NEW YORK (Reuters) - A 21-month-old girl is the first in the state of Michigan and second in the U.S. to die this year from a strain of the enterovirus that has infected more than 500 people across the nation, health officials said on Saturday.

Madeline Reid, who was stricken with Enterovirus D68 (EV-D68), passed away late on Friday while being treated at the Children’s Hospital of Michigan in Detroit, hospital officials said in a statement.

"It is never easy to lose a child, and our entire healthcare team at the Children’s Hospital of Michigan is deeply saddened by this family’s loss and mourns with them during this very difficult time," Rudolph Valentini, chief medical officer at the children's hospital, said.

Reid is the first in the state reported to have died from the virus, Michigan Department of Community Health spokeswoman Jennifer Smith said.

More than 500 people, mostly children, in 43 states and the District of Columbia have been infected with EV-D68 since mid-August, according to the U.S. Centers for Disease Control and Prevention.

This week, the CDC said that a 4-year-old Eli Waller of New Jersey, who went to bed last month in seemingly good health and died in his sleep, was the first fatality linked directly to the strain of the virus.

Aside from Reid and Waller, at least four others infected with Enterovirus D68 have died this year, although the CDC said it is unclear what role the virus played in their deaths.

EV-D68 is one of more than 100 non-polio enteroviruses, which are common at this time of year and cause 10 million to 15 million infections in the United States annually. Few people who contract Enterovirus D68 develop symptoms beyond a runny nose and low fever.

(Reporting by Laila Kearney Editing by W Simon)