Influenza disease can be classified as a zoonotic disease (animal disease which is transmissible to humans). As bird flu is caused by virus type A subtype H5N1 in Asia, H7N7 in Europe, and H9N2 in China and Hong Kong, H1N1 Swine fibers are categorized as zoonotic diseases.
Zoonotic disease transmission is divided into inter-animal, animal to humans and between humans.
Facing the influenza pandemic, World Health Organization (WHO) distinguishes this virus transmission phase into three periods namely prepandemic, interpandemic and pandemic.
Prepandemic period is divided into:
Phase 1: When the transmission occurs only between animals and there has been no outbreak in animals
Phase 2: When the transmission occurs between animals but has become a plague
Interpandemic period is divided into:
Phase 3: When the transmission from animals to humans occurs
Phase 4: Transmission between humans has occurred in a country
Phase 5: When the transmission occurs between people in two countries
Phase 6: When there is transmission between humans has occurred in many countries
Therefore, 30 April 2009, the WHO said all States must immediately activate all of pandemic preparedness plans. The threat of swine flu virus must be taken seriously.