#17,156
While its arrival was anticipated (see March 2022 FAO ALERT FOR THE AMERICAS), six weeks ago South America reported their first detection of HPAI H5N1 (see WOAH: Colombia Reports Two Outbreaks of HPAI H5N1), which has since been followed by multiple reports from Peru, Ecuador and Venezuela.
Although an exact number isn't known, a week ago Peruvian authorities estimated nearly 14,000 pelicans (and other seabirds) had died due to H5N1, and that number has certainly escalated since then. Today's headline from Euronews - Peru | Tens of thousands of seabirds have died from bird flu - is likely a fair assessment.
Beaches in Peru are reportedly littered with dead or dying birds, and for several days there has been a debate over closing affected beaches to the public.
While the risk to public health is considered low, it is not zero, which led Peru's Ministry of Health to issue the following statement on Monday.
Ministry of HealthWe've seen similar die offs of wild birds in Europe and in North America, but HPAI H5 does appear to be exacting a heavier toll among wild birds in South America. This may be due to a lack of previous exposure to HPAI H5 viruses, or potentially, to a recent change in the virus.
District municipalities are recommended to restrict access to beachesPress release
Digesa, Senasa and Serfor agree on a measure for the collection of dead or sick birds with avian influenza
December 5, 2022 - 6:56 p.mThe Ministry of Health (Minsa) held a meeting with authorities from the National Agrarian Health Service of Peru (Senasa) and the National Forest and Wildlife Service (Serfor) of the Ministry of Agriculture (Midagri) , in which it was agreed to recommend to district municipalities restrict access to beaches reported with the presence of dead or sick birds with avian influenza.
This means that local governments, within the framework of their powers, will limit access to beaches by schedule, in order to proceed to clean these spaces and prevent the spread of the disease to the detriment of human health.
Senasa and Serfor will be in charge of the protocols and procedures for the collection and disposal of dead birds, as well as the correct implementation with Personal Protection Equipment (PPE) for the personnel involved in these actions.
Since November, the presence of dead or sick birds has been reported on beaches in all departments of the Peruvian coast, mainly between Tumbes and Moquegua, with Tacna being the only region that has not reported cases to date.
Faced with this situation, Senasa declared a health alert for "highly pathogenic" H5N1 avian influenza in wild birds, in order to prevent this disease from spreading to backyard birds and commercial farms.
As indicated by the Pan American Health Organization ( PAHO), some strains of highly pathogenic avian influenza have the capacity to infect human beings, representing a threat to public health, when in direct or indirect contact with infected animals or with environments and surfaces contaminated with feces.
Three weeks ago, in Preprint: Rapid Evolution of A(H5N1) Influenza Viruses After Intercontinental Spread to North America, we looked at a preprint which found that the longer HPAI H5N1 had circulated in North America, the more genotypes it has generated.
And as might be expected, some of those genotypes were far more virulent in birds and mammals than others. The authors wrote:
Here, we show that the western movement of clade 2.3.4.4b was quickly followed by reassortment with local circulating viruses, resulting in the acquisition of novel polymerase gene cassettes.
These reassortant A(H5N1) viruses are genotypically and phenotypically diverse, with many causing severe disease with dramatic neurologic involvement, in mammals.
The proclivity of the current A(H5N1) 2.3.4.4b virus lineage to reassort and target the central nervous system warrants concerted planning to combat the spread and evolution of the virus within the continent and to mitigate the impact of a potential influenza pandemic that could originate from similar A(H5N1) reassortants.
It is reasonable to assume that as the HPAI H5 virus spreads across South America that it will encounter new LPAI viruses with which to reassort, and produce additional genotypes. How that might affect the impact and trajectory of the avian H5 virus is unknown, but it is a wild card that can't be ignored.
The `good news' from the above report is that so far, the H5 viruses they tested bound preferentially to avian alpha 2,3 receptor cells found in the gastrointestinal tract of birds, not the alpha 2,6 receptor cells most commonly found in the human respiratory system.
But the authors cautioned:
From a public health perspective, the increased pathogenicity of the reassortant A(H5N1) viruses is of significant concern. However, this is tempered by the avian virus–like characteristics of the viruses with respect to their receptor binding preference and their pH of HA activation. These characteristics probably need to change to enable sustained human-to-human transmission, although only a few amino acid changes among various influenza proteins are needed to switch these properties during adaptation in mammals.
So we watch events - such as the die-off of seabirds in Peru - with considerable interest, since changes in behavior could indicate a change in the threat posed by this constantly evolving virus.
Stay tuned.
