Around twenty sea lions were found dead on the coast of Tierra del Fuego, in the southernmost tip of Argentina, in early August. The analysis confirmed that seven of these marine mammals were infected with the highly pathogenic H5 avian influenza virus. Since then, authorities have reported outbreaks in various provinces across the country. The virus has spread rapidly across the south of the continent since a case was discovered in wild birds in Colombia in late 2022, and scientists are currently studying the risks of it reaching Antarctica.
The latest positive cases in sea lions in Argentina were reported this Monday in a statement in which the authorities warned that “the alert remains”. The samples came from mammals found dead in the cities of Claromecó and San Blas in Buenos Aires province and in the city of San Antonio Este in Río Negro province. Scientists had previously identified cases on various beaches and protected areas in the provinces of Tierra del Fuego, Río Negro, Chubut and Buenos Aires.
“This sea lion outbreak started in Peru, then moved to Chile and is now reaching Argentina,” warns Pablo Plaza, doctor of biology and researcher at Conicet, the main organization promoting science in Argentina. The species most affected by the virus is Otaria flavescens, also known colloquially as the one-haired sea lion, a brown carnivore that can weigh up to 350 kilos. “There are two hypotheses here,” he explains: “Either they were infected because they had contact with infected birds, which is the most common, or the virus has adapted in some way and is transmitted from sea lions to others.” Sea lion .”
The avian flu virus H5N1, which is currently spreading worldwide, originates from a pathogen that was first detected in 1996 in geese bred in China. It is a highly contagious subtype that has led to an unprecedented spread of the disease in birds. From Asia it made its way to Africa and Europe – where more than 50 million poultry were slaughtered in one year – and from there it made its way to North America via Iceland, scientists believe. In October 2022 it was first detected in wild birds in Colombia and from there spread throughout South America.
He jumped from birds to mammals. “If it reaches the fauna, it is a problem because wild animals are not easy to deal with,” warns Plaza. In Peru and Chile, where the situation was particularly serious, more than 15,000 infected sea lions died, according to the researcher – other estimates put the number at more than 20,000. “In the coming weeks we will have more evidence about the true extent of this outbreak in Argentina,” Plaza says.
The southernmost case of H5 avian influenza in a sea lion was discovered in Puerto Williams, Chile, in June. A report released Aug. 23 by OFFLU, the global network of animal influenza experts, said that “there is a significant risk” that the spread will “continue south and reach Antarctica and its coastal islands,” where the virus is located still not stopping at present. “This risk could increase in the coming months due to the spring migration of wild birds,” says the study, which warns that the “negative impact” of the virus on this ecosystem “could be immense.”
“Everyone is on alert because of this virus,” Plaza said. A team of Peruvian and Argentine scientists including Plaza warned in January that the arrival of the bird flu virus on the continent threatened protected birds in South America. In light of the mass die-off of sea lions earlier this year, the same team published the first draft of research suggesting the possibility that the pathogen has mutated and can be transmitted from mammal to mammal. “It is a further step in putting people at risk,” says Plaza, making it clear that the risk of infection between people is “low” for the time being.
In January, the Pan American Health Organization (PAHO) issued an alert about the “unusual” discovery of bird flu outbreaks in the Americas and the first confirmation of a case of human infection in the region. Analysis of this first case, which occurred in Ecuador, revealed the worrying lack of controls and monitoring. As of the first week of July 2023, according to the organization, 16 countries had registered cases in animals and two confirmed infections in humans – Ecuador and Chile. Since 2003, the virus has jumped to humans nearly 900 times, killing more than half of them.
To contain the spread, Argentine authorities have recommended not handling dead animals or animals with suspicious symptoms and avoiding direct contact or pet contact with these animals. In addition, they have asked that any suspicion that an animal may be infected with the virus be reported. Dead animals that were infected or suspected of having died from the virus are buried by authorities to avoid contamination or infection from other animals or people.