The heroin epidemic is spreading

A police officer held a bag of heroin confiscated as evidence in Gloucester earlier this year. John Moore/Getty Images/Getty

America’s heroin epidemic is spreading, breaking across state lines and drawing whole new regions in its maw of addiction, overdose, and death.

Heroin, a scourge once concentrated in a narrow belt across the Northeast and Midwest, has been loosed on the South, according to a Globe analysis of the latest data from the Centers for Disease Control and Prevention covering overdose deaths through 2015.

And with every step, heroin carries with it a new — even deadlier — partner: illicit fentanyl, which now contributes to over a third of all opioid-related deaths in the United States.

Together, these life-draining drugs are driving the nation’s opioid crisis, eclipsing once-urgent concerns about pills like Vicodin and OxyContin. While deaths from prescription opioids have been declining, overdoses from heroin and fentanyl rose 30 percent in 2015, making them a bigger killer than gun homicides.

Heroin on the move

Many of the 13,000 Americans who lost their lives to heroin in 2015 hailed from states that have been battling heroin for several years. Ohio and West Virginia top that list. They were the first US states to see a big spike in heroin deaths, back in 2013. And their heroin death rates remain the highest in the nation.

But in 2015 heroin escaped its stronghold across the Northeast and Midwest to wreak new havoc through the South. In Georgia and both Carolinas, heroin-related deaths increased by more than 45 percent. In Florida and Mississippi, they rose by 65 percent.

There are many reasons why heroin deaths are spreading, including the addictive character of the drug itself and the widening reach of the drug cartels — which seem to have gotten more nimble when it comes to moving product to communities around the country.

Whatever the exact cause, though, the 2015 data prove that we are in the midst of an expanding epidemic, with no fixed geographic boundary and no clear limit on the number of possible deaths. In fact, given that half the country remains largely untouched, there is still plenty of room for heroin to cross more borders, enter new markets, and claim ever more lives.

Fentanyl close behind

The map of heroin deaths may look bleak, but it gets worse. Because where heroin goes, fentanyl follows. And street fentanyl is an even more volatile drug.

Fentanyl isn’t new; in its prescription form, it’s a powerful and fast-acting painkiller, used by doctors to help patients recovering from surgery or struggling with severe pain.

But in the last few years, fentanyl crossed from the pharmacy to the street, where it has quickly become a leading killer. It’s 50 to 100 times more potent than heroin, so even tiny amounts can trigger an overdose. And it has the shape-shifting ability to be sold in various forms, whether disguised as prescription pills or cut into heroin.

State by state, illicit market by illicit market, fentanyl has been following the path of heroin. Indeed, one of the best ways to predict where fentanyl deaths are set to spike is to look at where heroin has already taken hold. That means places like Ohio and Connecticut, which ranked first and third in heroin deaths in 2014, and Massachusetts, where heroin has become endemic and where fentanyl now contributes to more than half of all opioid overdoses.

The big, fast-spreading picture

Heroin and fentanyl make a natural and deadly pair, with a conjoined future. Smuggling routes set up to transport heroin work just as well for fentanyl. And one of the most common uses for fentanyl is as an adulterate for heroin, which lets dealers market a cheaper and higher-potency product.

For the moment, heroin and fentanyl deaths are overwhelmingly concentrated in the eastern half of the United States, claiming more and more lives in places like Boston and Atlanta, while keeping clear of San Diego and Portland, Ore.

But that’s changing, quickly.

In 2015, heroin took a large southward leap. Its next jump could carry it to Texas and the Southwest. Or maybe the cartels will open an entirely new route through the population centers along the Pacific Coast.

Whichever path these drugs take, however, the toll is likely to be grim. In the worst case, if heroin and fentanyl capture the entire country, raising the national death rate to match the current situation here in Massachusetts, it would mean an additional 40,000 lost lives every year — more than the number of people who die in car accidents.