Microbiology of Respiratory Tract Infections Flashcards
How does the flu clinically present?
Fever Malaise Myalgia Headaches Cough Prostration
What is the aetiology of classical flu?
Influenza A or B virus
What is the aetiology of ‘flu-like’ illness?
Parainfluenza viruses & many others
Haemophilus influenza bacteria is a _______ invader
secondary
When does primary influenzal pneumonia occur mostly and who is affected?
Most during pandemic years
Can be disease of young adults
Hight mortality
In which demographic is secondary bacterial pneumonia most common?
Elderly
Infants
Debilitated
Those with pre-existing disease
Secondary bacterial pneumonia is a cause of ______ in all influenzal epidemics
mortality
What most commonly causes secondary bacterial pneumonia?
Haemophilus influenza
Flu is treated ______
symptomatically
Which antivirals can be used to treat flu?
Oseltamivir
Tanamivir
What are the requirements to prescribe an antiviral for flu?
Only when there is a risk of complication of when the flu is circulating / sometimes given prophylactically
Epidemiologically, when does flu occur?
Winter season
What does antigenic drift mean?
Epidemics in association with minor mutations in the surface proteins of the virus
What does antigenic shift mean?
Pandemics with rare, unpredictable, influenza A that come from an animal reservoir/mixing vessel
What does endemic mean?
Occurs naturally in a population
What does epidemic mean?
Outbreak of unexpected size (more than one area or country)
What is a pandemic?
Global distribution of disease
What about a flu pandemic/epidemic is often incorrectly predicted?
Site of origin
What makes up the name of a virus?
Virus type Geographic origin Strain number Year of isolation Surface proteins / Antigens
Influenza A H5N1 is a highly ________ _____ flu with observed _____ - _______ transmission and high mortality with less ready _____-______ transmission
pathogenic
avian
bird - human
human - human
Lab confirmation of influenza can occur by which methods?
Direct detection by PCR
Antigen detection
Immunofluorescence
Virus culture
How would a sample for lab confirmation of influenza by PCR be obtained?
Nasopharyngeal swabs in virus transport medium
Throat swabs in virus transport medium
Other respiratory samples
Between direct detection of virus of PCR and Antigen detection, which is better?
Direct detection
What are the methods to prevent flu via vaccine?
Killed virus
Live attenuated vaccine
How is a killed virus produced for vaccination against flu?
Virus cultured > inactivated > combined with adjacent
What does a killed virus vaccine against flu contain?
2 influenza A
1 influenza B