| Flu Infection |
| About Flu Flu is an acute infection of the bronchial tubes and is caused by the flu virus. Flu is extremely contagious. Flu viruses spread in respiratory droplets caused by coughing and sneezing. They usually spread from person to person. In addition, flu can have extremely serious consequences. Every year in the United States, on average 5% to 20% of the population gets the flu; more than 200,000 people are hospitalized from flu complications, and about 36,000 people die from flu. A new human influenza virus in which the outer coating is drastically altered appears a few times every century. This new virus can spread lightning-fast around the entire world. Such a worldwide epidemic or pandemic can contaminate up to 50% or more of the world population. Pandemics Pandemic is a worldwide outbreak of influenza. It is different from a seasonal outbreak or "epidemic" of influenza. Seasonal outbreaks are caused by subtypes of influenza viruses that already exist in human population, whereas pandemic outbreaks are caused by new subtypes or by subtypes that have never circulated among people or that have not circulated among people for a long time. Examples of pandemics include: Spanish flu, [A (H1N1)], caused the highest number of known influenza deaths: more than 500,000 American died, and up to 50 million people may have died worldwide. [1918-1919] Asian flu, [A (H2N2)], caused about 70,000 deaths in the US. First identified in China in late February 1957, the Asian flu spread to the United States by June 1957. [1957-1958] Hong Kong flu, [A (H3N2)], caused about 34,000 deaths in the United States. This virus was first detected in Hong Kong in early 1968 and spread to the United States later that year. [1968-1969] Both Asian flu and Hong Kong flu were caused by viruses containing a combination of genes from a human influenza virus and an avian influenza virus. Pandemic are divided into interpandemic, pandemic alert and pandemic periods. In interpandemic period, no new influenza virus subtypes have been detected in humans, but a circulating animal influenza virus subtype poses a substantial risk of human disease. In pandemic alert period, human infection(s) with a new subtype happens, but the spread is localized. In pandemic period, increased and sustained transmission in general population occurs. Why is Flu so contagious? The outer coating of the influenza virus changes from time to time, making the virus invisible to our antibodies that were built up during an earlier infection or vaccination. A slightly altered virus can easily set off a new epidemic. Thus there is no lifetime vaccine against influenza that lasts for a lifetime. Flu Vaccination Vaccination offers the most efficient protection to flu. In United States, October or November is the best time to get vaccinated. The present flu vaccines are a mixture of multiple vaccines, each offering protection to a certain virus strain. Vaccination reduces death and the amount of hospitalizations as a result of flu considerably. People at high risk for complications from the flu should get vaccinated. These include people 65 years and older, people who live in nursing homes or other institutes, people with chronic serious diseases, pregnant women and people in close contact with someone in a high-risk group (e.g. caregivers and health-care workers). How a vaccine works? Each year the World Health Organization determines which influenza viruses are the most likely to cause an influenza epidemic during the next winter period. Scientists grow viruses on chicken embryos or in cultures of animal cells. They purify the proteins originating from the outer coating of the harvested viruses and use it as vaccine. After inoculation in a human body, the immune system creates antibodies. After a few weeks, our body has produced sufficient antibodies to neutralize the viruses in case of an infection. Antiviral Agents for Influenza Four different influenza antiviral drugs (amantadine, rimantadine, oseltamivir, and zanamivir) are approved by the U.S. Food and Drug Administration (FDA) for the treatment and/or prophylaxis of influenza. All four have activity against influenza A viruses. However, sometimes influenza strains can become resistant to these drugs, and therefore the drugs may not always be effective. For example, analyses of some of the 2004 H5N1 viruses isolated from poultry and humans in Asia have shown that the viruses are resistant to two of the medications (amantadine and rimantadine). Monitoring of avian viruses for resistance to influenza antiviral medications is ongoing. Research Current influenza vaccines work by targeting to haemagglutinin and neuraminidase on the virus surface. These two proteins mutate from time to time. Acambis (a biotechnology company in Cambridge) starts to develop a new vaccine targetingon different protein, M2, that do not mutate, they hop it will be enough to offer permanent immunity against influenza. Acambis has teamed up with the Flanders Interuniversity Institute for Biotechnology to develop and license the flu vaccine. PowderMed announced that it has progressed its H5N1 Avian influenza vaccine programme into the final stages of preclinical development. PowderMed produces its H5N1 vaccine by cloning the H5 gene from the current circulating avian flu strain into its DNA vaccine backbone. They are ready to develop this vaccine, they plan to enter clinical trials by the summer of 2006. reference: British scientific team look for vaccine breakthrough that could offer human immunity for life. Yorkshire Post Today. August 6, 2005. Vaccine Against H5N1 (Avian Influenza) Manufactured for Clinical Development I-Newswire.com August 6, 2005. NEWS ON AUG 10 2005 US may order experimental flu vaccine U.S. may order millions of doses of an experimental avian flu vaccine from French vaccine maker Sanofi-Pasteur. Shots would be administered only if H5N1 evolves the capacity to be transmitted person to person - and if it reaches the United States. H5N1 is a subtype of an "A" strain of influenza. Recently, H5N1 triggered disease in humans. Reference Bird flu vaccine ordered, Newsday.com, August 9, 2005 HOME [1] What's the Difference Between a Cold and the Flu? Food Consumer.org September 13, 2009 |
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other website or blog.
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The first symptoms of a cold is getting a bit scratchy the first day, then the nose starts to run
on, followed by full blown sneezing and coughing on the fourth and fifth days, etc. It takes
several days for the common cold to get to full blown status.
Flu virus slams the patient to the ground with severe body aches, high fever, sore throat,
and coughs. While cold sufferers can limp along and actually function (albeit minimally), a flu
patient is rendered helpless. The difference comes down to intensity. Bacterial pneumonia,
which can be life threatening, is a very real threat to the flu patient; lungs, already severely
damaged from influenza, are susceptible to bacterial infection. The common cold patient's
problems are somewhat limited to sinusitis, bronchitis and otitis media (ear infections); none
of which are potentially fatal. [1]
on, followed by full blown sneezing and coughing on the fourth and fifth days, etc. It takes
several days for the common cold to get to full blown status.
Flu virus slams the patient to the ground with severe body aches, high fever, sore throat,
and coughs. While cold sufferers can limp along and actually function (albeit minimally), a flu
patient is rendered helpless. The difference comes down to intensity. Bacterial pneumonia,
which can be life threatening, is a very real threat to the flu patient; lungs, already severely
damaged from influenza, are susceptible to bacterial infection. The common cold patient's
problems are somewhat limited to sinusitis, bronchitis and otitis media (ear infections); none
of which are potentially fatal. [1]