A hospital worker who deliberately infected patients with hepatitis C and was responsible for the death of at least one of them has been jailed for 39 years.

David Kwiatkowski worked as a cardiac technologist in 19 hospitals in seven states before he was arrested in 2012.

The 34-year-old stole painkillers and infected dozens of patients in a number of states with the virus which he carried in his bloodstream. The virus damages the liver and authorities said that it played a part in one woman's death. The relative of another victim called him a serial killer.

He told the court in New Hampshire that he stole painkillers and replaced them with saline-filled syringes tainted with his blood.

Since his arrest, 46 people have been diagnosed with his strain of hepatitis C.

Before he was sentenced, Kwiatkowski apologised to his victims and said his crimes were a result of his addiction to painkillers and alcohol. He said he had been stealing drugs since 2003 and syringes since 2008.

He was hired at the New Hampshire Exeter Hospital in 2011. Before that, he had moved between hospitals despite being fired four times for allegations of drug use and theft.

I hate myself

"I don't blame the families for hating me," he said. "I hate myself. There's no excuse for what I've done. I know the pain and suffering I have caused."

US attorney John Kacavas said the 39-year sentence would ensure that Kwiatkowski was no longer in a position to harm innocent and vulnerable people.

In a victim statement, Kathleen Murray, whose mother was infected in Baltimore, said: "You may only be facing drug charges, but make no mistake, you are a serial killer."

Ronnie Murphy, whose mother Eleanor died, added: "You ultimately gave my mother a death sentence."

John Farley, assistant US attorney, said Kwiatkowski's actions were "exceedingly callous [and] unbelievably cruel".

Prosecutors said he had created a "national public health crisis".