Pan-animal epidemic lands in Argentina: What’s going on with bird flu that killed sea lions? | An epidemic that affects animals and has killed nearly all continents

The bird flu currently affecting Argentine sea lions is unprecedented. Authorities in jurisdictions along the Atlantic coast and in Patagonia decided to close beach access as a precautionary measure after more than 50 specimens were affected by the infection transmitted by migratory birds. They ask people not to come into contact with infected animals because, although this is rare, humans can get sick too. How does this hitherto defenseless virus work? How did it spread across continents and cause mass die-offs of different species?

“What is happening is extraordinary, We’re living in a pandemic: it’s synonymous with a pandemic, but in animals. It is a result of the forms of production we humans have; more and more intensive and less environmentally friendly. If not this virus, it will be another virus, like the coronavirus that we have in animal markets in China. ’ he pointed out. Pablo Plaza, Ph.D. in Biology, Conicet Researcher, Patagonia North Science and Technology Center. He added: “Pollution, combined with society’s advancement of natural ecosystems, leads to exposure to pathogens that could ultimately lead to the extinction of several species.”

The H5N1 variant of the A virus affects the species of Sophora flavescens (Otaria flavescens), commonly known as the “hairy sea lion”, a brown carnivore that can weigh up to 350 kilograms. The virus first infected birds and now also infects mammals, changing its epidemiology. And, from the experience with the coronavirus, you already know what to expect when the epidemiology changes. “From here on, we sleep with one eye open and the other closed; we don’t know what to expect. It’s a zoonotic pathogen through which it can be transmitted from animals to humans.’, details the expert on veterinary medicine and carrion birds.

He then goes on to advise: “Close contact with them on the beach must be avoided, and prevention is highly valued in poultry production.” Fortunately, no human-to-human contagion has been recorded so far. If so, there will be another color for international alerts.

“Very aggressive” variant

As experts warn, A “very aggressive” variant of the virus, which is characteristic of its rapid spread among sea lions in the same community. Once infected, they exhibit more or less the same symptoms: tremors, which can lead to seizures, disorientation and death. It is estimated that at least 450 species of wild birds can transmit avian influenza to mammals. “From spring we know that more than 400 migratory bird species will come to Argentine territory. Knowing the characteristics of the birds allows us to risk paying more attention to which of them and identify which ones can transmit the virus on a larger scale” , Plaza said.

It is spread through the mouth, the airways and secretions (saliva or mucus) and excretions such as urine or faeces (which remain on surfaces for a period of time). “Sea lions usually contract the disease by cohabiting with infected birds.They ate some outside, or, they got infected from participating in the same environmentbecause depending on the temperature and salinity, the virus persists for a while,” the scientists describe.

Although the strongest hypothesis is that the virus spread around the world from birds, the fact that the virus has mutated and successfully adapted and started to spread among mammals, from sea lions to sea wolves, cannot be ruled out.

Neither isolate nor vaccinate

The outlook becomes even bleaker when one considers the inability of health authorities to act in the same way as a human virus outbreak.. Sea lions are not vaccinated, and their isolation is nearly impossible.As a result, the immune system is unresponsive when encountering the virus Combats diseases affecting muscles, nerves and respiratory function with eventual mortality rates as high as 100%.

Experts explain it this way: “It is very difficult to vaccinate wild animals. The only examples of vaccinations I can remember were in the US, where the vaccinations were done on captive animals, primarily the California condor.As few people remain, they are protected from the flu’, he commented. This is an exception whose purpose is to prevent a serious problem threatened with extinction.

For their part, the few recorded cases of avian influenza have been linked to those who had maintained close and prolonged contact with the diseased species, possibly through work and poultry production in rural areas. As a precaution, extra caution is required with these workers and citizens are prevented from coming into contact with or approaching sea lions in coastal areas.

intercontinental journey

The virus present in sea lions corresponds to a subtype of highly pathogenic avian influenza, which is First discovered in Chinese birds in 1996. In particular, the virus has led to large animal population declines in areas where birds are intensively produced for human consumption. Relatively quiet for decades, Around 2020, the virus was observed to change its characteristics and occasionally affect mammals.

so, From Asia to Africa and Europe, more than 50 million poultry are slaughtered in less than a year. “Three years ago, in Europe, many birds and some mammals died. The outbreak then spread to Iceland, from there to the United States, and in October 2022 to South America.“, Square said. Recently, a large number of bird deaths have occurred in many places. in colombia and peru. The phenomenon has intensified, with 200,000 confirmed deaths.

“We saw 600 sea lions die, which seemed crazy to us, and we didn’t understand what was going on. This unusual mortality rate warrants investigation,” the Conicet researchers noted. Over time, More than 15,000 sea lions died between Chile and Peru. In this sense, one hypothesis is that the outbreak arrived in Argentina by migratory birds via the Peru-Chile-Tierra del Fuego journey. In August, the first reports indicated that Tierra del Fuego, Santa Cruz, Chubut (Peninsula Valdes), Rionegro, and Buenos Aires’ Mar del Plata, Necochea, Monte Sea lions died in the towns of Hermoso, Villagesell, and Coronel. Villarino has more cases under investigation.

According to Argentina, 57 mammals have died so far. One caveat, though: This figure is likely far lower than the real figure. As is the case with Sars CoV-2 and the vast majority of viruses: during a crisis, proving death is one of the most difficult tasks for countries.

What does the future hold for bird flu transmission? Here’s science trying to answer that question before it’s too late.

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