Week 7 - Fresher's Flu Flashcards
Name 5 viruses that infect the upper respiratory tract
Rhinovirus Coronavirus Influenza virus Parainfluenza virus Respiratory syncytial virus Herpesvirus Adenovirus Bocavirus Coxsackvirus
Name 5 viruses that infect the lower respiratory tract
Influenza virus Parainfluenza virus Respiratory syncytial virus Adenovirus Bocavirus Metapneumovirus
What are symptoms of a cold? How common are colds?
Sneezing
Rhinitis (blocked nose)
Cough/coryza
Sore throat
Common - multiple colds a year
What are the symptoms of the flu?
How frequent is the flu?
What is the onset?
Sudden onset (within hours)
Fever, chills, shivering
Headache
Myalgia (pain in certain muscle groups) - systemic, their whole body hurts
Cough
Rarely more than once per year, usually less frequent
Infectious from 24hrs pre symptoms to 5-7days after illness starts
Can sometimes have GI symptoms, vomitting and diarrhoea due to high temp
What is Fresher’s Flu?
Term used in UK
Affects students when they arrive at university
Usually doesn’t involve influenza
What are the potential causes of Fresher’s Flu?
- Upper Resp tract infection (exposure to novel viruses)
- Excess alcohol
- Lack of sleep
- Homesickness
- Adjustment to living independently
Usually doesn’t involve influenza
How do you diagnosis a cold?
Based on symptoms
Exclusion of more serious illness
Mild, self-limiting
Better within 7 days, usually feel better within 2/3 days
How do you diagnosis a flu?
Presence of fever and systemic symptoms
Prolonged illness 7-10 days
Rapid onset (within hours)
Contact with flu - travel or local outbreak
Lab diagnosis
Which animals does Influenza A affect?
- Humans
- Mammals
- Birds
Which animals does Influenza B affect?
Human
Seals
Which animals does Influenza C affect?
Human
Pigs
Dogs
Which animals does Influenza D affect?
Cattle
Pigs
How many cases of flu?
3 - 5 million cases a year
How many annual deaths are due to the flu?
250 000 - 750 000 deaths annually
Mostly in people over 65
Why is there a need for an annual vaccination?
The vaccine each year is based on predicted circulating strains
- Numerous flu viruses circulating at any given time
- Antigenic drift - minor changes in the antibody binding sites so the flu virus is not recognised by the immune system
- Antigenic shift - major changes with the circulating virus (combo with diff viruses - mix with avian/porcine with human virus) creating a new subtype of flu
- Potential for pandemic with antigenic shift
What to do if you think you have the flu?
- Rest
- Keep hydrated
- Keep warm
- Let people know
- Continue to take any prescribed medication (esp insulin)
- Self report
- Don’t take antibiotics - they don’t work on viruses
- Cover your mouth/nose when coughing
What are some red flags with the flu?
- Haemoptysis
- Persistent fever
- Confusion
- Non-blanching rash
- Persistently enlarged lymph nodes
- Lethargy
- Difficulty breathing
- Difficulty swallowing own saliva
What are 5 ways to avoid getting the flu?
- Get flu vaccine each year (even if you get the flu, the symptoms will be milder)
- Avoid being around people who have the flu
- Try not to touch your eyes, nose or mouth (germs enter the body easiest this way)
- Clean and distinct surfaces if you are sharing a home with someone with the flu
- Wash your hands regularly
Who are at greater risk of severe disease or complications when infected by the flu?
- Pregnant women
- Children under 59 months
- Elderly
- Individuals with chronic medical conditions (chronic cardiac, pulmonary, renal, metabolic, neurodevelopmental, liver, hematologic diseases)
- Individuals with immunosuppressive conditions (e.g. HIV/AIDs, people receiving chemotherapy or steroids, malignancy)
- Health care workers increased risk of getting the flu generally due to exposure
Name two viruses that commonly cause colds?
2 marks
Any two from: · Rhinovirus · Adenovirus · Coronavirus · Respiratory syncytial virus
List 3 symptoms of flu that distinguish it from a cold
3 marks
Any 3 from: · Fever >38ºC . Muscle aches · Rapid onset of symptoms (within hours) · Headache · Chest discomfort/cough
Name the two glycoproteins on the flu virus envelope that are the target for antiviral agents and vaccines
(1 marks)
Hemagglutinin (1/2 mark)
and
neuraminidase (1/2 mark)
Explain how osetltamivir (Tamiflu) works
2 marks
Oseltamivir is competitive inhibitor of an influenza’s neuraminidase enzyme (1/2 mark).
The enzyme cleaves the sialic acid which is found on glycoproteins (1/2 mark) on the surface of human cells that helps new virions to exit the cell (1/2 mark).
Oseltamivir prevents new viral particles from being released from an infected host cell (1/2mark).
Explain why flu vaccination needs to be administered annually.
(2 marks)
Multiple strains of flu can be in circulation (1/2),
Errors in virus replication mean that antigenic drift is continually producing variant viruses (1/2),
Previous infection or vaccination will not protect against new strains particularly if antigenic shift occurs (1)
Where are the different sites you can take someone’s temperature?
Oral
Rectal
Tympanic
Forehead
Which method of taking someone’s temperature is closest to the core temperature?
Tympanic and rectal
What is the range for having a high temperature for a baby or young child?
Above 38 degrees
What is the range for having a high temperature for a older child or adult?
37.2 - 37.5 degrees
For tympanic 35 degrees is high
What is tympanic temperature?
Reading someone’s temperature from their ear
Are upper resp tract or lower resp tract infections more serious?
Lower
How many URTIs do pre school children usually get in a year?
6-10 URTIs
Children aren’t very good at clearing their airways, they don’t cough properly and clear everything
Children will often present with constant runny noses when actually they are just getting infected from different viruses
What is part of the upper respiratory tract?
Nasal cavity
Pharynx
Larynx
What is part of the lower respiratory tract?
Trachea
Primary bronchi
Lungs
How many viruses can cause mild URTIs?
200+
Not pneumonia or bronchitis/chest infections
Which viruses specifically cause colds?
Main ones: Rhinovirus Coronavirus Adenovirus Respiratory Syncytial virus (can cause hospitalisation in young children)
Parainfluenza virus
Influenza B can be mild
What time of year is flu prevalent in the UK?
November - Feb/March
Winter months
What virus causes flu?
Influenza
What virus family is influenza a part of?
What are their properties?
Orthomyxovirus
Properties:
Single stranded RNA
Spherical or filamentous vision with numerous surface projections of glycoprotein
What is the main mode of transmission for influenza?
Respiratory droplets
If someone is coughing and sneezing near you and you breathe it in
Is influenza stable?
Yes very stable
Can survive at room temperature for days
Even more stable in cold temperature conditions
What is the structure of influenza?
Enveloped
Single-stranded RNA
Lots of glycoproteins on its surface
Haemagluttinin facilitates entry to the cell by binding to silica acid on epithelial cells in the URT
Neuraminidase cleaves new virus particles from host cell allowing release
HA and NA are targets sites for anti-viral drugs
How many different types of orthomyxoviruses are there?
7
4 of them are influenza
3 of them don’t cause diseases in humans (note Influenza D also doesn’t cause disease in humans)
Why do we get new flu viruses that no one has immunity to?
Adaptation of influenza viruses from humans, birds, pigs
What are some targets for anti-viral drugs?
Haemagluttinin which facilitates entry to the cell by binding to sialic acid on epithelial cells in the URT
Neuraminidase that cleaves new virus particles from host cell allowing release
8 segments of negative sense RNA (humans don’t have this)
What is negative sense RNA?
Single stranded RNA usually have a polarity - either positive or negative
They need to be converted into positive sense RNA to replicate
What protein allows the virus to enter the host cell?
Haemagluttinin
What protein breaks the virus off the host cell and allows it to be released?
Neuraminidase
The host cell dies after the virus leaves
When was the Spanish flu?
What influenza was responsible?
How many deaths did it cause?
1918-1919
Straight after WW2
H1N1
Influenza A
20-50 million deaths
When was swine flu? What are some general facts?
2009
H1N1
Started in Mexico
Disproportionate number of younger people got serious ill
Less lethal than initially feared (0.026% mortality rate)
When was avian flu?
2014
H5N1
Egypt
What mortality rate are pandemics?
2-3%
What are the two main treatments for flu?
Tamiflu (Oseltamivir) - oral preparation
Relenza (Zanamivir) - inhaled
What are some side effects from oseltamivir?
Slight increase in risk of GI disturbance and neuropsychiatric symptoms
What are some side effects from zanamivir?
Fewer systemic side effects but cannot be used in patients with asthma or COPD (risk of bronchospasm)
How does oseltamivir or zanamivir work?
Neuraminidase inhibitor
Oseltamivir is competitive inhibitor of an influenza’s neuraminidase enzyme (1/2 mark).
The enzyme cleaves the sialic acid which is found on glycoproteins (1/2 mark) on the surface of human cells that helps new virions to exit the cell (1/2 mark).
Oseltamivir prevents new viral particles from being released from an infected host cell (1/2mark).
Why are anti-influenza drugs controversial?
Side effects were in the headlines
Concern about how much was spent (£650 million) for only modest benefits (‘useless’)
How can you monitor the epidemiology of flu in the UK?
- Primary care monitoring of ILI (influenza-like illness) consultations (swabs not really sent off though)
- Self reporting
- Hospital cases
- Deaths (find out the virus that they died from)
- Respiratory virology at Colindale
Epidemiology internationally recorded by who?
WHO
Epidemiology in US recorded by who?
CDC
Centre of Communicable diseases
What are the different vaccinations available for flu in 2018?
Adjuvanted trivalent flu (aTIV) - licensed for over 65 years. Has 3 different strains of flu in it
Quadrivalent vaccine (QIV) - recommended for children aged 6 months to 2 years and adults from 18 years to 65 who are at increased risk from flu due to a long term health condition. Has antigens from 2 Influenza A strains and 2 Influenza B strains
Live attenuated influenza vaccine (LAIV) - Nasal spray and is licensed for children and young people from 2-18 years old. Targeted 2-3 years olds (through GP surgery) and school children from reception - Year 5 (through schools)
Who is targeted for the LAIV vaccine?
Live attenuated influenza vaccine (LAIV) - Nasal spray and is licensed for children and young people from 2-18 years old. Targeted 2-3 years olds (through GP surgery) and school children from reception - Year 5 (through schools)
Who is targeted for the QIV vaccine?
Quadrivalent vaccine (QIV) - recommended for children aged 6 months to 2 years and adults from 18 years to 65 who are at increased risk from flu due to a long term health condition. Has antigens from 2 Influenza A strains and 2 Influenza B strains
Who is targeted for the aTIV vaccine?
Adjuvanted trivalent flu (aTIV) - licensed for over 65 years. Has 3 different strains of flu in it
How are strains chosen for the vaccine?
They predict which strains may be prevalent but it is not uncommon for a new virus to infect people
Who should get vaccinated for the flu?
Risk groups that are at risk of having a severe disease or complications when infected by flu
Pregnant women
Children under 59 months (5 years)
Elderly
Individuals with chronic medical conditions (e.g. chronic cardiac, pulmonary, renal, metabolic, neurodevelopment, liver or haematological disease)
Individuals with immunosuppressive conditions (HIV/AIDs, receiving chemotherapy, steroids, malignancy)
Health care workers due to increased exposure to patients and risk further spread to vulnerable individuals
Why should we have an annual vaccination?
Numerous flu viruses circulating at any given time
Antigenic drift - minor changes in the antibody binding sites so the flu virus is not recognised by the immune system
Antigenic shift - major changes in the circulating virus, combo of different viruses, often assortments of material from avian and or porcine with human virus to create a new subtype of flu
Antigenic drift
minor changes in the antibody binding sites so the flu virus is not recognised by the immune system,
Antigenic shift
major changes in the circulating virus, combo of different viruses, often assortments of material from avian and or porcine with human virus to create a new subtype of flu
Happens due to reassortment of the RNA segments
What does myalgia mean?
Pain in a muscle/group of muscles
What does pyrexia mean?
Fever
What does rhinitis mean?
Inflammation of the mucous membrane of the nose caused by a viral infection or an allergic reaction
Leads to stuffy nose, runny nose and sneezing
What 3 types of influenza affects humans?
Type A, B, C
How many RNA segments does Type A Influenzae have?
8
How many RNA segments does Type B Influenzae have?
8
How many RNA segments does Type C Influenzae have?
7
What are some common features of Influenza Type A?
Most common type, causes most severe illness
Subdivided based on HA and NA glycoproteins on its protective envelope surface
The glycoproteins can vary in structure and are identified by a number
H3N2 and H1N1 are the most common type of A subtypes to infect humans and some other animals
What are the most common A subtypes that affect humans?
H3N2
H1N1
What are some common features of Influenza Type B?
Less common
Doesn’t mutate as often
Limited types of H and N glycoproteins on its surface
Only infects humans
What are some common features of Influenza Type C?
Least common and least likely to mutate of the three
Only has 1 species
Presence of haemagglutinin-esterase fusion proteins on surface used to enter and exit cells
Causes mild disease in children
Can infect humans and pigs
What is the pathophysiology of influenza?
Virus uses haemagglutinin to bind to silica acid sugars on the surface of epithelial cells in the URT
Endocytosis of virus and release of -ve sense RNA
RNA polymerase converts -ve sense RNA to +ve sense mRNA
mRNA transcribed into proteins and assembled into new viruses
Viruses leave cell via exocytosis using neuraminidase which cleaves sialic acid sugars from membrane
Symptoms of meningitis
Rare but serious disease
Involves inflammation of the meninges covering the brain and the spinal cord
Symptoms: Stiff neck Severe headache Fever Confusion Discomfort from bright lights Seizures Rashes
Flu bacteria can spread to the brain and cause meningitis
How long does it take for bacterial meningitis symptoms to happen?
Few hours
How long does it take for viral meningitis symptoms to happen?
Might appear over several days
Which influenza type affects humans only?
Type B
What type of nucleic acid is found within the viral genome?
Single-stranded negative sense RNA
Which of the following anti-viral drugs prevent the release of the virus from the host cell?
Neuraminidase inhibitor
Which symptoms would confirm your diagnosis of meningitis?
Stiff neck
Photophobia
How many RNA segments does type C influenza virus have?
7
When is flu contagious?
1 day before
2 weeks after feeling better
Who is not recommended to get the flu vaccine?
Severe egg alergies
History of Guillain Barre
What are high risk complications of influenza in children less than 6 months?
Neurologic (encephalitis and febrile seizures)
Reye syndrome
Diagnosis of Influenza
Rapid Influenza Diagnostic Tests (detects in minutes, vary in reliability, can detect type but not strain)
Viral culture
PCR (detects viral RNA)
What are the two general types of treatments for influenza?
Neuraminidase inhibitors
M2 Proton channel inhibitors (prevents replication)
How is the trivalent inactivated influenza vaccine administered?
Injected into the muscle
How do they predict the next flu strains?
Previous Seasons
Strains that are circulating around the globe
