Running Head: LYME DISEASE1

Running Head: LYME DISEASE1

Lyme Disease

Ashley Elwell

Concordia University

Introduction

Since I live in Minnesota checking for ticks when I get home from my outdoor adventures has become routine. As soon as you spot one that creepy crawly feeling of more tagging along takes a hot shower to get rid of. The real concern of bringing ticks home with you is the potential disease that they may carry. This can become a real concern for outdoors lovers. Knowing more about the disease and how to prevent it will benefit those living in areas that these ticks can be found. This paper looks at the epidemiology, biostatistics, biomedical basis as well as social and behavioral factors of lyme disease.

Epidemiology

Lyme disease is the most common vector borne disease reported in the United States (Orloski, et al., 2000) with around 25,000 cases reported per year (CDC, 2013). The etiologic agent is spirochete Borrelia burgdorferi which is carried by two types of ticks. The Ixodes scapularis, better known as the deer tick, is found in the northern midwest of the country. The disease is also carried by the Ixodes pacificus, more commonly known as the black legged tick found on the western coast. Rodents and small mammals serve as reservoirs for the disease. The people that live, work and play in infested areas where these ticks reside are most at risk of infection.

They are found in wooded areas mostly in the northeast from Virginia to Maine, Wisconsin, Minnesota and northern California (CDC, 2013) with the highest amounts of cases happening between the months of May and October (Rodhain, 1989). The most defining symptom of Lyme disease is erythema migrans which is a rash that develops as early as a day after a bite or as late as a month after. It has a distinctive ring like appearance around the bite making it an easy way of diagnosing the disease. Erythema migrans is a characteristic of the bacterial infection and is so specific to Lyme disease that no other tests are necessary to diagnose. Other symptoms are not as specific including malaise, headaches, muscle pain, fever, fatigue and joint pain (Orloski, et al., 2000). The generality of these symptoms in the absence of erythema migrans make testing necessary in order to diagnose Lyme disease. According to the American Lyme Disease Foundation lyme disease is not considered lethal by most physicians (ALDF, 2013). A study done by the CDC looking at lyme disease as an underlying cause of death on death certificates from 1999-2003 found only 23 cases out of 96,068 reported to be lethal resulting in a low mortality rate.

In order for Lyme disease to be diagnosed it must meet criteria. One is a physician-diagnosed erythema migrans that is five centimeters or larger in diameter. The other is at least one disseminated manifestation plus a laboratory confirmation of the infection. Testing includes an enzyme immunoassay or immunofluorescence assay. If that comes back positive then a Western immunoblot test is the last step. These are necessary steps to be taken in order to not misdiagnose a patient with Lyme disease and to be sure that a true incidence is being reported (Orloski, et al., 2000).

Research done among forest inspectorates in Poland found that 70 percent of those with general symptoms had a “permanent presence”. Only 25 percent experienced them “periodically” with even less, 5 percent, experiencing them “sporadically” (Lewandowska, et al., 2013). The incidence of disease was found to be more frequent with the older foresters that had been working in that environment longer increasing their amount of exposure.

To keep track of patterns of Lyme disease in the United States diagnoses are reported using a combination of passive, active and laboratory based surveillance. Passive is when a health-care provider diagnoses a patient and then reports that to either their local or state public health. The state then verifies this and can via the internet submit it to the CDC. Active surveillance is when public health staff make the effort to contact the health-care providers to find out what they have diagnosed. Laboratory-based surveillance is required in order to report a positive test to the health department (Orloski, et al., 2000).

Lyme disease is caused by the bite of infected ticks, which are found primarily on the west coast and northern Midwest of the United States. Those most at risk of contracting the disease are people who are exposed to the wooded areas and tall grasses where these ticks inhabit. There is also risk of them being carried indoors by rodents and pets such as cats and dogs. Symptoms can be vague and therefore diagnosis by laboratory tests are necessary to verify infection. A better understanding of lyme disease starts with the biology.

Biomedical Basis

The bacteria that causes Lyme disease belongs to the family Spirochetaceae, genus Borrelia and the species B. burgdorferi s. s. specifically in the United States and species B. affzeli and B. garinii in Europe (Krupka, et al., 2007). It has been found that people in the United States experience more joint pain while those in Europe have more skin and nervous system symptoms. The symptomatic difference from those suffering from Lyme’s disease in the United States and Europe is due to a structural difference between the species.

Borrelia Structure

Borrelia is a spirochete bacteria. It has a wavy or spiral shape. Its ability to be so infectious is due to the fact that it is motile. The bacteria has a flexible body and flagella that allow this. According to the University Hospital Heidelber (2009) the three types of the pathogen have different numbers of flagella which might explain the difference in symptoms experienced. The surface-exposed lipoproteins, OspA, are the main focus of vaccine efforts being researched.

B. burgdorferi Characteristics

This is a host associated bacteria, meaning it relies on a host to survive like the tick it resides in or animal or human it is passed on to. It is 10-30 um in length with 7-14 flagella for mobility. There is not a rigid cellular wall so this does not have an active role in keeping its shape. A special characteristic of this bacteria is that it does not have the circular chromosome and extrachromosomal that other spirochetes have but rather a linear one. The ends of the chromosome have closed hairpin telomeres which is not a common characteristic of a prokaryote. This is something found on the DNA of double stranded DNA viruses. The genomic structure and cell organization that is specific to this bacteria shows a past that was potentially involved “trans kingdom genetic exchange” (Barbour, 1993).

Transmission From Tick To Humans

Lyme disease is caused by the passing of Borrelia from infected ticks to animals or humans. Krupka, et al., (2007) gives a closer look at how this happens

● Borrelia attaches to the tick’s gut epithelium via OspA-TROSPA interaction.

● Intake of the human/animal blood with plasminogen.

● Plasminogen binds on the OspA and is activated.

● Borrelia then passes through the gut epithelium.

● Borrelia passes through the haemocoel to the tick salivary gland.

● The outer proteins of Borrelia change profile and binds to the immunosupressive Salp15.

● Borrelia leaves the tick.

● Borrelia enters the animal/human.

Cultivation

Successful cultivation is vital to research. Because this bacteria is unique in its structure as previously talked about it is also difficult to cultivate. With modifications a medium that has proved workable is the Barbour-Stonner-Kely (BSK). This is a fluid medium with a high density. In order for Borrelia to grow on this medium there are amino acids, cofactors, salts, N-acetyl-D-glucosamine and other variable components combined. This is a unique genome when it comes to the biology of Lyme’s disease which is why it continues to be studied.

Biological Effects on Body

Once the borrelia enters the blood stream of the animal/human immune response is triggered by the outer proteins (Krupka, et al., 2007). According to Mayo Clinic (2013) this response results in flu-like symptoms including fatigue, fever, chills, and body aches. A symptom specific to the borrelia infection is a bulls-eye like rash. If the infection continues joint pain and neurological problems may develop. In rare chronic cases there may be heart problems, swelling of the eyes, hepatits and severe fatigue. Common symptoms in reported cases and be found on among other statistics related to Lyme disease.

Biostatistics

Biostatistics such as 80% of Lyme disease cases happening in the regions of the northeastern and mid-Atlantic States lead to studies like one comparing genetics of the virus carrying tick to ticks without the virus found in other geographic areas (Qui, et al., 2001). It is thought that the genetic structure of the tick has been shaped by the history of the geographical area it resides. It is important with any disease to gather information that better help us prevent those that are at risk by educating the public with numbers they can comprehend and relate to. These numbers can then be compiled to create tables and charts for an even better understanding, like this graph showing the reported cases of Lyme disease by year in the United States (CDC, 2013).

According to the CDC Lyme disease was the “sixth most common nationally notable disease” in 2011. Of the cases diagnosed and reported that year 96% were found in 13 states of the Northeast and upper Midwest including Connecticut, Delaware, Massachusetts, Maryland, Maine, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Vermont, Virginia and Wisconsin (CDC, 2013). Statistical information on Lyme disease is closely collected, reported and monitored on a local level by health care providers diagnosing the cases and then on a national level by the Center for Disease Control and Prevention. The data is verified by the CDC and then put into a public use data set allowing anyone to access the information.

The data that is collected and then used when a case is properly diagnosed and reported includes location of the case (by county), the year the case was diagnosed, age of the affected person, their sex and the symptoms experienced. The symptoms reported include cardiac, meningitis/encephalitis, radiculoneuropathy, Bell’s palsy, arthritis and erythema migrans (CDC, 2013). This information is reported yearly, using the population as of July 1st of the year to calculate incidence rates. It is compiled by and then tables, charts and maps of the cases are created.

Access to these figures is at the CDC website in order to educate people of the risk they face. The tables available include cases by state and incidence by state for the years 2002-2011. Incidence is per 100,000 people. The charts people can look at are separated into cases by year, age and sex, month, and symptom. This gives the public many ways to look at the risk of Lyme disease like the time of year it is most reported. It also shows what the most popular symptom is for people at the time of diagnosis. The maps on the website, like the one ofReported Cases of Lyme Disease in 2011 (CDC, 2013) shown here, show the areas of the United States with the highest occurrence. This is shown by a dot per case placed in the county it was reported. The statistics for Lyme disease are collected and presented in a very efficient way to best get the information to the public. The information needs to be presented in most effective way to encourage people to take action. Behavioral and social factors must be taken into account to achieve this.

Behavioral and Social Factors

It does not seem like there would be significant social and behavioral factors for a disease such as Lyme’s that is contracted from worry free outdoor activities. There are however behaviors that will aid in prevention of contracting Lyme disease. A couple ways to look at the likelihood that an individual will take these steps are using the Health Belief Model and the Ecological Method.

Health Belief Model

According to Boston University School of Public Health (2013) the Health Belief Model is based on the individuals desire to avoid illness and the belief that a specific action will prevent or cure an illness. Whether or not a person will take recommended action to prevent illness is based on the following:

1. Perceived susceptibility- Does the individual feel they are at risk? Those living, working and playing in heavily wooded areas find themselves at higher risk of contracting Lyme disease via tick bite.

2. Perceived severity- Is the risk a serious one? Lyme disease, undiagnosed, can be a lethal illness. By the time it is diagnosed the affected person may have suffered from flu-like symptoms, joint aches and pains and even neurological symptoms.

3. Perceived benefits- The perception of the individual that action will be effective in reducing threat. People must believe or be convinced that preventative steps such as tucking in socks when out in the woods or tall grass, wearing hats, using repellents and checking for ticks after activity will reduce their threat of contracting Lyme disease. Residents in Connecticut responded to a community-wide education program with an increase of 7% checking for ticks and 5% using repellents to make a total of 99% of the population surveyed that used personal protective behaviors once told of the benefits (Gould, et al., 2008).

4. Perceived barriers- What obstacles to people see in taking the health action? The only obstacles apparent for people are that of convenience and cost. While 99% of the people in the community in Connecticut mentioned previously were taking protective measures, a majority of them would not spend more than 100 dollars to do so. On an individual basis this would not be a problem, but communities might face expenses at this level when treating large areas.

5. Cue to Action- The stimulus needed for an individual to take action. For many people the discovery of one tick is enough to take action. In my experience many cannot get rid of the “creepy crawly” feeling that more ticks are hiding. Once an individual is actually bitten they may have more incentive to take preventative action. There is also an increase of preventative behaviors in people that have had Lyme disease themselves or have had a family member with as well as an increase with age (McKenna, et al., 2004).

6. Self-efficacy- An individual’s confidence in performing the preventative behavior. With behaviors as simple as tucking pants into socks, applying bug repellent and checking for ticks in a hot shower after activity most people finding themselves at risk of Lyme disease are able to successfully take action to protect themselves.

Ecological Model

The Ecological Model (Schneider, 2011) can be applied to Lyme disease as followed. At the intra-personal level by educating individuals of their risk of contracting the disease and supplying them with preventative measures to take. At the intrapersonal level family and friends that share the same outdoor activities as well as coworkers who work in wooded areas will influence individuals to take action as they do. If parents teach their children to take part in preventative behaviors they will be more likely to continue this. Institutional factors would fall under businesses supplying employees with proper repellents and clothing. This would also include schools taking proper precautions when on field trips and teaching prevention in the classroom in areas where Lyme disease is prominent. The Community can help educate by posting information at trail and park entrances as well as treating areas of heavy foot traffic with tick insecticides. Public policy would come into play when keeping track of the incidence of Lyme disease, making sure that diagnosed cases are reported so data used to keep up to date information can be collected.

Summary

Research and surveillance of Lyme disease has led to a better understanding of where and when infection may occur. This together with education of the seemingly harmless symptoms of Lyme disease can lead to people making the connection and going in for diagnosis. While it is only prominent in certain areas of the United States it is something for locals and travelers to keep in mind and take preventative steps to avoid.

References

American Lyme Disease Foundation website. Retrieved from

Barbour, A. G. Fish, D. (1993). The Biological and Social Phenomenon of Lyme Disease. Science. Vol. 260(5114), June 1993, pp. 1610-1616.

Boston University School of Public Health. (2013). The Health Belief Model. Retrieved August, 4, 2013 from

Centers for Disease Control and Prevention website. Retrieved from

Gould, H. L., Nelson, R. S., Griffith, K. S., Hayes, E. B., Piesman, J., Mead, P. S., & Cartter, M. L. (2008). Knowledge, Attitudes, and Behaviors Regarding Lyme Disease Prevention Among Connecticut Residents, 1994-2004. Vector-Borne and Zoonotic Diseases. Volume 8, Number 6.

Krupka, M., Rask, M., Belakova, J., Horynova, M., Novotny, R., & Weigl, E. (2007). Biological bacteria of the Borrelia burgdoferi species group. Bromed Pap Med Fac Univ Palacky Olomouc Czech Repub, 151(2): 175-86.

Lewandowska, A., Kruba, Z., Filip, R. (2013). Epidemiology of Lyme disease among workers of forest inspectorates in Poland. Annals of agricultural and environmental medicine, 20(2):329-31.

Mayo Clinic. (2013). Retrieved from

McKenna, D., Faustini, Y., Nowakowski, J., Wormser, G. P. (2004). Factors influencing the utilization of Lyme Disease- prevention behaviors in a high-risk population. J am Acad Nurse Pract. 16(1): 24-30. Retrieved from

Orloski, K.A., Hayes, E. B., Campbell, G. L., Dennis, D. T. (2000). Surveillance for Lyme Disease-United States, 1992-1998. Surveillance Summaries, 49(SSO3):1-11.

Rodhain, F., Perez-Eid, C. (1989). Lyme disease: epidemiology. La Revue du praticien, 39(15):1291-3.

Schneider, M. (2011). Introduction to Public Health [Kindle Version]. Retrieved from Amazon.com

University Hospital Heidelberg. (2009). Structure of Bacteria That Causes Lyme Disease Detailed in 3D. Science Daily. Retrieved July, 28, 2013, from

Qui, W., Dykhulzen, D. E., Acusta, M.S., & Luft, B. J. (2001). Geographic Uniformity of the Lyme Disease Spirochete (Borrelia burgdorferi) and Its Shared History With Tick Vector (Ixodes scapularis) in the Northeastern United States.