Influenza is caused by influenza viruses which are spread worldwide and can change rapidly. The main transmission routes are droplets and aerosols, which are spread when sneezing, coughing or speaking of infected persons. Indirect transmission can also occur when secretions containing the virus get onto hands or surfaces and are then transferred into the respiratory tract of another person.
The incubation period for influenza is usually 1 to 2 days before symptoms appear. Infected persons often experience a sudden onset of symptoms, which fever, cough, Sore throat as well as headaches and muscle aches. Due to the high contagiousness of the virus, the disease often spreads in communities, especially during the flu season. It is important to take precautions to prevent transmission and protect yourself.
Influenza viruses are divided into three main types: Type A, Type B and Type C. Type A causes the most cases of influenza and accounts for over 70 percent of cases in a typical season. Types A and B are responsible for seasonal flu epidemics while type C is not a typical flu causes influenza.
The surface structure of the influenza viruses is formed by the glycoproteins hemagglutinin (H) and neuraminidase (N), with 18 H and 11 N variants. The subtypes of the influenza A viruses are named after these surface proteins, with examples such as A(H3N2) and A(H1N1) indicating different strains.
Although different influenza-strains cause similar symptoms, they differ genetically and can lead to different symptoms. influenza epidemics lead to different influenza epidemics. This diversity and the constant change in viruses make the monitoring and management of influenza outbreaks particularly challenging.
The influenzaalso known as true flu shows a variety of symptoms. Typical is a sudden onset of the illness, often accompanied by high feversevere headaches and pronounced aching limbs. Compared to a coldwhich usually only affects the respiratory tract, the symptoms of the flu more intense and affect the entire body.
Those affected may also suffer from a blocked or runny nose, general weakness, sweating and sometimes nausea and diarrhea. The symptoms usually last about a week, although the symptoms can subside relatively quickly. However, exhaustion and cough often persist for longer.
It is important to note that not all people with influenza show the typical symptoms; around a third of infections are asymptomatic. This means that symptoms are not always a clear indicator of the disease.
Common symptoms
Typical symptoms of flu (Influenza) include feverheadache, aching limbs and often a blocked or runny nose. The sudden onset of the disease is a characteristic feature and is often accompanied by other symptoms such as cough or sore throat associated. In addition to these main symptoms, general weakness, sweating, rhinorrhea and sometimes nausea or diarrhea may also occur.
It is important to note that while many sufferers show severe symptoms, there are also a significant number who are asymptomatic or only develop mild symptoms. The symptoms of flu often set in quickly and usually last around 5 to 7 days. However, exhaustion and cough can last longer, which can prolong the recovery process. Early recognition and treatment of symptoms are important to avoid complications.
Severe symptoms
The symptoms of influenza disease often appear quickly and severely. Typical symptoms are high feversevere headache and aching limbs as well as a dry dry cough. In severe cases, additional complications such as viral or bacterial pneumonia can occur, which are characterized by increased coughrespiratory problems and persistent fever manifest themselves. People over the age of 65, children under the age of 5 and people with chronic illnesses are particularly at risk, as they have a higher risk of severe disease progression. In such cases, specific antiviral therapy started within 48 hours of the onset of the first symptoms is crucial to improve the prognosis. The severity of the symptoms often also requires laboratory confirmation of the flu diagnosisespecially in high-risk patients. Early detection and treatment are crucial to avoid serious complications.
How the influenza is transmitted
The flu, also influenza is mainly transmitted by droplets in the air that are released during breathing. cough or sneezing of an infected person. These droplets can easily get onto the mucous membranes of people nearby and thus facilitate the spread of the virus. In addition, there is evidence that smaller aerosolized particles (less than 5 microns) remain in the air longer and can be inhaled during normal breathing or talking, contributing to airborne transmission.
Direct contact also plays a role in the spread of the flu. The virus can survive on surfaces, and if people touch contaminated objects and then touch their mouth, nose or eyes, they can become infected. This dual transmission route emphasizes the importance of good hygiene practices, such as frequent hand washing and avoiding contact with potentially contaminated surfaces, to prevent the spread of the virus. Overall, both droplet and contact transmission are important routes through which the Influenza is transmitted from person to person.
Incubation period and contagiousness
The incubation period for influenza is 1 to 2 days on average, during which the first symptoms such as fever or sore throat can occur. During this time, it is important to know that a sick person can be contagious. Infected individuals shed viruses capable of replication, which correlates closely with the severity of their symptoms. At the beginning of the illness, when symptoms are most severe, a greater amount of virus is usually excreted. This viral shedding peaks about four to five days after the onset of symptoms.
However, it should be noted that in some individuals, particularly immunosuppressed and severely ill patients, a longer period of viral shedding is possible. Caution is therefore required to prevent the further spread of the influenza especially in communal facilities or in close contacts.
Diagnosis of the flu
The diagnosis of influenza is mainly carried out using the nucleic acid amplification technique, in particular PCR, which is considered the gold standard in laboratory diagnostics. This method offers high sensitivity and specificity. Influenza rapid testssuch as antigen testsallow physicians to make quick decisions, especially for patients with pre-existing conditions, but the sensitivity of these tests is limited. tests only good to moderate.
The probability of a positive laboratory test decreases continuously after the first two days of the illness. It is therefore important to take a throat or nasal swab as soon as possible after the onset of symptoms and send it to the laboratory to ensure an accurate diagnosis.
Especially during a flu epidemic positive results from rapid tests are highly significant, but negative results do not rule out the possibility of a influenza infection is present. This underlines the importance of a comprehensive clinical evaluation in addition to the test results.
Differential diagnosis
The differential diagnosis between influenza and cold is crucial, as the two diseases differ significantly in terms of their symptoms and development. One flu often begins abruptly and with severe symptoms, while the cold develops gradually and is usually less severe. During a flu epidemic doctors can use the clinical characteristics to influenza often without additional laboratory tests, especially if the dominant viruses are influenza are.
However, for risk groups such as the elderly or patients with chronic illnesses, early laboratory tests are essential in order to make appropriate treatment decisions. The diagnosis of influenza is primarily carried out by nasal or throat swabs, supplemented by tests such as the influenza-PCR, which is considered the most important method. Additional pathogen diagnoses are particularly important in healthcare facilities in order to take timely infection prevention measures and prevent the spread of influenza control the spread of influenza. A clearly defined distinction between these diseases is therefore of great importance for adequate patient care.
The role of laboratory tests
The laboratory diagnosis of influenza plays a decisive role in the precise identification of the virus. It includes various techniques, whereby the nucleic acid amplification technique using PCR is considered the gold standard. The diagnosis is usually made using nasal or throat swabs, but other body fluids such as tracheal secretions or blood can also be used.
Influenza rapid tests offer the advantage of providing results within 15 minutes. However, they have a variable sensitivity, so a negative result does not necessarily mean that the patient is infected. influenza excludes influenza. Early collection of swabs after the onset of symptoms is therefore of great importance in order to identify specific viral genes and make an accurate diagnosis.
In addition, the Robert Koch Institute's (RKI) virological sentinel surveillance helps to monitor and analyze the spread of the virus through systematic laboratory diagnostic tests in patients with acute respiratory illnesses. These tests are fundamental for the control and prevention of influenza outbreaks.
Treatment options
For the treatment of influenza various antiviral drugs are available, including neuraminidase inhibitors such as oseltamivir (Tamiflu®), zanamivir (Relenza®) and peramivir (Alpivab®), as well as the polymerase inhibitor baloxavir marboxil (Xofluza®). These drugs can shorten the duration of the disease and prevent life-threatening complications in patients at risk. They are most effective if taken within 48 hours of the onset of symptoms. Early treatment is particularly important for older people and pregnant women in order to avoid severe courses of the disease.
These medications should always be prescribed by a doctor in order to monitor possible side effects and minimize the risk of viral strains developing resistance. Overall, early intervention in influenza is of great importance in order to protect the health of patients at risk.
Antiviral medication
Antiviral drugs play a crucial role in the treatment and prophylaxis of influenza. Available agents include the neuraminidase inhibitors oseltamivir, zanamivir and peramivir as well as the polymerase inhibitor baloxavir marboxil. These drugs can shorten the duration of the disease and prevent potentially life-threatening complications, particularly in high-risk patient groups.
It is important to use them only in certain patient groups to avoid the development of resistance. When used prophylactically, they have a protective effect of around 60% to 90%. They are most effective when taken within two days of the onset of symptoms, as they reduce the severity of symptoms and prevent the development of resistance. duration of fever duration of fever. In addition, the safety of neuraminidase inhibitors has been demonstrated with long-term use of up to 16 weeks, which is documented in national pandemic plans.
Prevention strategies
The prevention of influenza infections is crucial to minimize the spread of the virus. One of the most effective strategies is annual vaccination, which is recommended for everyone aged 6 months and older, with a few exceptions. Vaccinations usually protect against 3 to 4 different strains of the influenza virusand the composition is adjusted annually to take account of mutating viruses.
Experts analyze previous seasons and global virus strains to develop the best vaccine. It is estimated that vaccination can reduce infection rates in healthy adults by 70 to 90 percent as long as the vaccine proteins match the circulating strains.
In addition to vaccination, antiviral drugs can be used for prevention, especially for those at high risk of complications. These comprehensive approaches help to protect the health of the community and minimize the impact of the influenza flu.
Importance of the vaccination
The flu vaccination is a fundamental and cost-effective measure for the prevention of influenza. It should be given annually before the influenza season to protect both individual and community health. Vaccination reduces infection rates and helps to prevent prolonged absence from school, work and social activities. Children in particular play a crucial role in the spread of influenzawhich is why their vaccination also protects other age groups.
The effectiveness of the influenza-vaccination varies between 40% and 60%, but is higher in seasons when the vaccines are well matched to the circulating viruses. Risk groups, including the elderly, pregnant women and the chronically ill, are particularly at risk of more severe courses of the disease and should therefore urgently take advantage of the flu vaccination. Ultimately, vaccination is not only an individual decision, but also an important contribution to protecting the entire community.
Hygiene practices
Hygiene practices are crucial to reduce the risk of infection, especially with influenza virusesviruses. One of the most important measures is regular and thorough hand washing. This helps to minimize the transmission of viruses. In addition, people should keep their distance from people with symptoms of acute respiratory illness to further reduce the risk of infection.
Another important aspect is to avoid touching your face. Many viruses are transmitted by touch, especially if you touch your eyes, mouth or nose. Regular ventilation of indoor spaces is also a recommended hygiene practice to reduce the spread of viruses in the air and let fresh air in.
To effectively protect yourself and others from flu infections a combination of these hygiene measures and an annual flu vaccination is essential. By following these practices, together we can help reduce the spread of infection and promote the health of the community.
Risk groups for severe influenza
Certain risk groups are particularly susceptible to severe courses of influenza disease. Infants and young children have an increased risk as their immune system is not yet fully developed. People aged 60 and over are also at risk, as their immune response is often weaker and they frequently suffer from chronic illnesses. Pregnant women often experience more severe symptoms and complications due to physiological changes and a weakened immune system.
In addition, people with underlying chronic conditions such as asthma, diabetes mellitusheart disease, metabolic disorders and obesity have a significantly increased risk of serious consequences from a flu. These people in particular are at increased risk of complications such as pneumonia. It is therefore important that members of these risk groups take special precautions to protect themselves from influenza infection from influenza infection.
Special considerations for pregnant women
Pregnant women have during a influenza epidemic have an increased risk of contracting the virus during an influenza epidemic, as their immune defenses are lowered. Influenza infections can be more severe in pregnant women, which can potentially lead to serious complications for both the mother and the unborn child. The Standing Committee on Vaccination (STIKO) therefore recommends that pregnant women are offered an influenza vaccination from the second trimester of pregnancy to reduce the risk of serious illness.
It is particularly important to note that influenza can increase the risk of serious complications such as pneumonia in pregnant women. Due to the physiological changes in a pregnant woman's body, it may react differently to the influenza viruswhich requires specific medical monitoring and, if necessary, adapted treatment. It is therefore important for pregnant women to take preventive measures and consult their doctor regularly for the latest information on the state of the art. influenza-vaccination recommendations.
Historical effects of the influenza
Since 1889, there have only been six major influenza pandemicscaused by significant changes in the influenza strains and led to increased risks of infection and mortality. Influenza is one of the most serious infectious diseases in history and has claimed millions of lives. The devastating effects were particularly evident during pandemics, as these diseases placed a heavy burden on healthcare systems.
In Austria, statistics show that during the flu epidemics in the fall and winter months, between 5 and 15% of the population are affected, leading to significant consequences of illness. Initial risk groups such as schoolchildren and their relatives are particularly badly affected, followed by older adults in care facilities. This highlights the importance of vaccination measures and health prevention.
The course of the influenza season 2017/2018, during which nine children were diagnosed with "real flu", as well as the five child deaths in the 2018/2019 season, underline the urgency of recognizing the impact of influenza on society and to continue to monitor and combat it.
Current epidemiological surveillance
Current epidemiological surveillance, particularly in the area of influenzais of crucial importance for health surveillance in Europe and beyond. Programs such as the European Influenza Surveillance Scheme (EISS) collect weekly data on influenza cases in the EU and associated countries. This data enables a timely analysis of the disease, which is important for containing and combating outbreaks.
In Germany, the Robert Koch Institute (RKI) plays a central role by collecting the nationwide data on influenza and other notifiable diseases. Health authorities are obliged to report this information in accordance with the Infection Protection Act.
Every year, around 3 to 5 million people worldwide suffer a severe case of influenzawhereby in Germany during a flu epidemic between 4 and 16 million people are infected. These figures illustrate the relevance of robust surveillance in order to protect the population from the potential dangers of the influenza and to develop effective health promotion measures.
Strategies for public health
Public health responds to the influenza through various strategies to monitor and control the spread of the disease. One key measure is the annual flu vaccination, which is recommended for everyone aged 6 months and older. This vaccination is considered the most effective prevention method to influenza infections to reduce influenza infections.
In addition, institutions such as the Federal Office of Public Health in Switzerland and the European Influenza Surveillance Network (EISN) continuously collect epidemiological and virological data. This information helps decision-makers in the EU Member States to make informed decisions and take targeted measures to combat the spread of influenza. influenza influenza.
Particular attention must be paid to at-risk groups, as around 75 percent of influenza-related deaths in the USA during the 2018/2019 season involved people over the age of 65. Statistical methods are used to estimate mortality during the influenza waves to better understand the impact and respond in a targeted manner.
Source: istockphoto svetikd
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