| Re: Mexican Swine Flu |
Subject: Re: Mexican Swine Flu by JrRifleCoach on 2009/4/25 3:17:39 24 April 2009 -- The United States Government has reported seven confirmed human cases of Swine Influenza A/H1N1 in the USA (five in California and two in Texas) and nine suspect cases. All seven confirmed cases had mild Influenza-Like Illness (ILI), with only one requiring brief hospitalization. No deaths have been reported. The Government of Mexico has reported three separate events. In the Federal District of Mexico, surveillance began picking up cases of ILI starting 18 March. The number of cases has risen steadily through April and as of 23 April there are now more than 854 cases of pneumonia from the capital. Of those, 59 have died. In San Luis Potosi, in central Mexico, 24 cases of ILI, with three deaths, have been reported. And from Mexicali, near the border with the United States, four cases of ILI, with no deaths, have been reported. Of the Mexican cases, 18 have been laboratory confirmed in Canada as Swine Influenza A/H1N1, while 12 of those are genetically identical to the Swine Influenza A/H1N1 viruses from California. The majority of these cases have occurred in otherwise healthy young adults. Influenza normally affects the very young and the very old, but these age groups have not been heavily affected in Mexico. Because there are human cases associated with an animal influenza virus, and because of the geographical spread of multiple community outbreaks, plus the somewhat unusual age groups affected, these events are of high concern. The "Spanish" flu pandemic of 1918 and 1919 caused the deaths of 20-50 million people worldwide including up to 675,000 in the U.S. While only about 1% of those infected with the virus died, it became one of the deadliest viruses ever known to man. The 1918 flu has been described as capable of sickening and killing a person on the same day. The virus is an H1N1 type A influenza. Symptoms of infection were similar to, but more severe than typical, seasonal flu. Viral pneumonia leading to acute respiratory distress was the primary cause of death. Recently, the virus was reconstituted from frozen tissue samples from a woman who died from the virus. History: Unlike seasonal flu, where most deaths are seen in the elderly and children under 2-years-old, almost half of the deaths associated with the 1918 pandemic were in adults between 20 and 40-years-old. Scientists theorize that this could be because people over the age of 40 had previously been exposed to a similar flu that gave them some immunity. As the 1918 flu spread through the United States, public gatherings were reduced to prevent infections since doctors had no way to fight the infections. However, the virus was able to cross the ocean with troops arriving to fight in Europe during World War I. Foreign troops soon became exposed to the virus and carried it back to their home countries starting new waves of infection. Mechanism: Flu strains are named for the H and N proteins, hemagglutinin and neuraminidase, which stick out from the surface of the virus like spikes. These protein spikes allow influenza to infect and damage cells and are what the immune system recognizes. The hemagglutinin spike allows the virus to bind to and enter cells. After co-opting the cells molecular machinery to produce more viruses, the neuraminidase spike is used to escape the cell, destroying it in the process. The 1918 influenza is an H1N1 strain and research on the reconstituted virus shows that it was particularly infective and had the unusual property of being able to infect mice, which typical human influenza strains cannot. http://www.who.int/en/ |
