What is driving the spread of avian flu?

An “apocalyptic” mass mortality occasion that has left 1000’s of sea lions and elephant seals lifeless on the seashores of South America is elevating alarms amongst some California sea mammal specialists who worry comparable scenes may play out alongside California’s Pacific Coast and different continents because the H5N1 chicken flu continues its march throughout the globe.

The extremely pathogenic avian influenza virus has turn into infamous for its devastating impacts on wild and home chicken populations during the last 4 years, however solely lately has it inflicted so many deaths in a mammal inhabitants.

Up till now, the power of the virus to leap from mammal to mammal has been restricted, however the scale of infections and deaths in South America has raised troubling questions on whether or not one thing has modified.

Whereas it stays unclear whether or not this explicit pressure of H5N1 has improved its capacity to move simply between mammals, such a growth would have doubtlessly devastating consquences for endangered and non-endangered species alike.

The illness “presents an existential menace to the world’s biodiversity,” wrote Chris Walzer, government director of well being for the Wildlife Conservation Society in a January assertion, noting that the scene of lifeless elephant seals may “solely be described as apocalyptic.”

According to the Centers for Disease Control and Prevention, the H5N1 viruses circulating in birds “are believed to pose a low danger to most of the people in america; nonetheless, individuals who have job-related or leisure exposures to contaminated birds could also be at larger danger of an infection and may take applicable precautions outlined in CDC steerage.”

The World Well being Group has additionally deemed the danger of human-to-human transmission to be low, and notes that candidate vaccines have been developed for pandemic preparedness.

But the velocity with which the virus has destroyed once-thriving animal populations is breathtaking, stated Marcela Uhart, a wildlife veterinarian with UC Davis’ One Well being institute, who relies in Argentina.

In October, the mortality charge for new child elephant seal pups reached 96% on one seaside in Argentina — astronomically larger than the 0.8% mortality charge noticed there in 2022.

“Ten days and it’s accomplished. There’s nothing left alive,” Uhart stated.

Die-offs have additionally been noticed in South American dolphins and fur seals. And the virus is virtually knocking on Antarctica’s entrance door, the place greater than 100 million birds, together with colony-living penguins, and marine mammals congregate.

“There’s local weather change and habitat destruction,” that are taking their toll on the planet’s wildlife species, stated Rebecca Duerr, an avian veterinarian with Worldwide Fowl Rescue in Lengthy Seashore. “After which this. It’s grim.”

In California, some specialists say they fear concerning the vulnerability of sea lions and sea otters.

“California has been spared among the large die-off occasions being seen some place else on this planet. However we nonetheless have species which can be very weak to it. We’re not out of the woods by any stretch of the creativeness,” Duerr stated.

Colony nesting of seabirds and breeding of marine mammals happens all alongside the California Coast, the Channel Islands and Farallon Islands. They’re seasonally populated by such species as terns, sea lions and sea otters, amongst others.

“There’s an entire lot of concern nonetheless for what’s going to occur within the larger image over time,” she stated. “This summer season is breeding season, the time that different areas of the world have seen large die-offs at breeding colonies.”

The results wouldn’t be restricted to only the contaminated animals both, Duerr stated. These animals are important inside wider ecosystems. Guano produced from breeding chicken colonies gives vitamins for marine invertebrates and fish, for example.

And if sea otters have been to undergo such losses, that may endanger the well being of California’s huge kelp forests, which might be left prey to sea urchins, stated Christine Johnson, professor of epidemiology and ecosystem well being at UC Davis.

And though Southern and Northern hemisphere populations of marine mammals don’t have a lot, if any contact, Johnson stated the world is altering so shortly, we are able to’t actually be certain about something.

“The distribution of marine species is basically dictated on the place their meals goes, which itself is dictated by ocean traits and warming,” Johnson stated. “Are there species that are actually overlapping that hadn’t been earlier than, based mostly on local weather or different elements?”

She stated forces akin to local weather change and habitat destruction may have performed a job within the virus’ geographical enlargement, in addition to its preliminary and sustained grasp on wildlife.

“There’s growing proof that pandemics that come from wildlife, specifically, are growing in frequency,” Johnson stated. “There’s not a number of segregation or separation between wild animals and their pathogens” and home animals and other people.

Till lately, extremely pathogenic avian influenza, or HPAI, was thought-about strictly a poultry illness. It might flare up right here and there — primarily in Asia — and get stomped out shortly by killing all of the birds on an contaminated farm.

However in 2002, the virus jumped to wild birds, and in 2005, it had unfold to Japanese Europe, the place seven individuals have been contaminated after de-feathering wild swans. 4 of the individuals died. 9 years later, the illness reached North America — presumably by way of Alaska, the place birds from all over the world migrate and feast in the course of the summer season. And though it died down for a bit in Canada and the U.S. — flaring up often in Asia, Europe and Africa — it got here again with a vengeance in 2021.

Since that point, not solely have a whole bunch of hundreds of thousands of home birds been culled, however numerous numbers of untamed birds and animals have contracted the virus.

Julianna Lenoch, the nationwide coordinator of wildlife providers for the U.S. Division of Agriculture’s Animal and Plant Well being Inspection Service, stated that whereas scientists are ready for genetic data from South America, there isn’t a “proof that’s of excessive concern but in america, however I feel watching mammal spillover and potential mammalian unfold is one thing the worldwide group is on the lookout for.”

The company routinely samples wild birds, and solely samples mammals in which there’s suspicion.

“We decide them up from state companies or wildlife rehabilitation amenities or from somebody who has a sign of suspicion … so, what we have now might be an undercount,” she stated.

However to this point, the scenario in North America is totally different from the “craziness” being seen in South America.

In america and Canada, the one mammals which have gotten the illness — akin to foxes, skunks, coyotes and bears — are these recognized to scavenge on lifeless birds. There isn’t any indication there may be any mammal-to-mammal passage.

Sea otters calm down within the Morro Bay marina. Some marine mammal specialists fear that the furry mammals could also be weak to the spreading H5N1 chicken flu.

(Marc Martin / Los Angeles Instances)

However North American animals may additionally share a protection that South American wildlife doesn’t.

As a result of the virus has had a presence in North America since 2014, many of the continent’s wildlife has “some kind of base immunity to influenza,” stated Deborah Fauquier, a veterinary medical officer with the Nationwide Oceanic and Atmospheric Administration. “They’ve some antibodies. Perhaps not the proper ones … however they’ve seen the virus earlier than.”

“In South America … these populations have been mainly naive, and had not seen excessive path (influenza) earlier than. … So they simply don’t have that sort of immunity that we have now in our seals in addition to our birds,” she stated.

So, whether or not the large marine mammal die-offs are the results of a novel publicity to the illness, or as a result of the virus has acquired the power to maneuver between mammals, stays unclear.

In both case, nonetheless, it doesn’t bode effectively for wildlife within the final remaining areas of the world the place the illness has not been detected: Antarctica and Oceania — the area that features Australia, New Zealand and the encircling islands.

Uhart stated she was setting out in late February to pattern animals in Antarctica — hitching a trip on a cruise ship. Earlier than vacationers are allowed off the boat for a touchdown, she stated, she’ll exit and do surveillance and ensure the whole lot appears to be like regular; she’ll additionally gather samples.

“We’ve seen it sufficient,” she stated. “I do know very well what it appears to be like like.”

Johnson stated the nations of the world must be on heightened surveillance because the virus continues its scourge.

Simply as within the case of the coronavirus that triggered COVID-19, this flu pressure is continually evolving and altering — with new variants showing on a regular basis. But, fatigue is setting in amongst many governments internationally which were battling the virus for 3 or 4 years now.

“No person needs to consider or speak about one other pandemic,” she stated. However preserving a deal with on its whereabouts and adjustments is important for conservation, the ecosystem and human well being.

“I feel international locations want to start out making ready for the response efforts that’s wanted for … massive biosafety issues,” she stated. “It does have a excessive mortality charge in individuals and we’re speaking about a number of virus on the panorama.”