Lyme borreliosis is caused by Borrelia bugdorferi sensu lato, transmitted by the ticks of the Ixodes ricinus complex. The typical sign of the disease is so-called erythema migrans, which occurs on the site of the tick bite and may recede spontaneously. When the bacteria disseminate throughout the body mostly musculoskeletal and nervous systems are affected. Lyme disease is known to cause various late symptoms which may interfere with everyday activities and be even disabling.
Borrelia burgdorferi is transmitted by the ticks from the Ixodes ricinus complex (Ixodes persulcatus complex).
- The deer tick, Ixodes scapularis, plays the role of the vector in the north-eastern and midwestern part of the USA;
- The deer tick, Ixodes pacificus, is the vector in the west of the USA;
- The sheep tick, Iхodes ricinus, is involved in the transmission of the bacteria in Europe;
- The taiga tick, Ixodes persulcatus, is responsible for the spirochete transmission in Asia.
Humans become infected by the young tiny Ixodes nymph. They attach to a human who walks through tall grass or brush. The transmission happens approximately in 36-48 hours. The tick starts to feed and the bacteria escape into the human skin from the tick’s salivary glands. Borrelia replicates in the skin and after the incubation period of 3-32 days, erythematous lesion known as erythema migrans develops. Afterward, the spirochete spreads all over the body.
Public preventive measures
It is quite hard to control the spread of the ticks in their natural habitats. Acaricides are used to exterminate the ticks, landscaping in order to demarcate the lawns and areas where the ticks are spread. Sometimes the exclusion of rodents and deers may be necessary.
It is recommended to avoid tick-infested areas, especially the woods. While being in the forest a person should follow the trails and apply repellents containing DEET or permethrin to the skin and/or clothes. Permethrin cannot be applied to the skin, only clothes. Excessive amounts of DEET, when applied to the skin, may cause some serious adverse reactions. However, the repellents should be used with caution and shouldn’t be applied to the face and hands.
Furthermore, light-colored long-sleeved shirts and long trousers should be worn with the pant legs tucked into socks/boots in order to cover the skin as tightly as possible. However, ticks may also habit in gardens, lawns, and bushes, therefore, avoid touching the bushes or walking in the tall grass and always stay attentive.
After spending time in the woods the skin should be checked for the ticks or any signs of the bites. Ticks often attach to the lower extremities and moist body parts like groin or axillae. In children, ticks may also be found on the neck or head. It is believed that the spirochetes can be transmitted only if the tick is attached for at least 24 hours, respectively removal of the tick within 24 hours is considered sufficient to prevent the occurrence of Lyme disease. The tick should be removed with a special tool. Rapid test (which also has a tick removal tool) may be used to check whether the tick carries Borreliae or not.
Preventive antibiotic treatment should be given after a tick bite, especially if the presence of Borreliae was confirmed. A single dose of doxycycline of 200 mg is considered enough efficient to prevent Lyme disease if it is given within 72 hours after a person was bitten. Children under 8 years shouldn’t be given doxycycline.
Although the vaccine was developed it is not available at the moment.