NPR News

Tuesday's Illinois primaries could bring down the first congressional incumbent of 2018, set the stage for a highly competitive gubernatorial race, and give Democrats challengers against several possibly vulnerable GOP congressmen they're aiming to defeat in order to take back the House.

There are also big signs of Democratic enthusiasm, both in how many candidates are running and in the donations voters are willing to make.

Updated 10:43 a.m. ET

There has been a shooting at a high school in St. Mary's County, Md., resulting in two people being injured, according to the local sheriff's department. The suspected shooter has also been transported to a hospital.

Great Mills High School "is on lock down the event is contained, the Sheriff's office is on the scene additional information to follow," the St. Mary's County school district wrote in a tweet.

This year's World Happiness Report doesn't have too many surprises — Scandinavian countries occupy many of the smiliest slots. But there's a West African country that's getting rave reviews for its happiness. Togo, which ranked at the very bottom of the 2015 World Happiness Report, comes in this year as the "biggest gainer," the report says. That means Togo is the country with the most-improved level of happiness in the world.

WATCH: How A Tick Digs Its Hooks Into You

2 hours ago

Spring is here. Unfortunately for hikers and picnickers enjoying the warmer weather, the new season is prime time for ticks, which can transmit bacteria that cause Lyme disease.

How they latch on — and stay on — is a feat of engineering that scientists have been piecing together. Once you know how a tick's mouth works, you understand why it's impossible to simply flick a tick.