History of Swine Flu
1918 epidemic
Spanish Flu
In 1918, swine flu mutated into a severe human form in just a few months. Some of the victims became severely ill and died, while the rest suffered from mild symptoms. In the US, the first deaths were recorded among sailors in Boston in August 1918, and the epidemic quickly spread to all parts of the country. Between the autumn of 1918 and the spring of 1919, 548,452 people died of this flu in the US. In the UK, France and Germany, around 600,000 people died. Worldwide, the number of casualties was between 20 and 50 million, or maybe more. The puzzling fact is that the epidemic erupted almost simultaneously at distant locations, therefore it is likely that the virus was incubated in people with only mild symptoms or no symptoms at all. Other anomalous facts are that the disease attacked people in their twenties and thirties, thought to have strong immune systems, and most of the infections were lethal. At the military prison at Deer Island (Massachusetts) in Boston Harbor there was an attempt to develop a vaccine during the 1918 outbreak.
1976 U.S. outbreak
On February 5, 1976, an army recruit at Fort Dix said he felt tired and weak. He died the next day and four of his fellow soldiers were later hospitalized. Two weeks after his death, health officials announced that swine flu was the cause of death and that this strain of flu appeared to be closely related to the strain involved in the 1918 flu pandemic. Alarmed public-health officials decided that action must be taken to head off another major pandemic, and they urged President Gerald Ford that every person in the U.S. be vaccinated for the disease. The vaccination program was plagued by delays and public relations problems, but about 24% of the population had been vaccinated by the time the program was canceled.
There is “enough evidence to suggest that” about 500 cases of Guillain-Barré syndrome, resulting in death from severe pulmonary complications for 25 people, were caused by an immunopathological reaction to the vaccine in some people.Other flu vaccines have not been linked to Guillain-Barré syndrome.
2007 Philippine outbreak
On August 20, 2007, Department of Agriculture officers investigated the outbreak of swine flu in Nueva Ecija and Central Luzon, Philippines. The mortality rate is less than 10% for swine flu, if there are no complications like hog cholera. Earlier, or on July 27, 2007, the Philippine National Meat Inspection Service (NMIS) raised a hog cholera “red alert” warning over Metro Manila and 5 regions of Luzon after the disease spread to backyard pig farms in Bulacan and Pampanga, even if these tested negative for the swine flu virus.
2009 H1N1 flu outbreak
In March and April 2009, over 1,000 cases of swine flu in humans were detected in Mexico and the southwestern United States, causing more than 68 deaths in Mexico.Following a series of reports of isolated cases of swine flu,the first announcement of the outbreak in Mexico was documented on April 23. Some of the cases have been confirmed by the World Health Organization to be due to a new genetic strain of H1N1. The new strain has been confirmed in 16 of the deaths and 44 others are being tested as of 24 April 2009. The Mexican fatalities are mainly young adults, a hallmark of pandemic flu.
The current vaccine against the seasonal flu strain H1N1 is thought to be unlikely to provide protection.[25] Anne Schuchat, director of CDC’s National Center for Immunization and Respiratory Diseases, said that the United States cases were found to be made up of genetic elements from four different flu viruses—North American swine flu, North American avian flu, human flu A virus subtype H1N1, and swine flu virus typically found in Asia and Europe. For two cases a complete genome sequence had been obtained. She said that the virus was resistant to amantadine and rimantadine, but susceptible to oseltamivir (Tamiflu) and zanamivir (Relenza).
The new strain appears to be a recombinant between two older strains. Preliminary genetic characterization found that the hemagglutinin (HA) gene was similar to that of swine flu viruses present in U.S. pigs since 1999, but the neuraminidase (NA) and matrix protein (M) genes resembled versions present in European swine flu isolates. Viruses with this genetic makeup had not previously been found to be circulating in humans or pigs, but there is no formal national surveillance system to determine what viruses are circulating in pigs in the U.S.
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