A cold and a 'stomach flu' are very different from a flu. Influenza can be far more severe than the common cold and can even lead to death. Influenza and the common cold are caused by very different viruses. Gastroenteritis is commonly called "stomach flu" or "24 hour flu"; but that is a misnomer as it is not connected with actual flu.
Flu rapidly spreads around the world in seasonal epidemics, killing millions of people in pandemic years and hundreds of thousands in nonpandemic years. It creates health care costs and lost productivity. Three influenza pandemics in the 20th century, each following a major genetic change in the virus, killed millions of people all over the world. The world's current major influenza pandemic threat is H5N1; but it is at present mostly a flu in birds, not in people.
The term influenza has its origins in 15th century Italy, where the cause of the disease was ascribed to unfavourable astrologicalinfluences. Evolution in medical thought led to its modification to "influenza di freddo", meaning "influence of the cold", which by the 18th century became the prevalent terminology in the English-speaking world as well.
The Modern English word "influenza" was first attested in English in 1743 when it was borrowed during an outbreak of the disease in Europe and is derived from Italian "influenza". Which originally meant "influence" as it was believed influenza was caused by the stars. etymonline.com
Hippocrates first described the symptoms of influenza in 412 B.C.. Since then, the virus has undergone mutations and shifts and has caused numerous pandemics. The first influenza pandemic was recorded in 1580, since this time, various methods have been employed to eradicate its cause.
Influenza reaches peak prevalence in winter, and because the Northern and Southern Hemisphere have winter at different times of the year, there are actually two flu seasons each year. Therefore, the World Health Organization (assisted by the National Influenza Centers) makes two vaccine formulations every year; one for the Northern, and one for the Southern Hemisphere.
While most influenza outbreaks in the Northern Hemisphere tend to peak in January or February, not all do. For example, the influenza pandemic of 1918 and 1919 reached peak virulence during late spring and summer worldwide, and not until October in the US. It remains unclear why outbreaks of the flu occur seasonally rather than uniformly throughout the year.
One possible explanation is that, because people are indoors more often during the winter, they are in close contact more often, and this promotes transmission from person to person. Another is that cold temperatures lead to drier air, which may dehydrate mucus, preventing the body from effectively expelling virus particles. The virus may also linger longer on exposed surfaces (doorknobs, countertops, etc.) in colder temperatures. Increased travel and visitation due to the Northern Hemisphere winter holiday season may also play a role. NPR
It is possible and in many cases recommended to get vaccinated against influenza with a flu vaccine. Its effectiveness varies with many criteria.
Due to the high mutability of the virus, a particular flu vaccine formulation usually only works for about a year. The World Health Organization co-ordinates the contents of the vaccine each year to contain the most likely strains of the virus that probably will attack the next year.
It is possible to get vaccinated for the season and still catch the flu. The vaccine is reformulated each season for a few specific flu strains, but cannot possibly include all the different strains actively infecting people in the world for that season. This means that you could catch a virus not covered by the vaccine. Also, it takes about six months for the manufacturers to formulate and make the millions of doses required to deal with the seasonal epidemics; occasionally a new or overlooked strain becomes prominent during that six months and infects people even though they've been vaccinated (as in the 2003-2004 season). The vaccine may have partial coverage for these unexpected strains. It is also possible to get infected and then get vaccinated the next day, before flu symptoms appear, and still get sick with the very strain that the vaccine is supposed to prevent. The vaccine can take a few days to become effective.
Vaccines can cause the immune system to react as if the body were actually being infected, and general infection symptoms (many cold and flu symptoms are just general infection symptoms) can appear, though these symptoms are usually not as severe or as long lasting as the flu.
The viruses in the flu shot are killed (inactivated), so you cannot get the flu from a flu shot. The risk of a flu shot causing serious harm, or death, is extremely small. However, a vaccine, like any medicine, may rarely cause serious problems, such as severe allergic reactions. Almost all people who get influenza vaccine have no serious problems from it.CDC
Main article Flu treatment contains curative treatments, symptom treatments and unconventional treatments such as antivirals, decongestants, and echinacea, respectively.
If you get the flu, get plenty of rest, drink a lot of liquids, and avoid using alcohol and tobacco. You can take medications such as acetaminophen to relieve the fever and muscle aches associated with the flu. Children and teenagers with flu symptoms (particularly fever) should avoid taking aspirin as taking aspirin in the presence of influenza infection (especially influenza type B) can lead to Reye syndrome, a rare but potentially fatal disease of the liver. CDC
Improved influenza countermeasures require basic research on how viruses enter cells, replicate, mutate, evolve into new strains and induce an immune response.
The Influenza Genome Sequencing Project is creating a library of influenza sequences that will help us understand what makes one strain more lethal than another, what genetic determinants most affect immunogenicity, and how the virus evolves over time.
While all flu is caused by the family of virus species called Orthomyxoviridae, most flu is caused by the species Influenza A virus which is hosted by birds, but may infect several species of mammals.
Variants of flu virus are sometimes named according to the species the strain is endemic in or adapted to. The main variants named using this convention are: * Bird flu * Human Flu * Swine Flu * Horse Flu * Dog Flu
Influenza A virus subtype H5N1, also known as H5N1, is a subtype of the Influenza A virus that is capable of causing illness in many species, including humans.
