This is Avian Flu Watch: Global H5N1 Tracker.

From 2020 to now, H5N1 avian influenza has swept the globe, striking every continent except Australia, and intensifying in 2025. The World Health Organization reports that, as of August, there have been 990 confirmed human H5N1 cases since 2003, including 475 fatalities worldwide—a mortality rate near 48 percent. In 2025 alone, over 26 new human infections have been registered, with case clusters emerging in the Americas, Europe, Asia, and parts of Africa.

Let’s break down the current hotspots. In the Americas, the Pan American Health Organization confirms that since 2022, 19 countries have encountered 5,063 outbreaks. The U.S. dominated headlines with the first H5N1 cases in dairy cattle—over 17 states affected—California now leads with eightfold more herd outbreaks than other states, while Arizona and Wisconsin are flagged as rising epicenters. Human infections linked to livestock have surfaced, especially among dairy workers. Mexico and Argentina have reported fatalities, and notable transmission into wildlife threatens ecosystem disruption.

In Europe, Germany faced 103 outbreaks between June and September—culling over 500,000 birds—and Hungary lost 10,000 migratory cranes. The UK recently reported a poultry worker infection and even documented mammalian cases, suggesting expanded host risk. Between June and September, the European Centre for Disease Control records 19 human cases in the region, with three deaths. Asia remains vigilant with outbreaks in Cambodia, China, Bangladesh, and India. Cambodia, particularly, observed 11 new cases and two deaths since June, many in children exposed to sick poultry.

Visualizing global trend lines, avian flu’s graph surged sharply in wildlife in early 2024, plateaued in mid-2025, but with persistent spikes among livestock and sporadic human spillover, especially in high-density poultry regions and integrated farm systems. Infection rates for mammals continue to climb, with cattle-linked transmission increasing. Transmission models and geospatial studies show viral spread is primarily dictated by migratory bird pathways and trade. Regions with live bird markets, overlapping livestock sectors, and lax biosecurity remain high-risk.

Cross-border transmission is driven by wildlife migration, shared livestock operations, and uncontrolled animal trade. Case clusters trace to farms with scant safety protocols and places where personnel move freely between poultry and cattle zones, underscoring the need for better surveillance and targeted control.

Turning to international containment, some countries have demonstrated partial success. U.S. efforts with mandatory cattle testing and poultry culling have slowed spread but not halted it. Germany’s mass culling staved off larger outbreaks but led to economic strain. In contrast, regions with little biosecurity—particularly South and Southeast Asia—have struggled to curb transmission, reflected by ongoing human fatalities.

Emerging variants of concern dominate discussions. The clade 2.3.4.4b remains the main driver of global outbreaks, now capable of infecting a broader spectrum of mammals, including cattle, cats, and even sheep. Its genetic mutations increase fitness in mammalian hosts, raising fears of greater human susceptibility and facilitating interspecies transmission.

For travelers, the Centers for Disease Control and World Health Organization recommend avoiding live animal markets, farms, and close contact with wild birds in affected regions. Anyone working with livestock should follow strict hygiene protocols, report animal illnesses, and limit exposure to raw animal products.

Thank you for tuning in to Avian Flu Watch: Global H5N1 Tracker. Join us next week for the latest scientific updates. This has been a Quiet Please production. For more, visit Quiet Please Dot A I.

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