It’s springtime and those annoying, biting insects are making a comeback.

Annoying but also a major health threat.

The Centers for Disease Control and Prevention (CDC) released a report recently showing that diseases from biting insects including mosquitoes, fleas and ticks in the U.S. have tripled from 2004 through 2016.

The CDC says 640,000 cases have been reported in that period, but many go unreported.

South Carolina ranks in the bottom 20% of states reporting insect-borne diseases.

“Mosquitoes and ticks and infections are moving into new areas nationwide,” CDC Director Robert Red-field told reporters in a teleconference recently.

Nine new germs spread by mosquitoes and ticks have been discovered or introduced since 2004 and about 80% of vector control organizations lack critical prevention and control capacities, according to the CDC.