Bangladesh: 2025 & 2026 Bird flu in humans incl. H5N1

[Shiloh]

This post accounts for 2 cases.

Source: https://cdn.who.int/media/docs/defa...-assessment--from-23-april-to-27-may-2025.pdf


A(H5N1), Bangladesh
A human infection with an H5 clade 2.3.2.1a A(H5N1) virus was detected in a sample collected from
a child in Khulna Division in April 2025, who recovered from his illness. Genetic sequence data are
available in GISAID (E EPI_ISL_19875512; submission date 18 May 2025; Institute of Epidemiology,
Disease Control & Research (IEDCR); Virology - National Influenza Centre (NIC)). WHO was notified of
this case on 4 May 2025. In March 2025, an avian influenza A(H5N1) outbreak was reported in
poultry in the same district (Jessore) where the case resides.7
A second human infection with an H5 clade 2.3.2.1a A(H5N1) virus was retrospectively detected in a
sample collected from a child in Khulna Division in February 2025, who recovered from his illness,
according to genetic sequence data available in GISAID (EPI_ISL_19882255; submission date 26 May
2025; Institute of Epidemiology, Disease Control & Research (IEDCR); Virology - National Influenza
Centre (NIC)). WHO was notified of this case on 27 May 20​

 

[sharon sanders]

Please see:

H5N1 Avian Flu: FluTrackers 2016 - Current Global Case List​

 

[Shiloh]

Source: https://reliefweb.int/report/india/...-jun-2025-reporting-period-19-may-02-jun-2025

WHO South-East Asia Region Epidemiological Bulletin, 11th edition (2025), 04 Jun 2025. Reporting period: 19 May to 02 Jun 2025
Format Situation Report
Source WHO
Posted 5 Jun 2025
Originally published 4 Jun 2025


Bangladesh: Avian influenza A(H5N1)

Situation overview as of 27 May 2025

• An avian influenza A(H5N1) human infection clade 2.3.2.1a was detected in April 2025 in Khulna Division.

• Genetic sequence data (EPI_ISL_19875512) was submitted to GISAID on 18 May 2025.

• Of note, in March 2025, an avian influenza A(H5N1) outbreak was reported in poultry in Jessore, the same district where the case was found.

• A second avian influenza A(H5N1) human infection clade 2.3.2.1a was retrospectively detected from a sample collected in February 2025 in Khulna Division.

• Genetic sequence data (EPI_ISL_19882255) for this case was submitted to GISAID on 26 May 2025.

• Both cases have recovered. These mark the 9th and 10th A(H5N1) cases since the first case was detected in 2008.

​

 

[Commonground]

CHP Hong Kong Avian Influenza Report

Avian Influenza Report is a weekly report produced by the Surveillance Division of the Communicable Disease Branch of

the Centre for Health Protection. This report highlights global avian influenza activity in humans and birds.

VOLUME 21, NUMBER 28

Reporting period: July 6, 2025 – July 12, 2025 (Week 28)

(Published on July 15, 2025)

Summary

1. 2. 3. Since the previous issue of Avian Influenza Report (AIR), there was one new human case

of avian influenza A(H5N1) from Bangladesh reported by the World Health Organization

(WHO) in July 2025. From 2015 to 2024, 0 to 145 confirmed human cases of avian

influenza A(H5N1) were reported to the WHO annually (according to onset date).*

Since the previous issue of AIR, there were no new human cases of avian influenza

A(H5N6). Since 2014 (as of July 12, 2025), there were 93 human cases of avian influenza

A(H5N6) reported globally and 92 of them occurred in Mainland China. The latest case

was reported on July 24, 2024.

Since the previous issue of AIR, there were no new human cases of avian influenza

A(H7N9). Since March 2013 (as of July 12, 2025), there were a total of 1568 human cases

of avian influenza A(H7N9) reported globally (all were reported in the seven waves

between 2013 and September 2019). The latest case was reported on April 5, 2019.

* Since November 21, 2012, WHO only publishes information on human cases with avian influenza A(H5N1)

infection in “Influenza at human – animal interface: Monthly Risk Assessment Summary”. Only cases of human

infection with H5N1 involved in events that are unusual or associated with potential increased risks will be

reported in Disease Outbreak News. The latest report was published in July 2025.

1This week’s highlights

(Sources: World Health Organization (WHO), Overseas health authorities, National Health

Commission (NHC), Mainland health authorities, Ministry of Agriculture of the People’s Republic of

China, Centre for Health Protection (CHP) and World Organisation for Animal Health (WOAH;

Founded as OIE))
​

​​

Continued: https://www.chp.gov.hk/files/pdf/2025_avian_influenza_report_vol21_wk28.pdf

 

[Commonground]

WHO Influenza at the human-animal interface
Summary and risk assessment, from 28 May to 1 July 2025


• New human cases12: From 28 May to 1 July 2025, based on reporting date, the detection of

influenza A(H5N1) in nine humans, influenza A(H9N2) in three humans and influenza A(H10N3)

in one human were reported officially. Additionally, one human case of infection with an

influenza A(H5N1) virus was detected.

• Circulation of influenza viruses with zoonotic potential in animals: High pathogenicity avian

influenza (HPAI) events in poultry and non-poultry continue to be reported to the World

Organisation for Animal Health (WOAH).3 The Food and Agriculture Organization of the United

Nations (FAO) also provides a global update on avian influenza viruses with pandemic potential.4

• Risk assessment5: Sustained human to human transmission has not been reported from these

events. Based on information available at the time of the risk assessment, the overall public

health risk from currently known influenza viruses circulating at the human-animal interface has

not changed remains low. The occurrence of sustained human-to-human transmission of these

viruses is currently considered unlikely. Although human infections with viruses of animal origin

are infrequent, they are not unexpected at the human-animal interface.

• IHR compliance: All human infections caused by a new influenza subtype are required to be

reported under the International Health Regulations (IHR, 2005).6 This includes any influenza A

virus that has demonstrated the capacity to infect a human and its haemagglutinin (HA) 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 in humans

Current situation:

Since the last risk assessment of 27 May 2025, single laboratory-confirmed human cases of A(H5N1)

infection were detected in Bangladesh and India. Eight confirmed human cases of A(H5N1) infection

were reported to WHO from Cambodia.

1 This summary and assessment covers information confirmed during this period and may include information

received outside of this period.

2 For epidemiological and virological features of human infections with animal influenza viruses not reported in

this assessment, see the reports on human cases of influenza at the human-animal interface published in the

Weekly Epidemiological Record here.

3 World Organisation for Animal Health (WOAH). Avian influenza. Global situation. Available at:

https://www.woah.org/en/disease/avian-influenza/#ui-id-2.

4 Food and Agriculture Organization of the United Nations (FAO). Global Avian Influenza Viruses with Zoonotic

Potential situation update. Available at: https://www.fao.org/animal-health/situation-updates/global-aiv-with-

zoonotic-potential.

5 World Health Organization (2012). Rapid risk assessment of acute public health events. World Health

Organization. Available at: https://iris.who.int/handle/10665/70810.

6 World Health Organization. Case definitions for the 4 diseases requiring notification to WHO in all

circumstances under the International Health Regulations (2005). Case definitions for the four diseases

requiring notification in all circumstances under the International Health Regulations (2005).

1A(H5N1), Bangladesh

On 31 May 2025, Bangladesh notified WHO of one confirmed human case of avian influenza A(H5) in

a child in Chittagong division detected through hospital-based surveillance. The patient was

admitted to hospital on 21 May with diarrhea, fever and mild respiratory symptoms and a

respiratory sample was collected on admission. On 28 May, the IEDCR confirmed infection with avian

influenza A(H5) through RT-PCR. The N-type was later confirmed as N1. The patient has recovered,

and exposure to backyard poultry was reported prior to symptom onset. No further cases were

detected among the contacts of the case.

This is the 11th human infection with influenza A(H5N1) notified to WHO from Bangladesh since the

first case was reported in the Dhaka division in 2008 and the third confirmed case in 2025.
​
Continued: https://cdn.who.int/media/docs/defa...nd-assessment--from-28-may-to-1-july-2025.pdf
​

 

[sharon sanders]

Please see our Global H5N1 case list. link

 

[Michael Coston]

Adds a case in Bangladesh.....



HK CHP: Mainland China Retrospectively Reports 4 More H9N2 Cases - Cambodian H5N1 Update




#18,970



Last week Hong Kong's CHP reported two relatively recent (Sept) cases of human H9N2 infection on the Mainland, making the 20th and 21st cases announced in the last 6 months (since April 2025).

In the previous 6 month period (Oct 2024 - Apr 2025), China had reported 16 cases.​

In today's report, Hong Kong adds 4 retrospectively identified cases from last February. Details are unusually scant (even for China), with the only identifiers provided being `an individual' and the month.

Today's report also adds a small detail on the recent H5N1 cases in Cambodia.​

Last Friday, I reported on the Cambodia's 16th H5N1 Case of 2025, although there have been persistent reports of a 17th case that may have gone unreported in September.

According to the chart below, a 14 year-old female from Takeo Province was hospitalized (possibly Sept or early Oct). This case was not included in the most recent WHO report (26 August to 29 September).​

I've updated my map (see below) to reflect this 17th case.





Unlike the milder North American H5N1 clade 2.3.4.4b virus, this is an older clade 2.3.2.1e, which has proved fatal in nearly 50% of cases reported over the past couple of years and has skewed heavily towards younger (< 18) victims.

https://afludiary.blogspot.com/2025/10/hk-chp-mainland-china-retrospectively.html

​

 

[sharon sanders]

hat tip Michael Coston

snip

Current situation:

Since the last risk assessment of 25 August 2025, one laboratory-confirmed human case of A(H5) infection was detected in Bangladesh, and one laboratory-confirmed human case of A(H5N1) virus infection was detected in Cambodia.

A(H5), Bangladesh

On 19 August 2025, Bangladesh notified WHO of one laboratory-confirmed human infection with avian influenza A(H5) virus in a boy in Sylhet Division. The case developed fever and cough on 27 July and was admitted to hospital on 1 August. Oropharyngeal and nasopharyngeal swabs collected on 4 August and tested at the Virology Laboratory of the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b) and the Institute of Epidemiology, Disease Control & Research (IEDCR) tested positive for influenza A(H5) virus by reverse transcription-polymerase chain reaction (RT-PCR). on 14 August. Subtyping for the N-type was pending at the time of notification. The case was detected through the Hospital-Based Influenza Surveillance (HBIS) platform. The case was discharged on 7 August. A seven-member multidisciplinary team, comprising physicians, epidemiologists, an anthropologist, and a technologist, was deployed on 15 August to conduct an investigation. The child had no history of travel and no reported exposure to backyard poultry, however the family purchased chickens from a local market in the days preceding the child’s illness. All samples collected from contacts tested negative for influenza A(H5) virus. Samples collected poultry at two markets that were frequently visited by the family of the case tested positive for influenza A(H5) virus. This is the 12th human case of avian influenza A(H5) reported to WHO from Bangladesh and the fourth in 2025. Where the genetic sequence data is available, the viruses from the human cases thus far are identified as clade 2.3.2.1a viruses


https://cdn.who.int/media/docs/defa...sept_2025.pdf?sfvrsn=b145fc27_3&download=true

 

[Michael Coston]

WHO Influenza at the human-animal interface (March 31st): 13 Novel Flu Infections Detailed

WHO Influenza at the human-animal interface (March 31st): 13 Novel Flu Infections Detailed






#19,132

While avian flu reports may seem to have slowed in the first quarter of 2026, we've a new report from the WHO that announces (for the first time I've seen) at least 4 previously undisclosed cases, including a fatal H5N1 case in Bangladesh.

Today's Influenza at the Human-Animal Interference contains details on:

• 4 - A(H5N1) cases (3 Cambodia*, 1 Bangladesh)
• 5 - H9N2 Cases (4 China, 1 Italy)*
• 1 - H10N3 Case, China
• 1 - H1N1v Case, China
• 1 - H1N2v Case, China
• 1 - H3N2v Case, Brazil

* Note: We've seen another 4 H9N2 cases reported by China & 1 Cambodian H5N1 case since the Mar 31st cutoff​

The first, and arguably most significant of these new cases is this previously unannounced case out of Bangladesh:

A(H5N1), Bangladesh

On 9 February 2026, the National International Health Regulations Focal Point of Bangladesh notified WHO of a laboratory-confirmed human case of avian influenza A(H5) infection in a child from Chattogram Division. The patient, with no known comorbidities, developed symptoms on 21 January 2026 and was admitted to hospital on 28 January. A nasopharyngeal swab was collected on 29 January as part of the Hospital-based Influenza Surveillance (HBIS) platform for influenza-like illness (ILI) and severe acute respiratory infection (SARI) sentinel surveillance in Bangladesh. The patient was referred to a specialized private hospital and admitted to intensive care on 31 January.The patient died on 1 February.

On 7 February, the Institute of Epidemiology, Disease Control and Research (IEDCR), serving as the National Influenza Centre (NIC), received and tested the sample, confirming influenza A(H5) by real-time reverse transcription polymerase chain reaction (RT-PCR) on the same day. Virus characterization and whole genome sequencing was conducted at International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), which confirmed that the A(H5N1) virus belongs to clade 2.3.2.1a of highly pathogenic avian influenza A(H5N1) virus (Gs/GD lineage), similar to the clade of viruses circulating in local poultry since around 2011.

Genetic sequence data are available in GISAID (EPI_ISL_20367262; submission date 19 Feb 2026; Institute of Epidemiology,Disease Control & Research (IEDCR)).The case had exposure to household poultry, with two ducks and one chicken reportedly dying shortly before the case’s illness onset. Animal and environmental samples were collected and tested with RT-PCR and serology by the zoonotic investigation team of icddr,b. Two samples from ducks in the community and two samples from chicken meat in the freezer of household tested positive for influenza A(H5). Samples from symptomatic close human contacts tested negative for influenza.This is the first confirmed human case of avian influenza A(H5) reported in Bangladesh in 2026.

In 2025, four human cases of avian influenza A(H5) were reported.​

This makes the 12th case reported by Bangladesh, and the first fatal outcome. Today's report also cover the first three Cambodian cases of 2026, which we've previously discussed (see here, here, and here).



Note: A 4th Cambodian case was announced in April

The report then describes 5 recent H9N2 cases; 4 in China and 1 in Italy (ex-Senegal).

The two adult cases had underlying conditions. The first two cases had exposure to live bird markets.The last case had exposure to sick poultry. Samples from environments associated with the likely area of exposure of these cases tested positive for A(H9) viruses. The third case likely had exposure to contaminated environments or fomites. No further cases were detected among contacts of these cases.

A(H9N2), Italy, ex-Senegal

On 21 March 2026, Italy notified WHO of the detection of A(H9N2) virus in an adult male. The case had travelled to Senegal for more than six months and returned to Italy in mid-March 2026. Upon arrival in Italy, the case sought medical care, presenting with fever and persistent cough that had been present since mid-January. Laboratory investigations conducted on a bronchoalveolar lavage specimen on 16 March showed a positive Mycobacterium tuberculosis result, as well as detection of an un-subtypeable influenza A virus. The case was admitted to an isolation room under airborne precautions in a negative-pressure room and received antitubercular and antiviral treatment. As of 24 March, the patient was clinically stable and improving.​

We also get the first details on the Cryptic Announcement of 1 New H10N3 infection last February.

A(H10N3), China

On 9 February 2026, China notified WHO of one laboratory-confirmed case of human infection with an avian influenza A(H10N3) virus in a 34-year-old man from Guangdong province who developed symptoms on 29 December 2025. On 1 January 2026, he was admitted to hospital and diagnosed with severe pneumonia, severe acute respiratory distress syndrome (ARDS) and sepsis.

Oseltamivir treatment was initiated on 3 January. The patient's condition was stable at the time of reporting. On 12 January, the sample was sent to the provincial laboratory for testing. The result was positive forA(H10N3). On 14 January, the National Influenza Center confirmed the positive result.5 The patient works near two establishments that keep live poultry on the premises and chickens are present at the household.

Environmental samples collected from sites related to likely poultry exposure, including the patient's home, the workplace and a nearby poultry market tested negative for A(H10N3) influenza virus. No further cases were detected among contacts of these cases.A total of 98 close contacts of the patient were traced.Since 2021, a total of seven cases of human avian influenza A(H10N3) virus infection have been reported globally and all were from China​

Lastly, we get two brief descriptions of recent swine variant cases from China, and a more detailed (but belated) report from Brazil.

Swine influenza viruses in humans

Influenza A(H1N1)v, China

On 20 March 2026, China notified WHO of a laboratory-confirmed case of A(H1N1)v influenza virus infection in a child from Yunnan province. The patient had onset of illness on 30 January 2026, was hospitalized on 2 February with pneumonia, and recovered in a few days. The patient had reported exposure to domestic pigs prior to illness onset.

Influenza A(H1N2)v, China

On 3 February 2026, China notified WHO of a laboratory-confirmed case of A(H1N2)v influenza virus infection in a child from Yunnan province. The patient had onset of mild illness on 20 January 2026, and the infection was laboratory-confirmed on 2 February 2026. The patient had reported exposure to domestic pigs prior to illness onset. This case and the one above are not epidemiologically linked.​

Influenza A(H3N2)v, Brazil

On 26 January 2026, Brazil notified WHO of a laboratory-confirmed case of A(H3N2)v influenza virus infection. On 1 September 2025, a male child residing in the state of Mato Grosso do Sul presented with ILI symptoms and was taken to a health unit on 2 September. The patient had no reported comorbidities or recent travel history and reported being vaccinated against seasonal influenza in the last campaign.

On 9 September, a respiratory sample was collected at the health unit, which is a sentinel unit for ILI. On 12 September, the Central Public Health Laboratory of Mato Grosso do Sul (Lacen/MS) reported that the RT-qPCR test for influenza A virus subtyping amplified the influenza A marker along with the H3 marker, indicating a swine-origin variant of the influenza H3 virus. The sample was sent to the National Influenza Center (NIC) of the Adolfo Lutz Institute, where the A(H3N2)v was confirmed by molecular tests and genomic sequencing. The sequences were entered into GISAID on 1 October. The sample was also shared with the WHO Collaborating Centre at the US Centers for Disease Control and Prevention (CDC), where it was genomically and antigenically characterized.

An epidemiological investigation was conducted, which identified the case as a student at an agricultural school where pigs and laying hens are raised, although the institution's coordinators reported that the students had not had direct contact with pigs recently. It was reported that the case had contact with classmates who presented ILI symptoms during this period. All household contacts were vaccinated against seasonal influenza in the 2025 season, except for the patient's mother. To date, no other human cases of infection with the A(H3N2)v virus have been detected in association with this case.
​

While avian flu currently has the bulk of our attention, swine variant influenza poses perhaps an even greater pandemic risk. The CDC's IRAT (Influenza Risk Assessment Tool) lists 3 North American swine viruses as having at least some pandemic potential (2 added in 2019).

H1N2 variant [A/California/62/2018] Jul 2019 5.8 5.7 Moderate
H3N2 variant [A/Ohio/13/2017] Jul 2019 6.6 5.8 Moderate
H3N2 variant [A/Indiana/08/2011] Dec 2012 6.0 4.5 Moderate​

But there is much diversity among swine flu viruses around the globe, with China's EA H1N1 `G4' virus often cited as the biggest pandemic threat. We've also followed repeated spillovers in Brazil, and last year the Eurasian 1C Swine Influenza A Virus was labeled a `high pandemic risk'.

The reality is, surveillance and testing for swine influenza A viruses is notoriously sub-optimal, and many strains circulate under the radar.​

The fact that we are learning nearly 90 days after the fact about a fatal H5N1 case in Bangladesh, and more than 7 months after a novel H3N2 case in Brazil, reminds us that `no news' isn't necessarily `good news'.

https://afludiary.blogspot.com/2026/04/who-influenza-at-human-animal-interface.html

 

[Michael Coston]

WHO Influenza at the human-animal interface (May 8th): 10 Novel Flu Detections In Humans

WHO Influenza at the human-animal interface (May 8th): 10 Novel Flu Detections In Humans



#19,191


The WHO has released an update (dated May 8th, but only recently posted) of 10 human infections with novel flu reported between April 1st and May 8th, which includes:

• 3 - A(H5N1) cases (3 Cambodia, 1 Bangladesh, & India)
• 1 - A(H5N6) case reported by China
• 5 - A(H9N2) cases reported by China
• 1 - A(H1N2)v case reported by the United States

Of note, today's report brings the total number of lab-confirmed of human H5N1 cases since 2003 to 1000 (with 47.9% fatal). The actual number of cases is believed much higher.​

While some of today's case reports provide more detail than others, it appears that at least 3 of the 4 H5Nx cases in this update experienced delays in diagnosis.

1. The child in Bangladesh was hospitalized on March 29th - diagnosed with measles with bronchopneumonia - but only tested positive for H5N1 3 weeks later (Apr 20th).
2. The fatal H5N1 case in Cambodia was hospitalized on April 16th, but was only confirmed H5 positive on April 21st (died on the 22nd).
3. The child from West Bengal, India was admitted to the hospital for fever and cough on 19 March and discharged on 23 March. While no exact testing date is provided, India notified WHO on March 27th.

As we've discussed previously (see here, here, here, and here), it takes a certain amount of luck for novel flu infections to be detected, properly treated, and then reported to the relevant health authorities.

Patients may present with mild or atypical symptoms, and sample collecting and laboratory testing are not always 100% reliable. Some will never be
tested, and many cases will undoubtedly go unreported.​

I've reproduced the summary, and some excerpts on individual cases, below. I'll have a bit more after the break.

Influenza at the human-animal interface

Summary and risk assessment, from 1 April to 8 May 20261

• New human cases2: From 1 April to 8 May 2026, based on reporting date, detections of influenza A(H5N1) in three humans, influenza A(H5N6) in one human, influenza A(H9N2) in five humans, and influenza A(H1N2) variant ((H1N2)v) virus in one human were reported officially​

.• Circulation of influenza viruses with zoonotic potential in animals: High pathogenicity avian influenza (HPAI) events in poultry and non-poultry animal species continue to be reported to the World Organisation for Animal Health (WOAH).3 The Food and Agriculture Organization of the United Nations (FAO) also provides a global update on avian influenza viruses with pandemi cpotential.4 Additionally, low pathogenicity avian influenza viruses as well as swine influenza viruses continue to circulate in animal populations.

• Risk assessment5: Sustained human to human transmission has not been reported associated with the above-mentioned human infection events. Based on information available at the time of this risk assessment update, the overall public health risk from currently known influenza A viruses detected at the human-animal interface has not changed and remains low. At present,these viruses are not thought to be capable of sustained human-to-human transmission,although this could change as they evolve. Although human infections with viruses of animal origin are infrequent, they are not unexpected at the human-animal interface.

• IHR compliance6: This includes any influenza A virus that has demonstrated the capacity to infect a human and its haemagglutinin (HA) 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.​

(SNIP)

Avian influenza viruses in humans A(H5N1), Bangladesh

On 23 April 2026, Bangladesh notified WHO of one laboratory-confirmed human case of avian influenza A(H5) infection in a child from Sylhet Division. The patient developed fever and cough on 27 March 2026 and was admitted to hospital on 28 March with a clinical diagnosis of measles with bronchopneumonia.​

As part of hospital-based influenza surveillance, a sample was collected on 29 March and received by the Institute of Epidemiology, Disease Control and Research(IEDCR)on 20 April. The sample tested positive for influenza A(H5N1) on the same day by real-time reverse transcription polymerase chain reaction (RT-PCR). The patient was discharged on 30 March. No additional cases were reported among identified contacts. Epidemiological investigations identified exposure to household poultry.​

This is the second laboratory-confirmed human case of avian influenza A(H5N1) reported in Bangladesh in 2026.​

A(H5N1), Cambodia

On 22 April 2026, Cambodia notified WHO of one laboratory-confirmed human case of avian influenza A(H5) infection in a 66-year-old woman with comorbidities from Svay Rieng province. The patient developed symptoms on 15 April 2026 and was admitted to district hospital on 16 April and provincial hospital the next day.​

As part of severe acute respiratory infection surveillance, a sample was collected on 17 April and received by the National Institute of Public Health on 21 April. The sample tested positive for influenza A(H5N1) on the same day by real-time RT-PCR, and the result was confirmed by Institut Pasteur du Cambodge on 22 April. The patient died on 22 April. No additional cases were reported among 15 identified contacts. Epidemiological investigations identified exposure to sick and dead household chickens prior to illness onset.​

A(H5N1), India

On 27 March 2026, India notified WHO of one laboratory-confirmed human case of avian influenza A(H5N1) infection in a child from West Bengal state. The patient developed fever and cough and was admitted to hospital on 19 March. The patient was discharged on 23 March.

Laboratory testing at the Indian Council of Medical Research (ICMR) National Institute of Virology in Pune confirmed influenza A(H5N1). Genomic sequencing identified the virus as belonging to clade 2.3.2.1a, closely related to strains previously reported from Bangladesh and India in 2025. No additional cases were reported among identified contacts. Epidemiological investigations identified likely indirect exposure to poultry.This is the first laboratory-confirmed human case of avian influenza A(H5N1) reported in India in 2026.​

A(H5N6), China

On 29 April 2026, China notified WHO of one laboratory-confirmed human case of avian influenza A(H5N6) infection in a 55-year-old female with comorbidities from Chongqing Municipality. She had onset of symptoms on 16 April 2026 and was hospitalized on 23 April with severe pneumonia. The patient died on 3 May 2026. She had slaughtered and prepared poultry prior to onset of symptoms. Environmental samples collected from the food preparation tools at the patient’s residence tested positive for influenza A(H5). No further cases were detected among contacts of the patient.This is the first laboratory-confirmed human case of infection with an A(H5N6) virus detected since 2024.​

(SNIP)

A(H9N2), China

Between 7 April and 6 May 2026, China notified WHO of five laboratory-confirmed cases of A(H9N2)virus infection.​

The first case had comorbidities and developed severe pneumonia. All the cases except the child from Jiangxi had exposure to live bird markets or household birds. Samples from environments associated with the likely area of exposure of some of these cases tested positive for A(H9) viruses. No further cases were detected among contacts of these cases.​

(Continue . . . )

As always, the WHO spends a good deal of time imploring member nations to abide by the 2005 IHR regulationswhich require prompt notification of all human infections caused by novel flu subtypes.

It is critical that these influenza viruses from animals or from humans are fully characterized inappropriate animal or human health influenza reference laboratories. Under WHO’s Pandemic Influenza Preparedness (PIP) Framework, Member States are expected to share influenza viruses with pandemic potential on a timely basis15 with a WHO Collaborating Centre for influenza of GISRS. The viruses are used by the public health laboratories to assess the risk of pandemic influenza and to develop candidate vaccine viruses.​

But, according to a report 3 years ago (see Lancet Preprint: National Surveillance for Novel Diseases - A Systematic Analysis of 195 Countries), many member nations still lack the capability to fully investigate cases.

While none of these novel flu viruses currently show signs of spreading efficiently between humans, the general consensus is the next pandemic isn't a matter of `if', only a matter of `when' (see BMJ Global: Historical Trends Demonstrate a Pattern of Increasingly Frequent & Severe Zoonotic Spillover Events).​

The only real question is; will we be ready when it comes.

https://afludiary.blogspot.com/2026/06/who-influenza-at-human-animal-interface.html
​

 

[Michael Coston]

WHO: Bangladesh Reports 3rd H5N1 Human Infection for 2026

WHO: Bangladesh Reports 3rd H5N1 Human Infection for 2026

#19,245

In their latest Influenza at the human-animal interface Summary and risk assessment (from 13 June to 7 July 2026) - published over the weekend - the WHO has announced a 3rd H5N1 case in a Bangladeshi child in the past 6 months.

• Last April, we saw a fatal case reported from the Chattogram Division, in a child who fell ill on January 22nd, was hospitalized on January 28th, and who died on February 1st. The H5N1 infection was only determined posthumously, via lab analysis on Feb 7th.

• In early June we learned of a 2nd case, a child from Sylhet Division who was hospitalized on March 28th with a clinical diagnosis of measles with bronchopneumonia. The child was discharged on March 31st, but delayed testing by the IEDCR only revealed a positive H5N1 result on April 20th.

Today, we have another report which - once again - was only fully diagnosed belatedly, and this time the child was only seen as an outpatient. As with the last case, this case also hails from Sylhet Division.

Avian influenza viruses in humans

A(H5), Bangladesh​

On 15 June 2026, Bangladesh notified WHO of one laboratory-confirmed human case of avian influenza A(H5) infection in Bangladesh in a child from Sylhet Division. The case was detected notified through the National Influenza Surveillance, Bangladesh (NISB) platform as an influenza like-illness (ILI) case.​

The patient developed respiratory symptoms on 17 May 2026, received outpatient healthcare on 20 May. A clinical sample was collected that day and was received by the Institute of Epidemiology, Disease Control and Research (IEDCR) on 4 June as part of routine surveillance. ​

The sample tested positive for influenza A(H5) virus by real-time reverse transcription polymerase chain reaction (RT-PCR) on 11 June. The patient is now in good health and reported no travel history and no history of exposure to poultry.​

However, poultry deaths were reported in the area surrounding the patient’s residence. The outbreak investigation team identified and followed close and possible contacts. Samples from some of the close contacts as well as animal and environmental samples were collected for testing for
influenza. All contacts remained asymptomatic and all samples tested negative for influenza.​

This is the third laboratory-confirmed human case of avian influenza A(H5) reported in Bangladesh in 2026, and the 15th human case of avian influenza A(H5) reported to WHO from Bangladesh since 2008, including two fatal cases, one reported in 2013 and one in 2026​

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Sadly, this is a pattern we see far too often, and not just in Bangladesh. Delayed diagnosis not only endangers the patient's health, it risks unknowingly exposing others to the virus, and delays greatly reduce the effectiveness contact tracing or testing of others who may have been exposed.

We've seen numerous examples (see here, here, here, and here) of delayed diagnosis of novel flu in hospitalized patients, even here in the United States and in Europe (see H9N2 in Italy).

Admittedly, novel flu can often present with atypical signs and symptoms, or may be mild or even asymptomatic, and not justify hospitalization or comprehensive testing (which may not even be available in some parts of the world). ​

Additionally, standard throat swabs sometimes don't yield a positive result, and viral shedding can fluctuate over the course of infection, making false negatives not uncommon.

Recognizing the problem, in 2024 the ECDC issued guidance for member nations on Enhanced Influenza Surveillance to Detect Avian Influenza Virus Infections in the EU/EEA During the Inter-Seasonal Period.

In that summary, the ECDC pointed out:

Sentinel surveillance systems are important for the monitoring of respiratory viruses in the EU/EEA, but these systems are not designed and are not sufficiently sensitive to identify a newly emerging virus such as avian influenza in the general population early enough for the purpose of implementing control measures in a timely way.​

In January 2025 we saw a CDC HAN: Accelerated Subtyping of Influenza A in Hospitalized Patients, which urged immediate, and more thorough subtype testing of suspected flu cases.

Since these are recommendations, and not mandates, it isn't clear how fine a net we are casting at the local level (see Idaho Health HAN: Consider Avian Influenza A (H5N1) in Patients with Dairy Cattle or Poultry Exposure).​

Today's WHO report also summarizes 2 recent H9N2 cases (see chart below), and a novel H3N2v case from Brazil.

Influenza A(H3N2)v, Brazil​

On 25 June 2026, Brazil notified PAHO/WHO of a laboratory-confirmed human infection with an influenza A(H3N2)v virus detected in a child in Santa Catarina state. The patient had symptom onset on 12 June 2026 and due to worsening respiratory symptoms, healthcare was sought on 16 June.​

The patient was referred for hospital admission with a diagnosis of Severe Acute Respiratory Infection (SARI). Upon admission, an antigen test confirmed influenza A and the patient was placed in a private respiratory isolation room and antiviral treatment was initiated.

The patient was discharged on 19 June.

A nasopharyngeal swab sample was collected on 16 June and sent to the State public health laboratory for real-time RT-PCR. On 18 June, a swine-origin influenza H3 variant was suspected, and the sample was sent to the Laboratory of Respiratory Viruses, Exanthems, Enteroviruses, and Viral Emergencies (LVRE) at the Oswaldo Cruz Institute (Fiocruz/Rio de Janeiro) on 19 June.

Analyses confirmed the presence of an influenza A(H3N2)v virus via molecular testing and genomic sequencing. An investigation by the state and municipality epidemiological surveillance team found that all contacts were asymptomatic before, during and after the child’s illness.

The child's grandfather worked at a swine nursery housing approximately 5,000 animals, though he noted that sanitary barriers were in place. The child frequently visited the grandfather's home and had contact with him several days a week. This is the first human A(H3N2)v infection detected in the Brazil in 2026 and the first case reportedi n the state of Santa Catarina.​

In this case, a novel H3 flu virus was suspected in the child after 2 days in the hospital, but was not confirmed until sometime after the patient was discharged (date not explicitly stated).

It takes both planning - and certain amount of luck - to detect novel flu cases in the community, as confirmed cases only represent the very tip of the surveillance and reporting pyramid.

While there is no evidence that HPAI H5 is spreading efficiently from human-to-human right now, the evidence suggests that it is spilling over into humans more often than we know.

And even if there is some (as yet, unknown) species barrier that prevents H5 from ever becoming a pandemic, there are plenty of other viruses out there following similar paths.​

Eventually, one of them will get lucky. It's only a matter of time.


​https://afludiary.blogspot.com/2026/07/who-bangladesh-reports-3rd-h5n1-human.html