Introduction

Lyme disease is a tick-borne bacterial infection, usually from hard backticks known as Ixodes ticks, and surfacing around mid-late summer in temperate climate woodland areas. The main causative agent is Borrelia burgdoferi which causes it to be a multisystem disease, mainly affecting the skin and nervous system. This disease can also have an impact on inflammatory arthritis, uveitis, carditis and more. In the world we live in today, it is key to analyse the effects of changes in the environment on these types of diseases. Due to climate change, different regions’ climates are altering and this may allow new species to migrate to these regions. Environmental factors, such as droughts, vegetation, and humidity, affect the Ixodes tick species and cause variations in their response to antibiotics. We are going to explore this relationship and assess how this can be managed.  

Overview of lyme disease

Ixode ticks are more commonly found in temperate woodland regions in central Europe, and recently it has been found in northern latitudes (Scandinavia and North America). Annually ∼ 465,000 Americans are treated for Lyme disease, despite not all being infected. In places like Northern America, these ticks reside mainly within proximity of people’s homes, so it is key for these people to take great care (e.g., using repellents, wearing correct clothing, etc). Clinical symptoms can be nonspecific, so it is also important for doctors to take into consideration a patient’s past exposure and lifestyle. The ticks involved in Lyme disease go through four different development stages: egg, larva, nymph and adult. Only the egg stage doesn't require blood feeding and only the nymph and adult ticks can cause transmission of the disease.

Stage 1 - Lyme disease is initially classified by erythema migrans and low-grade fevers, which occur in the first localised stages of infection, which last for 1-28 days of initial infection. A rash may also develop in most cases within the first week of infection 

Stage 2 - The early-disseminated disease stage lasts for roughly 3-12 weeks. This stage is where we start to see signs of neurological impacts and joint pains. These symptoms last 12-20 weeks and rarely recur after. This stage is also the perfect window to perform tests, such as lumbar punctures, to rule out any other causes of symptoms

Stage 3 - Late-disseminated disease occurs anywhere between months and years of the initial infection. This is where we see the longer-term symptoms such as neurological impact, arthritis, Bell’s palsy, asymptomatic meningitis and much more

Diagnosis is more complicated as it is mainly through an observation of signs and symptoms. In terms of actual tests, blood tests are more commonly examined for disease-fighting antibodies, serology tests and polymerase chain reaction (PCR) examinations. The first identifying symptom is erythema migrans; however, it may not have been initially identified and might not have occurred at all.  Other problems your doctor can look out for are:

• Acute memory disorders
• Ankylosing spondylitis and rheumatoid arthritis
• Atrioventricular nodal block
• Cellulitis
• Contact dermatitis
• Gout and pseudogout
• Granuloma annulare
• Prion-related diseases

Treatment is dependent on the age and stage of the person. Stronger courses of antibiotics are required for people with more severe symptoms and recent studies show a move towards oral therapy. Doxycycline is the go-to antibiotic with the best results (except for young children and pregnant people). Younger children will be recommended a course of amoxicillin. After treatment, you should be monitored as some people with Lyme disease may experience post-treatment Lyme disease syndrome with no specific symptoms. 

Environmental factors influencing lyme disease

Ixodes ticks prefer pastures, forests and urban parks. These ticks tend to reside in areas with larger populations of their preferred hosts, such as rodents. A study conducted in Poland showed a correlation between increasing temperature and humidity with the prevalence and activity of these ticks. In Poland, these ticks had a peak activity period in May, but in other areas, such as Scandinavia and Ireland, these had different peak times. This study confirms that climate change is indeed facilitating the spread of Lyme disease through ticks. The definition of climate change states that it is a long-term change in the average weather patterns that have come to define Earth's local, regional and global climates. We can see that this holds when observing the rising temperatures, changes in precipitation patterns and the melting ice caps. Due to these changes, the tick habitats are expanding and are causing the ticks to migrate to different regions thus increasing the transmission of these infections. This can also lead to prolonged tick activity, which was observed in the study in Poland aforementioned. 

Mitigation and adaptation strategies

There are two key ways of preventing the spread of Lyme disease through ticks: through public health measures and environmental management. 

Public health measures  

This includes wearing protective clothing. Since ticks can be found in your gardens, it is important to step into any wildlife area with protective gear, such as thicker clothing. These measures can also be taken by using tick repellents. N, N –diethyl-meta toluamide (DEET) and permethrin, are effective at protecting against ticks but do not kill them. Spraying this on yourself or your clothes is highly recommended as it can reduce the risk of being infected and contracting Lyme disease. In areas where you know you may be exposed to ticks, it is also essential to perform tick checks. Removing any ticks as soon as possible (within 24 hours) can greatly reduce your risk of any chronic symptoms. Another key action to be taken is raising awareness through education. The local governments of these areas could set up seminars or go to schools to raise awareness in areas with these environments.

Environmental management 

 As we’ve established, higher temperatures and humidity levels increase tick populations, leading to a higher infection rate for Lyme disease. Managing vegetation can create a real difference in the amount of ticks by controlling their environment. This allows ticks to be managed, without removing them completely, which can be dangerous to the ecosystems. In areas frequently used by the public, barriers made of wood chips and gravel can help protect people from tick environments. Finally, wildlife hosts should also be managed. Ticks use rodents and deer as hosts, so reducing the interaction between tick-infested areas and these hosts can be greatly beneficial.¹⁰

Vaccines are being developed, and one in particular called VLA15, is being developed by Pfizer and Valneva. This vaccine looks very promising and focuses on the North American and European strains of Lyme disease. Having a vaccine for this disease will be pivotal, as it will create herd immunity and will provide broad protection over larger populations, which is the goal for any disease. 

Summary

Lyme disease is a tick-borne infection which can develop and cause life-altering implications. This has been established and discussed throughout this article. Treatment typically involves antibiotics and hopefully, we will soon have a vaccination for this disease. The environment has been changing over the last few decades, and we can see it is continuing on the same trajectory. These climate changes cause higher temperatures and changes in precipitation patterns. This has created an environment favourable for ticks and has encouraged them to migrate, be out for longer and grow in population; however, this is not ideal for humans. With these changes, there are more and more cases of Lyme disease across the northern latitudes.  We hope to decrease this by raising awareness and encouraging governments and people to take preventative measures. This includes wearing protective clothing, using repellents when needed, creating barriers and managing the environment. It is essential to be very careful of ticks and check your body after leaving an area with ticks.