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The fluis a communicable viral contagion of the respiratory system that touch on the nose , throat and lungs . It is because of influenza computer virus .
Symptoms of mild flu infections can resemble those of the common low temperature , which is also cause by viruses ; that said , flu symptom lean to be more intensethan dusty symptoms and amount on faster . And in severe cases , influenza symptom can be serious enough to run to hospitalization and death .
“The flu,” or seasonal influenza, is caused by influenza viruses, like those pictured above.
influenza viruses are categorized into four type : A , B , C and D. Types A and B are the most harmful to humans and cause seasonal flu epidemic ; in the Northern Hemisphere , flu time of year typically occurs from October to May , with eyeshade activityfrom December to February .
Influenza C can also taint people but causes very mild illness and is not associated with epidemics , while type D affects cattle and other animals and is not known to cause illness in humans .
grippe spread out between the great unwashed via viral particles in droplet rout out when an septic person coughs or sneezes , or through saliva convert via apportion utensils or kissing .
Some early symptoms of the flu can resemble symptoms people experience during a cold.
Each year , seasonal grippe sickens about1 billion citizenry worldwideand causes approximately290,000 to 650,000 respiratory deaths . In a given season , the U.S. seesabout 200,000 hospital care and 36,000 expiry from flu , although these numbers vary class to yr .
With rare exceptions , seasonal vaccines arerecommended for everyone 6 months and olderto avoid illness and to forbid serious knottiness from influenza . paw - wash , avoiding striking with sick people and disguise while in public can also quash the risk of contagion .
Facts about the flu
Everything you need to know about the flu
What are the symptoms of flu?
Although grippe is primarily a respiratory sickness , its symptom affect the entire body .
feverishness is one of the most common influenza symptoms , and it normally live on forthree to four day . Other symptoms include shivering , severe cephalalgia , sore throat , coughing , chest discomfort , and a airless or runny nozzle . Flu also convey muscle aching and utmost fatigue . In some instances , flu may make vomiting or diarrhea ; this occurs more often in children than in adult .
Symptoms vary from person to mortal , and they may be modest or very severe . In some cases , flu can lead to pneumonia , a austere lung infection , and require hospital care ; it can also raise the risk of serious lowly infections frombacteria . People are more at risk of produce serious complications from influenza if they have one or more underlying health conditions , such as diabetes ; bronchial asthma or inveterate lung disease ; tenderness or blood disease ; and liver or kidney disorderliness .
(Image credit: Image courtesy of the Wilson, Carragher and Potter labs)
Flu is more dangerous in people who are pregnant or who are old age 65 or older . child under 5 are vulnerable to severe influenza , and those under 2 are at specially high endangerment for developing serious illness . Having a weakened immune system due to disease or sure medical treatment , such as chemotherapy , can also bring up the risk of exposure of life - threatening complication .
What’s the difference between a cold and the flu?
grippe and colds are themost common respiratory infections in the United States . Both affect the tissue of the nose and throat , and both are make by viruses and propagate easily between people . However , there are some key difference between frigidness and the influenza .
Colds are stimulate by approximately200 unlike viruses , include rhinoviruses , adenoviruses andcoronaviruses(a broad mathematical group of viruses that includes the germ behind COVID-19 ) .
Cold symptoms usually appearwithin one to three daysof being infected and are mild at the starting time . They often include a titillation in the pharynx , sneezing , and a runny or stuffy nose . Symptoms typically peak within a week of onset , around Day 4 to 7 . Headache or febrility may develop , but these symptoms are uncommon in coldness . A cold ’s mean continuance is eight to 10 days . Most colds go out on their own , but over - the - riposte medications can facilitate remedy symptom and reduce pain .
(Image credit: National Archives)
Flu amount on quicker than a frigidity . In flu , pyrexia , chills , headaches , body ache and enfeeblement are typically the first symptom to appear . Flu infections can make pernicious complications and can worsen existing medical conditions , such asasthma , congestive heart failure or diabetes .
There are no medication to prevent or directly treat the coarse cold , whereas flu can be prevented through seasonal vaccine and can be treated within the first 48 minute of infection with theantiviral medicinal drug oseltamivir , better acknowledge asTamiflu .
How long does the flu last?
Flu symptoms typically look aboutone to four daysafter exposure to the virus , but grippe symptoms can speedily become severe . If the septic person is otherwise sound , symptoms usually lastfrom a few days to near two weeks , although being vaccinate and guide Tamiflu can shorten their continuance . influenza symptoms may last longer in some cases and can do fatigue that persistseven after other symptoms have ended .
For most people , a bout of flu is unpleasant and uncomfortable but not life-time - threatening . However , complications can develop that may prolong illness . Some complications are moderate , such as ear andsinus infections .
Other complication are more serious , such as viral or bacterial pneumonia . This inflammation of the lung takes place when the lung Sac , known as alveoli , fill with fluid and hinder breathing . retrieval from pneumonia cantake up to a month or longer . Flu can also trigger off sepsis , an extreme , body - broad immune chemical reaction . Runaway inflammation driven by sepsis can lead to tissue impairment and fatal organ failure .
(Image credit: NIAID/NIH)
What’s the difference between influenza A and influenza B?
Bird flu , or avian influenza , is because of flu A viruses . influenza viruses that infect humans and chick are both categorise by their H and N proteins , but avian influenza viruses taint birds as their main legion .
All of the flu A subtypes are found in razz , with two exceptions : subtypesH17N10 and H18N11 , which occur only in cricket bat . A handful of subtypes of avian influenza A viruses are known to occasionally infect humans : H5 , H6 , H7 , H9 and H10 .
grippe spreads between birds through contact with infected saliva , respiratory droplet or feces . Some strain of avian influenza cause mild sickness in birds ; others are pernicious . septic birdsmay sneeze or coughing , develop swelling in various organic structure parts , and appear uncoordinated or lethargic . That said , some hiss can carry and disperse influenza computer virus without fall sick themselves .
(Image credit: National Institute of Allergy and Infectious Diseases/NIH)
In people , avian influenza symptoms resemble those of seasonal flu and can roll from modest to serious , sometimes turning deadly . Symptoms also may let in conjunctivitis — eye irritation and redness .
There are variant of bird flu that affect cattle andmay be able to sickenpeople who tope raw milkfrom infect cows .
Person - to - person transmittance of bird flu has historically been reported in disjunct case involving one to two individuals , but not during the ongoing outbreak in the U.S. Avian grippe does not spread easily from person to person , but there is a growing peril that bird flu couldmutate to become more contagiousin humans , nurture the hazard of a bird grippe pandemic .
(Image credit: National Institute of Allergy and Infectious Diseases/NIH)
Glossary
Flu pictures
flu virus proteins in the act of ego - replication , captured with a microscope . The blue protein encloses the virus ’s RNA ( green ) , its transmitted stuff . An enzyme ( orange ) is reading and making written matter of the RNA , which is necessary for making copies of the virus .
soldier with influenza at the infirmary in Camp Funston , Kansas , in 1918 . Camp Funston is where the influenza epidemic first made a major appearance . flock from the clique carry the virus to other Army bases during World War I. The epidemic bolt down more than 50 million people worldwide , admit 675,000 Americans .
Colorized infection negatron micrograph of grippe A / H1N1 computer virus particles ( blue ) . Influenza A / H1N1 can infect both humans and animals , including birds and pigs , and is one of several strains bear on to seasonal flu irruption .
A colorized infection negatron micrograph shows swine grippe virus mote ( racy ) attached to and budding off of a cellular phone ( Orange River ) .
A level-headed volunteer receives an experimental cosmopolitan influenza vaccine as part of an early - phase angle clinical trial at the National Institutes of Health ( NIH ) Clinical Center in Bethesda , Maryland . scientist at NIAID ’s Vaccine Research Center ( VRC ) developed the vaccinum .
Discover more about the flu
— How do people die of the flu ?
— How long is the influenza transmissible ?
— How to get well faster when you have the flu , according to scientific discipline
This article is for informational purposes only and is not have in mind to offer aesculapian advice .
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