There have been 15 cases this year — the most since at least 2006 — of leptospirosis, which can cause serious liver and kidney damage and, in the city, typically spreads via rat urine. New York’s most recent anti-rat initiative, a $32 million program in 2017, targeted what Mayor Bill de Blasio said were the three most infested parts of the city: the Grand Concourse area of the Bronx; Bushwick and Bedford-Stuyvesant in Brooklyn; and a section of Manhattan encompassing the East Village, the Lower East Side and Chinatown.