Fact Sheet: Lyme disease
What is Lyme disease and how is it diagnosed?
Lyme disease (LD) is a bacteria disease caused by Borrelia burgdorferi. The LD is an animal-borne disease (zoonotic) transmitted by certain ixodid ticks or black-legged ticks, which are commonly reported in the United States. In addition to B. burgdorferi, other related species such as B. afzelii, and B. garinii cause LD in Europe and Asia (Shapiro, 2014).
The diagnosis of LD is sometimes difficult since the symptoms mimic other disorders. However, serologic tests are used in patients that have erythema migrans based on the clinical history of likely contact with ticks in certain areas, where LD is endemic. A two-tier serologic testing is often recommended since it involves ELISA quantitative tests to detect the antibodies concentration in B. burgdorferi and the use of Western blot whenever the ELISA results are positive. The most tested antibodies to B. burgdorferi include IgG and IgM, which provides an indication to the bacteria (Shapiro, 2014).
What is the problem?
The symptoms of LD depend on the stage of disease development from the initial tick bite. Early symptoms occur within the first month, following the tick bite, which includes an enlarging red rash (erythema migrans) around the area of bite (CDC, 2015). Other early symptoms include flu-like symptoms such as headaches, fever, swollen lymph nodes, chills, fatigue, and joint and muscle aches. Symptoms that occur later include widespread pain, arthritis, insomnia, dermatitis, bilateral hearing loss, epilepsy, tremors, psychosis, depressions, carditis and among others (Borgermans, Goderis, Vandevoorde & Devroey, 2014).
The mortality rates of LD patients depend on the magnitude and the time of treatment after infection. Most mortalities of LD are associated with Lyme carditis, occuring when the infection reaches the heart tissues. Although it is approximated that 1% of Lyme carditis occurs in all LD cases, only four deaths have been reported between 1985 and 2008, worldwide (CDC, 2015). It is also suggested that the mortality rate of LD is approximated at 1/100,000 cases (Halperin, Baker & Wormser, 2013).
What are the major risk factors?
The most notable risks of LD infections involve the recreational and occupational exposures to ixodid ticks during various outdoor activities such as hunting and farming in endemic areas, especially during the early summer and spring months when there are abundant tick nymphs (Shapiro, 2014).
What populations are at risk?
The incidences of LD infection is said to affect children aged between 5 and 14 years and middle-aged adults aged between 40 and 50 years. However, it is less frequent in females than in males due to the males’ over involvement in various outdoor practices in areas infested with ixodid ticks such as gardening (Shapiro, 2014). Moreover, the gender distribution in patients with LD is associated with the complexity of the infection along their genetics where females predominantly manifest cutaneous symptoms, while males have noncutaneous manifestations of Lyme borreliosis. Besides, the populations situated in areas habited with deer increases the risk of exposure to the infection due to human contact with deer ticks (Borgermans, Goderis, Vandevoorde & Devroey, 2014).
What is the incidence of the disease?
In the US, LD is the most prominent vector-borne disease, especially in the Northwest and the upper Midwest. Among the most common Nationally Notifiable diseases, LD was ranked fifth in the year 2014. In each year, it is estimated that 300,000 people in the United States are diagnosed with LD, with over 96% cases of the disease confirmed and reported from fourteen states (CDC, 2015). In Connecticut, the state with the greatest level of LD frequency, the occurrence of confirmed cases in 2002 was 133 per 100,000 people (Plotkin, Orenstein & Offit, 2013).
How is the disease treated?
In the early stages of LD, oral antibiotics, including amoxicillin, doxycycline, or cefuroxime axetil are used for treatments. However, the late stages of LD are treated using the intravenous antibiotics such as ceftriaxone or doxycycline (Shapiro, 2014).
How is the disease prevented?
LD can be prevented by breaking the life cycle of the disease transmission. Avoiding the tick-infested areas through recreation activities prevents humans contact with ixodid ticks. Moreover, applying the skin with the insect repellants containing N-diethyl-meta-toluamide (DEET) or wearing long pants and shirts or applying permethrin on clothing helps to prevent the skin tick bites. Tumbling the clothes in a dryer using high heat may kill any ticks attached to the clothing (Shapiro, 2014).
Since the ticks take about two hours to attach to the skin, having a bath within the two hours of exposure may also help in preventing tick bite infections. Additionally, regular inspection of the body and clothes for ticks after exposure and removing them is also a preventive measure. The application of acaricides on pets and in suspected areas with ixodid ticks, as well as the removal of leaf litter around homesteads or yards may help in reducing the risks to infection of LD. In the past, a vaccine provided protection against the infection of B. burgdorferi, but it is no longer available after it was discontinued in 2002 due to inadequate consumer demand (CDC, 2015).
References
Borgermans, L., Goderis, G., Vandevoorde, J. & Devroey, D. (2014). Relevance of Chronic Lyme disease to Family Medicine as a Complex Multidimensional Chronic Disease Construct: A Systematic Review. International Journal of Family Medicine, 2014, 2, 1-10.
Centers for Disease Control and Prevention (CDC) (2015). Lyme Disease. Retrieved from http://www.cdc.gov/lyme/index.html
Halperin, J. J., Baker, P., & Wormser, G. P. (January 01, 2013). Common misconceptions about Lyme disease. The American Journal of Medicine, 126, 3, 1-7.
Plotkin, S. A., Orenstein, W. A., & Offit, P. A. (2013). Vaccines. Edinburgh: Elsevier/Saunders.
Shapiro, E. D. (2014). Lyme disease. The New England Journal of Medicine, 371, 7.
