Guidance

How to report a case of acute flaccid paralysis or acute flaccid myelitis

Updated 15 November 2022

Applies to England

Introduction

Regulation 2(1)(b) of the Health Protection (Notification) Regulations 2010 place a duty on registered medical practitioners (RMPs) to report any suspected infections that present or could present significant harm to human health. This covers reporting of acute flaccid paralysis (AFP) and acute flaccid myelitis (AFM) not explained by a non-infectious cause. Appropriate testing of AFP or AFM cases not explained by a non-infectious cause, to exclude polio as a causative agent, is an integral component of polio surveillance. In addition, under Schedule 1 of the Health Protection (Notification) Regulations 2010, suspected cases of acute poliomyelitis are notifiable.

AFP or AFM is characterised by rapid onset of weakness of an individual’s extremities, often including weakness of the muscles of respiration and swallowing, progressing to maximum severity within 10 days. The term ‘flaccid’ indicates weakness accompanied by hyporeflexia or areflexia in the affected limb or limbs.

This document describes how reports should be made to the UK Health Security Agency (UKHSA) and the virological investigations that need to be undertaken.

Aims of surveillance

Aims of surveillance are to:

• investigate and exclude poliovirus infection
• investigate the potential contribution of other enteroviruses, especially enterovirus D68
• systematically characterise the illness and document long-term sequelae
• increase awareness of guidance on investigation and management of cases
• act as a focal point for national and international collaboration

How to report

Health professionals managing patients meeting the above case definition should be reported by calling your local Health Protection Team.

And have an enhanced surveillance questionnaire completed by their responsible clinician. UKHSA has an enhanced surveillance questionnaire which captures relevant clinical and epidemiological data:

• patient details
• presenting symptoms, particularly neurological and respiratory symptoms
• investigations performed to date, including virology, and results
• details and results of any neuroradiological investigations
• polio vaccination history, if available
• recent overseas travel history, if available

Samples to be sent to reference laboratory

The following samples should be taken as close as possible to the onset of neurological signs and symptoms and sent to the UKHSA Virus Reference Department (VRD). Appendix 1) has further details, including contact details for VRD.

Essential:

• 2 stool specimens (24 to 48 hours apart, within 2 weeks of onset of illness)
• throat swabs or nasopharyngeal aspirate (NPA) and
• cerebrospinal fluid (CSF), if collected

Further information

Further information on samples to be sent to the reference laboratories for AFP or AFM cases is in Appendix 1.

Information for patients or parents of children with AFP or AFM is available.

Appendix 1: Samples for AFP or AFM investigation

Samples required by UKHSA for the investigation of AFP and AFM cases

Complete sample sets should be sought for all AFP or AFM cases to maximise the likelihood of identifying enteroviruses.

The following samples should be collected, as close as possible to the onset of neurological signs and symptoms, and forwarded to the Virus Reference Department, UKHSA Colindale; locally stored samples may be forwarded if they are available and are of appropriate quality (see note 1):

Essential:

• 2 stool specimens (see note 2)
• throat swabs or nasopharyngeal aspirate (NPA) (see note 3) and
• cerebrospinal fluid (CSF), if collected (see note 4)

Notes

1.  Stored and fresh samples (of any sample type) should be original clinical materials. For non-faecal samples, cDNA or RNA extracts will only be accepted if original clinical materials are no longer available or are of insufficient volume; please contact the Enteric Virus Unit (EVU) prior to sending cDNA/extracts. Material in which enterovirus has been detected should always be included in the sample set; if there are multiple positive samples, please ensure those with the lowest Ct values are included. If enterovirus has not been detected locally, the requested sample set should still be forwarded.

2.  Stool specimens are required to exclude polio by poliovirus isolation, for all cases of AFP or AFM. Unadulterated stools, minimum 2g each and 2 separate samples collected 24 to 48 hours apart, should be forwarded. These should be collected within 2 weeks of onset of illness and appropriate, stored samples may be forwarded. If more than 2 weeks have passed since onset of illness and no earlier material is available, obtain 2 fresh stool samples. Faecal suspensions and faecal emulsions are unsuitable for poliovirus isolation. If it is impossible to collect stool samples, rectal swabs will be accepted. All faecal samples will also be tested for non-polio enteroviruses using molecular methods.

3.  Upper respiratory tract (URT) samples are important for the identification of enteroviruses that may be present in the URT whilst being undetectable in faecal samples, for example, EV-D68 and EV-A71. Example sample types include viral nose and throat swabs in UTM/VTM and nasopharyngeal aspirates.

4.  If CSF has been obtained, it should be forwarded regardless of local testing results. Note some enteroviruses, including EV-D68, are rarely detected in CSF, and testing of other sample types is required.

Request forms

• use the standard UKHSA enteric virus and polio request form (E1)
• provide clinical details on the form, including date of illness onset
• write ‘AFP/AFM’ on all forms
• provide sample collection dates
• provide a contact number for follow up with consultant microbiologist or virologist

Contacts

Laboratory and technical advice

Stuart Beard
Enteric Virus Unit: 020 8327 6154 / 6349
stuart.beard@ukhsa.gov.uk

Julian Hand
Polio Reference Service: 020 8327 7872
julian.hand@ukhsa.gov.uk

Clinical advice including laboratory investigations

Please contact Dr Maria Zambon at the Virus Reference Department in the first instance. If they are unavailable, please ask to speak to the Duty Virologist.

Virus Reference Department: 020 8327 6226
Monday to Friday 9:00am to 5:00pm