Influenza is a febrile illness with fever runny nose,sore throat head ache,fatigue and myalgias .It may be as sample as upper respiratory tract infection or may lead to pneumonia ,respiratory failure and death .It is a viral disease and there are three influenza viruses A,B and C and other subtypes like swain flu and bird flu.Flu can be caused by other viruses of less virulence viral organism.
Mode of transmission
Influenza can be spread in three main ways, by direct transmission (when an infected person sneezes mucus directly into the eyes, nose or mouth of another person); the airborne route (when some one inhales the aerosols ( air) produced by an infected person coughing, sneezing or spitting) and through hand-to-eye, hand-to-nose, or hand-to-mouth transmission, either from contaminated surfaces or from direct personal contact such as a hand-shake. In the airborne route, the droplets that are small enough for people to inhale are 0.5 to 5 micrometer in diameter and inhaling just one droplet might be enough to cause an infection. Although a single sneeze releases up to 40,000 droplets, most of these droplets are quite large and will quickly settle out of the air. How long influenza survives in airborne droplets seems to be influenced by the levels of humidity and ultraviolet radiation with low humidity and a lack of sunlight in winter aiding its survival.
As the influenza virus can persist outside of the body, it can also be transmitted by contaminated surfaces such as banknotes,doorknobs, light switches and other household items. The length of time the virus will persist on a surface varies, with the virus surviving for one to two days on hard, non-porous surfaces such as plastic or metal, for about fifteen minutes from dry paper tissues, and only five minutes on skin.So avaiding touching the above household items by patints will reduce the risk of spread. If the virus is present in mucus, this can protect it for longer periods (up to 17 days on banknotes). Avian influenza viruses can survive indefinitely when frozen. They are inactivated by heating to 56 °C (133 °F) for a minimum of 60 minutes, as well as by acids (at pH <2).
Reasonably effective ways to reduce the transmission of influenza include good personal health and hygiene habits such as: not touching your eyes, nose or mouth; frequent HAND hand washing (with soap and water, or with alcohol-based hand rubs); covering coughs and sneezes; avoiding close contact with sick people; and staying home yourself if you are sick. Avoiding spitting is also recommended.Although face masks might help prevent transmission when caring for the sick. there is mixed evidence on beneficial effects in the community. Smoking raises the risk of contracting influenza, as well as producing more severe disease symptoms.
Since influenza spreads through both aerosols and contact with contaminated surfaces, surface sanitizing may help prevent some infections.Alcohol is an effective sanitizer against influenza viruses. In hospitals, quaternary ammonium compounds and bleach are used to sanitize rooms or equipment that have been occupied by patients with influenza symptoms. At home, this can be done effectively with a diluted chlorine bleach.
During past pandemics, closing schools, churches and theaters slowed the spread of the virus but did not have a large effect on the overall death rate. It is uncertain if reducing public gatherings, by for example closing schools and workplaces, will reduce transmission since people with influenza may just be moved from one area to another; such measures would also be difficult to enforce and might be unpopular.When small numbers of people are infected, isolating the sick might reduce the risk of transmission.Vaccination against influenza with an influenza vaccine is often recommended for high-risk groups, such as children of 6 months to 2 years or and the elderly above 65 years of age and older , or in people between 2years to 64 years who have, other chronic health conditions including asthma, diabetes ,chronic bronchitis heart failure,renal failure alcoholic, or are immuno-compromised. Vaccination also is important for health care workers, and other people who live with or care for high risk people to keep from spreading flu to high risk people.
The United States authority on disease prevention, the centres for disease control and prevention (CDC), recommends that persons suffering from influenza infections:
• Should Stay at home
• Get plenty of rest
• Drink plenty of liquids
• Do not smoke or drink alcohol
• Consider over the counter medications like paracetamol, to relieve flu symptoms
• Consult a physician early on for best possible treatment
• Remain alert for emergency warning signs
Warning signs are symptoms that indicate that the disease is becoming serious and needs immediate medical attention. These include:
• Difficulty breathing or shortness of breath
• Pain or pressure in the chest or abdomen
• Severe or persistent vomiting
In children other warning signs include irritability, failing to wake up and interact, rapid breathing, and a blueish skin color. Another warning sign in children is if the flu symptoms appear to resolve, but then reappear with fever and a bad cough.
Guest Author: Dr.Faridullahshah
Physician internal Medicine.
MBBS, FCPS(med), FCPS (neuro)