Influenza
Influenza is also called flu. The infection affects the respiratory system parts such the nose, throat and lungs. It is of importance to differentiate this flu from stomach flu viruses that cause diarrhoea and vomiting.
This flu, for most people, is self-limiting. This means that these infected people get better on their own.
Causative Agent
Influenza is caused by Influenza viruses.
4 different types of influenza viruses are A, B, C and D
Epidemiology
5-15% of the population contract influenza per annum
Frequency of occurrence recorded at 3 to 5 million cases annually.
Deaths recorded surpass 250,000 per annum.
Historically, influenza is characterized by pandemic outbreaks every 10-50 years. Examples include;
- The Spanish flu; from 1918-1920.
- The Asian flu of 1957.
- The Hong Kong flu of 1968.
- The Russian flu of 1977.
- The swine flu pandemic of 2009.
Of all these 5 pandemic outbreaks, Spanish flu was the most severe.
Risk Factors
- Age. Seasonal Influenza has worse outcomes on paediatrics and geriatrics(extremes of age). For children, worse prognosis in those aged 1 years or less. For the old, it affects those above 65 years with worse outcomes.
- Weak immune system. Cancer therapies, chronic steroidal use, organ transplant and HIV/AIDS(immuno-suppressing syndrome) lead to weaker immune systems that are more susceptible to influenza virus
- Chronic diseases such as diabetes-HYP
- Chronic aspirin use. For individuals under 20 years who have been subjected to long term use of aspirin therapy, these persons are at risk of developing Reye’s syndrome if they are infected with influenza virus
- Obesity. Individuals with Body Mass Index of 40 kg/square meter or more are highly susceptible to Influenza virus.
Groups At Risk;
- Paediatric population less than 1 year old
- Geriatric older than 65 years old
- People living in over-crowded residential places for example nursing homes
- Women who become pregnant during the flu epidemic
- Individuals with weakened immunity
- Obese persons with Body Mass Index of 40 kg/square meter or more.
- Brain disorders that alter the way in which the brain processes information
- Chronically ill patients. For example individuals suffering from asthma, diabetes and heart disease.
Signs & Symptoms
- Eye pain
- Sore throat
- Headache
- Dry coughs
- Shortness of breath
- Runny nose
Diagnostic Tests
- Influenza virus is diagnosed by employing laboratory techniques such as;
- Polymerase chain reaction(PCR)- This is conducted to check for/ identify viral nucleic acids
Treatment & Management
- Influenza is treated using anti-viral drugs like oseltamivir
- Vaccination gives protection against Influenza virus sub-types H1N1 and H3N2 and two subtypes of Influenza B
- The disease s self-limiting in healthy persons who have a good immune system
- It is deadly in high risk groups
Control & Prevention
In order to control spread of the flu;
- Wash hands properly with clean soap and clean water or use an alcohol-based hand rub/ sanitizer( at least 60% alcohol concentration)
- Do not touch face or nose with the fingers
- Cover coughs with clean handkerchiefs. Do the same when sneezing.
- Avoid crowded places where the flu can spread easily
- Regularly clean working areas and surfaces