In the midst of the global COVID-19 pandemic in 2020, a new and troubling viral threat quietly emerged, largely overlooked. While attention was diverted, the highly pathogenic avian influenza virus, H5N1, underwent significant evolution, resulting in a new variant labeled 2.3.4.4b. This variant’s altered transmission pattern has now extended its reach to marine mammals, sparking concern among scientists and public health experts.
A recent study has brought to light a concerning development: H5N1 has penetrated marine mammal populations along the Atlantic coast of South America.
Researchers analyzing brain samples from deceased animals in an affected sea lion rookery in Argentina made a startling discovery. Every sample, spanning sea lions, fur seals, and terns, tested positive for H5N1, specifically the 2.3.4.4b variant.
This mutation’s unique ability to infect both avian and marine species signifies an alarming adaptability of the virus. Scientists fear the potential for a multi-species outbreak as the virus infiltrates diverse food chains within the region.
Previous observations of similar mutations in sea lions from Peru and Chile, coupled with a singular human case in Chile, underscore the gravity of this development.
Termed a “New Monster” by senior author Marcela Uhart, the variant initiated mass die-offs among seabirds in Europe before spreading globally, eventually reaching South America in 2022.
The true extent of the virus’s impact became painfully evident in August 2023 when it devastated sea lion populations at the southern tip of the continent, subsequently spreading northward.
Mortality rates among marine mammals, particularly elephant seal pups, soared to alarming levels, reaching 96% in surveyed areas by November 2023.
Since its introduction to South America, H5N1 has claimed the lives of over six lakh wild birds and 50,000 marine mammals.
While human transmission remains relatively low-risk, ongoing replication within mammalian hosts presents a concerning escalation of the threat.
As the virus progresses southward, scientists express grave concerns regarding its potential impact on Antarctica’s unique wildlife, notably penguins.
Surveillance efforts are underway in Antarctica to monitor the virus’s spread and its potential consequences on vulnerable species, emphasizing the urgent need for coordinated global action to mitigate the threat posed by this evolving viral variant.