A recent study published in PLOS Neglected Tropical Diseases by a multidisciplinary team representing both veterinary and human a medicine evaluated the presence and spread of leptospirosis among urban rat populations in Boston, Massachusetts. Researchers conducted a multi-year effort to determine the prevalence of Leptospira interrogans and other Leptospira infections in brown rats (Rattus norvegicus and R. rattus) and to learn how strains of these bacteria differ among populations of rats.