Deadly bird flu in elephant seals spreads to other species and California beaches this year

A worrying outbreak of highly pathogenic avian influenza (HPAI H5N1) is spreading across the Baía region of São Francisco, in the state of Califórnia. Inicialmente detected in elephant seals in Parque Estadual of Año Nuevo, the virus has already reached other species of marine mammals, raising alarms among experts and authorities. Access to the park was partially restricted and tours were canceled to contain the spread.

The situation took on a new and serious turn with the confirmation that the virus had spread to nearby public beaches, increasing the risk to wildlife and requiring increased caution from the population. The presence of H5N1 was identified in several animals found sick or stranded, highlighting the rapid and worrying dynamics of the infection.

Wildlife experts are on high alert, monitoring the evolution of the outbreak and the potential implications for the marine and terrestrial ecosystem off the California coast. Speedy sample collection and testing is crucial to mapping the extent of the problem and implementing effective control measures to protect vulnerable animal populations.

The expansion of the H5N1 virus

The director of Instituto of Estudos on Pandemias of UC Davis, Christine Johnson, confirmed that samples from sick animals revealed new alarming cases. Nove additional elephant seals tested positive for the virus, totaling sixteen live infected animals, a number that reflects only those tested, indicating likely underreporting.

In addition to elephant seals, the virus was identified in a sea lion from Califórnia and a southern sea otter, marking an expansion to different species of marine mammals in the region. Embora the main focus is in the Condado of San Mateo, Johnson warned of the detection of additional cases along the coast, both north and south of the Parque Estadual of

Monitoring and risks to public health

Despite the expansion, the risk to the general public is considered very low. Contudo, the probability of contracting the virus increases significantly for people who have had direct contact with infected animals. Therefore, authorities have issued a strong appeal for the population and their pets to keep their distance and avoid any contact with marine mammals and birds that are stranded, sick or dead on the beaches.

The presence of carcasses on public beaches has been reported, reinforcing the urgency of these recommendations. Cidadãos are advised to contact the Administração Nacional Oceânica and Atmosférica (NOAA) stranding hotline at 866-767-6114 to report any sightings. Essa measure is essential so that specialized teams can collect and analyze the animals, minimizing the spread of the virus.

If a person believes they have been exposed to a sick animal at the beach and begins to experience symptoms such as coughing, runny nose, fever or shortness of breath, it is crucial that they immediately seek medical attention and contact their doctor. Monitoring symptoms in humans, although the chance of contamination is low, is an important precaution for public health and to avoid any possible contagion.

Impact on threatened species and virus dynamics

The outbreak has been particularly tragic for already vulnerable species, such as the southern sea otter, which is listed as threatened by Lei of Espécies Ameaçadas of Extinção. The infection of an otter represents a severe blow to conservation efforts, given the ecological importance and delicate status of this population. Christine Johnson highlighted that the virus is “very opportunistic” and has the ability to infect a wide range of animals, which explains its rapid spread.

The HPAI H5N1 virus has also been confirmed in several seabirds, including western gulls, great auks and Brandt’s cormorants, demonstrating its adaptability to different hosts. Recent Pesquisas from Universidade from Califórnia into

The identified virus is known as HPAI H5N1 of genotype A3, first detected in Eurásia in 2022 and which spread in birds along Rota Migratória from Pacífico. Esta strain was responsible for the deaths of 3,500 northern fur seals and one Steller sea lion in a mass mortality event in Rússia in 2023. The current detection on the US coast of Pacífico represents the first time this specific variant of the virus has been found in the region, opening new fronts of research and concern about its genetic history and behavior.

The elephant seal colony of Año Nuevo

Parque Estadual of Año Nuevo is home to one of the most intensively studied elephant seal colonies in the world, under the leadership of Professor University researchers, in collaboration with Patrick Robinson, director of the Año Nuevo reserve, have been keeping a detailed record of the outbreak’s impact on the colony. The data collected reveals a worrying average of two dead and two infected animals per day since the beginning of the crisis.

The total number of deaths in the elephant seal colony has risen to 47 since the outbreak was initially detected, an alarming figure for the conservation of the species. Entre affected individuals, weaned pups were observed, which are particularly vulnerable, as well as large adult males, essential for the reproductive and social structure of the colony. Robinson highlighted that the mortality rate recorded this year was approximately four times higher compared to the previous year, underlining the unprecedented severity of the situation.

The discovery of an infected sea otter caused great sadness and concern among researchers. On an inspection last week, Robinson and his team were shocked to find the animal, as they expected to find five to ten dead sea otters a year in the park, usually due to shark bites. Este specific case, without evidence of predator attacks, immediately raised the suspicion of bird flu, leading to the urgent collection of samples for analysis.

Challenges in animal rescue and recovery

Given the complexity of the outbreak, Centro of Mamíferos Marinhos, responsible for rescuing live animals along 965 kilometers of the Californian coast, temporarily suspended elephant seal rescue operations. The measure, taken “as a precaution”, aims to protect the team and healthy animals from possible contamination. Nos behind the scenes, experts at the center are dedicating efforts to understanding the risks involved and updating safety protocols for future interventions.

All animals arriving at the center for treatment, regardless of species, are being tested for the HPAI H5N1 virus as part of new screening procedures. The good news is that, to date, none of the animals admitted to Centro of Mamíferos Marinhos have tested positive for the virus, suggesting that preventative measures are being effective in a controlled environment. Attention remains constant to prevent pathogen entry.

A point of hope came from the fact that the outbreak coincided with a period when 80% of the adult female elephant seal population had already begun their migration to feeding areas. Essa natural migration, on the one hand, disperses the animals, on the other, it may have reduced the direct impact of the virus on the main colony. Alguns baby elephant seals, like one affectionately nicknamed 007 by researchers, showed symptoms of the disease but fortunately managed to recover, offering a glimpse of resilience in the population.

Thousands of other seals in the park remain healthy, and the confirmed cases in the sea otter and sea lion are considered exceptions within their respective species. Embora the situation is still uncertain, Patrick Robinson expressed hope. “Of course, the outbreak is not over, and we are not very sure what will happen in the future, but I remain hopeful about it,” he said, indicating that surveillance and research efforts will continue intense.

Transmission and surveillance mechanisms

The precise details about how the virus spreads from one host to another are still being elucidated by experts. Travis points out that while the mechanisms are not entirely clear, “sometimes when viruses are very aggressive and kill quickly, they don’t spread as well.” Contudo, the concern extends to other species, such as sea lions, already previously affected by the virus in other regions, and to terrestrial animals such as coyotes, known for feeding on birds and seals on beaches.

UC Santa Cruz graduate student Frankie Gerraty has been monitoring this phenomenon using trail cameras, tracking infected animal carcasses. Sua research is vital to understand transmission dynamics and the role of terrestrial predators in the contamination chain.

Precautionary measures and official alerts

To keep the public informed about the evolving situation and safety recommendations, it is widely advised that people regularly consult the UC Davis website. The university is committed to providing detailed weekly updates on the outbreak, ensuring the public has access to the most recent and accurate information.

Collaboration between research institutions, government agencies and the community is essential to face the challenge posed by this outbreak. Continued surveillance, in-depth research and public awareness are the key tools to protect the rich biodiversity of the California coast and mitigate the risks associated with HPAI H5N1.