Dr Robert Latham, chief of medicine at Saint Thomas Hospital in Nashville.

Washington - Eight people have now died from a rare form of meningitis after receiving injections of a steroid commonly used to alleviate back pain, US officials said on Monday.

The total number of patients had nearly doubled in the past two days to 105, said the Centres for Disease Control and Prevention, a government-run facility based in Atlanta (CDC), Georgia.

At least 75 healthcare facilities in 23 states received the contaminated steroid, according to the centre, which has initiated a recall. Infections have been reported in nine states.

Meningitis is an inflammation of the protective membranes covering the brain and spinal cord, usually caused by a bacteria or virus.

The latest outbreak was found to be caused by a fungus that is common in the environment but rarely causes meningitis, the centre said.

This form of the disease is not contagious. Because the injections were administered directly into the patient's spine, the pathogen had a direct route to the spinal cord and brain.

The symptoms take some time to develop, and are “very mild at first,” the CDC said. They include headache, fever, nausea and stiffness of the neck.

The infection was traced to steroids in syringes made at the New England Compounding Centre, a specialty pharmacy in Framingham, Massachusetts, news reports said.

The manufacturer has voluntarily expanded the recall to all products distributed from its Framingham facility, the CDC said. - Sapa-dpa