Biology subjects

Gonzalez-Aravena, M.

Publications and source records attributed to Gonzalez-Aravena, M..

3 recordsLinked to original sources

bioRxiv2024

Confirmation of Highly Pathogenic Avian Influenza (HPAI) H5N1 Associated with an Unexpected Mortality Event in South Polar Skuas (Stercorarius maccormicki) during 2023-2024 Surveillance Activities in Antarctica

From December 2023 to March 2024, a surveillance program to detect HPAI H5N1 was performed on Antarctica Territory, at Fildes Peninsula (King George Island, Maritime Antarctic), and James Ross Island. At Fildes Peninsula, samples from marine birds and mammals from four sampling locations were collected, based on their accessibility and the presence of animal colonies: Ardley Island, which presents a high concentration of Gentoo penguins (Pygoscelis papua); Ardley Cove were small groups of likely non-reproductive Chinstrap penguins (Pygoscelis antarcticus); Southern elephant (Mirounga leonina) and Weddell (Leptonycotes wedellii) seals haul-out sites; and, a nesting site of Southern giant petrels (Macronectes giganteus). On February 28th the surveillance group received a request for sample collection, due to the observation of deceased seabirds at James Ross Island in the area neighboring the Lachman lakes (63.7989 S, 57.8105 W). Six samples from five dead South polar skuas (Stercorarius maccormicki) were collected on March 3rd, 2024. All samples were collected adhering to the Antarctic Treaty guidelines. After collecting a total of 943 samples from Fildes Peninsula all results tested negative, and no individuals had clinical signs or behaviors compatible with HPAI. However, all samples from South polar skuas from James Ross Island were confirmed positive for HPAI H5N1 clade 2.3.4.4 by specific real-time RT-PCR reactions. These results confirmed the first mortality event registered in Antarctica (south of 60{degrees}S) caused by HPAI H5N1, in this case on South polar skuas. Further studies are needed to genetically characterize the virus and to better understand the role of skuas in the dynamics of viral dissemination in Antarctica.

microbiology↗

bioRxiv2020

Four novel Picornaviruses viruses detected in Magellanic Penguins (Spheniscus magellanicus) in Chile

Members of the Picornaviridae comprise a significant burden on the poultry industry, causing diseases such as gastroenteritis and hepatitis. However, with the advent of metagenomics, a number of picornaviruses have now been revealed in apparently healthy wild birds. In this study, we identified four novel viruses belonging to the family Picornaviridae in healthy Magellanic Penguins (Spheniscus magellanicus), a near threatened species found along the coastlines of temperate South America. We collected 107 faecal samples from 72 individual penguins. Twelve samples were initially sequenced by high throughout sequencing with metagenomics approach. All samples were subsequently screened by PCR for these new viruses, and approximately 20% of the penguins were infected with at least one of these viruses, and seven individuals were co-infected with two or more. The viruses were distantly related to members of the genera Hepatoviruses, Tremoviruses and unassigned viruses from Antarctic Penguins and Red-Crowned Cranes. Further, they had more than 60% amino acid divergence from other picornaviruses, and therefore likely constitute novel genera. That these four novel viruses were abundant among the sampled penguins, suggests Magellanic Penguins may be a reservoir for several picornaviruses belonging to different genera. Our results demonstrate the vast undersampling of wild birds for viruses, and we expect the discovery of numerous avian viruses that are related to Hepatoviruses and Tremoviruses in the future. ImportanceRecent work has demonstrated that Antarctic penguins of the genus Pygoscelis are hosts for an array of viral species. However, beyond these Antarctic penguin species, very little is known about the viral diversity or ecology in this highly charismatic avian order. Through metagenomics we identified four novel viruses belonging to the Picornaviridae family in faecal samples from Magellanic Penguins. These highly divergent viruses, each possibly representing novel genera, are related to members of the Hepatovirus, Tremovirus genera, and unassigned picornaviruses described from Antarctic Penguin and Red-crowned Cranes. By PCR these novel viruses were shown to be common in Magellanic Penguins, indicating that penguins may play a key role in their epidemiology and evolution. Overall, we encourage further sampling to reveal virus diversity, ecology, and evolution in these unique avian taxa.

ecology↗

bioRxiv2018

Warm Temperatures, Cool Sponges: The Effect of Increased Temperatures on the Antarctic Sponge Isodictya sp.

Although the cellular and molecular responses to exposure to relatively high temperatures (acute thermal stress or heat shock) have been studied previously, only sparse empirical evidence of how it affects cold-water species is available. As climate change becomes more pronounced in areas such as the Western Antarctic Peninsula, it has become crucial to understand the capacity of these species to respond to thermal stress. Here we use the Antarctic sponge Isodictya sp. to investigate how sessile organisms (particularly Porifera) can adjust to acute short-term heat stress, by exposing this species to 3 and 5 {degrees}C for 4 hours, corresponding to predicted temperatures under high-end 2080 IPCC-SRES scenarios. Assembling a de novo reference transcriptome (90,188 contigs, >93.7% metazoan BUSCO genes) we have begun to discern the molecular componentry employed by Isodictya to adjust to environmental insult. Our initial analyses suggest that TGF-{beta}, ubiquitin and hedgehog cascades are involved, alongside other genes. However, the degree and type of response changed little from 3 to 5 {degrees}C, suggesting that even moderate rises in temperature could cause stress at the limits of this organisms capacity. Given the importance of sponges to Antarctic ecosystems, our findings are vital for discerning the consequences of increases in Antarctic ocean temperature on these and other species.

genomics↗