Avian Influenza Expands Its Reach: H9N2 in Italy, H5N1 Persists Globally

Overview

Two strains of avian influenza are simultaneously making headlines in April 2026, painting a picture of a global zoonotic threat that is both geographically expanding and taxonomically diverse. The subtypes in question — H9N2 and H5N1 — represent different ends of the avian influenza risk spectrum, but together they underscore a persistent challenge for international public health surveillance. Italy has reported its first confirmed imported case of H9N2 avian influenza in a traveler returning from Senegal, while China continues to record sporadic human H9N2 infections. In parallel, H5N1 avian influenza is still circulating in US poultry flocks and has now been confirmed in marine mammals along the California coast. One human death linked to H5N1 has been recorded globally in 2026, according to the World Health Organization. The overall current risk to the general public remains low, but the concentration of events across multiple continents is drawing sustained attention from health authorities.

Current Situation

Image: Pexels/Yunus Erdogdu

Italy’s case, reported to the WHO on 21 March 2026, involves an adult male who had recently returned from Senegal. Genomic sequencing confirmed the virus as Influenza A(H9N2), a subtype previously documented almost exclusively in Asia and with only three prior confirmed cases outside of China in the past decade. Notably, Italian epidemiological investigators found no history of exposure to poultry and no contact with any individual displaying similar symptoms before the patient became ill — leaving the source of infection unresolved. Under the International Health Regulations (IHR 2005), any human infection with a novel influenza A subtype must be reported to the WHO as an event with the potential for significant public health impact; Italy complied with that obligation.

Meanwhile, China added at least three more laboratory-confirmed H9N2 infections in April 2026. According to CIDRAP, the WHO has now recorded 162 human H9N2 cases globally since 2015, with all but three of those cases reported in China. Of the five H9N2 cases confirmed so far in 2026, four were in China and one is the Italy import. H9N2 infections in humans typically produce mild to moderate respiratory illness, and the strain has not demonstrated sustained human-to-human transmission, but its endemicity in poultry across Asia keeps it in regular contact with human populations.

On the H5N1 front, the WHO confirmed at least one human death associated with H5N1 zoonotic influenza in 2026. In the United States, the USDA has been tracking poultry outbreaks that, while showing signs of decline by late April, caused significant disruption during the month. One outbreak affected a turkey facility in Minnesota housing 63,000 birds. The Dakotas registered the highest concentration of poultry outbreak activity in April. CIDRAP reported that by the final days of the month, detection rates were falling — a tentatively encouraging signal, though not yet a basis for lowering vigilance.

Affected Regions

The geographic breadth of avian influenza activity in April 2026 is notable. In Europe, Italy stands as the sole confirmed human H9N2 case, and the ECDC has been monitoring the situation through its Communicable Disease Threats Reports for weeks 15 and 17, which flagged avian influenza alongside other circulating pathogens. The absence of any secondary cases in Italy, and the lack of a clear epidemiological link to poultry, leaves open questions that authorities continue to investigate.

West Africa, specifically Senegal, is now implicated as the probable location of the Italian patient’s exposure, representing the first time H9N2 has been epidemiologically linked to sub-Saharan Africa in a travel-associated case. Whether H9N2 is present in Senegalese poultry, and at what prevalence, is not yet confirmed, but the finding may prompt targeted surveillance efforts in the region.

In China, H9N2 is considered endemic in live poultry markets, and sporadic human cases are a consistent feature of surveillance data. The four Chinese cases reported in 2026 follow a pattern seen in previous years: geographically distributed, generally mild outcomes, and without evidence of human-to-human spread.

In North America, H5N1 activity is distributed across the United States with notable intensity in Midwestern agricultural states. The detection of H5N1 in California marine mammals adds a wildlife dimension to the picture. Marine mammals — sea lions and similar species — have previously been identified as susceptible to H5N1 in other outbreak contexts, and their infection indicates widespread environmental persistence of the virus, particularly along migratory bird routes that overlap with coastal ecosystems.

Risk Assessment

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For most people reading this, the immediate personal risk remains low. Neither H9N2 nor H5N1 has demonstrated efficient or sustained transmission between humans, which is the defining threshold that would elevate either strain toward pandemic concern. That said, health authorities are not treating current events as routine.

The unresolved source of the Italian H9N2 infection — a traveler with no documented poultry contact — is an unusual finding that warrants careful investigation, as the absence of a known exposure chain is epidemiologically significant.

For H9N2, the principal at-risk population remains individuals with occupational or incidental exposure to live poultry, particularly in settings where biosecurity measures are limited. The Italian case complicates that risk profile slightly. For H5N1, agricultural workers on affected poultry operations represent the clearest exposure risk in the United States. Dairy farm workers, who faced documented H5N1 risks in 2024 and 2025, remain a population warranting continued surveillance attention.

The detection of H5N1 in marine mammals carries ecological concern beyond immediate human health risk, as these animals can serve as mixing vessels for influenza viruses and their illness may indicate broader environmental contamination in coastal zones.

Globally, the WHO classifies the risk of H9N2 to the general public as low. The same low-risk classification applies to H5N1 outside of direct animal-contact settings. However, both strains are monitored under pandemic preparedness frameworks precisely because influenza A viruses can evolve unpredictably, and conditions that allow repeated human exposure increase the statistical probability of adaptive mutations.

Prevention & Response

Authorities at multiple levels are responding to the current situation with surveillance intensification rather than emergency containment measures, which is appropriate given the risk levels involved. In Italy, health authorities implemented monitoring and contact tracing following the H9N2 notification, and no additional cases have been identified in the weeks since. The WHO has published a full Disease Outbreak News report on the Italian case, and the ECDC has incorporated avian influenza tracking into consecutive weekly Communicable Disease Threats Reports.

In the United States, the USDA continues to test and respond to poultry flock outbreaks, with standard protocols including culling affected flocks and establishing movement controls in affected areas. Surveillance of farmworkers on affected operations has been a component of the US response since H5N1 first spread to dairy cattle in 2024.

On the vaccine front, there is a meaningful development. Moderna has initiated Phase 3 clinical trials of its mRNA-based H5 pandemic influenza vaccine candidate, mRNA-108. This is a significant milestone: mRNA vaccine platforms, proven during the COVID-19 pandemic, offer the potential for rapid large-scale deployment should an H5N1 strain acquire the capability for human-to-human transmission. The fact that a Phase 3 trial is now underway reflects the investment governments and manufacturers have made in pandemic preparedness infrastructure since 2020.

For travelers to regions with active avian influenza circulation — including parts of Southeast Asia, South Asia, and now potentially West Africa — standard guidance applies: avoid contact with live poultry or birds in markets, practice rigorous hand hygiene, and seek medical evaluation promptly if respiratory symptoms develop within ten days of potential exposure. Clinicians should be alert to travel history when evaluating patients with influenza-like illness, particularly those returning from regions not typically associated with H9N2, as the Italian case demonstrates that the virus’s geographic footprint may be broader than current surveillance data captures.

Sources

• WHO Disease Outbreak News – Avian Influenza A(H9N2), Italy, April 2026
• CIDRAP – WHO reports H5N1 death among variant zoonotic flu cases seen this year, April 29, 2026
• CIDRAP – 3 more H9N2 avian flu cases confirmed in China, April 21, 2026
• CIDRAP – Avian flu detections drop across the US, April 30, 2026
• CIDRAP – More California marine mammals confirmed to have H5N1 avian flu, April 23, 2026
• CIDRAP – Quick takes: Avian flu vaccine trial, April 22, 2026
• ECDC Communicable Disease Threats Report, Week 17 (18–24 April 2026)
• ECDC Communicable Disease Threats Report, Week 15 (4–10 April 2026)