Influenza factsheet - Fact sheets. Influenza, or flu, is a highly contagious respiratory illness caused by influenza viruses. The symptoms are more serious than a common cold. An annual flu shot is your best protection against influenza.
Influenza Treatment. Antiviral medicines are an important tool in both controlling influenza by treating the patient’s infection and helping to prevent severe illness that can result from flu, including bacterial pneumonia.
Influenza A and B are the two types of influenza that cause epidemic seasonal infections nearly every year. Influenza A can be found in many species, including humans, birds, and pigs. Due to the breadth of potential hosts and its ability to genetically change over a short amount of time, influenza A viruses are very diverse.
Influenza A virus causes necrosis of the respiratory epithelium in the tracheobronchial tree and nasal turbinates. Desquamation of the ciliated epithelium, edema, hyperemia, increased secretions, and congestion may therefore result in a secondary bacterial infection.
Wild aquatic birds, including gulls, terns, and shorebirds, and wild waterfowl, such as ducks, geese and swans are considered reservoirs (hosts) for avian influenza A viruses.
Unlike bacterial infections, the influenza virus is best treated with bedrest. Most people feel better after a few days. Fluids, such as the following, are also helpful in treating symptoms of the flu: water....Common antiviral prescriptions include:zanamivir (Relenza)oseltamivir (Tamiflu)peramivir (Rapivab)
Influenza, or “the flu,” is a common wintertime illness caused by a virus. Most people who get it will recover on their own, even without treatment. But recovery often takes days or weeks, and during that time you can feel miserable.
How long does Type A flu last? Symptoms typically last five to seven days, although they can linger for up to two weeks.
If you have influenza, you can expect the illness to go away on its own in about 7 to 10 days. In the meantime, you can take steps to feel better: Get extra rest.
Can flu be treated? Yes. There are prescription medications called “antiviral drugs” that can be used to treat flu illness.
ContinuedDrink plenty of fluids. You need lots of liquids when you have a fever.Breathe hot air. Hang out in a steamy shower or cover your head with a towel and hold it over a sinkful of hot water to ease dry throats and nasal passages.Don't take antibiotics . ... Eat healthy. ... Don't smoke. ... Keep the flu to yourself.
Thankfully, killing influenza can be achieved by wiping with simple detergents, diluted bleach, or hydrogen peroxide. If chemicals are not desired, flu also dies in the presence of steam, a fact known for well more than 100 years.
These remedies might help you feel better:Stay hydrated. Water, juice, clear broth or warm lemon water with honey helps loosen congestion and prevents dehydration. ... Rest. Your body needs rest to heal.Soothe a sore throat. ... Combat stuffiness. ... Relieve pain. ... Sip warm liquids. ... Try honey. ... Add moisture to the air.More items...
Type A influenza is generally considered worse than type B influenza. This is because the symptoms are often more severe in type A influenza than in type B influenza. Type A influenza is more common than type B influenza. Researchers suggest that most adults have considerable immunity against type B influenza.
If you're young and healthy, the flu usually isn't serious. Although you may feel miserable while you have it, the flu usually goes away in a week or two with no lasting effects. But children and adults at high risk may develop complications that may include: Pneumonia.
Well there's good news and bad news on that front. I'll start with the bad news. It is possible to get the flu twice during the same flu season. Since there are two types of flu strains – influenza A and influenza B – if you get influenza A, you can also get influenza B.
If you have influenza, you are likely to get better within a week or so by: resting in bed. taking mild pain relief to reduce your pain. drinking plenty of liquids . eating light foods when you are hungry. In some people, the flu can be severe and lead to serious complications such as pneumonia.
Influenza type C can cause an illness in children that is similar to the common cold. Most people who have flu are infected with the influenza type A virus. This virus has caused flu pandemics — the worldwide spread of a new disease.
A new vaccine is needed every year because influenza viruses change constantly. Flu vaccine is available for everyone aged over 6 months. The vaccine is particularly recommended if you are at risk of complications of influenza, or if you live or work with people at high risk of getting the flu.
Influenza A is a bit like a very bad cold, but a cold doesn't usually cause aches and pains or a high fever. If your symptoms get worse instead of better, it's best to see a doctor. You should also get help straight away if you feel chest pain, you are short of breath, dizzy or confused, or you are vomiting a lot.
In some cases, these types of influenza can be passed on to humans. Bird flu: Avian influenza — also known as 'bird flu' — is a subtype of influenza virus A (H5N1) that mainly affects birds. The virus has caused serious infections in humans and deaths but has not been found in Australia. Swine flu: This is a type of influenza A virus found in pigs.
Influenza A viruses can be classified based on the antigenic variation of these HA and NA proteins. To date, 16 major antigenic variants of HA and 9 antigenic variants of NA have been recognized which are found in numerous combinations, and these so-called virus subtypes (e.g., H1N1, H7N7, H16N3) are used in influenza A virus classification and nomenclature (Webster et al., 1992; Fouchier et al., 2005 ). The classification system is biologically relevant, as host antibodies that recognize one HA or NA subtype will generally not cross-react with other HA and NA subtypes. The antigenic variation of the HA and NA proteins is in agreement with the major genetic variation of the respective genes of avian influenza A viruses ( Figure 28.2 ). For instance, the maximum amino acid sequence identity between HA of any two different HA subtypes is 79%, and within a subtype can be as low as 86% ( Fouchier et al., 2005 ). The genetic variation of the HA and NA genes in the avian reservoir is of the same order of magnitude as the genetic variation of the surface glycoproteins of primate lentiviruses, a notoriously variable group of viruses ( Karlsson Hedestam et al., 2008 ).
Influenza A virus was transmitted in a laboratory setting when a researcher was infected by a ferret that had been infected with a strain of influenza A virus and which ‘sneezed violently at close range’ while it was being examined.29 Ferrets are susceptible to influenza A and B viruses. Mink that are in mink farms have been found to be infected with influenza A viruses. 30
Influenza A virus (IAV) is an enveloped virus of the Orthomyxoviridae with a negative-sense single-stranded RNA genome. During virus cell entry, viral and cellular cues are delivered in a stepwise manner within two distinct cellular compartments—the endosomes and the cytosol. Endosome maturation primes the viral core for uncoating by cytosolic host proteins and host-mediated virus disaggregation is essential for genome import and replication in the nucleus. Recent evidence shows that two well-known cellular proteins—histone deacetylase 6 (HDAC6) and karyopherin-β2 (kapβ2)—uncoat influenza virus. HDAC6 is 1 of 11 HDACs and an X-linked, cytosolic lysine deacetylase. Under normal cellular conditions HDAC6 is the tubulin deacetylase. Under proteasomal stress HDAC6 binds unanchored ubiquitin, dynein and myosin II to sequester misfolded protein aggregates for autophagy. Kapβ2 is a member of the importin β family that transports RNA-binding proteins into the nucleus by binding to disordered nuclear localization signals (NLSs) known as PY-NLS. Kapβ2 is emerging as a universal uncoating factor for IAV and human immunodeficiency virus type 1 (HIV-1). Kapβ2 can also reverse liquid-liquid phase separation (LLPS) of RNA-binding proteins by promoting their disaggregation. Thus, it is becoming evident that key players in the management of cellular condensates and membraneless organelles are potent virus uncoating factors. This emerging concept reveals implications in viral pathogenesis, as well as, the promise for cell-targeted therapeutic strategies to block universal virus uncoating pathways hijacked by enveloped RNA viruses.
Influenza A viruses are the most clinically significant and are divided into subtypes based on antigenic differences in the HA and NA genes.
Influenza A viruses originating from animals can adapt to infect humans following a genetic mutation or exchange. Identification and characterization of circulating animal influenza viruses are therefore crucial for human influenza pandemic preparedness. The primary risk factor for human infection appears to be the direct or indirect exposure to infected live or dead animals or contaminated environments. As described in the WHO Manual on Animal Influenza Diagnosis and Surveillance, the objective of surveillance in lower animals (such as pigs) and birds is to complement the human influenza surveillance network, to understand the ecology of influenza viruses that are relevant to human and animal health, to determine the molecular basis of host range transmission and the spread in new hosts, and to identify molecular markers of influenza viruses that can transmit between species especially to humans.
The most severely immunocompromised patients are those who have been diagnosed with a hematologic malignancy, solid organ tumor, or who have other conditions that require immunosuppressive therapies and/or solid organ or stem cell transplants.
Rigorous vaccination programs and improved pharmacotherapy have decreased the impact of influenza on the general population; however, influenza still remains a serious threat to severely immunocompromised individuals. The 2009 pandemic was a reminder that it is still unclear how well current vaccination strategies and current pharmacotherapy can perform in preventing and mitigating illness in immunocompromised individuals.
Uncomplicated influenza signs and symptoms typically resolve after 3-7 days for the majority of people, although cough and malaise can persist for >2 weeks, especially in elderly people and those with chronic lung disease.
Uncomplicated influenza illness is typically characterized by the abrupt onset of constitutional and upper respiratory tract signs and symptoms (e.g., fever, chills, myalgia, headache, malaise, nonproductive cough, sore throat, and rhinitis). However, many people who are sick with influenza virus infection do not manifest ...
Certain people are at increased risk for complications from influenza. In young children, otitis media and respiratory complications such as croup, bronchiolitis, and tracheitis can occur. Other complications in children include cardiac (myocarditis and pericarditis), musculoskeletal (severe myositis), and neurologic (encephalopathy, encephalitis, transverse myelitis, and acute disseminated encephalomyelitis). Reye syndrome is associated with influenza (more common with influenza B than influenza A virus infections) and salicylate exposure; however Reye syndrome with influenza is very rare since aspirin use in children with influenza or varicella was recommended against in 1982. In peopleof all ages, influenza can result in dehydration, and exacerbation of underlying chronic medical conditions (e.g. heart failure, myocardial infarction, cerebrovascular accident, diabetes, chronic obstructive pulmonary disease, asthma), Both primary influenza viral pneumonia and secondary invasive bacterial pneumonia (most commonly with Streptococcus pneumoniae, Staphylococcus aureus, methicillin-sensitive or methicillin-resistant, and group A Streptococcus) can lead to acute lung injury, respiratory failure, acute respiratory distress syndrome, septic shock, and multi-organ failure. Invasive infection with Neisseria meningitidis resulting in meningococcemia and meningitis can follow influenza.
Among young children with influenza, nausea, vomiting or diarrhea may also occur with respiratory symptoms.
Influenza Treatment. Antiviral medicines are an important tool in both controlling influenza by treating the patient’s infection and helping to prevent severe illness that can result from flu, including bacterial pneumonia.
Two other drugs, rimantadine (Flumadine®) and amantadine (Symmetrel®), were used to treat flu infection in the past. They worked by disrupting ion channels in the wall of the virus, preventing the virus from replicating during the initial stages of infection, soon after its been taken inside a human cell. However, rimantadine and amantadine are only effective in treating Influenza A, and several strains of flu have already developed resistance to them. Thus, the two medicines are no longer recommended in the United States for treating the flu.
Antiviral medicines are an important tool in both controlling influenza by treating the patient’s infection and helping to prevent severe illness that can result from flu, including bacterial pneumonia. When taken promptly, antiviral drugs can reduce the severity of the flu’s worst symptoms, and can shorten the length of the illness by an average of one day. Taking antiviral drugs early is especially important for people who are at high risk for flu complications, such as the elderly or people with compromised immune systems.
People with higher levels of antibodies against the stem portion of the influenza virus hemagglutinin (HA) protein have less viral shedding when they get the flu, but do not have fewer or less severe signs of illness, according to a new study published in mBio.
J Park et al. Evaluation of pre-existing anti-hemagglutinin stalk antibody as a correlate of protection in a healthy volunteer challenge with influenza A/H1N1 pdm virus. mBio DOI: 10.1128/mBio.02284-17 (2018).
Both influenza A and influenza B are extremely contagious. People who get either type can spread the virus to others from up to six feet away when they cough or sneeze.
These subtypes are based off of the combination of two proteins on the viral surface: hemagglutinin (H) and neuraminidase (N). There are 18 different H subtypes and 11 different N subtypes.
These antiviral medications are most effective when started within the first 48 hours of your illness. They’re ineffective in treating illness caused by influenza C.
Getting lots of rest, eating a healthy diet, and drinking plenty of fluids helps your body fight the virus as well.
In 2017, H3N2 spread to dogs in Florida. In 2015, this same strain also infected dogs in an earlier outbreak in Chicago. Influenza A viruses can be further broken down into strains. Unlike influenza A, influenza B isn’t further divided into subtypes.
It’s most common during the fall and winter months. It typically spreads through respiratory droplets when a person who has the flu sneezes or coughs. The family of viruses that influenza is a part of is large. You may have heard that there are different types of influenza viruses — particularly influenza A and influenza B.
Influenza C is regarded as the least serious of the three types that humans can get. It typically produces a mild respiratory illness in adults. But there’s some evidence that it can cause serious respiratory illness in children under age 2. The CDC.