March 27, 2019 -- The CDC for the first time will be monitoring the nation’s tick population and the diseases the pests may be carrying.

The effort comes as the number of people diagnosed with serious diseases caused by things like ticks, fleas, and mosquitoes has more than doubled over the past few decades. Ticks caused the vast majority of those diseases.

Its aim is to assess where Americans might be most likely to get a tick-borne illness.

“For the first time this year, the CDC is funding states to conduct widespread surveillance of ticks and the pathogens they can transmit, in addition to funding human disease surveillance and education and prevention,” says Anna Perea of the National Center for Emerging and Zoonotic Infectious Diseases’ Division of Vector-Borne Diseases. “Taken together, the data can help define areas where ticks are spreading, the infectious pathogens that they carry, and where risk of tick-borne disease is increasing.”

Richard S. Ostfeld, PhD, a disease ecologist with the Millbrook, NY-based Cary Institute of Ecosystem Studies, called the CDC's step "great news."

“The CDC will be able to paint a picture of where risk is occurring, and it will provide us with better data than we have ever had before with geographic coverage of the ticks, where they are moving, and how infection prevalence is changing," he says.

In 2017, the number of tick-borne disease cases reported to the CDC rose 22%, to 59,349. But the number of Americans with tick-related diseases was likely much higher -- closer to 300,000 to 400,000 -- because not all Lyme disease cases are reported to the CDC, says John Aucott, MD, chairman of a national tick-borne disease working group, supported by the U.S. Department of Health and Human Services.

“It is hard to predict what will happen in any given year, but the long-term trends are obvious,” says Aucott, who’s also director of the Johns Hopkins Lyme Disease Clinical Research Center. “There are more tick-borne disease [cases] every year.”

The most common illness caused by a tick bite is Lyme disease. In 2017, there were 42,743 cases of Lyme disease, up 17% from 2016, according to the CDC. Lyme represented 72% of all tick-borne diseases reported in 2017. Ticks carry other diseases, such as anaplasmosis, ehrlichiosis, Rocky Mountain spotted fever, babesiosis, tularemia and Powassan virus, but these diseases are rarer than Lyme.