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
How is given a killed virus vaccine against flu?
High-risk adults for complications
Hearth care workers
Children aged 6 months - 2 years at risk of complications
How is a live attenuated vaccine against flu administered?
Intra-nasally
Who is offered a live attenuated vaccine against flu?
Primary and aged 2-5 children
In which age group is the live attenuated vaccine against flu more effective than killed virus?
Children and young adults aged 2-17
What does the protective efficacy of the flu vaccine depend on?
Vaccine to circulating virus match
Why is the protective efficacy of the flu vaccine never greater than 70%?
Because the strains constantly change
When is influenza most common?
In winter
When is parainfluenza 1 most prevalent?
Summer
When is Rhinovirus species A most common?
Found year-round
How can pneumonia caused by Mycoplasma pneumonia, Coxiella burnetti, or Chlamydia be treated?
All respond to tetracycline and macrocodes (e.g. clarithromycin)
Mortality through mycoplasma pneumonia, coxiella bunetti or chlamydia induced pneumonia is typically ____ than classical bacterial penumonia
lower
How can Mycoplasma pneumonia, coxiella brunette or Chlamydia be confirmed in the lab?
Serology (actue / convalescent bloods to lab in gold-top vacutainers) Virus detection (PCR on respiratory swabs or secretions - only Mycoplasma in Tayside)
Mycoplasma pneumoniae is a common cause of _____-______ _____ and has it’s highest incidence in ____________
Community-Acquired pneumonia
Children ü young adults
How is mycoplasma pneumoniae transmitted?
Person - Person
Coxiella brunetti curasse _____/______ of unknown origin
pneumonia / pyrexia
What is pyrexia?
Fever / Raised temperature
What does Chlamydophila psittaci cause?
Psittacosis (usually presents as pneumonia)
What do Coxiella burnetti and Chlamoydophila psittaci have in common?
Uncommon sporadic zoonosis
Where is chlamoydophila psittaci caught from?
Pet birds
What is the clinical presentation of bronchiolitis?
1st or 2nd year of life
Fever
Cough
Wheeze
What does the clinical presentation of bronchiolitis in severe cases include?
Grunting
Low PaO2
Intercostal or sternal in-drawing
What are the possible complications of bronchiolitis?
Respiratory and cardiac failure
What are the risk factors for developing complications of bronchiolitis?
Premature birth
Pre-existing respiratory or cardiac disease
What is the aetiology of bronchiolitis?
(resp.) Syncytial virus (most common, > 80%) Human rhinovirus Parainfluenza Human metapneumovirus Coronavirus Adenovirus Influenza virus Enterovirus
How can aetiology of bronchiolitis be confirmed in the lab?
PCR on that / perusal swabs
How is bronchiolitis treated?
Supportively
What is the epidemiology of bronchiolitis?
Epidemics every winter
Very common
How is bronchiolitis controlled?
No vaccine
Nosocomial spread in hospital wards
Passive immunisation > poor efficacy/cost-effectiveness
What is the epidemiology of metapneumovirus?
Most children positive by age 5
Found in wide age range
World-wide distribution
Winter seasonality
Metapneumovirus may be second to respiratory virus in ______
bronchiolitis
Metapneumovirus causes similar symptoms as RSV in _______
children and adults
How is metapneumovirus confirmed in the lab?
PCR
What is sampled to confirm metapneumovirus in the lab?
samples by throat swabs in viral transport medium
Bronchoalveolar lavage
Endotracheal aspirate
What current panels are run for PCR for lab confirmation of pneumonia?
Flu A and B Parainfluenza 1-4 4 coronavirus species Metapneumovirus Adenovirus RSV Rhinovirus Mycoplasma pneumonia
Chlamydia trachomitis is an STI that can cause _____ _____
infantile pneumonia
How is infantile pneumonia caused by chlamdia trachomitis diagnosed?
PCR on urine from mother or child pernasal/throat swabs
How is Chlamoydophila pneumoniae transmitted?
Person - person
How is chlamoydophila pneumoniae picked up?
Possibly by test for Psittacosis
Where is MERS CoV most common?
Saudi Arabia
What does MERS CoV stand for?
Middle East Respiratory Syndrome coronavirus
What is the fatality rate of MERS CoV?
35%