A Nevada jury April 9 found two UnitedHealth Group Inc. subsidiaries must pay $500 million in punitive damages for failing to adequately oversee Dr. Dipak Desai, whose alleged unsafe practices led several of his patients to contract hepatitis C.

Desai was part of the provider network of the two HMOs, Health Plan of Nevada and Sierra Health Services.

The case was brought, along with several other separate actions, after patients who were treated at clinics owned by Desai contracted hepatitis C because of unsafe injection practices. See Meyer v. Health Plan of Nevada Inc., No. A5837999.

Last week, the same jury ordered the insurers to pay a total of $24 million in compensatory damages to Bonnie Brunson and Helen Meyer, the two plaintiffs in the case.

The total $524 million award is the largest in the U.S. in 2013 so far, according to data compiled by Bloomberg, the company reported.

In a statement issued after the verdict, Health Plan of Nevada said “The number announced today has no grounding whatsoever in reality – it represents fantasy damages, not punitive damages. We have a compelling case for appeal since the jurors were barred from hearing extensive evidence and testimony about how Dr. Desai’s covert, criminal practices were hidden from the entire community, including Health Plan of Nevada.”

“The only numbers that matter here are the higher insurance premiums that Nevadans may pay if health plans are held liable for the criminal conduct of independent doctors,” the statement said.

According to Bloomberg, Robert Eglet, Brunson’s attorney, said in an interview after the verdict was announced that the award “should help prod insurers to put the quality of services provided by their doctors ahead of profits.”