Select a condition Absence seizures Acne ADHD Age-related macular degeneration AIDS Alzheimer's disease AMD Amebic dysentery Anal tears Angina, stable Angina, unstable Ankle sprain Anorexia Anxiety Appendicitis Arthritis Asthma in adults Asthma in children Athlete's foot Atrial fibrillation Attention deficit hyperactivity disorder (ADHD) Autism Back pain Bacterial vaginosis Bad breath Bedsores Bedwetting Bell's palsy Benign prostatic hyperplasia Bipolar disorder Bladder infection in women Blood pressure Breast cancer Breast pain Bronchiectasis Bronchiolitis Bronchitis Bulimia Bunions Burning mouth syndrome Burns and scalds Canker sores Cardiac arrest Carpal tunnel syndrome Cataracts Cellulitis and erysipelas Chickenpox Childbirth, heavy bleeding Childbirth, tear or cut Chlamydia Chronic bronchitis Chronic fatigue syndrome Chronic obstructive pulmonary disease Chronic prostatitis Chronic tension type headache Cold sores Colic in babies Colon and rectal cancer Colon and rectal cancer screening Colonic diverticular disease Common cold Conjunctivitis Constipation in adults Constipation in children COPD Crib death Deep vein thrombosis Dementia Depression in adults Depression in children Diabetes, type 1 Diabetes, type 2 Diarrhea in adults Diarrhea in children Diverticular disease Ear infection, middle ear Ear infection, outer ear Ear infection with discharge Ear infection with fluid Ear pain during air travel Ear wax Eczema Emphysema Endometriosis Enlarged prostate Epilepsy Episiotomy Erection problems Essential tremor Febrile seizures Fertility problems Fibroids Flu Gallstones Genital herpes Genital warts GERD GERD in children Glaucoma Gonorrhea Gout Group B streptococcus H. pylori infection Halitosis Hay fever Headache, chronic tension type Head lice Heart and circulation problems in diabetes Heart attack Heartburn Heart failure Heavy periods Heel pain Hemorrhoids Hepatitis B Hepatitis C Hernia Herpes, genital Herpes simplex eye infection High blood pressure High blood pressure in pregnancy High cholesterol HIV infection Hyperactivity IBS Incontinence in women Infection in newborn babies Infertility Influenza Insomnia in adults Irritable bowel syndrome Jaundice in newborn babies Jet lag Kidney infection Kidney stones Leg cramps Leg ulcers Lewy body dementia Lung cancer Lyme disease Macular degeneration Malaria prevention Manic depression Mastalgia Measles, mumps and rubella: prevention Melanoma Meniere's disease Meningococcal disease Menopause Migraine in adults Migraine in children MMR prevention Morning sickness Multiple sclerosis Nail infection, fungal Neck pain Nicotine addiction Non-Hodgkin's lymphoma Nosebleeds in children Obesity Obsessive-compulsive disorder OCD Oral thrush Osteoarthritis Osteoporosis Ovarian cancer Painful periods Pancreas cancer Panic attacks Parkinson's disease PCOS Pelvic inflammatory disease Perineal care Peripheral arterial disease Peripheral vascular disease Pneumonia Polycystic ovary syndrome Postpartum depression Postpartum hemorrhage Post-traumatic stress disorder Preeclampsia Pregnancy, nausea Premature birth Pressure sores Prostate cancer Prostatitis, chronic Psoriasis PTSD Raynaud's disease Rectal cancer screening Recurrent cystitis Reflux in children Rheumatoid arthritis Scabies Schizophrenia Seasonal allergy Shoulder pain Sickle cell anemia Sickle cell disease SIDS Sinusitis Skin cancer (melanoma) Skin cancer (squamous cell) Sleep apnea Sleep problems in children Slipped disk Smoking Sore throat Stomach ulcers Stress headache Stress incontinence Stroke, emergency care Stroke prevention Sudden infant death syndrome Swimmer's ear Tennis elbow Tension headache Testicular cancer Thrush (oral) Tic douloureux Tinnitus Tonsillitis Toxoplasmosis in pregnancy Trigeminal neuralgia Underactive thyroid Urinary tract infections in children Varicocele Varicose veins Vascular dementia Warts Whiplash Wisdom teeth, impacted Wrinkles Yeast infection, vagina

Select treatment area Bladder & Kidneys Blood Brain & nervous system Cancer Children's health Diabetes Digestive system Ear, nose & throat Eating & weight Eyes Fertility Heart and circulation Hormones Infections Lungs & breathing Men's health Mental health Mouth Muscles & bones Pregnancy & childbirth Sexual health Skin Sleep Staying healthy Travel health Women's health

Lyme disease is an infection you can get from being bitten by tiny creatures called ticks. The disease is caused by bacteria that are carried by some ticks. When the tick bites you, the bacteria can get into your body.

There are different kinds of ticks. The ones that can give you Lyme disease are called deer ticks because they often live on deer. The infection can spread to people because deer ticks also bite humans. Dogs and other pets can get infected too.

Ticks look a bit like tiny spiders. They go through three different stages of growth, called larva, nymph and adult. At each stage of their growth they feed on the blood of different animals, including small animals like squirrels, mice and some birds. Most cases of Lyme disease happen in the late spring and summer when the young nymph ticks are active and people are spending more time outdoors.¹

If a tick bites you it can be worrying. But this doesn't mean you'll definitely get Lyme disease. Not all ticks carry the bacteria that cause Lyme disease.² The chance of a tick being infected with these bacteria depends on which part of the country you are in.

Also, the tick has to feed from your skin for a long time for it to pass on the bacteria.² Doctors think that a tick has to stay feeding on your skin for at least 18 hours to 24 hours for there to be a risk of it passing on the bacteria.

The sooner you spot and remove a tick, the less risk there is that it can pass on the bacteria that causes Lyme disease.² See How to remove ticks.

If you are bitten by a tick, it's a good idea to check for the early symptoms of Lyme disease.

Ticks are found in places where there are lots of deer and small animals: forests, plains and areas of high grass.^{3 4} Ticks that can pass on Lyme disease are most commonly found in the north-eastern and north-central United States, although you can catch the infection in almost every state.^{1 2}

People who are most at risk of getting Lyme disease include:^{3 4}

• People who go walking in or who camp near long grass
• People who live in areas where there are lots of deer
• Farmers
• Forestry workers
• Workers in contact with deer
• Other workers in woodland.

A lot of people who visit these areas for pleasure tend to be at risk from ticks. This may be just because they don't know about the risk from ticks, and so they don't take precautions.

If you work in or go walking in areas where there are ticks, then it is useful to know about the things you can do to prevent tick bites.^{5 6} For more information, see How to prevent tick bites.

There's no evidence that you can catch Lyme disease from another person, a pet, or other insect bites.³ And there's no evidence that you can catch the disease from food, water or the air.³ The bacteria that cause Lyme disease can live in blood that has been stored for donation. People with long-term Lyme disease have been asked not to donate blood.³

This information is for educational use only, and is not a substitute for prompt professional medical advice. Readers should always consult a physician or other professional for advice and treatment. ©BMJ Publishing Group Limited 2008. All rights reserved.