Two days ago the UK Health Security agency released an updated risk assessment on China's Highly Pathogenic H5N6 virus, which has infected more than two dozen people over the past 12 months (see Avian influenza A(H5N6): risk assessment).
China's H5N6 virus isn't the only zoonotic avian flu of concern, a field that expanded earlier this year with the of `European' H5Nx 184.108.40.206b viruses to having at least some pandemic potential (see CDC Adds Zoonotic Avian A/H5N8 To IRAT List).
The UK released updated guidance on local exposure to infected birds and potential treatment of cases last March (see Managing the human health risk of avian influenza in poultry and wildbirds), but there are other non-domestic avian flu threats - including H5N1, H7N9, and H9N2 - that could be brought in by infected travelers.
After three years of relatively few reported human infections - avian flu appears once again on the ascendent - but with limited surveillance and reporting from many parts of the globe, and the recent the loosening of international travel restrictions, there is a high degree of uncertainty over how much of a threat it really poses.
Therefore, the UKHSA continues to remind practitioners this week on how to recognize, test, and manage potential avian influenza infections. Yesterday the UKHSA published updated guidance on:
Investigation and initial clinical management of possible human cases of avian influenza with potential to cause severe human disease
Updated 17 November 2021
ContentsInformation for health professionals
Case definition for possible cases
1) Assess if the above case definition is met
2) Results of testing
3) Public health management of contacts of confirmed human cases of avian influenza
4) Guidance on post-exposure chemoprophylaxis of contacts
Case definition for possible cases
a) fever ≥ 38°C
b) acute respiratory symptoms (cough, hoarseness, nasal discharge or congestion, shortness of breath, sore throat, wheezing or sneezing)
c) other severe or life-threatening illness suggestive of an infectious process
Additionally, patients must fulfil a condition in either category 1 or 2 of the exposure criteria below.
For H7N9, H9N2, H5N1, H5N6 and any other avian influenza associated with severe human disease:
1) close contact (within 1 metre) with live, dying or dead domestic poultry or wild birds, including live bird markets, in an area of the world affected by avian influenza** or with any confirmed infected animal, in the 10 days before the onset of symptoms
2) in the 10 days before the onset of symptoms, close contact* with:
- a confirmed human case of avian influenza
- Human case(s) of unexplained illness resulting in death from affected areas**
- human cases of severe unexplained respiratory illness from affected areas**
*This includes handling laboratory specimens from cases without appropriate precautions, or was within 1 metre distance, directly providing care, touching a case or within close vicinity of an aerosol generating procedure, from 1 day prior to symptom onset and for duration of symptoms or positive virological detection.
**For H7N9, H5N1 and H5N6 see the HCID country list. For H9N2, affected areas include China and Oman. If unsure, discuss with UKHSA Clinical and Public Health team (CPH).
Caution: Clinicians should be aware of other respiratory infections among travellers with similar presentations, such as Legionnaire’s disease or MERS-CoV, if there is an appropriate travel or potential exposure history for those infections. Consult the MERS-CoV possible case algorithm to inform assessment.
Today, the UKHSA followed up with the following gudiance for healthcare professionals:
Reminder for health professionals on recognising possible human cases of Avian Influenza and accessing testing
Published 18 November 2021
Reminder for health professionals on recognising possible human cases of avian influenza and accessing testing
With increasing foreign travel and people entering England from other countries, health professionals may receive enquiries from recent travellers about acute respiratory illness. In some instances, countries of travel may have previously reported human cases of avian influenza viruses that have been associated with severe human disease. In 2021, there have been increased numbers of human cases of avian influenza A(H5N6) in China compared to historical levels, as well as the first detection in Lao PDR.
Health professionals should refer to published guidance for the investigation of possible human cases of avian influenza viruses that have been associated with severe human disease. The exposure criteria are outlined in the guidance; it is important is to determine if the individual has been within 1 metre of poultry or wild birds, in an affected country, in the 10 days prior to onset of symptoms.
In particular, be aware of persons with:
fever ≥ 38°C OR acute respiratory infection symptoms OR other severe / life-threatening illness suggestive of an infectious process
on questioning, report exposures to birds (including poultry) in affected countries
If an individual with this clinical presentation reports such an exposure, they should be assessed for avian influenza in addition to coronavirus (COVID-19) and other respiratory infections.Between the diverting of already limited global surveillance resources to combating the COVID pandemic, and a continued reluctance of some nations to report disease outbreaks in a timely manner (see Flying Blind In the Age Of Pandemics & Emerging Infectious Diseases), it is increasingly difficult to know what infectious disease threats may be brewing.
The guidance also includes information relating to persons with exposures to confirmed human cases
If an individual meets the clinical and exposure criteria outlined in the guidance, the following steps should be taken:
For persons who meet the possible case definition, testing should always be submitted via the UKHSA PHL Duty Microbiologist / Virologist as this is the established testing pathway for avian influenza subtypes; health professionals are advised not to rely on other routes to exclude avian influenza infection.
- ensure appropriate isolation and infection prevention and control measures including correct use of specific PPE (as described in guidance document)
- discuss the possible case with the Duty Microbiologist/Virologist at nearest UKHSA Public Health Laboratory (PHL) – see outline of laboratory investigations
- if the PHL Duty Microbiologist / Virologist agrees that testing is indicated, follow the laboratory investigations algorithm and inform the relevant HPT
- treat and investigate as clinically indicated; following agreement with the PHL that testing is indicated, start oseltamivir treatment if not already done so (do not wait for results of avian influenza diagnostic tests)
Avian influenza A(H5N6) is one of the infections classified as a high consequence infectious disease (HCID). HCIDs are rare in the UK but when they have occurred previously, they have been typically associated with recent travel to an area where they are known to be endemic or where an outbreak is occurring.
As international travel continues to increase, health professionals should take a thorough travel history from all patients and ask about exposures that may increase the risk of different airborne or contact HCID infections, for example contact with animals or their urine or droppings, bites from ticks and contact with unwell people. Further details on the other diseases considered HCIDs, links to key guidance documents and how to access specialist advice can be found in our High consequence infectious diseases (HCID) guidance.
Health professionals wishing to determine the HCID risk in any particular country, can view an A to Z list of countries and their respective HCID risk.
Chief Medical Advisor, UK Health Security Agency