The International Health Regulations (IHR) was first adopted by the World Health Assembly (WHA) in 1969 and covered six diseases. The Regulations were amended in 1973, and again in 1981, to focus on just three: cholera, yellow fever, and plague. In 1995, in consideration of increases in international travel and trade, and the emergence, re-emergence and international spread of diseases and other threats, the WHAcalled for another substantial revision. This revision extended the scope of the IHR from a limited number of diseases to any potential public health emergency of international concern, irrespective of origin or source, including those involving the natural, accidental or deliberate release of biological, chemical or radio-nuclear materials. The revised IHR, or IHR (2005), entered into force on 15 June 2007.