A new pandemic

There was some controversy about the lowest “excess deaths” recorded in Sweden during 2020–2022, indicating a lower excess mortality due to COVID-19. This is controversial, and the estimation of the excess deaths compared to the prior years is a very indirect measure of actual COVID-19 mortality and can be affected by various confounding factors. Because of the variable approach adopted by different countries to document COVID-19 deaths, especially at the beginning of the pandemic with a lack of proper testing, excess deaths during the pandemic period are an inexact measure of actual COVID-19 deaths.

Total COVID-19 deaths per million population (2020–2024)

One of the troublesome consequences of Sweden’s approach was that 40 percent of all COVID-19 cases were recorded in older individuals aged more than 70 years. Most of the deceased lived in long-term care facilities. COVID-19 death rates were also higher among the poorer population.

A national COVID-19 commission was established early in the pandemic by the Swedish government to examine how Sweden handled the pandemic. They submitted their final report in 2022. According to the commission, the larger number of deaths in the older population was probably due to increased community transmission facilitated by the lack of rigorous community isolation protocols early in the pandemic.

#18,579

While the threat of HPAI H5N1 in livestock - and sporadic spillovers into humans - have garnered most of our bird flu attentions this past year, there has been a massive, and underappreciated, impact on both avian and mammalian wildlife around the globe. 

Numbers are impossible to quantify, but hundreds of millions of wild birds have died, and hundreds of thousands - perhaps millions - of wild mammals have succumbed to the virus. 

A few past blogs on this carnage include:

Travel Med. & Inf. Dis.: Pacific and Atlantic Sea Lion Mortality Caused by HPAI A(H5N1) in South America

EID Journal: Recent Changes in Patterns of Mammal Infection with Highly Pathogenic Avian Influenza A(H5N1) Virus Worldwide

EID Journal: Mass Mortality of Sea Lions Caused by HPAI A(H5N1) Virus (Peru)

But even if that never happens, the impact on our shared ecosystem - and the loss of hundreds of millions of birds and hundreds of thousands of mammals - is enormous and growing.

Last year we followed attempts to protect the endangered California Condor from HPAI H5N1, after more than 20 deaths were reported in the wild (see USFWS Update: 21 Condor Deaths Attributed To HPAI H5).  As scavenger birds, Condors feed almost exclusively on carrion, which increasingly runs the risk of being infected with HPAI H5 (see USDA Mammalian HPAI Infection List).

While the knock-on effects of HPAI's damage to wild birds and mammals are difficult to predict, it isn't hard to imagine what the loss of a half billion birds might have on the mosquito population in some regions - or the loss of scavenger birds on the efficient cleanup of carrion - both of which could adversely affect human health.

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As many wild animal populations are already under strain from habitat loss, climate change and other global change drivers, previously neglected threats such as some emerging infectious diseases can rapidly decimate wildlife populations1. One such emerging disease in wildlife is the highly pathogenic avian influenza caused by the A H5N1 virus.

(SNIP)

An estimated half a billion domestic fowl have died of H5N1 (ref. 4), and this number is rising; mortality in wildlife is more difficult to quantify than in poultry, but the effects are substantial. By mid-2024, H5N1 infections were documented in at least 406 bird and 51 mammal wild species (according to reports on the World Animal Health Information System (WAHIS)), and available reports suggest that multiple millions of wild animal individuals may have died (Fig. 1a).

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Eighteen months ago, in Avian Flu's New Normal: When the Extraordinary Becomes Ordinary, I wrote about the numbing effect that comes with the constant barrage of HPAI H5 reports from around the world.  

Events that were nearly unthinkable two or three years ago (e.g. Repeated trans-Atlantic introduction of avian flu from Europe, the spread of HPAI H5 across the length of South America, numerous spillovers of H5 into mammalian species, and the arrival of HPAI H5 to Antarctica) have now become `the new normal'.

Admittedly, for many it is easier to turn a blind eye to what is happening, as long at it doesn't affect them directly. But $10 for a dozen eggs may not be the worst fallout we'll see from this virus, 

We underestimate HPAI's threat at our own, considerable, peril.