Bird flu in sea lions: Ten keys to understanding the outbreak experts fear

if Avian Influenza can be transmitted to humans or to more marine species, including those consumed by humans, and how it differs from the influenza virus that caused the 2009 pandemic. These are some of the questions experts answered when infections were recorded in sea lions – the first in mammals in Argentina – Highly pathogenic variants with nearly 100% mortality.

Sea lions infected with bird flu: They claim ‘never seen such a serious infectious disease before’


Since mid-August, in Tierra del Fuego, Santa Cruz, Chubut, Rio Negro and in Buenos Aires’ Mar del Plata, Necochea, Montehermoso, Gosei About 200 sea lions have been found dead in towns such as Villa El and Colonel Rosales.

Consultants teramAriel Vagnozzi, a veterinarian from the National Institute of Agricultural Technology (INTA) who specializes in avian viruses, and Diego Rodríguez, a biologist and researcher from Conicet and the National University of Mar del Plata (UNMDP), provide some keys to understanding this phenomenon.

What is avian influenza?

“This is the name of a highly contagious disease caused by the influenza A virus. There are several subtypes within this virus genus,” including the H5N1 subtype registered in sea lions, Vagnozzi said. “All variants of influenza A are found only in wild birds; that is why they are considered important reservoirs of the virus and play a very important role in the global spread of the disease,” he added.

Is it related to the H1N1 subtype that caused the pandemic in 2009?

“H1N1 belongs to influenza A and is the cause of human outbreaks. The two viruses are not related and the H1N1 virus originated in pigs.” INTA experts said.

How is bird flu transmitted to Argentine sea lions?

“The virus arrived in South America last year through migratory birds. The first and most serious case occurred in Peru earlier this year, where seabirds died in large numbers. The virus mutated and infected sea lions, causing mass deaths of sea lions.” Rodri Gus explained.

He continued: “The virus was spreading southward due to the movement of animals, and by mid-year there were deaths in southern Chile, and a few weeks ago, due to interactions between the Pacific and Atlantic colonies, “it reached Tierra del Fuego. The fire started and rose from there (to the Argentinian coast) within a few days. ”

What are the symptoms in infected animals?

“Avian influenza is a respiratory disease, so of course it causes difficulty breathing and lots of mucus. It also has effects on the nervous system, which manifests as disorientation, lack of coordination, and even the inability to move in infected animals,” UNMDP researchers explain road.

In this sense, he emphasized: “This is a highly contagious disease that is almost 100% fatal. Except for those animals with good immunity and low infection rates, there is no other fate except death.”

How do these infections affect the species’ ability to survive?

Especially when it comes to sea lions, Rodriguez said the death toll of sea lions in the country, which stands at about 200, “isn’t that catastrophic so far, but we have to pay close attention and watch how things develop.”

In Peru and Chile, he said, the impact was “very severe, with thousands of animals dying, but not to a degree that would endanger the survival of the populations.”

Is it possible for the virus to spread to other species?

“One of the most relevant characteristics of influenza viruses is their ability to evolve, giving them the potential to infect a variety of animal species. It is impossible to predict how the situation will continue, whether the epidemic among sea lions will last for a long time, or whether the virus will Could it spread to other species, even humans.

However, he emphasized that “transmission from one species to another is usually infrequent, and when this occurs, the virus is not always able to spread on a large scale, as this requires adaptation.”

Given that the closer a new infecting species is genetically, the “easier” this adaptation will be, is the risk to humans greater given recent cases in mammals?

“It is possible that avian influenza viruses can be transmitted to humans, but the probability is low. The fact that viral infections are found in mammals in nature may mean that this possibility increases. Approaching and handling animals killed by influenza increases More possibilities,” the veterinarian warned.

However, he assured that while there have been reports of infection in mammals (marine, wild and domestic cats, foxes, ferrets and coatis) around the world, “no sustained infection in humans has been recorded to date”. It’s just that “one” has a relatively small number of global cases and no human-to-human transmission of infection.

Can infections in sea lions be transmitted to marine species consumed by humans?

“As far as fish, molluscs, crustaceans and other aquatic products are concerned, no significant avian influenza infections have been detected so far,” Rodriguez said.

Will the outbreak affect summer in affected areas?

“The infections in Peru and Chile lasted about a month and a half to two months, and we expect the infection rate here to be faster,” the biologist said. Given the region’s history, authorities in affected areas hope that Argentina’s outbreak will At the end of the summer, although the epidemic is currently “in full swing”, its duration depends on the dynamics of wildlife.

What advice is there for people in affected areas?

Given that the goal is to “avoid cross-contamination,” experts unanimously advise people not to travel to areas where inanimate or symptomatic sea lions are present, especially not to bring pets to avoid eventual exposure to sea lions. Virus.

Clara Olmos reports for Télam news agency

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