On Jul. 20, 2007, the U.S. Centers for Disease Control and Prevention (CDC) announced in MMWR that revised International Health Regulations (IHRs) had gone into effect for the U.S.

The revised IHRs described the obligations of World Health Organization (WHO) member states to assess and manage serious health threats that have the potential to spread beyond their borders and 2) provide guidance for meeting those obligations.

Under the revised IHRs, member states must report to WHO cases of smallpox, poliomyelitis caused by wild-type poliovirus, human influenza caused by a new virus subtype, and severe acute respiratory syndrome.