Citizen scientists discover disease-carrying ticks in 83 new US counties

Researchers discovered that ticks capable of carrying Lyme and other tick-borne diseases were found in 83 counties where they had previously never been recorded, according to a recent study powered by citizen scientists from across the United States.

With logistical and cost constraints hindering more in-depth research of human contact with ticks, Nathan C. Nieto, PhD, assistant professor of microbiology at Northern Arizona University, and colleagues called on residents from across the U.S. to send in their ticks to be tested through a free program offered by the Bay Area Lyme Foundation.

“Citizen science can offer information on national patterns in health issues and simultaneously convert the public from passive recipients of information to active participants in a scientific study and, in effect, increase the body of scientific knowledge on an issue that is directly affecting them,” the authors wrote in PLoS One.

By using citizen scientists, Nieto and his colleagues hoped to determine the prevalence and distribution of ticks, as well as human exposure to tick-borne illnesses, which have been steadily on the rise.

According to the CDC, since 2004, seven new tick-borne pathogens have been reported in the U.S. and the annual number of reported vector-borne illnesses has tripled from 27,388 to 97,075 during that time. Although many factors contribute to this rise, the CDC said ticks have been moving north into territories where the climate had previously been too cold for them to survive, which could contribute to the spread of the diseases.

“This study could help people to understand there’s a lot more out there than just the couple of things that we’re generally nervous about when it comes to ticks,” Nieto told Infectious Disease News.

When the study began in January 2016, Nieto and colleagues expected to get approximately 2,000 ticks and planned for most to come from the San Francisco Bay area, but significant participation from the public brought in more than expected.

Nearly 1.5 years after the free service had been made known to the public through the Bay Area Lyme Foundation website, the team had 16,080 ticks, comprising more than a dozen species, from 49 states to study, a response the authors say stems from the public’s “desire for knowledge into disease ecology and epidemiology.”

Each submission included basic information on the sender’s interaction with the tick — the location, date collected, habitat type, whether it was found on a human, pet, or other host, and the activity of the individual who found the tick. 

“There was no way our little lab would have been able to get that kind of data without the collaboration of the Bay Area Lyme Foundation and the citizen scientists,” Nieto said. “It was massive and wonderful.”

Teams of scientists then screened the collected ticks for Borrelia burgdorferi, the bacterium that causes Lyme disease in the U.S. and found ticks capable of carrying it in 83 counties where they had not previously been recorded, according to the study. Additionally, researchers checked for a parasite called Babesia microti that causes human babesiosis, a disease that can cause influenza-like symptoms, such as fever, headache, body aches, nausea and fatigue, and can be life threatening. The study found that this parasite was present in ticks from several states where the disease had not yet been reported.

“It’s important to know that there are areas outside of the regions most people associate with ticks that have a variety of ticks and tick-borne diseases,” Nieto said. “That needs to be on clinicians’ radars, so they can avoid going down a rabbit hole trying to diagnose something that could be from a tick bite.”

According to the authors, having these data could help understand the geographical patterns and distribution of ticks as well as the risk associated with tick-borne illnesses, something the very localized studies frequently done by laboratories and government agencies cannot do easily.

Nieto said he and the researchers still have plenty of data left to sift through, but they hope to begin comparing the collected data with those of traditional methods of sampling to find differences and commonalities and calculate risks.

“We’re going to start to figure out what the true diversity of bacteria are in different regions,” Nieto said. “We’ll be able to isolate and clarify where we have Lyme bacteria and its nearest neighbors that are either infectious or noninfectious and looking at the evolutionary history of these pathogens.”– by Caitlyn Stulpin

Disclosures: The authors report no relevant financial disclosures.