Biological Attack

As the annual hajj came to its end in early October, and hundreds of thousands of pilgrims departed Saudi Arabia having honored the highest traditions of Islam, the kingdom cautiously breathed a sigh of relief: No epidemic erupted among the roughly 1.4 million visitors. But though it may have seemed that attentions were focused on concern over the possible spread of the Middle East respiratory syndrome MERS — a disease that has affected more than 135 people in eight countries, killing 45 percent of those infected — for months Saudi health authorities have been keeping a nervous eye on another disease, polio, which is spreading rapidly across the Middle East, most recently inside war-torn Syria.