Polioviruses and enterovirus

Question 1

Where is Polio not currently eradicated? What subtype is circulating there?

Answer 1

Afghanistan and Pakistan
Type 1

Question 2

When was the last UK derived case of natural poliovirus?

Answer 2

1984

Question 3

What is the difference between Salk and Sabin vaccine

Answer 3

SalK - killed IPV
Sabin - live attenuated OPV

Salk: 3 strains, Mahoney (type 1 poliovirus), MEF-1 (type 2 poliovirus), and Saukett (type 3 poliovirus), grown in vero cells and deactivated with formulin

OPV has two forms: one biovalent (types 1 and 3), one trivalent. In 2016, 155 countries switched to bivalent based on type 2 being eradicated and that the bivalent has better efficacy against 1 and 3.

Question 4

OPV can cause vaccine derived outbreaks, which subtype is most likely to cause outbreaks

Answer 4

Sabin 2 strain - 90% vaccine derived cases

Question 5

Where is UK surveillance of enterovirus in sewage occurring?

Answer 5

London and Glasgow
?expanded - need to check

Question 6

When did the vaccine derived outbreaks of polio occur in London?
What are the details of the outbreak

Answer 6

Feb - July 2022
118 genetically linked isolates of serotype 2 Sabin strain. Recombination with another enterovirus C

‘vaccine-derived’ poliovirus type 2 (VDPV2)

Response: Targeted vaccination with IPV in specific areas of London for children under 5

As part of routine surveillance, it is normal for 1 to 3 ‘vaccine-like’ polioviruses to be detected each year in UK sewage samples (usuallyone-off when an individual vaccinated overseas OPV)

As a response, a novel oral polio vaccine type 2 (nOPV2) was developed with the aim to provide a safer form of vaccination against type 2 strains with less risk of reverting to infectious polio- not sure whether this was given in UK (I don’t think so)

Question 7

Define:
vaccine like poliovirus
vaccine derived poliovirus

Answer 7

Less than 6 SNP difference in VP1 region from vaccine strain.
6-10 SNP difference in VP1 region from vaccine strain.

Question 8

Enterovirus causing HFM

Answer 8

A71, Cocksackie A10, A16

Question 9

Picornovirdae causing encephalitis

Answer 9

Entero- A71(list more)
Parecho (parachecho A is only one that causes infections in humans)
Echovirus

Question 10

Picornoviridae causing AFP

Answer 10

Enterovirus- Polio (Enterovirus A, B, C), A71, D68, C105
Echo virus 11

Note: Outbreaks of echo 11 have cause severe neonatal sepsis with hepatitis cases in europe

https://www.ecdc.europa.eu/en/news-events/epidemiological-update-echovirus-11-infections-neonates#:~:text=Since%202022%2C%20and%20as%20of,two%20fatal%20E11%20neonatal%20cases.

Question 12

Causes of haemorrhagic conjunctivitis

Answer 12

Cocksackie A24

echo 70

Cocksacie B

Adenovirus

Question 13

Describe enterovirus typing, what do they do

Answer 13

1 Sequencing part of the VP1 capsid protein gene is the gold standardfor EV typing, and should be performed according to the WHO recommendations

2 5′NCR sequencing should not be used for EV type identification

3 Use VP2 and VP4 capsid protein gene sequencing for EV typing if
VP1 sequencing fails

4 Consider sequencing additional parts of the genome or obtaining full
genome sequence if a new recombinant form of EV is suspected.

Question 14

How long can polio shed in poo

Answer 14

6 weeks

Question 15

MRI findings in enterovirus AFM

Answer 15

Gray matter changes