One professor calls it a "hidden threat": Bloodsucking ticks that carry an array of diseases hitch rides on deer as the mammals multiply across the country, popping up in forests, parks and even our front lawns.

That probably means ticks in more places than ever in the USA in 2019, said Thomas Mather, a University of Rhode Island entomologist known as "The Tick Guy." And that could mean more Americans are at risk from tick-borne illnesses such as Lyme disease.



"The phenomena of deer in more places and in ever-increasing proximity to people is, I think, the largest factor affecting the ticks-in-more-places trend," said Mather, who calls springtime "almost a perfect storm" for ticks.

Mather runs Rhode Island's TickEncounter Index, which monitors tick populations based on data from volunteers across the country. The continental USA is listed for "high" activity through May 15 except for three states: California, Oregon and Washington.

Mather traced the uptick primarily to that "hidden threat" of deer moving closer and closer to where we live. He pointed to his son, a Boston suburbanite who sees deer in his tree-lined neighborhood.

America's deer population boomed over the past century, from dwindling numbers in 1900 to an about 33.5 million in 2017 – a population larger than Texas.

“The more commonly you see deer in your area, the more likely it is you’re going to see ticks," Mather said.

Lyme disease could hit 2 million mark next year

Black-legged ticks, or deer ticks, have "pretty strong" numbers in New England, the Mid-Atlantic and Upper Midwest, said Mather, who's heard from volunteers in the region.

Black-legged ticks that carry Lyme disease "are far and away most responsible for tick-borne diseases," he said.

Tick-borne disease cases more than doubled from 2004 to 2016, according to the Centers for Disease Control and Prevention, and Lyme disease accounted for 82% of all cases.

Next year, the number of people with tick-borne Lyme disease could hit almost 2 million nationwide, scientists said in the peer-reviewed journal BMC Public Health.

The disease's symptoms include fever, headache, fatigue and skin rashes, the CDC said, but untreated infections can spread to the heart, joints and the nervous system.

More:CDC apologizes for hiding ticks on muffin to warn of Lyme disease

It's not just black-legged ticks: Lone Star ticks and Gulf Coast ticks carrying less common diseases are on the move in certain regions, Mather said.

“And these types of ticks all have one thing in common: They utilize whitetail deer as a blood source in some part of their life cycle," he said.

America's booming deer population can be traced to fewer predators, fewer hunters, hunting regulations and new spaces – think lush parks and suburban landscapes – that let deer thrive, said Anthony DeNicola, president of White Buffalo, a Connecticut-based nonprofit group dispatched to cull deer herds everywhere from tony suburbs to all of Staten Island.

Efforts to manage deer have been too little, too late, DeNicola said, and quiet residential areas have let deer become comfortable, shedding ticks near people's doorsteps.

“You’re shoveling against the tide," he said.

What's needed is a paradigm change, DeNicola said, for Americans to view deer less like majestic Bambis and more like health threats that spread diseases.

"We have the tools to kill deer, but you have to train the hunter to not think as a recreationalist but as a manager," he said.

How to avoid ticks – in your yard and on your body

Here are tips on how to avoid ticks (and the deer that bring them) on your property and on your person, according to the University of Rhode Island's TickEncounter Resource Center:

Keep out deer, which bring ticks to your yard, and mice, by which ticks become infected. Clean and clear spaces around sheds, woodpiles and any other enclosed areas where mice might like to hide, and consider deer-resistant plants, a deer fence and deer repellent sprays.



which bring ticks to your yard, and mice, by which ticks become infected. Clean and clear spaces around sheds, woodpiles and any other enclosed areas where mice might like to hide, and consider deer-resistant plants, a deer fence and deer repellent sprays. Tick-repellent clothing is the best (and simplest) way to prevent bites. Such clothing can be purchased, or DIY methods for clothes already owned can be used. If you don't have tick-repellent clothing, tucking pants into socks is one way to keep ticks out.



is the best (and simplest) way to prevent bites. Such clothing can be purchased, or DIY methods for clothes already owned can be used. If you don't have tick-repellent clothing, tucking pants into socks is one way to keep ticks out. If you've been outside, check for ticks in the places they prefer: armpits, backs of knees, waistbands and other tight, constricted spaces. Check everywhere: Attached ticks don't wash off during a shower.



check for ticks in the places they prefer: armpits, backs of knees, waistbands and other tight, constricted spaces. Check everywhere: Attached ticks don't wash off during a shower. If you do spot a tick: Remove it with tweezers, grasping close to the skin and pulling steadily upward to keep from breaking the tick. Disinfect the skin area with rubbing alcohol.

Contributing: Frank Witsil, Detroit Free Press