A new immunological multiplex blood test promises to revolutionize the diagnosis of tick-borne diseases (TBD) by offering a single test to simultaneously identify up to eight pathogens, including Borrelia burgdorferi, which causes Lyme disease. Details of the test were published in Scientific Reports and comes from a team led by researchers from Columbia University's Mailman School of Public Health.
"The number of Americans diagnosed with tick-borne disease is steadily increasing as tick populations have expanded geographically," says lead co-author Rafal Tokarz. "Each year, approximately 3 million clinical specimens are tested for TBDs in the U.S. Nonetheless, the true incidence of TBDs is likely greatly underestimated, as patients with presumed TBDs are rarely tested for the full range of tick-borne agents, and only a fraction of positive cases are properly reported,” adds lead co-author Nischay Mishra.
The test, called TBD-Serochip, is described as the “first multiplex, array-based assay for serodiagnosis of tick-borne diseases.” The array slide contains approximately 170,000 12-mer linear peptides that represent protein sequences of major antigens from TBD agents. By testing for antibodies in the blood, TBD-Serochip can simultaneously identify up to 8 major pathogens present in the US. These include Anaplasma phagocytophilum, Babesia microti, Borrelia burgdorferi, Borrelia miyamotoi, Ehrlichia chaffeensis, Rickettsia rickettsii, Heartland virus and Powassan virus.
To test TBD-Serochip, the team examined sera from patients with confirmed Lyme disease, babesiosis, anaplasmosis, and Powassan virus disease. They identified a wide range of specific discriminatory epitopes that demonstrated accurate diagnosis of each disease. Even previously undiagnosed infections were also identified. The team concluded the test to be a “promising tool for a differential diagnosis not available with currently employed serologic assays for TBDs.”
"Diagnosing tick-borne illness is a difficult journey for patients, delaying effecting treatment," says senior author Ian Lipkin. "The TBD Serochip promises to make diagnosis far easier, offering a single, accurate test for eight different TBDs. Early detection of infection enables rapid and appropriate treatment."
Apart from its utility as a diagnostic platform, TBD Serochip can serve as a powerful research tool for studying TBDs. The technology can be used to investigate individual antibody responses in patients with TBD, looking at the interplay of TBD agents on disease manifestation and progression. It could also examine the impact of genetic diversity of tick-borne pathogens on the host immune response.
Image: The Lone Star tick is a common biting tick widely distributed in the southeastern and eastern United States. Image courtesy of the CDC.