Tick-Borne Diseases in America: Lyme Disease and RMSF

Introduction

Part predator, part parasite, the tick is considered by many to be America's most harmful bug. Living in humid and overgrown areas, these creatures make rural America particularly prone to the various diseases they carry. From Lyme disease to Rocky Mountain Spotted Fever, ticks are the primary proliferators of zoonotic diseases in North America (Edlow, 2004). These diseases lack vaccines and are difficult to manage once a person is infected. This essay covers tick-borne diseases, why they have become such a major issue in recent times, existing treatments for the infections, and predictions of potential epidemics.

Background: The Rise of Tick-Borne Diseases

There are more than 20 tick-borne diseases in the United States. Among the most commonly reported, Lyme disease infects an estimated 300,000 people annually (National Academies of Sciences, Engineering, and Medicine, Health and Medicine Division, Board on Global Health, Forum on Microbial Threats, 2016). It was not until the spread of Lyme disease that ticks began to be considered a major public health threat. Previously, humans did not often pursue outdoor recreational activities and were more likely to live in suburban or urban areas (Danbom, 2017). However, as more people move into rural areas and spend more time in nature, the risk of tick-borne diseases has grown, raising concern among scientists about the possibility of an even larger outbreak in the future (Danbom, 2017). With more cases reported each year and a growing number of people living with Lyme disease, it is important to understand why these infections persist and what can be done to decrease exposure to tick bites.

One reason some researchers believe tick-borne diseases are on the rise is climate change. However, a recent study suggests that warming temperatures may actually reduce pathogen densities in tick bites:

"Several studies have shown that replication rates of mosquito-borne pathogens increase with temperature, but we are aware of no studies addressing this issue for tick-borne pathogens. Alternatively, the immune responses of many invertebrates are temperature sensitive, so it is possible that ticks will be more likely to reduce pathogen densities or even clear their infections at warmer temperatures" (Ostfeld & Brunner, 2015, p. 18).

This suggests that although climate change is a concern, it may not directly exacerbate the prevalence of tick-borne illness. The issue instead appears to lie in the increased time people spend outdoors and the growing number of people living in rural areas. Over the past two decades, people have been moving deeper into the American South and other rural regions where high humidity and dense vegetation make exposure to ticks more likely (Danbom, 2017).

While numerous groups are working toward the eradication of tick-borne diseases, efforts to develop vaccines have yielded only limited progress. There is still no definitive vaccine available for major tick-borne diseases like Lyme disease. "Both vaccine classes were similarly highly immunogenic. A new vaccine with high safety standards, better efficacy, low cost, and public acceptance is yet to be developed" (Badawi, Shering, Rahman, & Lindsay, 2017). Therefore, with growing concerns over tick-borne diseases, the best means of prevention remains careful clothing choices and regular inspection for tick bites.

Looking ahead over the next few decades, the drive to eradicate tick-borne diseases is largely motivated by the profound impact of Lyme disease on those infected. Lyme disease is not curable in the sense that a course of antibiotics will completely eliminate the bacteria from the body (Badawi, Shering, Rahman, & Lindsay, 2017). Some individuals have been able to clear the infection and return to an asymptomatic life, but many who do not respond to standard treatment must contend with lifelong symptoms. Lyme disease, and to a lesser extent Rocky Mountain Spotted Fever, have driven increased public awareness of tick-borne diseases and the steps people should take to prevent infection.

Lyme Disease: Symptoms, Treatment, and Prevention

The primary cause of Lyme disease is the bite of the deer tick or wood tick. The distinctive bull's-eye rash has become synonymous with the disease. The corkscrew-shaped bacteria transmitted through tick bites can penetrate virtually any part of the human body, producing a range of shifting symptoms (Fallon & Sotsky, 2017). The standard treatment for bacterial infection from most tick-borne diseases consists of several weeks of antibiotics. The shorter the interval between infection and treatment, the better the outcome.

Some people do not notice a tick bite and may wait weeks before seeking treatment, either from unawareness or fear. This delay can result in a prolonged battle with infections like Lyme disease, which require prompt intervention (Sanchez, Vannier, Wormser, & Hu, 2016). Because many tick bite cases occur in rural settings — such as parts of Minnesota or Georgia — those living far from medical facilities may have difficulty accessing timely care. Without proper, speedy treatment, patients risk lifelong complications from Lyme disease and other tick-borne illnesses.

In pregnant women, untreated Lyme disease can spread to the fetus in the womb and may, in rare cases, result in stillbirth (Fallon & Sotsky, 2017). Pregnant women infected with Lyme disease can be treated with antibiotics. The two established options are amoxicillin, taken three times daily for two weeks, and cefuroxime, taken twice daily for two to three weeks (Fallon & Sotsky, 2017). Newer treatment approaches involve doxycycline, which may be used during the first trimester but not during the second or third trimesters, and generally should not exceed 10 days for most patients. Some cases, however, may require up to six weeks of treatment: "…no longer than 10 days when doxycycline is used and prescription of a 14-day course of oral doxycycline for early neurologic Lyme disease in ambulatory patients. The duration of antimicrobial therapy for babesiosis in severely immunocompromised patients [may extend] to 6 weeks" (Sanchez, Vannier, Wormser, & Hu, 2016, p. 1767).

Beyond antibiotic therapy, preventive measures include checking the body for ticks after spending time outdoors and applying DEET-based insect repellent. The most effective way to avoid tick bites is to stay out of forested areas, tall grass, and lakesides where humid conditions support tick populations (Fallon & Sotsky, 2017). Symptoms associated with Lyme disease that have fueled public awareness campaigns include rash, stiff neck, memory problems, fatigue, arthritis, numbness and tingling in the hands and feet, and loss of control over facial muscles. These symptoms can persist for a lifetime depending on how long the individual was exposed to the bacteria and their immunological response. Although Lyme disease is commonly associated with the northeastern United States, it can occur throughout the country — much like the other well-known tick-borne illness, Rocky Mountain Spotted Fever.

Conclusion

Ticks are a serious problem for Americans, particularly in humid and overgrown areas where the risk of bites is greatest. While no vaccines currently exist to prevent tick-borne infections, practical steps can reduce exposure. Wearing long-sleeved shirts and pants and carefully inspecting the body after time outdoors are the most effective preventive measures. Treatment options for infected individuals — including pregnant women — consist of antibiotics such as amoxicillin, cefuroxime, and doxycycline, typically taken two to three times daily over several weeks. Although Lyme disease and Rocky Mountain Spotted Fever can profoundly affect the quality of life of those infected, methods of prevention and treatment are available when infections are caught early.

The first and most critical step is checking the body for tick bites and, if one is found, seeking prompt medical attention. As more people move into rural areas and spend time enjoying outdoor recreation, awareness is essential — especially during the warm, humid months when tick populations are most active. Ticks may not have commanded serious public attention in the past, but they certainly do now. Rocky Mountain Spotted Fever and Lyme disease are just two of more than twenty tick-borne diseases that can leave those infected with lifelong health conditions. Knowledge and prompt assessment of tick bites may be what prevents these diseases from reaching epidemic levels, especially across rural America.