By Megan Brooks
WebMD Health News
Nov. 15, 2018 -- Tick-borne diseases are once again on the rise in the United States, and the reasons aren't clear, the CDC says.
In 2017, state and local health departments reported a record number of cases of tick-borne diseases to the CDC, according to surveillance data. Cases of Lyme disease, Rocky Mountain spotted fever, Powassan virus, and other tick-borne illnesses increased from 48,610 cases in 2016 to 59,349 cases in 2017.
The numbers are probably higher, the CDC says, because many cases of tick diseases are never reported.
The 2017 increase mirrors a rise in tick-borne diseases reported in the United States. Between 2004 and 2016, the number of cases doubled, and researchers discovered seven new tick-borne disease-causing germs.
U.S. Not Ready for the Threats
Although the reason for the increase in tick-borne disease is unclear, the CDC says several things can affect tick numbers each year, including temperature, rainfall, humidity, and host populations, such as mice and other animals. In any year, tick numbers vary by region, state, and county. Heath care provider awareness, testing, and reporting can also play a role.
In a report released in May, the CDC said diseases caused by mosquito, tick, and flea bites more than tripled from 2004 and 2016. It concluded that the United States is not fully prepared to control these threats.
The agency has encouraged state and local public health agencies to:
- Build and sustain public health programs that test and track germs and the mosquitoes and ticks that spread them.
- Train staff on ways to prevent and control carriers of disease.
- Educate the public about how to prevent bites and control germs spread by mosquitoes, ticks, and fleas in their communities.