#15,564
Six days ago, in Laos: First Reported H5N1 Human Infection In 18 Months, we saw the first confirmed human infection with HPAI H5N1 since a 21-year-old male was diagnosed with the virus in Nepal in March of 2019.
Once the king of the bird flu world - and #1 on our pandemic worry list - HPAI H5N1 activity abruptly began to fade after Egypt's record setting 2015 outbreak (in many places supplanted by H5N8), and human infections around the globe fell precipitously.
Scattered outbreaks in wild birds and poultry have continued - particularly in Southeast Asia, the Middle East, and the Indian subcontinent - but the traditional hotspots of human infection (Indonesia, Egypt, Cambodia & China) have reported no cases in more than 3 years.
Some of that may be due to less-than-aggressive testing and reporting, but most of it has been attributed to an attenuation of the local H5N1 strains due to the acquisition of genes from low pathogenicity avian influenza A virus progenitors.
Between these evolutionary changes - and the use of vaccines that often mask symptoms without preventing infection - reports of wild bird die offs and poultry outbreaks have steadily declined the past few years.
But of course, evolutionary directions can change over time, and so we monitor threats like H5N1 closely.
Today the OIE has published an official notification from the government of Laos of two poultry outbreaks of HPAI H5N1 (1 in August, the other September) - the first in that country in nearly two years - in Saravane (aka Salavan) Province, the same place where their human infection was reported last week.
While it is likely this flare up HPAI H5N1 in Laos is an isolated event, Laos lies beneath the East Asian-Australian Flyway migratory bird flyway (see map below), and so we'll be watching for any reports of H5N1 emerging from other Southeast Asian nations (e.g. Cambodia, Thailand, Myanmar, etc.) which also lie along this north-south migratory route.
