, most importantly, kinder to the hedgehog. It keeps stress to a minimum while at the same time preventing further loss of blood, with subsequent anaemia, from an animal already weakened due to disease or injury.
I would like to express thanks to Dr. Huw Griffiths, Dept. of Geography, University of Hull, and Keith Warner (MRCVS), a veterinary surgeon at the Minster Veterinary Practice, York, England, for invaluable help and discussion.
Keymer I.F., Gibson E.A. & Reynolds D.J., Zoonoses and other findings in hedgehogs (Erinaceus europaeus): a survey of mortality and a review of the literature. The Veterinary Record, March 16:245-249, 1991.
Morris P.A ., The Handbook of British Mammals, 2nd edn. Eds.G.B.Corbet, H.N.Southern, Oxford. Blackwell Scientific Publications:36, 1977.
Reeve, N., Hedgehogs, T. & A.D. Poyser Limited, London:1-313, 1994.
Smith, J.M.B., Diseases of hedgehogs, Vet. Bull. 38:425-430, 1968.
Stocker L., The Complete Hedgehog, Chatto & Windus, London, 1987.
Sykes L. & Durrant J., The Natural Hedgehog, Gaia Books Ltd., London, 1995.
Mammal News, The Mammal Society Newsletter, 61, 1985B.
Dr Bunnell received her PhD in 1982 for research into playful behaviour in the Polecat (Mustela putorius) in relation to family group activity. She lectures in biological sciences in the Faculty of Health, University of Hull, England and is a member of the Scientific and Medical Network.
Other areas of research involve various aspects of bioelectromagnetics, such as the effects of altered states of consciousness on enzyme kinetics, brainwave patterns, and breathing efficiency in asthmatics.
In her spare time she runs a sanctuary for hedgehogs, taking as many ailing animals from York RSPCA Animal Home as space and time permits. This currently stands at 72 animals this year owing to recent extensive flooding of York and the surrounding countryside. The hedgehogs are rehabilitated and all survivors (about 85%) returned to the wild.
Copyright © Toni Bunnell 2001-2006