Swine flu, also called as pig flu or swine influenza, is a viral infection caused by infection by influenza type-A virus subtype H1N1. The scientific name is Influenza virus type A/California/09/2009(H1N1)-like virus infection, but common media names are “novel flu”, “swine flu” and “H1N1 flu”. There are three types of influenza viruses i.e. A, B, C. Types A and C are endemic in swine, but rarely infect humans. Humans are infected by type B virus. Influenza virus type A and C very rarely infect humans, but out breaks of swine influenza have been reported several times in history.
The recent outbreak is spread of influenza type A (H1N1) which was first reported in Mexico in March, 2009. The virus responsible was isolated on 24th April, 2009. By 28th April the same strain was detected in Spain, England, Israel and New Zealand, with a total of 4,000 suspected cases. Due to such fast spread WHO has raised the pandemic alert phase from level 4 to level 5 on 29th April. The latest swine flu statistics till now, i.e. May 1st 2009 are 539 confirmed cases, more than 4,400 strongly suspected cases and 13 deaths.

Let’s understand some basics first. Pandemic, which is the extended form of an epidemic, is the spread of an uncommon infectious disease agent across a huge geographic area or in several geographic areas. Phase 5 WHO pandemic alert is the second highest alert and it means an imminent pandemic.

Phase 1: The infective agent is circulating in animals only.
Phase 2: The infective agent circulating among animals is reported to cause human infection.
Phase 3: The animal or human-animal infective agent has infected humans sporadically or in small scattered clusters. Human to human (H2H) transmission sufficient enough for a pandemic is not present.
Phase 4: Significant H2H transmission reported and is strong enough to cause a pandemic.
Phase 5: H2H transmission is occurring in at least 2 countries in one/same WHO region. It means an imminent pandemic.
Phase 6: It is pandemic. Community-level out-breaks in 3 or more countries in at least 2 WHO regions. It means global pandemic is coming.

With the spread of disease, increased demand of anti-viral medication will soon deplete the existing medication supply. CDC and WHO are concerned about this out-break because of the novelty of virus strain, H2H transmission, and a high mortality rate noted in Mexico. But WHO officials have also commented on 29th April that majority of people recovered completely from the infection without any medical support or anti-viral medication.