To foster greater coordination on surveillance, research, education, and prevention of tickborne diseases, CDC established TickNET during 2007. TickNET is a public health network that includes partners from state health departments and academic institutions collaborating through the Emerging Infections Program (EIP), staff of state and local health departments collaborating through the Epidemiology and Laboratory Capacity (ELC) cooperative agreement, and CDC staff in the Division of Vector-Borne Diseases and the Division of Parasitic Diseases and Malaria. We will briefly describe key TickNET projects completed or currently underway.

TickNET provides funding to state and local health departments through the ELC cooperative agreement to help sustain and enhance routine surveillance for tickborne diseases. Approximately 18 state and local health departments are funded annually for Lyme disease surveillance, with priority given to states with a reported incidence of Lyme disease greater than the national average and to bordering states where the disease may be spreading. During 2014, an additional 7 state and local health departments received ELC funding to support surveillance for other tickborne diseases.

Together with ELC funding for program support, funding through EIP has allowed TickNET partners in Maryland, Minnesota, and New York to undertake special studies to quantify underreported tickborne diseases. These studies include a review of patient charts and codes from the International Classification of Diseases, Ninth Edition, and provide insights into the use of electronic medical records for public health surveillance. Other studies in Massachusetts, Minnesota, and New York are examining ways to streamline the evaluation of positive laboratory reports by using random sampling methods. Results from these and related studies will become available in 2015.

During 2008, TickNET partners at EIP sites in Connecticut, Maryland, Minnesota, and New York conducted a survey of commercial, clinical, and state laboratories to evaluate practices and volume of testing for 5 leading tickborne diseases. Collectively, 7 large commercial laboratories reported testing ≈2.4 million patient specimens for evidence of B. burgdorferi infection during 2008, at an estimated cost of $492 million. After correcting for test sensitivity, specificity, and stage of illness, the overall frequency of infection among patients for whom samples were tested was estimated at ≈12%. Applied to the total number of specimens, this percentage yielded an estimated 288,000 true B. burgdorferi infections (range 240,000–444,000) among source patients during 2008 (18). Results of this study will be compared with results of other ongoing CDC studies to estimate the overall frequency of Lyme disease and other tickborne infections in the United States.

Frequency is but one measure of the public health importance of a disease. To better quantify the public health burden of tickborne diseases, TickNET EIP partners in Connecticut, Maryland, Minnesota, and New York have undertaken a study to quantify current costs associated with individual cases of Lyme disease. Begun during 2014, the Cost of Lyme Disease study uses a prospective survey design to capture individual and societal costs of Lyme disease, including out-of-pocket medical costs, nonmedical costs, and productivity losses, as well as total direct medical costs to society by using billing codes from enrolled patients’ providers. This estimate will be used to guide impact assessments of current and future prevention methods.

As an adjunct to personal protective measures such as use of insect repellents, several yard-based interventions have been proposed to reduce tick abundance in the home environment. To assess the efficacy of such interventions in preventing human illness, TickNET sites have insti­tuted a series of studies to evaluate the efficacy of novel and commercially available prevention strategies. One study, a randomized, blinded, placebo-controlled, multi­state trial assessing the effectiveness of acaricide barrier sprays, will cover ≈2,700 households in 3 states, with out­comes measures including tick density on acaricide-treated properties, the number of tick–human encounters, and the number of tickborne diseases in humans. (Study results are forthcoming.) A second study, begun in Connecticut dur­ing 2012, uses a similar design to evaluate the effective­ness of bait boxes that apply fipronil to rodents that are the reservoirs of B. burgdorferi. Used by veterinarians to pre­vent flea and tick infestations on dogs, fipronil kills ticks on the rodents for several weeks and may potentially interrupt the local transmission cycle of B. burgdorferi. This study of 625 enrolled households will be completed during 2016.

Recent experience indicates that additional tickborne pathogens are waiting to be discovered. In collaboration with the Tennessee and Minnesota health departments, the Mayo Clinic, and Vanderbilt University, TickNET has recently initiated a study to identify novel agents of tickborne disease. Over the next 3 years, >30,000 clinical specimens from US patients with suspected tickborne diseases will be screened by using high-throughput molecular methods designed to detect bacteria, followed by use of genomic sequencing to characterize detected pathogens. The ultimate goal is to better describe the epidemiologic and laboratory features associated with recognized and novel tickborne pathogens and to guide the development of new diagnostic methods.

Although sometimes overlooked, tickborne diseases pose an increasing threat to public health. Factors driving the emergence of tickborne diseases are poorly defined, but current prevention methods are clearly inadequate. Addressing this problem requires a multidisciplinary approach with input of entomologists, epidemiologists, educators, and infectious disease and communications specialists. Built on the pillars of the EIP and the ELC cooperative agreements, TickNET provides a collaborative network that brings together these resources at the federal and state levels to enhance surveillance, improve prevention, and identify new tickborne diseases.