Lyme Disease
Definition
Lyme disease is a common tick-borne illness. Lyme disease is mainly found in the eastern United States and upper Midwest. Lyme disease is caused by the bacterium Borrelia burgdorferi. The bacteria is transmitted to humans by the bite of an infected tick, primarily Ixodes scapularis (also known as the black legged or deer tick). Photos of the tick can be seen by visiting bugguide.net.
Lyme disease is reportable to the Iowa Department of Public Health by Iowa Administrative Code 641 Chapter 1.
Symptoms
Lyme disease affects various parts of the body. Not everyone who gets Lyme disease will experience the same symptoms.
Early Infection
The best and earliest sign of infection is a rash, called erythema migrans (EM). EM will appear in around 60% - 80% of patients. EM may appear within a few days to a month, usually at the site of the tick bite. The rash will first appear as a small, red bump. Over the next few days, the redness expands. As the rash expands, it begins to look like a bull’s eye, with a red center and a red ring surrounding a clear area. EM should not be mistaken for any initial skin irritation at the site of the bite which fades within about a week.
Early Spread
If left untreated, multiple EM rashes may appear within 3-5 weeks after the tick bite. The onset of more than one rash shows that the infection has spread into the blood. The secondary rashes look like the first bull’s eye rash, but usually smaller in size. A person may experience additional symptoms like:
- Mild eye infections
- Paralysis of the facial muscles (Bell’s palsy)
- Headache
- Fatigue
- Muscle and joint pain
- Abnormal heart rhythm (<10% of cases)
Late Disease
Later symptoms of Lyme disease can present days to months after infection and last for several years, but tend to resolve on their own. Symptoms that may be seen in late disease include:
- Recurrent arthritis commonly in the knees and shoulders
- Impairment of mood, sleep, or memory
- Paralysis of the muscles in the face
- Pain or tingling in the extremities
- Meningitis and encephalitis
Causes
In the United States, the Lyme disease bacterium is carried mostly by deer ticks. Ticks are most likely to spread the Lyme disease bacterium during their pre-adult stage (nymph). Nymphs are brown, very small and difficult to see. Nymphs are most common between May and July and found in tall grasses and brush of wooded areas. Towards the end of summer and into fall, ticks mature and are less likely to spread disease.
Ticks painlessly attach themselves to a host and feed on the host's blood until they're swollen to many times their normal size. Scientific data suggests that ticks need to remain attached for 24 – 48 hours before the host is infected with the bacterium. An attached tick that looks swollen could have been attached long enough to transmit bacteria. A tick should be removed as soon as possible. See prevention for the proper removal technique.
Risk Factors
Spending time outdoors can increase your chances of getting Lyme disease. The most common risk factors for Lyme disease include:
- Spending time in wooded or grassy areas. Deer ticks are found in wooded areas, so people who spend time in these areas should take precautions.
- Exposed skin. Ticks attach easily to bare skin. If you're in an area where ticks are common, protect yourself and your children by wearing long sleeves and long pants and keep your pets out of tall grasses and brush.
- Not removing ticks quickly or correctly. A person can only be infected with the bacterium if the tick stays attached for 24-48 hours. If a tick is removed before that time, your risk of infection is reduced.
Prevention
The best way to prevent Lyme disease is to avoid tick-infested areas. If you do spend time in these areas, the following can reduce your risk of infection.
- Wear long-sleeved shirts and long, light-colored pants tucked into socks or boots.
- Stay on trails when walking or hiking and avoid high grass.
- Use insect repellants. Repellants that contain DEET should be used in concentrations no higher than 15% for children and 30% for adults. Remember, repellants are not recommended to be used on infants. Permethrin is a repellant that can only be applied to clothing, not exposed skin.
- After each day spent in tick-infested areas, check yourself your children, and your pets for ticks. Ticks tend to prefer the back of the knee, armpit, scalp, groin, and back of the neck.
- Promptly remove any attached tick. Folk remedies, such as burning the tick with a match or covering it with petroleum jelly or nail polish, are not effective and can be dangerous because they may force the tick to regurgitate its gut contents, increasing the risk of disease transmission. The tick removal method described below is proven to be effective, and is recommended by the Centers for Disease Control and Prevention.
- Carefully grasp the tick by using tweezers to grip the tick by its mouthparts which are close to the skin. Do not squeeze the tick’s body.
- Pull steadily directly away from your skin. Because removing the tick is your main goal, do not be overly concerned if its mouthparts break off in the process (as they will be shed naturally).
- Clean the wound and disinfect the site of the bite.
Prevention of Lyme disease also involves keeping wildlife (especially deer and rodents) out of your backyard and making your yard less attractive to ticks.
- Remove leaf litter and brush from around your home.
- Prune low-lying bushes to let in more sunlight.
- Keep your grass short.
- Plant deer resistant plants near your home.
- Keep woodpiles in sunny areas off the ground.
- Clean up the ground around bird feeders.
- If you are going to use insecticides around your home, always follow the label instructions and never apply these chemicals near streams or other bodies of water.
Treatment
People treated with appropriate antibiotics in the early stages of Lyme disease usually recover rapidly and completely. Antibiotics commonly used for oral treatment include doxycycline, amoxicillin, or cefuroxime axetil. Treatment guidelines for acute lyme disease are posted on the CDC website.
Statistics
Lyme disease Incidence Data
For more detailed information and statistics on all notifiable diseases, please see our current annual report located in the reports section of the CADE homepage.
Additional Resources
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Educational Materials
Tick-borne disease brochures and other materials can be ordered for free by completing this form.
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