Influenza is a highly communicable or contagious acute respiratory infection. Although there are numerous influenza strains; there are 3 main types responsible for causing the flu. These are Influenza A, B, and C. These types can be further categorized by subtypes and strains of the virus. Broken down into the basics are: Influenza type A and B are responsible for respiratory illness; the flu or influenza (WebMD). Type C is actually a milder respiratory illness with little to no symptoms at all.
In a human; the respiratory tract is lined by epithelial cells which cover from the nasal cavity to the air sacs of the lungs. The influenza virus infects the epithelial cells located in the respiratory tract. The virus is then spread by airborne respiratory droplets, from skin contact, or touching something that has been contaminated recently and then touching their nose or mouth. Some of the symptoms associated with influenza are similar to that of the common cold; yet they tend to be more severe (WebMD). They include fever, headache, fatigue, muscle weakness, sore throat, runny or stuffy nose, dry cough, pharyngitis, gastroenteritis, nausea, vomiting, or diarrhea.
Influenza strains are vigorously active and constantly evolving (Flu.gov). Evolution of these strains is caused by rapid viral mutation or re-assortment. Two causes for these changes are antigenic shifting or drifting. Antigenic shift causes sudden, unexplained changes to the virus. Antigenic drift causes minor point mutations, with small change to the virus. The virus enters the host by evading the immune system. Antibodies no longer recognize the newer strains of the virus; the host is unaware of the problem until the infection is already underway (Medicinenet).
Healthcare providers administer rapid tests, viral cultures, antigen tests, antibody tests, polymerase chain tests, or serology; in order to properly diagnose a patient (Flu.gov). Although there is not cure for this, there are some treatments available. Treatments can depend on the severity or length of the illness. Antivirals are used to reduce or lessen the severity of symptoms it causes. These include: Tamiflu, amantadine, or flumadine. Also helpful may be antihistamines, expectorants, decongestants, or analgesics to reduce stuffy or runny nose, fever, aches, or pain. Fluids, rest, and sleep are helpful as well. A preventative measure for the flu is to get the flu vaccine. This can be administered long before the onset of symptoms; which is much different that an antiviral medication.
The influenza virus tends to be common among those with compromised immune systems. This includes individuals with chronic or infectious diseases, children, pregnant women, or the elderly (WebMD). Yet this disease or illness is not limited to the individuals that fall within these categories. On average each year; between 5% and 20% of the US population get the flu. The average number of Americans hospitalized each year because of flu...