Researchers from Colorado State University and Northern Arizona University enlisted hundreds of citizen scientists throughout the United States to give a more accurate picture of where tick-borne diseases occur. Their findings appeared in the scientific journal PLOS ONE on Thursday.
“Our study may be a new way of understanding exposure to tick-borne diseases,” explained Daniel Salkeld, a disease ecologist with Colorado State University. “Normally the approach is to rely on reported disease cases, or to look at ticks in natural habitats. Our data represent that in-between, middle ground: It shows when people or animals got bitten, and where, and what they got exposed to.”
Originally, the study was intended to focus on the San Francisco Bay Area and illuminate the growing public health concerns about Lyme disease, a poorly understood disease transmitted to humans, dogs and other pets via tick bites.
But once the researchers reached out to citizen scientists about collecting ticks that bit them or their pets, the response from around the country was overwhelming.
“The overwhelming participation from residents throughout the country and the surprising number of counties impacted demonstrates that a great need exists throughout the country for this information,” said Nathan Nieto of Northern Arizona University, who led the diagnostic testing of each tick received in the mail. “This study offers a unique and very valuable perspective, as it looks at risk to humans that goes beyond the physician-reported infection rates and involved ticks that were found on or near people.”
Nieto and Salkeld analyzed nearly 16,000 ticks sent to them through the mail from participants from every state but Alaska, and from Puerto Rico. About 90 percent of the ticks were removed from either pets or humans.
Nieto and his team then analyzed the ticks, testing them for the presence of Lyme disease and babesiosis, a debilitating disease that afflicts mostly livestock.
What they found was illuminating, including the identification of 83 counties and 24 states where ticks carrying disease-causing bacteria hadn’t been previously documented.
Additionally, the research tested for Borrelia miyamotoi – bacteria related to Lyme disease – and found a high prevalence throughout tested regions. The bacteria are not typically tracked by public officials, according to the study.
Tick scientists typically study disease vectors in a highly localized way, but enlisting citizen scientists allowed them to look at disease prevalence in a big-picture context. The approach could be used to determine how Lyme disease and other tick-borne diseases spread.
“For example, we could start to look at what species of ticks are active, when and where,” Salkeld said. “And how does this differ from across the north or south, or the Midwest to California? There could be all kinds of subtle variations.”
Lyme disease is an infectious disease that causes short-term issues like fever, chills, headache and fatigue. In the majority of cases, the disease is cured by a course of antibiotics. But in some cases, mostly when the disease is left untreated, people can develop chronic and occasionally debilitating health problems with symptoms consistent with fibromyalgia or chronic fatigue syndrome.