Lyme disease is caused by infections of the bacterium Borrelia burgdorferi (stained blue in inset, among red blood cells) which is transferred to humans via blood-sucking bites from the tick, Ixodes scapularis. Lyme disease can cause flu-like symptoms in the short term and more serious illnesses in the long term, if not treated. Why is Lyme disease on the rise in eastern North America? White-footed mice occupy a broad ecological niche—they occur in most communities regardless of habitat quality. Many other species, like the opossum, are absent from low-quality forest fragments. Based on this information and the data in Question 12, propose a hypothesis to explain the observed relationship between increased forest fragmentation and increased incidence of Lyme disease.

Verified step by step guidance

1. Identify the key ecological players involved: Borrelia burgdorferi, Ixodes scapularis (tick), and white-footed mice.
2. Understand the role of white-footed mice in the ecosystem: They are common in various habitats and are known carriers of Borrelia burgdorferi.
3. Analyze the impact of forest fragmentation: It leads to reduced biodiversity, leaving behind species that thrive in fragmented habitats, like white-footed mice.
4. Formulate a hypothesis: Increased forest fragmentation reduces the presence of predators and competitors of white-footed mice, leading to a higher population of these mice. This results in a higher number of ticks feeding on these mice, increasing the spread of Borrelia burgdorferi.
5. Predict the outcome: As forest fragmentation increases, the incidence of Lyme disease rises due to higher populations of white-footed mice and subsequently more Borrelia burgdorferi-carrying ticks.

Key Concepts

Lyme Disease and Its Pathogen

Lyme disease is an infectious disease caused by the bacterium Borrelia burgdorferi, which is primarily transmitted to humans through the bites of infected ticks, particularly Ixodes scapularis. Understanding the life cycle of this bacterium and its vectors is crucial for comprehending how the disease spreads and the factors that influence its incidence.

Ecological Niche and Species Interactions

An ecological niche refers to the role and position a species has in its environment, including its habitat, resource use, and interactions with other organisms. The white-footed mouse, which thrives in various habitats, can serve as a reservoir for Borrelia burgdorferi, thus influencing the dynamics of Lyme disease transmission, especially in fragmented habitats where other species may be less prevalent.

Forest Fragmentation and Disease Ecology

Forest fragmentation refers to the process where large, continuous forests are divided into smaller, isolated patches, often due to human activities. This alteration of habitat can lead to increased contact between wildlife, such as ticks and their hosts, and humans, potentially elevating the risk of zoonotic diseases like Lyme disease, as fragmented landscapes may favor species that are competent reservoirs for pathogens.