"I believe it should be done... I would do it without hesitation, but this issue should be discussed with Aleksanyan," Yelena Lvova said.
Lvova said prosecutor Vladimir Khomutovsky had announced on Wednesday, without Aleksanyan's consent, that the former Yukos official has AIDS.
"Aleksanyan was never part of any risk group - this disease is in no way connected with any 'immoral' aspect of his lifestyle," Lvova said.
Investigators accuse Aleksanyan of embezzling over 8 billion rubles ($329 million) from Yukos production unit Tomskneft as well as shares worth over 12 billion rubles ($493 million) from other oil companies, and of laundering the stolen assets.
He has pleaded not guilty.
Lvova said the authorities' statement saying that Aleksanyan refuses to be treated for AIDS is not true. She said Aleksanyan had agreed to an anti-retrovirus therapy in July 2007, but treatment has not yet been started.
She also said the second criminal case against ex-Yukos head Mikhail Khodorkovsky and ex-Menatep head Platon Lebedev and the case of Aleksanyan could be united into one case.
"Theoretically there is the possibility that the criminal cases could be united," she said.
The new charges against Khodorkovsky and Lebedev, who were convicted of fraud and tax evasion in 2005, include stealing government shares, expropriating oil, and laundering $25 billion earned from oil sales in 1998-2004. Both businessmen have denied the allegations, calling them politically motivated.
Khodorkovsky, who acquired oil assets through controversial privatization deals in the 1990s, has insisted that his prosecution was orchestrated by the authorities to silence his criticism of President Vladimir Putin, and as part of a campaign to bring oil and gas assets under the Kremlin's control.
Once Russia's largest oil producer, Yukos collapsed after claims of tax evasion, which led to the company being broken up and sold off to meet debts. The bulk of its assets were subsequently bought by government-controlled oil company Rosneft.
