Forty-nine highly infectious tuberculosis patients have cut through wire fencing to break out of a hospital isolation unit, apparently because they wanted to spend Christmas with their families.

The mass escape last week highlighted the problems faced by South Africa as it struggles to cope with an epidemic of virtually incurable TB that feeds off the AIDS virus and kills most of its victims. South Africa has an estimated 5.4 million people living with the AIDS virus.

There have been around 400 confirmed cases of the incurable strain known as XDR-TB, or extremely drug resistant TB. But activists say the actual number is probably much larger, because testing methods are not sophisticated enough to detect the new strain and many people die before they can be diagnosed.

Eastern Cape authorities said Tuesday that were still searching for 29 TB patients who escaped between Wednesday and Friday last week from the Jose Pearson Hospital near the coastal city of Port Elizabeth, the South African Press Association said. Twenty had returned in response to appeals, and authorities said they hoped more would follow suit.

A spokesman for the department, Siyanda Manana, said Friday that the 49 patients — all with multidrug resistant (MDR) and extremely drug resistant (XDR) TB had escaped through holes they had cut through the hospital's perimeter fences.

Notices to return, issued by the state attorney's office, were delivered to the patients' homes.

"So far 20 have returned; we are expecting more to come back soon," said Manana.

Although forced confinement of patients violates most medical ethics, authorities say they have no choice but to put the wider public good above individual rights. Confinement for XDR-TB is at least six months.