Outline
Introduction
Lyme disease is the most common vector-borne bacterial disease in the US. It is spread through black-legged tick (or deer tick) bites. The pathogen that causes the disease is called Borrelia burgdorferi. Some other species of the same bacteria also cause the disease but in rare cases. B. afzelli and B. garinii are the main species found to cause the disease in European and Asian locations. Lyme disease was first recorded in the town of Old Lyme in Connecticut, 1975. The disease is not fatal but can get serious over months, or even years, if untreated. Genetic factors can affect the after-effect of Lyme disease in patients.
Transmission
Lyme disease is spread by black-legged ticks, or Ixodes scapularis. They get infected when feeding on deers, birds, and mice.
They attach to the human body, usually in unnoticeable areas when the person is in a woody or bushy environment. For the transmission of bacteria from the tick to the human bloodstream to occur, the tick has to be attached to the body for at least 36 - 48 hours. Often, adult ticks are spotted and removed from the body before 36 hours. However, the young ticks, which are barely the size of a poppy seed, are more difficult to spot and hence transmit the bacteria more frequently. During removal, if the tick appears to be swollen, you can assume it has been in your body long enough for transmission to occur. The bacteria can sometimes infect the placenta when in pregnant women. There is no scientific proof that the bacteria can be spread through direct contact between humans.
Tick attachment
Ticks have good mechanisms for attachment and feeding. They use their back leg to hold onto a surface such as grass and extend their arms above. This position is called “questing”. When a host brushes past the location of the tick, it grabs onto them and holds on. In humans, ticks are mostly found in unnoticeable places, such as hairline, behind ears and neck, in the navel, armpits, waistline, groin, behind knees, and between toes. A tick takes any time from 10 mins to 2 hours to get ready for feeding. It cuts into the surface of the skin to insert its feeding tube. The tick secretes its saliva on the feeding spot. This saliva has anesthetic properties, which explains why most of the time hosts do not feel the tick biting them.
Tick removal
Removing ticks can be tricky. Using tweezers is highly recommended. Remove the tick by pulling it from as close as possible to your skin. Sometimes, some parts of the tick (such as its mouth) may not come along with its body. In such a case, it is better to leave it up to your body to heal your skin. After removing the tick, clean the area with rubbing alcohol or wash with soap. We need to take careful measures while disposing of the tick to make sure it will not be able to infect anyone else. There are multiple ways you can do this. Flush it down the toilet, wrap it in tape or place it in a plastic bag to make it immobile, or you can put it in alcohol to kill it.
Tick testing
Some people test the discovered ticks to see if they have a possibility of being infected. However, testing ticks will not prove if you have the infection or not, and hence should not be used as an indicator to start medication. Always start taking medicines only upon a doctor’s prescription, after you experience some symptoms. The reason why tick testing is not reliable is twofold: if the tick is infected, it does not mean that the person also is. There is a chance that the transmission of bacteria had not occurred yet. If the tick is not infected, it is not guaranteed that the person is not infected either. Another infected tick could have bitten them that they did not know about.
Symptoms
Symptoms appear in three stages: early localized, early disseminated, and late disseminated.
However, symptoms for these stages can overlap with one another. Like most diseases, symptoms of Lyme disease vary from person to person. The main symptom to look out for is a bullseye-shaped rash that may appear around the side of the tick bite.
Other common symptoms are fatigue, headache, fever, joint pains, muscle ache, and swollen lymph nodes. Lyme disease can also affect your sleep and concentration. In severe cases, the patients may have meningitis and Bell’s palsy [ paralysis in one side of the face]. Heart and liver problems and inflammation in the eye can be seen in some rare cases of Lyme
Diagnosis
Lab tests can be done to diagnose Lyme disease infection, but it is only reliable if it’s been done on the patient a significant amount of time after the possible tick bite. The body should be allowed time to identify the pathogen and produce antibodies to destroy it.
The lab tests are done in a 2 step process: ELISA test and Western blot test.
The enzyme-linked Immuno-absorbant assay, or the ELISA test, checks the blood for antibodies against the Lyme-causing bacteria. The chances of false positives are high for this specific test. Western blot tests will only be done if the ELISA test shows positive or indeterminate results. There are Polymerase Chain Reaction tests also available to diagnose Lyme disease. It assesses the cerebrospinal fluid or joint fluid. This test is not recommended to diagnose.
Treatment
A healthcare provider will prescribe antibiotics to treat the disease. For the early stages of Lyme disease, oral antibodies are prescribed.
Usually, doxycycline is prescribed for adults and children less than 8 years old. Amoxicillin is another oral antibiotic that is prescribed for young children and pregnant or breastfeeding mothers.
Another type of antibiotic is intravenous drugs. They are prescribed if the disease is severe enough to affect the central nervous system. It is a 2-3 week medication course. It has some side effects such as decreased white blood cells and mild diarrhea. Before getting any medications, the patients are recommended to share their current medications and details about when symptoms appeared.
Post-Lyme syndrome
Sometimes, even after completing the whole course of medications, some patients may still experience symptoms. This is called a post-Lyme syndrome. This usually affects motility and cognitive abilities. It may take months or years to recover from the post-lyme syndrome.
Prevention
Lyme disease is more prevalent in hot and humid weather when more people would want to go out and do adventurous activities such as hiking and camping. When going outdoors into bushy areas, make sure to cover all exposed skin. Ticks can also be carried into your yard through animals. Clear any woods and keep the underbrush to a minimum. Use insect repellants, lemon oil, and eucalyptus oil on the skin for more protection. Be sure to check its restrictions before using it on children. If you already had Lyme disease in the past, there is an equal amount of chance that you can get it again. Apply tick control products on pets so they will avoid bringing the ticks into houses and yards. Dogs even have a vaccine for Lyme disease. When you come back home after going outside, make sure to put clothing and gear in the heater to kill any ticks. Shower immediately and check in unnoticeable spots for any ticks. Before doing activities, you can use permethrin chemicals on clothing and gear for protection against ticks.
Vaccine
Lyme disease vaccine is available for dogs. In the past, a safe, effective, and FDA-approved vaccine was also available for humans. It was called LYMErix and produced by GlaxoSmithKline. It was tested to be a 75% effective vaccine. It worked in an unconventional method than usual vaccines. The vaccine contained bacteria neutralizing substances that would be injected into the bloodstream. When a tick bites a vaccinated person, it draws the neutralizing substance along with blood. The bacteria in the tick would be killed by the neutralizing substance before it can be transmitted into the host’s bloodstream. However, the vaccine was defamed and sued by anti-vaccine forces.
Sources
“Tick Removal and Testing.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 5 Aug. 2021, www.cdc.gov/lyme/removal/index.html.
“Transmission.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 29 Jan. 2020, www.cdc.gov/lyme/transmission/index.html.
“Lyme Disease.” Genetic and Rare Diseases Information Center, U.S. Department of Health and Human Services, rarediseases.info.nih.gov/diseases/12073/lyme-disease.
“Signs and Symptoms of Untreated Lyme Disease.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 15 Jan. 2021, www.cdc.gov/lyme/signs_symptoms/index.html.
“Diagnosis and Testing.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 21 May 2021, www.cdc.gov/lyme/diagnosistesting/index.html.
“Lyme Disease.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 24 Oct. 2020, www.mayoclinic.org/diseases-conditions/lyme-disease/diagnosis-treatment/drc-20374655.
“Preventing Tick Bites.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 30 Mar. 2021, www.cdc.gov/lyme/prev/index.html.
Oaklander, Mandy. “What Happened to the Lyme Disease Vaccine?” Time, Time, 17 June 2021, time.com/6073576/lyme-disease-vaccine/.
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