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Lyme disease is a tick-borne articular, neurological and cardiac disease, which agent is a bacterium of the spirochaetes family, Borrelia burgdorferi.
Lyme disease is a widespread disease in North America, currently in the US and Canada, it is the first vector borne disease (a disease that is transmitted to humans or other animals by an insect or other arthropod). In the United States, more than 10,000 cases are reported annually; about 90% of them are from the states of Massachusetts, Connecticut, Illinois, Delaware, Minnesota, Rhode Island, Virginia, New Jersey, Maryland, Pennsylvania, New York, Wisconsin and Minnesota.
Lyme Disease Causes and Risk Factors
Lyme disease is caused by the bacterium Borrelia burgdorferi. This bacterium is transmitted to humans through a tick bite. Ticks that transmit the bacteria are about the size of 3 mm to 5 mm long; they feed on blood. They live in several mammals such as deer, rabbit and rodents.
All tick bites, however, do not lead to infection. Ticks eat slowly, so it takes some time to pass the bacteria in human blood. Anyway, if you get bitten by a tick, to reduce the risk of contracting Lyme disease, remove it as soon as possible, especially within 24 hours – see removal method below.
Individuals at risk of Lyme disease include:
- Loggers
- Campers
- Forest rangers
- Hunters
- Mushroom harvester.
Lyme Disease Symptoms
Lyme disease develops in three phases:
Primary Phase – this first phase of the illness is characterized by chronic lesion called erythema migrans, occurring after about three days to one month after the tick bite. This is an initial small, red bump on the center point of the sting which extends concentrically to form a ring. It is accompanied by a low fever, headache, pain in joints and muscles. The skin lesion often disappears within three weeks.
Phase 2 – The secondary phase is characterized by extensive erythema, neurological disorders (radiculitis, meningitis), cardiac problems (irregular heartbeat, chest pain) and joint pain and inflammation. Those symptoms can last a few weeks to months.
Phase 3 – this later phase occurs several years after the tick bite. It is characterized by large and severe erythema associated with progressive atrophy of the skin. You may also experience chronic rheumatism of one or more joints and neurological problems: memory loss, difficulty concentrating, mood changes, numbness or weakness in your limbs, and paralysis of one side of your face (Bell’s palsy).
How Lyme disease is diagnosed?
The diagnosis of Lyme disease is based firstly on an assessment of the symptoms. During the exam, your doctor may ask you questions about your medical history and things or places that may have exposed you to spirochetes. You can also be recommended tests and exams if you have symptoms of arthritis, neurological or cardiac problems associated with Lyme disease. Tests and exams that can be performed in the diagnosis of Lyme include:
Enzyme-linked immunosorbent assay (ELISA) test – Elisa test is often used in the diagnosis of Lyme disease; however, it is not always conclusive. If the result is negative it is not necessary to conduct further tests. A positive ELISA associated with typical signs of Lyme disease requires the confirmation of Western blot.
Western blot test – this test is usually done to confirm the diagnosis. It helps distinguish between antigens of different species of Borrelia, by their difference in molecular weight.
Polymerase chain reaction (PCR) – this test is an important tool in the detection of Borrelia burgdorferi. It is mostly used in the cases of chronic Lyme arthritis to detect bacterial DNA in fluid drawn from an infected joint.
Lyme Disease Treatment
If you realize that you are bitten by a tick, you should remove it as soon as possible. Do not try to crash in it on your skin. To remove ticks attached to your skin, use tick twister to not leave the mouth-parts of the tick implanted in your skin. Grasp firmly and carefully the head of the tick next to your skin. Pull gently until the tick is removed from the skin.
After removing the tick, clean the place where it clung to your skin with soap and water or disinfect the area with alcohol. Write down the date of the tick bite. Monitor the bite site and control your body for any symptom of lyme.
Lyme disease can cause various types of effects, including neurological problems such as facial paralysis and weakness in your limbs. You must follow the treatment completely to prevent complications.
Treatment is based on antibiotic therapy. It aims primarily at stopping the clinical symptoms and prevents late neurological complications. In general, Lyme is treated by either oral antibiotic (doxycycline, amoxicillin or cefuroxime axetil) for a period of 14- to 21 or intravenous antibiotherapy which can last for up to 28 days. Depending to the reaction of your body to the drugs, intravenous antibiotics (ceftriaxone sodium, cefotaxime sodium, etc.) can cause adverse effects: diarrhea, lower white blood cell count, gallstones, etc.
Lyme Disease Prevention
Besides deer and other animals, ticks can be on the grass or in trees and clinging for a potential host. If they feel your presence, they will try to attach on your skin. Once on the skin, they will bite you to get your blood. Therefore, you need to take precautions in wooded or grassy areas, mostly during the period of contamination which is usually May to October.
- Use insect repellents
- Wear long clothes and closed shoes
- Wear light-colored clothing to locate ticks easily
- In period of contamination, always check your children and your pets for ticks
- After visiting a place where ticks live, clean yourself, your children and your pet
References :
1 – Centers for Disease Control and Prevention (CDC): Reported Lyme disease cases by state, 1993-2007; National Lyme disease risk map
2- Mayo clinic -; test and diagnosis of lyme disease
