The 19-year-old daughter of Josef Fritzl, the Austrian “horror dad” accused of imprisoning his daughter for 24 years and fathering her seven children, has woken from a coma, The Daily Mail reported Tuesday.

Kerstin, born to Fritzl and his daughter Elisabeth during her years in captivity, was placed in an artificial coma after she suffered a severe kidney infection and organ failure last month. Doctors have begun the process of slowly waking her up as her condition improves.

Kerstin was freed in April when Fritzl, 73, took her to a hospital after she collapsed in his cellar in Amstetten, Austria.

She began showing signs of life over the weekend, and her family told the Daily Mail she has opened her eyes.

• Click here to see photos of Josef Fritzl and the "House of Horrors."

Elisabeth is recovering with her five other children in a psychiatric clinic near the hospital.

“Elisabeth and family are very happy, but they know they mustn't get their hopes up too high,” a source close to the victims told the Daily Mail. “Kerstin's incredibly fragile. She'll be in bed a long time — probably months.”

Albert Reiter, one of the doctors caring for Kerstin, said that one concern is that the infection may have left her with a shortage of oxygen, and resulting brain damage, the Mail reported.

“The medication keeping her in an artificial coma is being slowly reduced,” Reiter told the Daily Mail. “This is the first phase in the process of eventually waking her up. How long this will take is something we cannot say.”

Authorities say Fritzl has confessed to locking up his daughter and repeatedly raping and impregnating her. Investigators say he also told them three of the children were raised in a cellar at his home, three others were brought up above ground and one died in infancy.

Fritzl's alleged double life fell apart when Kerstin was hospitalized with the infection.

Unable to find medical records for the woman, doctors appealed to her mother to come forward. Fritzl accompanied Elisabeth to the hospital on April 26 and was detained after she divulged what had allegedly happened to her.

Click here to read more on this story from the Daily Mail.