Citizen Scientist Study Fuels Launch of First Interactive U.S. County Map of Ticks Carrying Diseases

PORTOLA VALLEY, Calif., Oct. 20, 2021 /PRNewswire/ -- Bay Area Lyme Foundation, a leading nonprofit funder of innovative Lyme disease research in the U.S., today announced the launch of interactive national tick maps of U.S. counties based on data published in mSphere, a multidisciplinary open-access journal of the American Society for Microbiology.  The new data identify Ixodes ticks carrying disease-causing pathogens in 116 counties which were not previously identified by the Centers for Disease Control (CDC).

"The area known to harbor disease-carrying ticks continues to expand, and we hope people across the U.S. will use these interactive maps to learn more about the risks for their hometowns, their family's residences and vacation spots," said Linda Giampa, executive director, Bay Area Lyme Foundation. "The citizen scientists contributing to this study allowed the country's collective tick knowledge to advance further than even the CDC could do at this time. Gaining the support of citizen scientists allowed us to collect from many counties across the country where ticks are not usually collected and tested, or they are not tested for these pathogens."

Citizen scientists collected and provided the ticks evaluated in the study as part of Bay Area Lyme Foundation's Free Tick Testing program, which collected more than 20,400 ticks, of which 8,954 are Ixodes ticks capable of carrying the most common tick-borne pathogens. The research was conducted through a partnership between Bay Area Lyme Foundation, Northern Arizona University, Colorado State University and the Translational Genomics Research Institute (TGen).

The study evaluated the distribution and prevalence of the four most common tick-borne pathogens: Borrelia burgdorferi sensu lato, the group which causes Lyme disease; Borrelia miyamotoi, which causes tick-borne relapsing fever; Anaplasma phagocytophilum, which causes human granulocytic anaplasmosis, and the protozoan pathogen, Babesia microti. The types of ticks that were tested were Ixodes scapularis, which is also known as the blacklegged tick or the deer tick, and  are found in the Northeast, Midwest and South, and Ixodes pacificus, also known as the western blacklegged tick, which live in the West. The interactive maps only represent data from this citizen science study, and do not represent the total risk of tick-borne infections in the US.

Lyme disease findings
Overall, Borrelia burgdorferi sensu lato, the bacterium that causes Lyme disease was identified in 293 U.S. counties across 29 states, and in 1,279 (14%) ticks submitted. Lyme bacteria were found in ticks in 75% of all counties in the Northeastern United States, and in 23% of ticks submitted from this region. In the Midwest, the bacteria were found in 78% of counties with more than five submitted I. scapularis ticks. In the West, Lyme bacteria were also found in ticks in 26% of the surveyed counties and, in the South, Lyme bacteria was found in ticks from 15% of the surveyed counties, where the prevalence of the bacteria among submitted ticks was 3%.

Tick borne relapsing fever findings
The bacteria which causes tick borne relapsing fever, Borrelia miyamotoi, was identified in 80 counties, primarily in the Northeast and West. Approximately 1% (113 ticks) of the ticks tested from the Northeast were carrying carried the bacteria. The bacteria were also detected in 2.5% of Southern counties and 4% of those in the West.

Anaplasmosis findings
The bacteria causing human granulocytic anaplasmosis, a tick-borne disease carried by ticks that can lead to organ failure, was detected in 128 counties across the U.S. with a prevalence of up to 5.3% among ticks in each county. This included 42% of counties in the Northeast, 20% of counties in the Midwest and 24 % of counties in the West with more than five ticks.

Babesiosis findings
Babesia microti was identified in 71 counties in the Northeast, Midwest and South, and an average of 2% of ticks submitted from these counties carrying the parasite. Babesia microti was not detected in any ticks in the West. A related parasite, Babesia duncani, is found in Western states but was not evaluated in this study.

"These maps will be eye-opening for many Americans as it makes it easy to see that ticks carrying disease-causing bacteria can be commonly found across the US," stated Tanner Porter, MS, a research associate at TGen and the lead author on the study. "If you aren't aware of the possibility of ticks, either in your backyard or whilst traveling, you are unlikely to look for them – but an unseen tick can still transmit a pathogen and cause disease. It is important for everyone to know to look for ticks, be aware of the pathogens that they carry, and takes steps to mitigate their risk."

This new study expands on previous research identifying ticks capable of carrying Lyme and other tick-borne diseases in 83 counties (in 24 states) where these ticks had not been previously recorded.  These included:  Alabama, Arizona, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Montana, Missouri, Nevada, North Carolina, Ohio, Oregon, South Carolina, Tennessee, Texas, Utah, Virginia, Washington, and Wisconsin. Some of the new county reports are likely due to travel-associated exposures (e.g., Montana), but many counties are in close proximity to previously known locations, illustrating either spreading range of ticks or the need for expanded on-the-ground surveillance. The study builds on recently released CDC data that added 100 counties to the list of those with disease-carrying ticks,

The tick-testing initiative supported by Bay Area Lyme Foundation and conducted by Northern Arizona University, led by the late Nate Nieto, PhD, informed this study. Ticks sent to the initiative from January 2016 through August 2019 were tested free of charge. These data were categorized, mapped, and recorded, as well as provided to the submitter. Ticks were submitted from every state except Alaska. The program received a six-fold increase in tick submissions over initial estimates, representing unprecedented national coordination of a 'citizen science' effort and diagnostic investigation.

Not all public health agencies throughout the United States have tick collection, disease risk assessment systems and/or tick-borne disease reporting requirements, and CDC reports have previously relied on research of Borrelia burgdorferi sensu stricto, a strain of the Lyme-causing bacteria that differs slightly from Borrelia burgdorferi sensu lato that was evaluated by researchers in this study.

Typical tick collection methods involve researchers canvasing various terrain with large sheet-like material, which collects ticks, but does not take into account a tick's natural attraction to mammals. The limitations of citizen studies include uneven awareness of the program across geographic areas, the fact that ticks may remain attached to a person as they travel, and reliance on motivation of people who encounter ticks.

About Lyme disease
The most common vector-borne infectious disease in the country, Lyme disease is a potentially disabling infection caused by bacteria transmitted through the bite of an infected tick to people and pets. If caught early, most cases of Lyme disease can be effectively treated, but it is commonly misdiagnosed due to lack of awareness and unreliable diagnostic tests. There are nearly 500,000 new cases of Lyme disease each year, according to the most recent CDC statistics. As a result of the difficulty in diagnosing and treating Lyme disease, more than two million Americans may be suffering from the impact of its debilitating long-term symptoms and complications, according to published reports and Bay Area Lyme Foundation estimates.

About Bay Area Lyme Foundation
Bay Area Lyme Foundation, a national organization committed to making Lyme disease easy to diagnose and simple to cure, is the leading public not-for-profit sponsor of innovative Lyme disease research in the US. A 501c3 non-profit organization based in Silicon Valley, Bay Area Lyme Foundation collaborates with world-class scientists and institutions to accelerate medical breakthroughs for Lyme disease. It is also dedicated to providing reliable, fact-based information so that prevention and the importance of early treatment are common knowledge. A pivotal donation from The LaureL Foundation covers overhead costs and allows for 100% of all donor contributions to Bay Area Lyme Foundation to go directly to research and prevention programs. For more information about Lyme disease or to get involved, visit www.bayarealyme.org or call us at 650-530-2439.

SOURCE Bay Area Lyme Foundation

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