China - 3 fatal avian flu H5N6 human cases so far in 2024 - CDC Weekly Epi Investigation Into H5N6 Cases (Dec 2024)

[Michael Coston]

WHO/ECDC On 1st H5N6 Human Infection of 2024



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Avian influenza reports out of China have become increasingly scarce, but today the ECDC is reporting on China's 90th known human H5N6 infection, and the 1st of 2024. The patient, described as a 52 year-old female living in Fujian Province, was hospitalized on April 22nd, and died 8 days later.

While I've not seen this case mentioned China's weekly influenza report, or Hong Kong's Weekly avian influenza roundup, is does appear in the latest WHO Western Pacific Regional Office Avian Influenza Weekly Update Number 947, which provides following details.

Human infection with avian influenza A(H5N6) virus

Between 10 to 16 May 2024, one new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. The case was a 52-year-old female from Fujian Province in China with the date of onset on 13 April 2024. She was admitted to the hospital on 22 April and diagnosed on 24 April. The case passed away on 30 April.

Before the onset of illness, the case had exposure to backyard poultry. All samples from close contact and environment have tested negative for influenza.

To date, a total of 91 laboratory-confirmed cases of human infection with influenza A(H5N6) virus, including 36 deaths (CFR 40%), have been reported to WHO in the Western Pacific Region since 2014. The last case was reported from China, with an onset date of 25 November 2023.

Today, the ECDC's Communicable disease threats report, 18-25 May 2024, week 21 carries the following report.

Avian influenza A(H5N6) – Multi-country – Monitoring human cases

Overview:

Update: A new fatal case of avian influenza A(H5N6) has been reported from Fujian Province in China. The patient was a woman in her 50s who had exposure to backyard poultry before the onset of symptoms on 13 April 2024.

On 22 April, she was hospitalised and two days later diagnosed with avian influenza A(H5N6) infection. The patient died on 30 April 2024. No new cases have been detected among close contacts of the case. Samples from close contacts, poultry and environment tested negative.

Summary: Since 2014, and as of 21 May 2024, 91 laboratory-confirmed cases, including 36 deaths (CFR: 40%), of human infection with influenza A(H5N6) virus have been reported, including six cases reported in 2023 and one case in 2024 (all from China). The cases were reported from China (90) and Laos (1).

Sources: WHO Avian influenza weekly update Number 947

ECDC assessment:

Sporadic human cases of avian influenza A(H5N6) have been previously observed. No human-to-humantransmission has been reported to date. Sporadic zoonotic transmission cannot be excluded. The implementation of personal protective measures for people directly exposed to poultry and birds potentially infected with avian influenza viruses will minimise the remaining risk. The risk of zoonotic influenza transmission to the general public in EU/EEA countries is considered to be very low.

Actions:

ECDC monitors avian influenza strains through its epidemic intelligence and disease network activities and collaborates with the European Food Safety Authority (EFSA) and the EU reference laboratory for avian influenza to identify significant changes in the epidemiology of the virus. ECDC works with EFSA and the EU reference laboratory to produce a quarterly report on the avian influenza situation. The most recent report was published in March 2024.

Last time this event was included in the Weekly CDTR: 17 May 2024

Maps and graphs

Figure 1. Distribution of confirmed human cases of avian influenza A(H5N6) virus infection by year of onset and country, 2014 - 16 May 2024 (n=91)

Getting reliable, and timely, information out of China on avian flu has always been difficult, but it has become even more challenging over the past few years. Reports to the WHO are often delayed, and contain few details.

Although the steady decline in reported H5N6 cases since 2021 may indicate fewer actual infections, it is difficult to verify, given the lack of independent reporting in that country.

https://afludiary.blogspot.com/2024/05/whoecdc-on-1st-h5n6-human-infection-of.html

[sharon sanders]

Please see:

FluTrackers Global H5N6 Cumulative Case List

[Michael Coston]

WHO WPRO Reports 2nd H5N6 Case In Fujian, China In 2024





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In a small notice in their most recent Avian Influenza Weekly Update Number 951, the Western Pacific office of the WHO announced the 2nd H5N6 case in China for 2024, which - like the one announced last month - was in Fujian Province.

In both cases, no town was mentioned, only that both patients hailed from Fujian province (Pop. 38.5 million 46,873 mi²). The first case was described as a `. . . woman in her 50s who had exposure to backyard poultry before the onset of symptoms on 13 April 2024.' She died on April 30th

We learn even less about today's case, only that it was a 41 year-old male with onset on May 8th. No likely exposure is mentioned, only that the patient suffered severe pneumonia and has passed away.

Human infection with avian influenza A(H5N6) virus

Between 7 June to 13 June 2024, one new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. The case is a 41-year-old male from Fujian Province, with an onset of illness on 8 May 2024. The patient was hospitalized with severe pneumonia and the case was confirmed positive for A(H5N6) on 14 May. He subsequently passed away. To date, a total of 92 laboratory confirmed cases of human infection with influenza A(H5N6) virus, including 37 deaths (CFR 40%), have been reported to WHO in the Western Pacific Region since 2014. The last case was reported from China, with a symptom onset date of 13 April 2024.

Getting reliable, and timely, information out of China on avian flu has always been difficult, but it has arguably become even more challenging since the emergence of COVID. Reports to the WHO are often delayed, and contain few details.

Today's case was reported to the WHO relatively quickly, since the patient was confirmed positive on May 14th, and a notification was made `between June 7 & June 13th'. Call it 3 or 4 weeks delay. Not ideal, but far quicker than many other cases we've seen.

While China's H5+H7 poultry vaccination program which was launched in 2017 quickly eradicated the H7N9 virus, it appears to have been less successful in controlling H5N6. Nearly all human cases report recent contact with live poultry, yet we almost never hear of a symptomatic outbreak in domesticated birds.

Recent studies (see mSphere: An HPAI H5N6 Virus With Remarkable Tropism for Extra-respiratory Organs in the Ferret Model) suggest the H5N6 virus continues to adapt to mammalian hosts, while 2 years ago the Lancet published Resurgence of H5N6 Avian Influenza Virus in 2021 Poses New Threat to Public Health.

H5N6 - along with Cambodia's clade 2.3.2.1c H5N1 virus - remind us that HPAI H5 continues to explore multiple evolutionary paths, and that we may see others emerge over time.

https://afludiary.blogspot.com/2024/06/who-wpro-reports-2nd-h5n6-case-in.html

[sharon sanders]

Please see:

FluTrackers Global H5N6 Cumulative Case List


and these recent Fujian province threads:

China - Adenovirus pneumonia increased 20-30% in May from April, conjunctivis mentioned - at a Fujian hospital - June 8, 2024

China - The number of respiratory admissions in major hospitals in Fuzhou, Fujian province has increased - March 12, 2024

[Michael Coston]

HK CHP Monitoring Another Fatal H5N6 Infection (Anhui, China)






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It's been more than 3 years since Anhui province has reported an H5N6 case (link), but today Hong Kong's CHP is reporting on a fatal case (70, F) who fell ill following a visit to a live poultry market in the middle of June and died on July 8th.

While getting reliable, and timely, reports out of China can be a challenge, this is only the 3rd case reported on the Mainland this year. The other two cases were from Fujian Province, and all three have proved fatal.

It is certainly possible that there are cases that are either not being detected by local surveillance, or are simply not reported. The ECDC chart below shows we are a far cry from where we were in 2021 (n=35 cases).


But these reports - along with Cambodia's recent surge in clade 2.3.2.1c H5N1 virus infections - remind us that HPAI H5 continues to explore multiple evolutionary paths, and that we may see others emerge over time.

CHP closely monitors human case of avian influenza A(H5N6) on Mainland

The Centre for Health Protection (CHP) of the Department of Health is today (July 25) closely monitoring a human case of avian influenza A(H5N6) on the Mainland, and again urged the public to maintain strict personal, food and environmental hygiene both locally and during travel.

The case involves a 70-year-old female living in Hefei in Anhui Province, who had visited a live poultry market before the onset of symptoms. She developed symptoms on June 17 and was admitted to a hospital for treatment on June 19. She passed away on July 8.

From 2014 to date, 92 human cases of avian influenza A(H5N6) have been reported by Mainland health authorities.

"All novel influenza A infections, including H5N6, are notifiable infectious diseases in Hong Kong," a spokesman for the CHP said.

Travellers to the Mainland or other affected areas must avoid visiting wet markets, live poultry markets or farms. They should be alert to the presence of backyard poultry when visiting relatives and friends. They should also avoid purchasing live or freshly slaughtered poultry, and avoid touching poultry/birds or their droppings. They should strictly observe personal and hand hygiene when visiting any place with live poultry.

Travellers returning from affected areas should consult a doctor promptly if symptoms develop, and inform the doctor of their travel history for prompt diagnosis and treatment of potential diseases. It is essential to tell the doctor if they have seen any live poultry during travel, which may imply possible exposure to contaminated environments. This will enable the doctor to assess the possibility of avian influenza and arrange necessary investigations and appropriate treatment in a timely manner.

While local surveillance, prevention and control measures are in place, the CHP will remain vigilant and work closely with the World Health Organization and relevant health authorities to monitor the latest developments.

The public should maintain strict personal, hand, food and environmental hygiene and pay attention to the following issues to prevent avian influenza:

• Avoid touching poultry, birds, animals or their excrement, or contaminated environment;
• When buying live chickens, do not touch them and their droppings. Do not blow at their bottoms. Wash eggs with detergent if soiled with faecal matter and cook and consume the eggs immediately. Always wash hands thoroughly with soap and water after handling chickens and eggs;
• Eggs should be cooked well until the white and yolk become firm. Do not eat raw eggs or dip cooked food into any sauce with raw eggs. Poultry should be cooked thoroughly. If there is pinkish juice running from the cooked poultry or the middle part of its bone is still red, the poultry should be cooked again until fully done;
• Wash hands frequently, especially before touching the mouth, nose or eyes, before handling food or eating, and after going to the toilet, touching public installations or equipment such as escalator handrails, elevator control panels or door knobs, or when hands are dirtied by respiratory secretions after coughing or sneezing; and
• Wear a mask if fever or respiratory symptoms develop, when going to a hospital or clinic, or while taking care of patients with fever or respiratory symptoms.

The public may visit the CHP's pages for more information: the avian influenza page, the weekly Avian Influenza Report, global statistics and affected areas of avian influenza, the Facebook Page and the YouTube Channel.

Ends/Thursday, July 25, 2024

Recent studies (see mSphere: An HPAI H5N6 Virus With Remarkable Tropism for Extra-respiratory Organs in the Ferret Model) suggest the H5N6 virus continues to adapt to mammalian hosts, while 2 years ago the Lancet published Resurgence of H5N6 Avian Influenza Virus in 2021 Poses New Threat to Public Health.

All of which makes the lack of information coming out of China less than reassuring.

https://afludiary.blogspot.com/2024/07/hk-chp-monitoring-another-fatal-h5n6.html

[sharon sanders]

Case list updated:

FluTrackers Global H5N6 Cumulative Case List

[Michael Coston]

China CDC Weekly: Infection Tracing and Virus Genomic Analysis of Two Cases of Human Infection with Avian Influenza A(H5N6) — Fujian Province, China




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In June of this year, in WHO WPRO Reports 2nd H5N6 Case In Fujian, China In 2024, we learned of two fatal H5N6 infections, both hailing from Fujian Province, China, and which occurred within a few weeks of each other.

While the reports we get from China are often bereft of details, they sometimes fill in the gaps in follow-up reports, such as appears this week in China's CDC Weekly.

The two cases, it is now revealed, both resided in Quanzhou City, Fujian Province, China. The first fell ill on April 13th, and the second on May 9th. They lived less than 20 miles apart, and both were treated in the same hospital.

But the epidemiological investigation did not turn up any other links between them, and the viruses were sufficiently different to rule out human-to-human transmission.

While reassuring, they did find a number of worrisome mutations which may increase the virus's ability to infect, and transmit, in humans (see chart below).





While Case A had direct contact with poultry, Case B did not. This has led to the theory that Case B was exposed while walking down a path that came within 8 meters of a poultry shed.



Although direct exposure to infected poultry is the most common route of exposure to avian flu viruses, we've seen a number of cases whose likely exposures were cited as simply living near, or walking past an LBM (see J. Infection: Aerosolized H5N6 At A Chinese LBM (Live Bird Market)).

Case reports have slowed out of China the past few months, but we monitor this virus closely, as HPAI H5N6 continues to be one of the deadlier strains of HPAI H5, with a greater than 50% case fatality rate (among known cases).

I've only posted some excerpts from the China CDC report, so follow the link to read it in its entirety.

Outbreak Reports: Infection Tracing and Virus Genomic Analysis of Two Cases of Human Infection with Avian Influenza A(H5N6) — Fujian Province, China, April–May 2024
Yanhua Zhang1; Jingjing Wu1; Qi Lin1; Jianming Ou1; Xiaoqi Qi1; Youxian Zheng2; Fengping Li2; Yuwei Weng1,
Summary
What is known about this topic?

Global human cases of zoonotic influenza A(H5N6) have increased significantly in recent years, primarily due to widespread circulation of clade 2.3.4.4b virus since 2020. Concurrent with this trend, sporadic human infections with clade 2.3.4.4h H5N6 avian influenza virus continue to occur. The high mortality rate associated with H5N6 virus infections has emerged as a critical public health concern.

What is added by this report?

Through comprehensive field epidemiological investigations and laboratory analyses, we identified the infection sources for these cases and conclusively ruled out human-to-human transmission. Genetic analyses revealed that while the virus maintains its avian host tropism, it has acquired mutations that may enhance human receptor binding affinity, viral replication capacity, pathogenicity, and neuraminidase inhibitor resistance.

What are the implications for public health practice?

The ongoing viral mutations increase the potential for H5 subtype avian influenza viruses to overcome species barriers and cause human epidemics. Enhanced surveillance strategies incorporating advanced technologies, such as metagenomic sequencing, are essential for early risk detection and management. Special attention should be directed toward cancer patients and immunocompromised individuals, who demonstrate increased susceptibility to avian influenza virus infections and require targeted prevention and control measures.

(SNIP)

DISCUSSION

Comprehensive analysis of epidemiological and laboratory data demonstrated that cases A and B were independent events with no epidemiological links. Medical observation of all close contacts revealed no signs of infection, providing strong evidence against human-to-human transmission in both cases.

Environmental investigation plays a crucial role in tracing avian influenza virus infections. Although both cases were associated with poultry illness or mortality prior to symptom onset, initial environmental sampling from the patients’ poultry sheds yielded negative results. This unexpected outcome can be attributed to two factors: the rapid disposal of diseased poultry before patient illness onset, which eliminated environmental viral evidence, and the implementation of thorough disinfection measures by families or health authorities prior to sampling. Nevertheless, viral genetic sequencing analysis of samples from surrounding poultry sheds near Case B provided definitive evidence for outbreak source identification.

The transmission routes differed between the two cases. Case A’s infection likely resulted from direct contact with diseased poultry, while Case B, who had no direct poultry exposure, suggested an alternative transmission pathway. Genetic analysis revealed 100% nucleotide sequence identity between Case B’s virus and samples from poultry shed Z, while distinct genetic differences were observed in viruses from shed Y and local live poultry markets. This evidence strongly indicates shed Z as Case B’s infection source. Although the viruses from both cases showed high sequence similarity, they were not identical, ruling out direct transmission between cases. The absence of infection among close contacts further confirms the lack of human-to-human transmission.

The location of poultry shed Z, approximately 8 meters from Case B’s regular walking route, suggests potential aerosol transmission over this distance. Notably, both cases exhibited compromised immune status: Case A experienced heavy rain exposure before illness onset, while Case B had nasopharyngeal cancer with ongoing chemotherapy and radiotherapy. The absence of symptoms among family members despite potential viral exposure suggests that immunocompromised status may represent a significant risk factor for H5N6 avian influenza virus infection in humans.

While genomic analysis revealed no significant recombination compared to recent H5N6 viruses, several concerning features were identified, including a highly pathogenic HA protein cleavage site and mutations associated with increased virulence, human infection potential, enhanced viral replication, and possible neuraminidase inhibitor resistance. The ongoing H5N1 outbreak in mammals in the United States heightens concerns about potential cross-species transmission and human epidemic risk. Although sustained human-to-human transmission of H5 subtype viruses remains undocumented, these findings underscore the critical importance of enhanced surveillance and robust pandemic preparedness measures.

https://afludiary.blogspot.com/2024/...acing-and.html