Palermo, July 25 - The health of Mafia kingpin Bernardo Provenzano, who has been in a prison hospital since the beginning of June, has taken a turn for the worse, doctors said on Thursday. According to medical reports the former boss is "alert only when stimulated...has limited speech and altered states of consciousness". Arrested in 2006 after 43 years on the run, Provenzano has been subjected to the so-called 41-bis treatment for Italy's most dangerous criminals. They can be kept in single-person cells in maximum-security jails, almost entirely cut off from the outside world in order to prevent further criminal activity. The ex-Mafia chieftain, once nicknamed "The Bulldozer", is serving life for various murders including ordering fatal bomb attacks on anti-mafia prosecutors Giovanni Falcone and Paolo Borsellino in 1992.