NEW YORK — Every New York City mayor has waged war — and mostly lost — against one of humanity’s most cunning and enduring foe: rattus norvegicus. But has the city’s vilest enemy, better known as the common brown rat, finally met its match?

Mayor Eric Adams introduced a former elementary school teacher and anti-rat activist as his new “rat czar” on Wednesday. Officially, Kathleen Corradi, the mayor’s new hire, will be known as the director of rodent mitigation.

Corradi is tasked with battling the potentially millions of rats lurking in myriad urban nooks and crannies, subway tunnels and empty lots.

Hers is a new job, which the city advertised with a help-wanted ad seeking applicants who are “bloodthirsty,” possess “killer instincts” and could commit to the “wholesale slaughter” of rats.

“When I first saw this job posting, I wasn’t sure if it was real. ‘Blood thirsty’ is not a word you usually see in a job description and it’s certainly not a word I usually (use to) describe myself,” Corradi said in a news conference at a Harlem park.

“You’ll be seeing a lot of me and a lot less rats,” she vowed.

Rats have long bedeviled the city, a top public concern along with crime, homelessness and exorbitant rents. No traps nor poisonous bait have fully succeeded in reducing their numbers. Rats have thrived in subway tunnels and burrows within empty lots and city parks.

“Rats are smart, they are resilient,” said Adams, a Democrat. “Many of us live in communities where rats think they run the city.”

Over the past year, residents have called in almost 3.2 million rat sightings to the city’s 311 service request line, just shy of the record number of complaints in 2021.

“Rats have proven to be one of the most formidable opponents that humans have faced. Here in New York City, we’re locked in a constant battle,” said Councilmember Erik Bottcher, whose district includes Times Square.

New York City’s approach is in contrast to some efforts by animal-rights advocates in Paris, where there could be more rats than its 2.2 million people, perhaps twice as many, according to some estimates. A strike by garbage workers left some streets teeming with rats.

The animal rights group Paris Animaux Zoopolis has been trying to convince Parisians that “rats are not our enemies!”

Adams thinks otherwise.

As Brooklyn borough president, he once showed reporters a bucket filled with a toxic soup meant to drown rats.

“There were people that were yelling, you know, ’Oh you murderer. You murderer!’” the mayor said. “You know, we can’t be philosophical about things that impact the quality of life of New Yorkers.”

And he’s had trouble controlling them even outside the Brooklyn townhouse he owns — something he mentioned in jest Wednesday.

In February, the mayor challenged a pair of citations issued to him by his own health department for not doing enough to control rodents outside the townhouse. The administrative judge sided with the mayor on one citation but ordered him to pay $300 for the other.

In November, the mayor signed legislation intended to reduce the city’s rat problems, including new rules limiting how long garbage can sit out on curbs.

“The fewer rats the better,” said Nina Daugherty, a Harlem resident who came upon the news conference while jogging through a local park.

Corradi’s first task will be to launch a “rat mitigation zone” in Harlem, where the city will invest $3.5 million to roll out “an accelerated rat reduction plan” deploying 19 full-time and 14 seasonal employees to combat rats. Strategies that work in Harlem will be extended elsewhere.

Besides the “ick,” factor, rats can spread disease like leptospirosis. On rare occasions, the ailment can lead to meningitis and cause the kidneys and liver to fail.

Corradi said her job will be to combat rats by taking away their food sources — often garbage and food scraps.

“I have a long history with rats,” she said. As a 10-year-old, she gathered signatures for an anti-rat petition in her neighborhood. She also led efforts by New York City schools to control the vermin in school buildings.

It’s not the first time a New York mayor has appointed a rat czar. Rudy Giuliani anointed one of his deputy mayors to handle the job — although Corradi will be the city’s first director of rodent mitigation.

During his time in office, Giuliani established a task force, which spawned a boot camp called the “rodent academy” that still produces cadres of foot soldiers hoping to vanquish the city’s army of rats.

Former Mayor Bill de Blasio budgeted more than $30 million in his own failed bid to conquer rats. One plan relied on dry ice to suffocate rats in their burrows. It proved comedic at one demonstration for journalists when workers chased — but never caught — one of the fleeing vermin.

“Everyone tried,” Adams said, acknowledging the city’s noble efforts — and ultimate failures.

“We needed someone that was going to put all the pieces together and all the players together to coordinate this entire symphony of fighters. We needed a maestro.”