(1997) TICKS! Ixodid (hard) ticks are tiny insect-like creatures found in grassy or wooded areas. They attach themselves to passing animals and humans, and feed by biting through the skin and sucking blood. When they have gorged themselves on blood they drop off again. In some parts of the world ticks are important carriers of parasitic, bacterial and viral diseases, while some species may cause paralysis by their salivary secretions. In the UK the most common ticks are Ixodes ricinus (the 'castor bean' sheep and cattle tick, but also found on dogs and cats), Ixodes canisuga (the dog tick), and Ixodes hexagonus (the 'hedgehog' tick, but also found on dogs and cats). Only single or small numbers are found on the host. Ixodes ricinus - the castor bean tick, so called because of its superficial resemblance to the castor bean - is commonly found on farm animals and deer who are the natural host. Distribution is localised with high numbers found on heathland areas. This tick can be found in most parts of Britain and feeds from March to June. However, in western England, Wales, western Scotland and Ireland there is some feeding from August to November. Larvae, nymphs and adults are parasitic only once yearly during their three years of life. Ixodes canisuga - the dog tick - is difficult to eradicate in kennels, where it may occur in large numbers. Feeding of this species is intermittent, the tick leaving the host to hide in crevices. In old premises these may be myriad. Leaving areas empty is not practical as the ticks can survive very long periods without feeding. In these cases, redesigning to eliminate crevices is advisable. Alternatively initial scrubbing with hot 5% washing soda to eliminate protective dirt is necessary, followed by pressure-hosing and finally cleansing with a synthetic pyrethroid. Ixodes hexagonus - the hedgehog tick - resembles the dog tick and is about the same size. It is found on hedgehogs and other wild mammals. Spring and autumn peaks of feeding activity are recorded on wild mammals. Ticks spend most of their life off the hosts. A typical three-year ixodid life cycle is: a) Eggs laid on the ground. b) Hatch in 2-7 weeks. c) Larvae feed on host (3-12 days), drop off and rest (6-90 days) and moult. d) Nymphs feed on host (3-12) days), drop off and rest (17-100 days) and moult. e) Adults may live up to 3 years; females are capable of laying between 2000 and 8000 eggs in their life times. The mouth parts are well-developed with the posterior curved teeth on the hypostome (dental area) preventing dislodgement by force whilst gorging on a host. Care must therefore be taken in order to remove the hypostome as well as the body from the site (failure to do so may cause local inflammation, and if a foreign-body granuloma develops it will need to be removed surgically). Before manual removal of a tick, a drop of methylated spirit, surgical spirit, alcohol, TCP or nailpolish remover should be first applied to encourage the tick to relax. The tick should then be grasped with tweezers or the fingers, as close to the host's skin as possible, and pulled out slowly and gently with a twisting motion. Squeezing or bursting of the tick should be avoided and antiseptic applied to the wound. Insecticidal shampoos, sprays and powders can alternatively be used to remove ticks. Lyme's Disease Lyme's disease is an illness caused by bacteria which live in the guts of some ticks. These bacteria can be passed to humans and animals if an infected tick bites them. It is not known what percentage of ticks carry Lyme's disease. The disease was first diagnosed in Britain in 1985, in southern England. Symptoms normally start between a week and a month after being bitten. In humans, the first sign is often a red blotch around the site of the tick bite. This rash can spread to form a large circle up to 20" across. Flu-like symptoms may occur either before the skin rash or about the same time. Headache and chills, tiredness and joint aches may last several weeks without treatment. Fever is more common in children. More serious complications sometimes develop weeks or months after the bite. The most common long-term problems can include tingling in the hands and feet, and Bell's Palsy (paralysis of the facial muscles). Early treatment with antibiotics is effective against short-term symptoms and may prevent or lessen the seriousness of any long-term complications. Lyme's disease in dogs and cats is extremely rare and this may be due to an inborn resistance to the infection. When symptoms do occur it is usually in the form of a shifting lameness. Confirmation of infection can only be made by a blood test. Treatment is possible in the early stages when antibiotics lead to a complete cure.