This update follows BEH No. 19/2000 of May 9, 2000, and outlines the main developments since that date. Following the occurrence of cases of serogroup W135 meningococcal infection among pilgrims returning from Mecca and their family members, in addition to the DGS recommendations of April 8 regarding chemoprophylaxis, enhanced surveillance, based on immediate reporting by the DDASS and the CNRM of all suspected cases of meningococcal infection caused by serogroup W135, has been implemented. A descriptive study is underway to track the spread of the strain and assess the need for specific control measures. A descriptive study is underway to track the spread of the strain and assess the need for specific control measures.