INFLUENZA AND OTHER RESPIRATORY VIRUSES

Transcription

1 INFLUENZA AND OTHER RESPIRATORY VIRUSES Lung Foundation Australia Patient Seminar 21 st October 2017 Lynette Reid Respiratory Clinical Nurse Specialist, RHH

2 What is influenza (the flu )? Influenza (flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness. There are three main types of influenza virus that can cause infection in humans types A, B and C Influenza A and B viruses are responsible for seasonal flu epidemics each year. There are many different strains and sub-types

3 Type A Influenza Viruses Divided into subtypes, e.g. H1N1, H2N3 Haemagglutinin (H) protein involved in cell attachment during infection Neuraminidase (N) protein that enables the virus to be released from the host cell

4 How the Flu Virus Can Change: Drift and Shift (mutations) Influenza viruses are constantly changing. They can change in two different ways: One way they change is called antigenic drift. These are small changes in the genes of influenza viruses that happen continually over time. When this happens, the body s immune system may not recognize those viruses The other type of change is called antigenic shift. Antigenic shift is an abrupt, major change in the influenza A viruses. This results in a new strain that can spread through the population (pandemics) Therefore a new influenza vaccine is prepared each year to best match the strains predicted for the coming influenza season

5 What are the symptoms? People with flu typically experience some or all the following symptoms for at least a week: o Fever and chills o Cough, sore throat and runny or stuffy nose o Muscle aches, joint pains o Headache o Fatigue (feeling very tired)

6 Not all respiratory viruses are the flu The common cold is mainly an infection of the nasal passages and the oropharynx (pharyngitis) There are many viruses that cause colds. The most common are: o Rhinovirus o Coronaviruses o Parainfluenza o RSV o Adenovirus o Metapneumovirus

7

8 Severe or worsening flu symptoms Seek medical advice if the illness quickly becomes worse or if any of the following occurs: odifficulty breathing or shortness of breath opain or pressure in the chest oconfusion or sudden dizziness opurple or blue discolouration of the lips opersistent vomiting

9 How is influenza spread? Flu viruses are mainly spread by droplets when an infected person coughs or sneezes Flu can be spread after touching surfaces where infected droplets have landed The flu virus can live for up to five minutes on the hand and up to a day on hard surfaces Adults with flu are infectious from the day before symptoms start until 5-7 days later. This may be longer in people with weakened immunity fm?orgid=457&pid=50294

10 How is it diagnosed? Doctors usually diagnose influenza based on symptoms The diagnosis can be confirmed by testing a sample taken from the back of the nose and throat, or Blood test

11 How is it treated? Symptoms can be managed by rest Paracetamol can help reduce fever and relieve headache and muscle aches Antiviral medications (Tamiflu) can reduce the severity and the duration of influenza. o They need to be taken within 48 hours of the first symptoms. o This medication needs to be prescribed by a doctor o They are usually considered for people at higher risk of complications from flu infection

12 How to reduce the spread of influenza Cover your face when you cough or sneeze and throw used tissues in a bin Wash your hands thoroughly and often. Use alcohol-based hand rub Stay at home until you re well. Wait at least 24 hours after fever resolves so you don t infect others Avoid contact with sick people Having a flu vaccine every year is the best prevention

13 Influenza vaccination The best way to prevent influenza is to have the flu vaccination every year before winter People at higher risk of influenza complications (e.g. people with chronic lung disease) are strongly recommended to have an annual influenza vaccination, and are eligible for free influenza vaccine under the National Influenza Vaccination Program ishing.nsf/content/immunise-influenza

14 Respiratory viruses and pneumonia Complications of the flu, such as pneumonia, do occur particularly in those with a chronic lung disease, e.g. COPD Pneumonia is an infection and inflammation of the lungs A wide variety of bacteria and viruses can cause pneumonia The most common bacterial cause of pneumonia acquired in the community is Streptococcus pneumoniae (pneumococcus)

15 COPD and pneumonia People with COPD have greater risk for pneumonia because their lungs may be weakened or structurally damaged, they may have reduced ability to filter bacteria and viruses or their immune system may be suppressed The 23-valent pneumococcal vaccination is recommended for all adults aged 65 years or over An additional dose is recommended for adults with chronic lung disease, e.g. COPD or severe asthma (e.g. requiring frequent hospital visits)

16 Laboratory confirmed influenza notifications, Tasmania

17 References Australian Prescriber; Pneumococcal vaccines past, present and future (2013) Centers for Disease Control and Prevention; Influenza (Flu) (2017) Department of Health and Human Services; Flu Fact Sheet (2016) _unit/infectious_diseases/flu Lee, G & Bishop, P. (2013). Microbiology and Infection Control for Health Professionals New South Wales Government Influenza Fact Sheet (2016)