Influenza

About Influenza Flu, or influenza, is a highly contagious acute respiratory illness. Flu season generally occurs annually all over the world, during the cold season. Flu is caused by the Influenza virus that invades and multiplies in the respiratory tract. Influenza viruses are divided into three types: A, B, and C.

• Influenza types A and B are the primary causes of the disease and responsible for epidemic outbreaks.
• Influenza type C is a sporadic cause of predominantly upper respiratory tract disease such as the common cold and pharyngitis.

The influenza virus is unique in that its structure changes each year. Major changes cause worldwide epidemics called pandemics. Minor changes cause the annual local outbreaks. Pandemics are estimated to occur every 10 to 20 years while local outbreaks occur every 2 to 3 years. Who are at risk of getting flu? Any person is at risk of getting flu. The risks are higher if you belong to any of the following groups:

• Those who belong to extremes of age generally have low immune functions to fight the virus.
• Those with chronic debilitating illnesses (e.g., asthma, emphysema, kidney disease, diabetes).
• Smokers and chronic alcoholics with secondary liver dysfunction.
• Children in day-care centers and adoption homes.
• Children on long-term aspirin therapy.
• Women in their 2nd or 3rd trimester of pregnancy.
• Residents of nursing homes.

Mode of Transmission Entry of the virus into the respiratory tract:

• via droplets from an infected person through coughing talking and sneezing
• through contact with the surfaces, material and clothing contaminated with discharges of an infected person

Transmission through a community is rapid, with the highest incidence of illnesses occurring within 2 to 3 weeks of introduction, and with the outbreak lasting for 6 to 10 weeks. How do you know that you have flu? (signs and symptoms) The incubation period of flu is 1 to 4 days-- once you get infected with the virus, it takes 1 to 4 days for you to feel symptoms due to the disease.

• Headaches, muscle aches, joint pains, body malaise and fatigue that can be severe during the first few days but will slowly improve.
• Sore throat
• Cough which starts as dry and hacking and progresses by the 3rd day to wet with thick mucus. Your cough can worsen during the next 4-7 days and can last for over 2 weeks. You have a higher risk to develop bronchitis and pneumonia if you smoke.
• Fever with a temperature of 38oC to 40oC, with or without chills, within 12 hours from onset of infection. Fever is higher in children and can reach to as high as 41oC.
• Nasal congestion, watery eyes or runny nose.
• Vomiting and/or diarrhea. Diarrhea is more common in children less than 6 years of age.

Treatment To prevent complications and to allow your immune system to work:

• rest
• comfortable room temperature
• increased fluid intake

Symptomatic drug treatment:

• For fever, headache, muscle and joint pains: Analgesic/Antipyretic agents – Paracetamol, Ibuprofen
• For runny and stuffy nose: cold Medications – Phenylpropanolamine
• For dry cough – Dextromethorphan
• For productive cough: Guiafenesin, Carbocisteine, Bromhexine, Ambroxol

Other notes:

• Aspirin should not be given to children.
• Antibiotics to be given only to complications of influenza such as pneumonia or otitis media.

When should you call your physician? Call your physician if you note the following:

• Fever recurs after it has gone for1-2 days, or you continue to have high-grade fever after 4 or 5 days.
• Cough becomes wheezy, with difficulty in breathing and the presence of bloody or yellow-green mucus and phlegm.
• You have chronic illness (e.g., asthma, cancer, diabetes, kidney problems) or your chronic condition worsens.
• Ear pain and/or ear discharge.
• Prolonged headache, confusion, frequent muscle twitching, seizures or convulsions and general body weakness.
• Bleeding in any part of your body.
• Rapid or irregular heartbeat.

Prevention

• influenza vaccination preferably to be given anytime from February to June
• provide a separate room for a person sick with influenza
• cover mouth and nose when sneezing or coughing to prevent spread of the virus
• Avoid persons with the disease. Distance yourself at least 1 meter from people who are coughing or are sick with influenza. Adults with flu are typically contagious for 5-7 days from fever onset. In children, they are contagious for 7-10 days and even longer (up to 4 weeks) in patients with low natural defense mechanism.
• wash hands frequently with soap and water

What are the complications of flu?

• Pneumonia - manifests as high-grade fever, brassy cough, lack of appretite, drowsiness, difficulty in breathing, and increased phlegm and mucus production
• Otitis media - can present as earache or fluid coming out of the ears
• Reye’s Syndrome (rare complication) - marked by delirium, seizures, stupor, coma, and death.