WHO IHR Infographic
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Although the battle against COVID-19 continues, the zoonotic threats we were following intently a year ago haven't gone away. They continue to evolve and adapt, and occasionally jump species, and pose the same level of threat to humanity as they did before our current pandemic began.
And while it isn't something anyone wants to hear, there's no rule prohibiting another pandemic from starting before COVID-19 has ended.
Global surveillance and reporting of zoonotic infections - while always spotty - appears to have deteriorated further since the coronavirus pandemic emerged. A week ago, in Saudi MOH: 5 Months Without A MERS-COV Update, we looked at the dearth of reporting on a number of infectious diseases, including MERS, Influenza, and African Swine Fever.
Some reports do filter in, including last week's Alberta Canada Reports Rare Case of H1N2v `Swine' Flu and last July's CDC FluView: Novel A/H3N2v Case Reported In Hawaii. And while details are scant, last week Hong Kong's Avian Flu report mentioned a 5th LPAI H9N2 human infection from the mainland for 2020 (note HK reported 1 case in February).
H9N2: Avian Influenza A(H9N2) Y280 lineage [A/Anhui-Lujiang/39/2018] Virus
Low pathogenic avian influenza A(H9N2) viruses are enzootic in poultry in many countries in Africa, Asia, the Middle East, and Europe. Since the late 1990s when the first human infections with avian influenza A(H9N2) virus were identified, detection of this virus has been reported infrequently in humans and in swine and other mammals. In 2018, there were 7 reported human infections, most with known exposure to poultry and with the majority involving viruses of the Y280 lineage.
Summary: A risk assessment of avian influenza A(H9N2) Y280 lineage A/Anhui-Lujiang/39/2018 virus was conducted in July 2019. The overall IRAT risk assessment score for this virus falls into the moderate risk category. The summary average risk score for the virus to achieve sustained human-to-human transmission was 6.2. The average risk score for the virus to significantly impact public health if it were to achieve sustained human-to-human transmission was 5.9, also in the moderate range. For a full report click here pdf icon[356 KB, 5 pages].
Over the summer we also saw renewed concerns over EA H1N1 `G4', which is circulating in China's swine, and has been described as having substantial `pandemic potential' (see FAO/OIE/WHO Tripartite Statement on the Pandemic Risk of Swine Influenza).
Late last week the World Health Organization updated their Novel Influenza Summary for the first time since last July, and while only 2 new human infections with novel flu are listed, they include a curious report on 16 previously unreported H9N2 cases from China (with unrepeatable test results), and an oft repeated reminder of the duty to report novel flu cases under the 2005 IHR rules and regulations.
• New infections1 : Since the previous update on 10 July 2020, one human infection with an avian influenza A(H9N2) virus and one human infection with an influenza A(H3N2) variant virus were reported. 2
• Risk assessment: The overall public health risk from currently known influenza viruses at the human-animal interface has not changed, and the likelihood of sustained human-to-human transmission of these viruses remains low. Human infections with viruses of animal origin are expected at the human-animal interface wherever these viruses circulate in animals.
• Risk management: Selection of new candidate vaccine viruses (CVVs) for zoonotic influenza viruses for pandemic preparedness purposes was done during a recent WHO consultation.3
• IHR compliance: All human infections caused by a new influenza subtype are required to be reported under the International Health Regulations (IHR, 2005).4 This includes any influenza A virus that has demonstrated the capacity to infect a human and its haemagglutinin gene (or protein) is not a mutated form of those, i.e. A(H1) or A(H3), circulating widely in the human population. Information from these notifications is critical to inform risk assessments for influenza at the human-animal interface.
Avian Influenza Viruses Current situation:
Avian influenza A(H5) viruses
According to reports received by the World Organisation for Animal Health (OIE), various influenza A(H5) subtypes continue to be detected in birds in Africa, Europe and Asia.
Avian influenza A(H7N9) viruses There have been no publicly available reports from animal health authorities in China or other countries on influenza A(H7N9) virus detections in animals in recent months.5
Overall, the risk assessments have not changed.
Avian influenza A(H9N2) viruses
Since the last update on 10 July 2020, one new laboratory-confirmed human case of influenza A(H9N2) virus infection was reported from China to WHO on 28 August 2020. The infection was detected in a 4-year-old female from Guangdong Province, China, who had exposure to domestic poultry. She developed mild symptoms on 3 August and was admitted to a hospital on 4 August. The patient was sampled as part of routine influenza-like illness (ILI) surveillance, has recovered, and no further cases were detected among family members at the time of reporting.
In July 2020, a manuscript describing 16 human cases of A(H9N2) infection detected in January and February 2019 was published in the Virologica Sinica journal.6 WHO became aware of the findings after the genetic sequences of the 16 H9N2 viruses had been uploaded to GenBank and included in the preparatory materials for the zoonotic component of the WHO consultation on composition of influenza virus vaccines for use in the 2021 Southern Hemisphere Influenza Season held from 29 September to 1 October 2020.7 WHO has worked with its partners in GISRS, including the WHO Collaborating Center for Reference and Research on Influenza at the Chinese Center for Disease Control and Prevention (CDCD), Beijing, China, to review the currently available information.
Further investigations, including laboratory characterization by the WHO Collaborating Center at the CDCD, which has been coordinating with the authors of the paper, were completed. The WHO Collaborating Center did not detect influenza A(H9N2) virus material in respiratory swabs and no antibodies to influenza A(H9N2) viruses detected in sera specimens; two samples from the 16 cases were positive for A(H1N1)pdm09 but no other influenza viruses were detected by PT-PCR. The author of the paper also repeated their tests and could not confirm detection of A(H9N2) viruses in the specimens. Avian influenza A(H9N2) viruses are enzootic in poultry in Asia and increasingly reported in poultry in Africa.
(SNIP)
Current situation: Influenza A(H3N2) variant virus (A(H3N2)v)
Since the last risk assessment of 10 July 2020, one human case of infection with a swine influenza A(H3N2)v virus was reported to WHO from the United States of America on 25 July 2020. The infection was detected in a child in the state of Hawaii who developed an influenza-like illness on 30 June 2020. The patient received healthcare on 1 July and a sample was collected as part of routine influenza surveillance. On 24 July, the United States Centers for Disease Control and Prevention confirmed an influenza A(H3N2)v virus. No exposure to swine was reported and the source of the patient’s infection was underway at the time of reporting. The patient was not hospitalized, has recovered and no human-to-human transmission was reported. This is the first influenza A(H3N2)v virus infection identified in the United States since 2018.
The Virologica Sinica report on 16 H9N2 cases (all from the same hospital in Hubei) mentioned above can be accessed at:
Xuan Dong, Jiasong Xiong, Chaolin Huang, Jie Xiang, Wenjuan Wu, Nanshan Chen, Danning Wen, Chao Tu, Xueli Qiao, Liang Kang, Zhongzi Yao, Dingyu Zhang & Quanjiao Chen
Virologica Sinica (2020)
The inability of the WHO Collaborating Center to replicate these results is more than a little curious. Hopefully we'll get some additional information on these cases in the near future.
Avian flu activity has been greatly suppressed the past 3 years following China's massive poultry vaccination campaign of 2017 - which probably accounts for much of the drop in novel flu infections we've seen in humans the past few years - but there is a good deal of uncertainty over how much of the global picture we are seeing.
As we discussed more than 2 months ago, in Flying Blind In the Age Of Pandemics & Emerging Infectious Diseases, even when the world is not hampered by a pandemic, global surveillance and reporting of pandemic threats has often been sketchy.
From Indonesia’s refusal to share H5N1 virus samples to the Saudi’s chronic foot dragging on MERS, to China's slow rolling of releasing H7N9 information, we’ve seen many examples where the spirit – and at times the actual letter – of the 2005 IHR has been ignored by member nations.
The WHO can only report what is reported to them by member nations, and far too often there are political, societal, and economic incentives for some governments to hold `bad news' close to the vest.
Which may help explain why WHO EMRO hasn't posted a monthly MERS-CoV update since January, and the FAO hasn't posted a bi-weekly update on African Swine Fever in Asia since early March.
While it is unlikely that we are missing any major outbreaks of novel flu around the world, our ability to see the `next big thing' coming appears severely diminished.
