VERMILLION S.D. – A team of University of South Dakota researchers, led by Hugh Britten, Ph.D., a professor in the Department of Biology, is working with the South Dakota Department of Health (DOH) to survey tick populations throughout eastern South Dakota to learn more about tick-borne diseases.
The goal for Britten and his team is to carry out systematic surveys for black-legged, or deer, ticks in eastern South Dakota. The black-legged tick is an important vector for borrelia burgdorferi, the causative agent of Lyme Disease.
“Tick surveillance has become a priority in recent years as Lyme Disease and other tick-borne illnesses have spread in the U.S.,” said Britten. “The black-legged tick had not been reported present in South Dakota until 1992 when it was found on a deer in Brookings County and a dog in Codington County. It is hypothesized that some tick species carry important human disease organisms and have been able to expand their geographic ranges due to global climate change.”
Ticks are collected by dragging a one-meter by one-meter white flannel “flag” through the vegetation along specific routes for specific lengths of time. Once a tick is collected, weather conditions, vegetation conditions and other environmental conditions are recorded. The ticks themselves are then examined under a dissecting microscope in the Britten Lab at USD.
Britten credits his graduate and undergraduate student researchers who have made multiple discoveries to advance the tick research. He said that the project began with Lauren Maestas, a former graduate assistant in the department.
“Lauren was fascinated by ticks but came to USD to research fleas and plague in small rodents and prairie dogs,” said Britten. “As a side project, he did some tick surveillance in eastern South Dakota and discovered a black-legged tick population in four counties between 2015 and 2017.”
Britten and Maestas began to collaborate with researchers at Texas A&M University and found that one of the black-legged ticks was carrying the Lyme Disease organism. Maestas published two papers on his findings, which caught the attention of Joshua Clayton, Ph.D., M.D., the state epidemiologist with the South Dakota DOH, in 2019.
Holly Black, an undergraduate student within the biology department, discovered an established population of lone star ticks in Clay and Union County -- counties the Centers for Disease Control and Prevention once considered to be outside the range for that species of ticks.
“The lone star tick is a primary vector for human monocyte ehrlichiosis and carries the causative agents of tularemia, spotted fever rickettsioses like Rocky Mountain spotted fever and the development of a red meat allergy,” said Britten. “It is important that Holly made this discovery as health care professionals can now become informed and diagnose patients accordingly.”
Britten will continue to survey lands during the summer of 2020 while collaborating with the South Dakota DOH. The lone star and black-legged ticks collected in the summer of 2019 have been sent to the CDC for further testing.