Lyme Disease By Farrah Jangda Disease Name: Lyme Disease Lyme disease is a common tick-borne bacterial infection transmitted from the bite of a tick in United States and Europe (2). It is caused by the bacteria, Borrelia burgdorferi. Etiologic Agent: Borrelia burgdorferi Transmission: Lyme disease is caused by the bacteria Borrelia burgdorferi that is transmitted via an infected tick bite. The tick bites onto the skin allowing the bacteria to enter the blood stream. From the time bitten, it takes 24-72 hours for the bacteria to enter the blood (7). These ticks are blacklegged or deer ticks. The ticks are as small as a poppy seed and brown in color which makes them hard to spot (7). Reservoirs: Borellia burgdorferi are found in middles guts of blacklegged or deer ticks. General characteristics of Borrelia burgdorfer: Borrelia burgdorferi is a spirochetes and are not classified as Gram-positive or Gram negative. They usually appear as Gram-negative since the last dye used is safranin. B. burgdorferi has an outer membrane that contains an LPS-like substance, an inner membrane and a periplasmic space which contains a layer of peptidoglycan, making it have a Gram-negative type cell wall (6) Key tests for identification Lyme disease can be difficult to diagnose since many early symptoms like headache fatigue and fever are associated with many other illnesses (1). The hallmark of Lyme disease, erythema migrans does not occur in ¼ of the patients. Currently, there are two tests, ELISA and Western Blot. ELISA is a blood test, people with Lyme disease will test positive but some who do not have it may test positive. If Elisa is positive then the Western Blot test is performed, if this test is positive then the person has Lyme disease, if negative then Elisa test was a false positive (1). Signs and symptoms of disease: Signs and symptoms can vary and can infect different parts of the body. The earliest sign of Lyme disease is a small red bump that appears after a tick bite, it doesn t appear in all patients. Within 30 days from the bite, some patients may see a rash in the area they ve been bitten. This rash is the hallmark of Lyme disease and is known as erythema migrans. Erythema migrans rash is uniformly round and red and in a few days can grow to about 12 inches and has a bull s-eye appearance. About 70% patients have a rash from the bite and about 30% of those have the bull s-eye appearance (5). Other early symptoms of Lyme disease are flu-like symptomsheadaches, fever, chills, fatigue, muscle and joint pain and swollen lymph nodes.
If the disease goes untreated, many serious. As the infection progresses, patients start experiencing more serious symptoms. These symptoms are severe headaches, neck stiffness, arthritis, heart palpitation, inflammation of the brain and spinal cord, shooting pains, numbness or tingling in the hands or feet. As the disease continues to go untreated serious neurological probloms develop. This could be after weeks or even years. When patients have neurological problems, the membranes aroung the brain develop inflammation and might also experience paralysis of one side of the face. Some may experience post-treatment Lyme Disease Syndrome (PTLDS) in which they continue to experience fatigue and muscle and joint pain (3). Historical information: Lyme disease is relatively newly recognized. In 1975, there was a outbreak of juvenile rheumatoid arthritis in Lyme, Connecticut which led Dr. Allen Steere to discover the disease is a tick-borne illness. The etiologic agent of Lyme disease was discovered by Willy Burgdorfer in 1982. Burgdorfer, isolated spirochetes from the mid guts of Ixodes or deer tick. He did an experiment showing these spirochetes react with immune serum from patients and cause the illness. Lyme disease was identified in Texas in 1984 (6) Virulence factors: This bacteria requires iron, humans have high levels of iron that helps the bacteria to survive. A protein on the surface of the bacteria is important for its growth (2). Treatment and Control: In most cases, Lyme disease can be treated by antibiotics. The most commomly prescribed antibiotics are doxycycline, amoxicillin and cerfuroxime axetil. Treatment works best when the antibiotics are administered in early stages of the disease (7). Best method to control the disease is to prevent exposure and spread awareness of areas with tick exposures (4). Prevention, Vaccine and New Trials: The best method to prevent an infection is to avoid exposure to vector ticks (4). Best ways to avoid exposure to tick bites is by using bed nets, wearing long-sleeved clothing, apply insect repellant and use window screens. If a tick gets on to skin, immediate removal may prevent from
getting the infection since it usually takes the bacteria 24-72 hours to enter the patient s blood stream. Be aware of areas with high tick exposures and often check skin for ticks. For now, there aren t any vaccinations for Lyme disease. During early stages of Lyme disease, it can be difficult to diagnose since the tests may not show up as positive. NIAID has been supporting scientists that have identified genome sequences of B. burgdorferi so with the use of advance technology they can come up with better diagnostic tools (1). Local cases or outbreaks: Texas is an endemic for the blacklegged tick. In Texas, about 50-275 cases of Lyme disease are reported annually. The majority of Lyme disease cases in humans occur in the spring and summer time and mostly in Northeastern and North Central regions of U.S. Lyme disease it the most prevalent tick-borne disease in the United States (5). This figure shows cases of Lyme Disease in the United States from 1995-2014. Global cases or outbreaks Almost every country has diseases that are transmitted by parasites. Some countries have either high, low, or moderate occurrences but almost every country has at least one such case (8).
This map shows the spread of Lyme Disease worldwide. References: 1. National instate of allergy and infectious disease. "Lyme Disease Diagnostics Research".https://www.niaid.nih.gov/diseases-conditions/lyme-disease-diagnosticsresearch. September 28, 2016. May 9, 2017. 2. Clinical Infect Diseases. "The Clinical Assessment, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: Clinical Practice Guidelines by the Infectious Diseases Society of America". https://academic.oup.com/cid/article/43/9/1089/422463/the-clinical-assessment- Treatment-and-Prevention. 01 November 2006. May 9, 2017 3. Centers of disease control and prevention. "Lyme Disease". https://www.cdc.gov/lyme/diagnosistesting/index.html March 4, 2015. May 9, 2017 4. Eberwine-Villagran, Donna. "Small bites can be big threats," experts warn on World Health Day. http://www2.paho.org/hq/index.php?option=com_content&view=article&id=9441%3a2 014-small-bites-can-be-big-threats-experts-warn-on-world-healthday&Itemid=1926&lang=en. 14 April 2014. May9, 2017 5. Infectious Disease Control Unit. "Lyme Disease". http://www.dshs.texas.gov/idcu/disease/lyme/description/ April 3, 2017. May 9, 2017.
6. Todar, Kenneth. "Borrelia burgdorferi and Lyme Disease". http://textbookofbacteriology.net/lyme.html April 2, 2014. May 9, 2017 7. Mayo Clinic Staff. "Diseases and Conditions Lyme Disease". http://www.mayoclinic.org/diseases-conditions/lyme-disease/basics/symptoms/con- 20019701 April 03, 2016. May 9, 2017 8. Bayer AG. "Occurrence maps". http://www.cvbd.org/en/occurrence-maps/worldmap/. March 2013. may 9, 2017