How Urbanization Affects Spread of Lyme Disease

As communities across the U.S. replace forests and woodlands with housing developments and other new construction, researchers are noting an increase in Lyme disease. To help prevent the spread of Lyme disease, Dr. Ivan Castro-Arellano, a disease ecologist and wildlife researcher at Texas State University, is exploring how urbanization and its effects on mammals impact the spread of pathogens. 

Lyme disease, which spreads from animals to humans, is one of the fastest growing zoonotic diseases in the United States. Counties considered high-risk for Lyme disease grew 300% between 1993 and 2012. Caught quickly, Lyme disease is easily treated with antibiotics, but if it goes untreated it can lead to chronic issues such as Lyme arthritis, facial palsy and impaired memory. 

Many such zoonotic diseases have been increasing globally, researchers say, partially because of the displacement of animals. While medium- and large-sized mammals are displaced or eradicated by the removal of forested areas, white-footed mice and deer thrive in small patches of green space. Mice and deer are contributing to favorable conditions for an increase in the ticks that spread the pathogens causing Lyme disease.

Although East Texas has a similar pattern of woodland space compared to new construction as the northeast United States, Texans contract the disease at lower rates. This fact piqued the interest of Castro-Arellano. In addition to studying the area where the disease is prevalent, he decided to study where the disease is not prevalent to find keys to prevention. 

Castro-Arellano is part of a team of biologists, veterinarians and biomedical researchers that have been collecting samples and trying to understand what makes East Texas different. He believes that the climate, or certain species of East Texas mammals who kill ticks, could be contributing to the reduced tick population in East Texas. 

Castro-Arellano’s goal is to apply knowledge of a disease’s context and contributory factors to prevent the spread of pathogens and keep mammals – both wildlife and humans – healthy. 

Source: Texas State University