Democratic Sen. Patrick Leahy has urged the government to explore a possibile terrorist link to an outbreak of West Nile virus that has killed 54 people this year. “I think we have to ask ourselves: Is it coincidence that we’re seeing such an increase in West Nile virus or is that something that’s being tested as a biological weapon against us?” said Leahy, who chairs the Senate Judiciary Committee. Leahy’s office was one of several to receive anthrax-laden envelopes last year, the Associated Press reports. Leahy said he could point to no specific evidence that the outbreak of the mosquito-borne virus was linked to terrorism, and a spokesman for the Centers for Disease Control and Prevention said there is no evidence to suggest an act of bioterrorism. Nearly 1,300 people in the U.S. have so far contracted West Nile. “In the times in which we live, questions about our vulnerabilities are unavoidable,” the Vermont senator said in a written statement. “Finding all the answers we can is more important than ever.”