A Maryland resident died of rabies in the state's first such case in nearly four decades.

The death was confirmed by the state's Department of Health and Mental Hygiene, which did not release any other information about the victim. Officials don't know how the individual came to contract the virus.

Fewer than five cases a year of rabies in humans have been diagnosed in the U.S. over the past decade. While 320 animals with rabies were reported in Maryland last year, the last case of human rabies in the Free State was in 1976.

Rabies can be spread through saliva, tears and respiratory fluid, but most cases come from animal bites, the department said. Dogs, cats and ferrets in Maryland are legally required to be vaccinated against the rabies virus.