Swine Flu Outbreak

[NOV]

The 2009 swine flu outbreak is an epidemic that began in April 2009 with a new strain of influenza virus. The new strain is commonly called swine flu, but some authorities object to the name and it is also called Mexican flu, swine-origin influenza, North American influenza, and 2009 H1N1 flu.

The outbreak is believed to have started in March 2009 and was classified as meeting the criteria for the World Health Organization pandemic Phase 5 status on 29 April. Local outbreaks of an influenza-like illness were first detected in three areas of Mexico, but the virus responsible was not clinically identified as a new strain until April 24, 2009. Following the identification, its presence was soon confirmed in various Mexican states and in Mexico City. Within days, isolated cases (and suspected cases) were identified elsewhere in Mexico, the U.S., and several other Northern Hemisphere countries.

By April 28, the new strain was confirmed to have spread to Spain, the United Kingdom, New Zealand, and Israel, and the virus was suspected in many other nations, with a total of over 3,000 candidate cases, prompting the World Health Organization (WHO) to change its pandemic alert phase to "Phase 5", which denotes "widespread human infection". Despite the scale of the alert, the WHO stated on April 29 that the majority of people infected with the virus have made a full recovery without need of medical attention or antiviral drugs.

The new strain is an apparent reassessment of four strains of influenza A virus subtype H1N1. Analysis at the United States Centers for Disease Control and Prevention (CDC) identified the four component strains as one endemic in humans, one endemic in birds, and two endemic in pigs (swine). One swine strain was widespread in the United States, the other in Eurasia.

In late April both the United Nations WHO and the U.S. CDC expressed serious concern about the situation, as it had the potential to become a flu pandemic due to the novelty of the influenza strain, its transmission from human to human, and the unusually high mortality rate in Mexico.

On April 25, 2009, the WHO formally determined the situation to be a "public health emergency of international concern", with knowledge lacking in regard to "the clinical features, epidemiology, and virology of reported cases and the appropriate responses". Government health agencies around the world also expressed concerns over the outbreak and are monitoring the situation closely.

Mexico's schools, universities, and all public events will be closed from April 24, 2009 to May 6, 2009. On April 27, 2009, a few schools in the U.S. closed due to confirmed cases in students. Two days later the action extended to 18 more U.S. schools as the disease became more widespread in the U.S., the same day WHO Director General Margaret Chan said "It really is the whole of humanity that is under threat in a pandemic," and the Mexican government ordered a shutdown of all non-essential activities in the government and private sector, amounting to a shutdown of most of the country's economy.

According to the WHO, "In annual influenza epidemics 5-15% of the population are affected with upper respiratory tract infections. Hospitalization and deaths mainly occur in high-risk groups (elderly, chronically ill). Although difficult to assess, these annual epidemics are thought to result in between three and five million cases of severe illness and between 250 000 and 500 000 deaths every year around the world. Most deaths currently associated with influenza in industrialized countries occur among the elderly over 65 years of age.

http://en.wikipedia.org/wiki/2009_swine_flu_outbreak