#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
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.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.
- 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).
- The fatal H5N1 case in Cambodia was hospitalized on April 16th, but was only confirmed H5 positive on April 21st (died on the 22nd).
- 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.
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.
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.
As always, the WHO spends a good deal of time imploring member nations to abide by the 2005 IHR regulations which require prompt notification of all human infections caused by novel flu subtypes.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.
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.
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.
