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Ticks suck !

 

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There are numerous tickborne diseases that  can infect humans and cause disease. Several different tick species are responsible for transmitting these diseases and can be found throughout different geographic regions of the United States. In addition, some tick species can transmit more than one disease. Symptoms can be similar among the tickborne diseases and diagnosis of these diseases can be difficult.

Many tickborne diseases produce similar symptoms in humans and can manifest clinically as asymptomatic or mild illness to  life-threatening illness. The most common symptoms of tickborne diseases include muscle aches, fever, headaches, fatigue, joint pain, stiff neck, facial nerve palsy and rash. Not every person with a tickborne disease will develop a rash and the proportion of people that do varies with each disease.

Treatment for tickborne diseases varies but generally includes supportive therapy. Antibiotic therapy is useful for those diseases caused by bacteria and doxycycline is commonly used for several diseases. The duration of therapy varies by disease.

The diagnosis of tickborne diseases can be very difficult, particularly because the symptoms can be non-specific. However, the clinical signs in conjunction with the patient’s history can offer some clues. A history of a tick bite or tick exposure and where this occurred can be helpful.

Certain laboratory tests, such as a CBC or metabolic panel, can also offer some good information.  Diagnostic tests include serology, PCR (polymerase chain reaction), IHC (immunohistochemistry) and culture.

 

Tickborne diseases in the United States

 

 

 

Lyme disease is the most commonly reported tick-borne disease in the United States and was the most commonly reported vectorborne illness in the United States. In 2014, it was the fifth most common Nationally Notifiable disease.

In 2014, 96% of confirmed Lyme disease cases were reported from 14 states:

  • Connecticut
  • Delaware
  • Maine
  • Maryland
  • Massachusetts
  • Minnesota
  • New Hampshire
  • New Jersey
  • New York
  • Pennsylvania
  • Rhode Island
  • Vermont
  • Virginia
  • Wisconsin

 

Lyme disease is passed to humans by the bite of black-legged ticks (also known as deer ticks in the eastern United States) and western black-legged ticks infected with the bacterium Borrelia burgdorferi. The Lyme disease bacterium normally lives in mice, squirrels, and other small mammals.

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Lyme disease may cause one or more of the following symptoms:

  • An expanding circular rash called erythema migrans (may look like a red bulls-eye at the site of the tick bite)
  • Fever
  • Joint and muscle pains
  • Headache
  • Chills
  • Fatigue
  • Swollen lymph nodes

 

 

 

 

Ticks can attach to any part of the human body but are often found in hard-to-see areas such as the groin, armpits, and scalp. In most cases, the tick must be attached for 36-48 hours or more before the Lyme disease bacterium can be transmitted. If left untreated, infection can spread to joints, the heart, and the nervous system.  

There is no evidence that Lyme disease is transmitted from person-to-person through touching, kissing, or having sex with a person who has Lyme disease. There are no reports of Lyme disease transmission through breast milk. 

 

 

Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics. Steps to prevent Lyme disease include using insect repellent, removing ticks promptly, applying pesticides, and reducing tick habitat.

 

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Recognize the signs and symptoms of Lyme disease and act quickly. The early diagnosis and proper treatment of Lyme disease are important strategies to avoid the costs and complications of late-stage illness.

Early Lyme disease: The early stage of Lyme disease is usually marked by one or more of the following signs and symptoms: • a characteristic skin rash, called erythema migrans • fatigue • chills and fever • headache • muscle and joint pain • swollen lymph nodes.

Late Lyme disease: Some signs and symptoms of Lyme disease may not appear until weeks or months after a tick bite: • Arthritis is most likely to appear as brief bouts of pain and swelling, usually in one or more large joints, especially the knees. Erythema migrans (bull’s eye) rash • Nervous system symptoms can include numbness, pain, nerve paralysis (often of the facial muscles, usually on one side), and meningitis (fever, stiff neck, and severe headache) • Rarely, irregularities of the heart rhythm may occur. • Problems with memory or concentration, fatigue, headache, and sleep disturbances sometimes persist after treatment. Different people exhibit different signs and symptoms of Lyme disease. Some people never develop a bull’s-eye rash. Some people only develop arthritis, and for others nervous system problems are the only symptom of Lyme disease.

 

Testing:  

Serologic testing for Lyme disease is complex. Rational ordering and interpretation of these test results requires some understanding of the basic underlying principles and performance characteristics of the tests. The test results do not rule in or rule out Lyme disease; however, the results make a clinical diagnosis of Lyme disease more (or less) likely.

Currently, a two-stage testing process to measure the body’s production of antibodies to Lyme disease bacteria is recommended: 1) an enzyme immunoassay (EIA) or enzyme-linked immunosorbent assay (ELISA) or less frequently, an “IFA” (indirect immunofluorescence assay), followed by 2) a Western immunoblot of samples that tested positive or equivocal by EIA or IFA. These tests measure antibodies that the body makes against Lyme disease bacteria. 

Seroconversion can take as long as 6-8 weeks after a tick bite. The false-negative rate for ELISA is 32% in early disease.

 

Management:

Antibiotic selection, route of administration, and duration of therapy for Lyme disease are guided by the patient’s clinical manifestations and stage of disease, as well as the presence of any concomitant medical conditions or allergies.

Treatment of Lyme disease is as follows:

  • Adult patients with early localized or early disseminated Lyme disease associated with erythema migrans: Doxycycline, amoxicillin, or cefuroxime 
  • Children under 8 years and pregnant or nursing women with early localized or early disseminated Lyme disease: Amoxicillin or cefuroxime

 

Infectious Diseases Society of America recommendations for Lyme disease treatment

Lyme Disease treatment

** Doxycycline is contraindicated in patients younger than 8 years and in pregnant women. 

 

 

Summary:

  • Lyme Disease is the most common tickborne disease in the United States
  • Diagnosis can be difficult as symptoms can be non-specific.
  • Patients may initially present with flu-like symptoms and may or may not have a rash.
  • In most cases, the tick must be attached for 36-48 hours or more before the Lyme disease bacterium can be transmitted.
  • Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics.
  • There is no evidence that Lyme disease is transmitted from person-to-person.
  • Seroconversion can take as long as 6-8 weeks after a tick bite. The false-negative rate for ELISA is 32% in early disease.

 

 

 

 

 

References:

Tickborne Diseases of the United States: Centers for Disease Control

Lyme Disease : Centers for Disease Control

Lyme Disease : Medscape

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