A deadly outbreak of fungal meningitis has left four people dead and dozens still ill in a number of US states.
The outbreak is believed to be linked to steroid injections given for pain relief at two clinics in Tennessee, the Centres for Disease Control and Prevention revealed.
Two people have so far died in the state, with 18 others becoming ill.
Four other states have reported cases, with a total of 26 illnesses and four deaths altogether.
"Some are improving and some are in critical condition," said Dr David Reagan, chief medical officer for the Tennessee Health Department.
The other cases are in Virginia, Maryland, Florida and North Carolina. Virginia and Maryland have each had one fatal case.
A Massachusetts chemist suspected as the source of a steroid linked to the outbreak has voluntarily suspended operations.
The New England Compounding Centre said it started a voluntary recall on September 26 and was working closely with the authorities to try to find the source of infection.
A specialist at Vanderbilt University says he believes the country will see more cases of the rare meningitis - which is not infectious - over the next few weeks.
Dr William Schaffner, chairman of Vanderbilt's Department of Preventive Medicine, has been following the investigation into the cause of the infection since it was first detected in a patient at the university's hospital about two weeks ago.
Dr Schaffner said he believed part of the reason for the Nashville cluster was early detection.