Avian influenza Flashcards
How is pathogenicity in avian influenza assessed?
Based on its pathogenicity in poultry
How long after exposure to avian flu can you prescribe prophylactic NI?
Up to 7 days post exposure
Which groups exposed to AI would require active follow up under the strict approach? How long for?
Vets/farm workers etc with direct contact with birds, their eggs or faecal material and not wearing PPE
Members of the public who inadvertently handled a sick or dead bird, or handled faecal material, in a bird confirmed to have AI
Passive surveillance if PPE used
Follow up for 10 days
What is the prophylaxis for exposure to AI? What is the exceptional subtype to this rule?
Same as seasonal flu - 75 mg OD for 10 d
H7N9 double dose
Think this is wrong now??
Management of a ?avian flu patient in hospital
Isolate in negative pressure room
Treat with oseltamivir before result available
Contact HPT/micro/virology
2x samples from each site (ie 2 samples from each eye if conjunctivitis) collected in VTM
Upper and LRT samples (CAT B transport, CL3)
Criteria for suspecting avian flu in a patient
1) Clinical criteria:
Fever >38 or
Acute respiratory symptoms or conjunctivitis or
Other life threatening symptoms suggestive of infection
AND
2) Exposure criteria:
Within 1 m of poultry or wild birds in an area affected by AI, or with any AI infected animal - up to 10 days prior to symptom onset
Close contact with a confirmed case of human AI or case of severe illness or death in a patient from bird flu affected area
What human cases of avian influenza have we had in the UK?
H5N1 - 2022 - duck keeper and 4 H5N1 cases as part of asymptomatic surveillance testing
H1N2 - 2023 - mild symptoms, untypable flu so sequenced, virus similar to circulating UK swine strains
Brief notes on:
H5N1
H7N9
H5N6
H9N2
H7N7
H5N1 - HPAI endemic in poultry, has caused large outbreaks in birds, has infected mammals, no sustained human to human transmission - 52% mortality
H7N9 - LPAI in poultry, reassortant caused human cases in China in 2013 ~1500 cases and 40% mortality. Vaccination of chickens since 2017 and only sporadic cases since
H5N6 - 2 HPAI lineages, only 1 has caused human disease. Asian lineage associated with severe human disease - 40% mortality
H9N2 - LPAI common in Asia, N America and Middle East, sporadic human cases. Low mortality but reassortment potential
H7N7 - HPAI in Europe, now endemic in horses. Low mortality in humans, 90% have conjunctivitis
Brief notes on AI Genotype B3.13
Outbreak in 2024 in US dairy cattle, caused reduced feeding, reduced milk yield, thick discoloured milk, fever - no death.
A(H5N1) clade 2.3.4.4b - and is a reassortant of Eurasian/N American origins
E627K mammalian adaption in PB2 seen only in one human case, cats also infected
Mild infection, respiratory and conjunctivitis. No human to human transmission
Symptoms of avian influenza in birds
Can be asymptomatic esp ducks and geese
Swollen heads
Lack of appetite
Reduced egg production
Respiratory distress
Diarrhoea
Lack of coordination
Infection can occur through contact with bird faeces, respiratory secretions and feathers
Which birds are vaccinated against H5 in the UK?
What vaccines are available?
Only zoo animals (but not in Scotland)
Nobilis Influenza H5N2
Innovax-ND-H5
Which human H5 vaccine has the UK just purchased as part of pandemic preparedness? What type of virus is it and what is the strain?
Zoonotic influenza vaccine Seqirus
Inactivated and adjuvanted A/Astrakhan/3212/2020 (H5N8)-like strain (CBER-RG8A) (clade 2.3.4.4b)
