Overview

Flu (influenza) is a contagious respiratory illness spread by coughs and sneezes. It can be very unpleasant, but you'll usually begin to feel better within about a week.
You can catch flu all year round, but it's especially common in winter, which is why it's also known as seasonal flu.
Flu isn't the same as the common cold. Flu is caused by a different group of viruses that infect the nose, throat, and sometimes the lungs. the symptoms tend to start more suddenly, be more severe and last longer.

Symptoms

• At first, the flu may seem like a cold with a runny nose, sneezing and sore throat. Colds usually start slowly. But the flu tends to come on quickly. And while a cold can be miserable, you usually feel much worse with the flu. Common symptoms of the flu often — but not always — include a fever as well as aching muscles, chills and sweats. Other symptoms include: • Headache. • Dry, persistent cough. • Shortness of breath. • Tiredness and weakness. • Runny or stuffy nose. • a high temperature (fever) of 38C (100.4F) or above • Sore throat. • general aches and pains Vomiting and diarrhea also are flu symptoms. But they are more common in children than in adults.

Causes

• Influenza is caused by viruses. These viruses travel through the air in droplets so If you have a flu and you sneeze or cough, tiny droplets of fluid containing the virus are launched into the air. These droplets spread about 1 metre and are suspended in the air for a while so they can be breathed in by someone else who may then become infected. These tiny droplets of fluid can also land on surfaces. Anyone who touches these surfaces can catch a flu if they pick up the virus on their hands and then touch their nose or mouth. If you have a flu and you touch your mouth or nose and then touch a person or object such as computer keyboard without first washing your hands, then you can transfer the virus to that person or object. People with the virus are likely contagious from about a day before symptoms appear until about 5 to 7 days after they start. Children and people with weakened immune systems may be contagious for a slightly longer time. Influenza viruses are constantly changing, with new strains appearing often. If you've had influenza in the past, your body has already made antibodies to fight that specific strain of the virus. If future influenza viruses are like those you've come across before, either by having the disease or by getting vaccinated, those antibodies may prevent infection or lessen its severity. But antibody levels may decline over time. And antibodies against past influenza viruses may not protect you from new influenza strains. New strains can be very different from what you had before.

Risk factors

• • Age. Seasonal influenza tends to have worse outcomes in young children, especially those age 12 months and younger. Adults older than age 65 also tend to have worse outcomes.
• • Weakened immune system. Cancer treatments, anti-rejection medicines, long-term use of steroids, organ transplant, blood cancer or HIV/AIDS can weaken the immune system. This can make it easier to catch the flu virus and may increase the risk of developing complications.
• • Living or working conditions. People who live or work in facilities with many other residents, such as nursing homes, are more likely to get the flu. People who are staying in the hospital also are at higher risk
• • Chronic illnesses. Chronic conditions may increase the risk of influenza complications. Examples include asthma and other lung diseases, diabetes, heart disease, nervous system diseases, previous history of stroke, metabolic disorders, problems with the airway, and kidney, liver or blood disease.
• • Race or ethnicity. In the United States, people who are American Indian or Alaska Native, Black, or Latino all may have a higher risk of influenza complications.
• • Aspirin use under age 20. People who are younger than 20 years of age and receiving long-term aspirin therapy are at risk of developing Reye's syndrome if infected with the influenza virus.
• • Pregnancy. Pregnant people are more likely to develop influenza complications, particularly in the second and third trimesters. This risk continues up to two weeks after the baby is born.
• • Obesity. People with a body mass index (BMI) of 40 or higher have an increased risk of flu complications.

Complications

• Complications of flu mostly affect people in high-risk groups, such as the elderly, pregnant women and those who have a long-term medical condition or weakened immune system. If you get flu while you're pregnant, there's a risk that the infection could cause problems with your pregnancy. Flu may cause you to go into premature labour (before 37 weeks of pregnancy), or it may result in your baby having a low birth weight. Occasionally, getting flu during pregnancy can result in a miscarriage or stillbirth. If you're young and healthy, the flu usually isn't serious. Although you may feel awful 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. • Bronchitis. • Asthma flare-ups. • Heart problems. • Ear infections. • Acute respiratory distress syndrome. Pneumonia is one of the most serious complications. For older adults and people with chronic illnesses, pneumonia can be deadly.

Prevention

• The best way to prevent flu is to get vaccinated every year. For this reason, The U.S. Centers for Disease Control and Prevention (CDC) recommends annual flu vaccination for everyone age 6 months or older. The flu vaccine can lower your risk of getting the flu. The flu vaccine lowers your risk of having serious illness from the flu each year and needing to stay in the hospital due to flu. The flu vaccine also lowers your risk of dying of flu. The influenza vaccine isn't 100% effective because it doesn't work against every possible type of flu virus, so it's also important to Control the spread of infection by: • Wash your hands. Wash your hands well and often with soap and water for at least 20 seconds. If soap and water aren't available, use an alcohol-based hand sanitizer with at least 60% alcohol. Make sure friends and family that you're around regularly, especially kids, know the importance of hand-washing. • Avoid touching your face. Keeping your hands away from your eyes, nose and mouth helps keep germs away from those places. • Cover your coughs and sneezes. Cough or sneeze into a tissue or your elbow. Then wash your hands. • Clean surfaces (such as your keyboard, telephone, and door handles). Regularly clean often-touched surfaces to prevent spread of infection from touching a surface with the virus on it and then your face. • Avoid crowds. The flu spreads easily wherever people gather — in childcare centers, schools, office buildings and auditoriums and on public transportation. By avoiding crowds during peak flu season, you lower your chances of infection. Also avoid anyone who is sick. And if you're sick, stay home for at least 24 hours after your fever is gone so that you lessen your chance of infecting others.

Extra Information

This is done by Teryaq.info team with the help of:
1- www.cdc.gov
2- mayoclinic.com
3- www.healthdirect.gov
4- www.nhsinform.scot