US health officials have confirmed more than 90 cases of a rare fungal meningitis that has been linked to a steroid used to ease back pain.

The Massachusetts pharmacy that made the steroid said it was co-operating with investigators.

The Centers for Disease Control and Prevention (CDC) posted updated figures to its website on Sunday.

The death toll stood at seven, the same number as on Saturday. The outbreak is spread across nine states: Florida, Indiana, Maryland, Michigan, Minnesota, North Carolina, Ohio, Tennessee and Virginia.

The CDC figures show there are 91 cases in the US altogether.

The steroid linked to the outbreak has been recalled, and health officials have been scrambling to notify anyone who may have received an injection of it.