BOSTON -- An organ donation turned deadly in Boston after doctors discovered transplanted kidneys were infected with a hard-to-detect virus.

The Boston Globe reported that a 70-year old woman died at Boston Medical Center after receiving a kidney from a 49-year-old homeless man who died in March. The hospitals were not releasing either of their names because of patient confidentiality rules.

The donor had suffered irreversible brain damage after cardiac arrest.

A 57-year old man who received the donor's other kidney was in critical condition at Beth Israel Deaconess Medical Center.

Health officials said the donor was carrying a virus known as lymphocytic choriomeningitis virus or LCMV, which is usually transmitted by rodents.

It's the same virus that killed three transplant patients in Massachusetts and Rhode Island in 2005, the Globe said.

Doctors had tested the donor's organs for easily detected bugs, such as AIDS, herpes and hepatitis, but they said it takes too long to thoroughly screen for all germs and some patients lives are at risks if they get no organ transplant at all.

New England Organ Bank, the region's organ procurement agency, said the organs showed no signs of having other infections, but the homeless donor was considered high risk.

The patients were informed of his status and decided to proceed with the transplants anyway, doctors said. The man had waited four years for a kidney.

Samples from the donor and two recipients were rushed to the Centers for Disease Control after the woman died and all tested positive for the virus. Most people catch it after exposure to rodent droppings, wild animals or pets.