Lyme disease symptoms and treatment in humans

What Is Lyme disease?


Lyme disease is an infectious disease caused by the bacteria Borrelia burgdorferi and its siblings Borrelia garinii, Borrelia afzelii and the newly found Borrelia mayonii. (Citation: 1, 3) 

These bacteria come from a select group of bacteria called the Spirochetes, they are long, thin and have a spiral shape. Lyme disease is a recent discovery, although it has most likely been around for over 5,300 years as indications for the disease were found in the Tyrolian ice mummy recently (Citation: 4). Lyme disease was only named in the 1970s (after one of the towns in Connecticut where it was observed through an outbreak of arthritis in children), and the B. Burgdorferi bacteria was classified in 1981 by Dr. Willy Burgdorfer. (Citations: 5, 6, 7)

Lyme disease is transmitted to humans through the bite of infected ticks of the sub-family Ixodes. These ticks are external parasites with a hard shield – also called hard-bodied or “hard” ticks. Common ticks that can spread Lyme are the deer tick (Ixodes scapularus) for north-eastern, mid-Atlantic and the north-central USA, the western black-legged tick (Ixodes pacificus) on the Pacific Coast, the castor bean tick (Ixodes ricinus) in Europe and the taiga tick (Ixodes persulcatus) in Eurasia.(Citations: 8, 9, 10)


How common Is Lyme disease?


Lyme is an emerging disease, with increasing patient numbers. (Citation: 9) The World Health Organization estimates that there are over 500,000, often unreported, Lyme disease cases in the whole world every year (Citation: 11). There were more than 25,000 confirmed cases in the USA alone in 2015 (Citation: 12). In the USA Lyme disease is concentrated in the forested areas in North East and upper Mid-West, with 95% of the Lyme disease cases reported from only 14 states. (Citation: 13) Other focal areas are in forested regions of Asia, Europe (North-West, Central and East see map (Citation: 14) and Asia. (Citation: 15)


Is Lyme disease contagious?


Lyme Diseases is caused by a bite of a tick (mostly a nymph, sometimes an adult tick) infected with the Borrelia bacteria (see the different types mentioned above). These ticks primarily live in forested areas, but they can also be found in parks, gardens, dunes, sheltered meadows and moorlands. So, for travelers the risk is higher in rural areas, especially if they go camping or hiking. (Citation: 16) The ticks actually like to bite animals more than humans, and animals (especially deer in the USA) form an important reservoir for the disease.(Citation: 18) The disease is not transmitted from person-to-person – it safe to come into close contact with infected individuals. But having had Lyme disease before does not protect one from getting it again.

It should be noted that ticks that can spread Lyme disease can also spread other diseases like Tick-borne meningoencephalitis (parts of Europe and Asia), babesiosis (Citation: 16) (parts of the USA and Europe) and anaplasmosis (Citation: 17) (parts of USA, rare in Europe).


What are the signs and symptoms of Lyme disease?


Lyme disease has three stages: Early localized, early disseminated and late. (Citation: 18) The early localized stage takes place between 3-32 days after the infected tick bite. The first sign in more than 75% of patients is Erythema migrans: a migrating red, ring-shaped rash that often clears between the center and the outer border (up to 50 cm in diameter) giving a bull’s eye appearance. This usually fades in 3-4 weeks, even without treatment. The early disseminated stage takes place days to weeks after the first rash. Usually, there are smaller round skin rashes with hard edges and flu-like symptoms like fever, chills, myalgia and headache (Citation: 19). There can also be neurological (15%) and heart problems (8%). (Citation: 15) If left untreated the late stage (months-years after infection) develops, in which there is often (60%) recurring arthritis, but there can also be neurological and skin problems.


How Is the diagnosis of Lyme disease Made?


As Borrelia bacteria are specialized bacteria (spirochaetes), they do not stay in the bloodstream like other bacteria. Therefore, diagnosis can’t be conducted by looking for the bacteria in the blood. However, diagnosis is accomplished by identifying antibodies against the bacteria, through a process called serological testing.


What is the treatment for Lyme disease?


Treatment of Lyme disease is with antibiotics (Citation: 20) like doxycycline, amoxicillin or cefuroxime axetil. Intravenous treatment (e.g. with penicillin or ceftriaxone) might be needed for patients with neurologic or heart problems due to Lyme disease. In the early stages of Lyme disease people usually recover quickly, in later stages of the diseases longer treatment and follow-up might be needed.


Are there complications of Lyme disease in humans?


If Lyme disease is left untreated, it will move to the later stages of the disease. This can result in heart problems (such as rhythm disorders), neurological problems (such as paralysis of the facial muscles and damage to nerves), problems with cognition (= problems with information processing in the brain, for example impaired memory) and Lyme arthritis (chronic infection of joints, often the knees). (Citation: 21)


What are the preventive measures for Lyme disease?


There is currently no vaccine or prophylaxis for Lyme disease. Lyme disease can be prevented (Citation: 22) in many ways. Researchers have found out that personal and environmental protective measures against ticks work. (Citation: 23)

• Prevent walking in wooded/grassy areas. If you have to, stay in the middle of the paths and avoid going through high grass.

• Cover your skin (long trousers, long sleeves, wear a hat, gloves), especially in areas where ticks are common. You could consider treating your clothes with an insecticide like DEET.

• Use an insect repellant containing DEET on uncovered skin.

• After your outdoors activities check your skin (you might need a helper to look at areas that are difficult for yourself to check) for ticks. It should be noted that the ticks that transmit Lyme disease can be tiny, about the size of a head of a pin. It is best to remove the tick as soon as possible (Citation: 24), but at least within two days. This because it usually takes 36-48 hours for the Borrelia bacteria to move from the tick’s gut to the tick’s saliva and then through your skin to the bloodstream. (Citation: 25)

• After tick removal one should be on the lookout for development of any rash or any other symptoms and if they occur a doctor should be contacted.

• Ensuring the animals around you (e.g. your pets) do not have ticks.

• Creating a tick-safe zone around houses

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  4. Kean and others in Inflammopharmacology. 2013 Feb;21(1):11-20. doi: 10.1007/s10787-012-0153-5. Epub 2012 Oct 25. The musculoskeletal abnormalities of the Similaun Iceman (“ÖTZI”): clues to chronic pain and possible treatments. Weblink:
  5. Bay Area Lyme Foundation. See
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  10. Steer and others in J Clin Invest. 2004 Apr 15; 113(8): 1093–1101.doi: 1172/JCI200421681. PMCID: PMC385417. The emergence of Lyme disease. Accessed online 8th September 2017. Weblink:
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  14. European Centre for Disease Prevention and Control. Accessed online on 8th September 2017. Map of Current known distribution of ixodus ricinus in Europe
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  23. Eisen and others in J Med Entomol. 2016 Jul 20. pii: tjw103. [Epub ahead of print]. Evidence for Personal Protective Measures to Reduce Human Contact with Blacklegged Ticks and for Environmentally Based Control Methods to Suppress Host-Seeking Blacklegged Ticks and Reduce Infection with Lyme Disease Spirochetes in Tick Vectors and Rodent Reservoirs. Weblink:
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