Infectious disease caused by bacteria from the Genus Borrelia

Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to humans by the bite of infected blacklegged ticks. Typical symptoms include fever, headache, fatigue, and a characteristic skin rash called erythema migrans. If left untreated, infection can spread to joints, the heart, and the nervous system. Lyme disease is diagnosed based on symptoms, physical findings (e.g., rash), and the possibility of exposure to infected ticks; laboratory testing is helpful in the later stages of disease.

Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics. Steps to prevent Lyme disease include using insect repellent, removing ticks promptly, landscaping, and integrated pest management. The ticks that transmit Lyme disease can occasionally transmit other tick-borne diseases as well.

Lyme Disease Life Cycle

Knowing the complex life cycle of the ticks that transmit Lyme disease is important in understanding the risk of acquiring the disease and in finding ways to prevent it.


The life cycle of these ticks requires 2 years to complete. Adult ticks feed and mate on largeImage of a squirrel. animals, especially deer, in the fall and early spring. Female ticks then drop off these animals to lay eggs on the ground. By summer, eggs hatch into larvae.

Larvae feed on mice and other small mammals and birds in the summer and early fall and then are inactive until the next spring when they molt into nymphs.

Nymphs feed on small rodents and other small mammals and birds in the late spring and summer and molt into adults in the fall, completing the 2-year life cycle.

Larvae and nymphs typically become infected with Lyme disease bacteria when they feed on infected small animals, particularly the white-footed mouse. The bacteria remain in the tick as it changes from larva to nymph or from nymph to adult. Infected nymphs and adult ticks then bite and transmit Lyme disease bacteria to other small rodents, other animals, and humans, all in the course of their normal feeding behavior.

Interrupting the Lyme Disease Life Cycle
Blocking a tick protein that protects Borrelia burgdorferi as it moves from mammalian hosts back to the tick that infected them might reduce incidences of Lyme disease, a Yale School of Medicine researcher report

Developing Salp25D-based strategies to interrupt the Borrelia burgdorferi life cycle may lead to new methods of reducing the incidence of Lyme disease,

Lyme disease FAQ : Frequently Asked Questions

What is Lyme disease?
Lyme disease is a bacterial disease caused by Borrelia burgdorferi (boar-ELL-ee-uh burg-dorf-ERR-eye). Within 1 to 2 weeks of being infected, people may have a "bull's-eye" rash with fever, headache, and muscle or joint pain. Some people have Lyme disease and do not have any early symptoms. Other people have a fever and other "flu-like" symptoms without a rash.

After several days or weeks, the bacteria may spread throughout the body of an infected person. These people can get symptoms such as rashes in other parts of the body, pain that seems to move from joint to joint, and signs of inflammation of the heart or nerves. If the disease is not treated, a few patients can get additional symptoms, such as swelling and pain in major joints or mental changes, months after getting infected.


Can animals transmit Lyme disease to me?
Yes, but not directly. People get Lyme disease when they are bitten by ticks carrying B. burgdorferi. Ticks that carry Lyme disease are very small and can be hard to see. These tiny ticks bite mice infected with Lyme disease and then bite people or other animals, such as dogs and horses, passing the disease to them.


How to Avoid Tick Bites

• When out of doors several precautions can minimize your chances of being bitten.
• Tuck your pant legs into your socks and your shirt into your pants.
• Wear light colored clothing. Dark ticks are more easily spotted against a light background.
• Inspect clothes often for ticks. Have a companion inspect your back.
• Apply repellents according to label instructions. Applying directly to clothing appears to be most effective.
• Upon returning to the home remove clothing and wash or put it in the dryer for 30 minutes to kill any ticks.
• When you get in from the field shower and inspect your body thoroughly. Especially check groin, navel, armpits, head and behind knees and ears. Have a companion check your back, or use a mirror.
• Inspect children at least once daily for ticks. When in heavily infested areas inspect children every three to four hours.
• When hiking stay in the middle of trails. Do not bushwhack.
• Clear brush from around your premises and keep grassy areas mown.
• Avoid plantings that especially attract deer and other animals.
• Limit watering of lawns.
• Judicious use of environmental insecticides to kill ticks may be necessary in some areas.