Bird flu pushes south, relentless to sea lions in Argentine Patagonia

In early August, the carcasses of about two dozen sea lions were found off the coast of Tierra del Fuego, Argentina’s southernmost tip. Analysis confirmed that seven of the marine mammals were infected with the highly pathogenic H5 avian influenza virus. Authorities have since reported outbreaks in different provinces of the country. Since cases were detected in wild birds in Colombia in late 2022, the virus has spread rapidly to the southern part of the continent, and scientists are studying the risk of the virus reaching Antarctica.

The Argentine sea lions reported the latest positive case in a statement on Monday, in which authorities warned that “alerts remain in place”. The samples were taken from dead mammals found in the municipalities of Cleromeco and San Blas, in the province of Buenos Aires, and in the municipality of San Antonio Este, in the province of Rionegro. Previously, scientists had detected cases on various beaches and protected areas in the provinces of Tierra del Fuego, Río Negro, Chubut and Buenos Aires.

“This outbreak of sea lions started in Peru, then spread to Chile, and now it has spread to Argentina,” said Pablo Plaza, Ph.D. warned.The virus first affected the species Sophora flavescensCommonly known as the single-haired sea lion, it is a brown carnivore that can weigh up to 350 kg. “There are two hypotheses here,” he explained: “either they got infected because they came into contact with infected birds (which is the most common), or the virus somehow adapted and spread from sea lions to Sea lion.” Sea lion. “

The avian influenza virus H5N1 currently circulating around the world originated from a pathogen first detected in geese raised in China in 1996. It is a highly contagious subtype that is causing unprecedented spread of the disease in birds. Scientists believe the virus traveled from Asia to Africa and Europe – where more than 50 million poultry are slaughtered a year – and from there to North America via Iceland. In October 2022, the virus was first detected in wild birds in Colombia, from where it spread to South America.

He jumped from bird to mammal. “When it gets to the fauna, that’s a problem because you can’t easily deal with wild animals,” Plaza warned. In Peru and Chile, where the situation has been particularly severe, more than 15,000 infected sea lions have died, according to the researchers — and more than 20,000 by other estimates. “In the coming weeks, we will have more evidence of the true extent of the outbreak in Argentina,” Plaza said.

In June, cases of H5 avian influenza were detected in sea lions in the southernmost tip of Puerto Williams, Chile. An August 23 report by OFFLU, a global network of animal influenza experts, said there was “a significant risk” that transmission “will continue south and reach Antarctica and its offshore islands,” where the virus remains . does not exist. “This risk is likely to increase in the coming months due to spring migration of wild birds,” the survey wrote, warning that the virus’ “negative impact” on the ecosystem “could be substantial.”

“The whole world is on alert for this virus,” said Plaza, who was part of a team of Peruvian and Argentinian scientists who warned in January that the arrival of the bird flu virus on the African continent threatened South America’s protected birds. Following the mass die-off of sea lions earlier this year, the team published the first draft study showing that the pathogen may have mutated to allow transmission between mammals. “This is another step forward in terms of risk to humans,” Plaza said, clarifying that the risk of the virus spreading from person to person is currently “very low.”

In January, the Pan American Health Organization (PAHO) issued an alert that it had detected an “unusual” outbreak of bird flu in the Americas and confirmed the first human infection in the region. Analysis of the first case, which occurred in Ecuador, has revealed a worrying lack of control and surveillance. According to the organization, as of the first week of July 2023, 16 countries had registered animal cases, and two countries, Ecuador and Chile, had confirmed human infections. Since 2003, the virus has infected humans nearly 900 times, killing more than half.

To mitigate transmission, Argentine authorities recommend not handling dead animals or animals with suspicious symptoms, and avoiding direct contact with these animals or contact with pets. In addition, they are asking for notifications of any circumstances where animals are suspected to be potentially infected with the virus. Authorities buried the carcasses of animals infected or suspected to have died from the virus to prevent contamination or transmission to other animals or people.

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