influenza commonly known as the flu is a highly contagious respiratory disease caused by the influenza virus there are three types of the influenza virus that can infect humans influenza types a b and c influenza types a and b are responsible for the annual regional flu epidemics or the flu season which is when cases of influenza rise and spans from about September to Jan with peaks around December to April on the other hand influenza c may lead to mild illness but not epidemics or pandemics
The respiratory tract can be divided into two regions the upper respiratory tract and lower respiratory tract the upper respiratory tract includes the nose nasal cavity oral cavity pharynx epiglottis larynx and the upper part of the trachea while the lower respiratory tract includes the lower part of the trachea and the lungs containing the bronchi then the bronchioles onto the alveolar ducts and finally into the alveoli these tiny air-filled sacs are the body’s primary sites of oxygen and carbon dioxide gas exchange the gases move across the alveolar-capillary membrane with oxygen moving from the alveolar sacs into the bloodstream and carbon dioxide moving from the bloodstream into the alveolar sacs to give off this allows for a consistent oxygen supply to carry out body function
Risk Factors and causes
The influenza virus invades the respiratory tract and uses it to spread
the infection flu is typically transmitted from person to person via respiratory droplets or in some instances, aerosolized particles that are expelled from the respiratory tract of an infected individual these droplets can be propelled a few feet into the air when talking coughing, or sneezing and can then land in the eyes noses or mouths of people nearby or get breathed into the lungs less as often as possible the infection is communicated in a roundabout way when an individual contacts a sullied surface and afterward before cleaning up they contact their eyes nose or mouth individuals are most likely to spread the virus to others one day before symptom onset until about five to seven days after becoming sick so people are at expanded risk for getting the infection assuming they have close contact with tainted people or are in little spaces with huge gatherings during influenza season particularly if they’re not vaccinated against influenza common places where the influenza virus spreads include schools workplaces nursing homes or on public transportation.
After a person’s secondary bacterial infection client infectious little pathogens typically multiply and spread throughout the cells lining the upper respiratory tract in response to this the immune system launches an inflammatory response which results in visible tracheobronchial redness and swelling as well as mucus discharge as these cells start to produce more mucus that can help trap and eventually expel these pathogens in certain cases the disease can become more severe and spread to nearby areas leading to complications like a sinus or ear infection if the virus starts to invade the lower respiratory tract suspect can potentially develop pneumonia characterized by fluid or pus build-up in the lungs, in addition, by this the body becomes more susceptible to a secondary bacterial infection susceptible at higher risk of developing complications include children under four years of age and adults over 62 as well as susceptible who are pregnant or have a chronic heart or lung disease.
The flu infection shows side effects that show up around four days after openness and last about seven days normal side effects incorporate cerebral pains fever chills exhaustion shortcomings and muscle hurts clients may likewise encounter a runny nose with watery nasal release an irritated throat and a hack after auscultating the lungs breath sounds are commonly typical now in addition to the other symptoms, influenza b can also lead to gastrointestinal symptoms like nausea vomiting, and diarrhea most of these symptoms get better in a week but the cough often persists for up to two weeks and clients with comorbid conditions or over 63 may have to continue lethargy or weakness for weeks after the flu.