Lyme Disease: Symptoms and Prevention

Lyme Disease is an infectious disease affecting the skin, brain, nerves and joints, which is caused by a bacterium called Borrelia burgdorferi. The bacteria is transmitted to humans through the bite of the deer tick. Lyme disease is the most common tick borne disease in the US. Annually, 300000 people are diagnosed with Lyme disease each year. The disease is encountered in the north eastern states of the US which reflects the distribution of the bacteria and tick in the US.

Causative Agent of Lyme Disease

The disease is caused by the bacteria Borrelia burdorferi which is a spirochete (named for its spiral shape). The bacteria exist in the bodies of wild rodents including the white footed mouse. The ticks acquire the bacteria during a blood meal. The transmission of the bacterium to the humans occurs after the tick is attached to the skin for over 24 hours.

Symptoms of Lyme Disease

The symptoms of Lyme disease vary depending on the stage. There are three stages which may have overlapping symptoms. The disease generally progresses from one stage to the next, however occasionally individuals may not experience any symptoms till a later stage is reached. These are the symptoms experienced:

Early localised disease: This occurs within a month of the tick bite, with a spreading circular red rash at the site of the bite, called erythema migrans.  This rash is absent or missed in 20% of individuals.

Early disseminated disease: This occurs weeks to months after initial infection, with multiple skin lesions of erythema migrans in addition to neurological and heart involvement.

• Meningitis with headaches and neck stiffness
• Neuropathies with weakness and numbness of the hands and feet
• Heart block, a type of rhythm abnormality

Late Disease: This develops months to years after the initial infection and is predominantly a chronic arthritis with joint pain of migratory nature (the joints are affected one after the other).

Diagnosis of Lyme Disease

In the initial stages, the rash along with a history of exposure to the tick in an endemic location is adequate to diagnose the disease. Tests are often inconclusive in the early stage and are not necessary. In the later stages, the following tests are helpful to diagnose the disease:

• Blood tests: The most common tests are blood tests to look for antibodies (immune molecules) produced against Lyme disease.
• Culture: culture of the blood, cerebrospinal fluid and synovial fluid may be attempted but are not always helpful
• Electrocardiogram (EKG): This records the electric activity of the heart which is done to diagnose heart block
• Nerve conduction studies: These tests are useful in the case of neuropathies

Treatment of Lyme Disease

Lyme disease can be completely cured with the use of antibiotics. In early stages, the antibiotic doxycycline is to be taken orally for duration of 10 to 21 days. It is important to note that this dug cannot be given in children below 8 years and in pregnant women where alternative medications are prescribed.

Later stages and more severe disease may require a longer duration of therapy or even intra venous medications.

Prognosis of Lyme Disease

This is a common infectious disease that is completely curable if identified and treated early. Quite often, the disease resolves on its own through effective immune response by the body. The symptoms of the later stages involving the heart and brain may occasionally be non reversible even with antibiotics.

Prevention of Lyme Disease

The disease can be prevented by avoiding the black legged deer tick which is responsible for the transmission of the disease. Individuals living in or travelling to areas with a high risk of disease transmission are advised to avoid tick infested areas and to protect from bites using repellents and clothing covering the arms and legs. In the event of a tick bite, remove the tick completely using tweezers as soon as possible. If unsure of the duration of tick attachment, keep a watch for early symptoms to identify the disease early in order to begin early therapy.

References:

• Al CAN et. Incidence of Clinician-Diagnosed Lyme Disease, United States, 2005–2010 – Volume 21, Number 9—September 2015 – Emerging Infectious Disease journal – CDC. [cited 2018 Jun 24];
• Borreliosis – National Library of Medicine – PubMed Health [Internet]. [cited 2018 Jun 24]