By Luc Cohen NEW YORK (Reuters) – U.S. prosecutors in Manhattan said on Monday they filed a civil lawsuit against Cigna Corp accusing the health insurer of overcharging the government’s Medicare Advantage program by making it appear patients were more ill than they actually were. Prosecutors said Connecticut-based Cigna obtained tens of millions of dollars in Medicare funds between 2012 and 2019 by submitting false diagnoses for patients in cases in which providers retained by the company had not conducted the necessary tests. Prosecutors did not specify how much money they were seeking in dam…