The potentially fatal MERS virus that originated in Saudi Arabia two years ago has spread to Turkey for the first time, the World Health Organization said Friday. In a report on its website, the organization attributed the spread to a 42-year-old Turkish citizen who had been working in the Saudi city of Jidda; he fell ill there last month and flew two weeks ago to the Turkish city of Hatay, where he was hospitalized and died within days. The organization said medical investigators confirmed that the man had suffered from MERS, or Middle East Respiratory Syndrome, and they were checking others in Turkey and Saudi Arabia who had been in contact with him during his symptomatic phase. Saudi Arabia has been under enormous pressure to control the disease, which can incubate in camels and other livestock. The Saudi authorities have been faulted for having allowed MERS to proliferate, particularly in Jidda, Riyadh, the Saudi capital, and the holy city of Mecca, where pilgrims from the entire world converge for the annual hajj. Pilgrims are known to have spread the disease to Iran, Jordan and Algeria. The W.H.O. said that as of Friday, it had tallied 883 MERS cases worldwide, including at least 319 deaths. Most cases are in Saudi Arabia.