Biology subjects

Soto, F.

Publications and source records attributed to Soto, F..

4 recordsLinked to original sources

bioRxiv2025

Mass mortality at penguin mega-colonies due to avian cholera confounds H5N1 HPAIV surveillance in Antarctica

In the austral summer 2023/2024, H5N1 high pathogenicity avian influenza virus (HPAIV) was reported for the first time in Antarctica. Concerns of HPAIV causing high mortality of seabirds and mammals prompted immediate efforts to track its spread and impact on endemic wildlife. In March 2024, we visited the Danger Islands archipelago, that hosts two mega-colonies of Adelie penguins, and observed an unusual mortality estimated in thousands of Adelie penguins and other species. Swabs and tissues were collected for molecular detection of infectious agents from 49 carcasses, and additional tissues for histology from a selection of 9 carcasses. We unexpectedly detected Pasteurella multocida DNA in 46 of 49 individuals, and diagnosed avian cholera, and not HPAI, as the cause of death of most of these animals. By metagenomics, we retrieved the genomic sequences of the Pasteurella multocida strain which caused the epizootic, and the phylogenetic analysis showed a close relation with strains previously reported in the Southern Ocean area. This study confirms avian cholera as a relevant cause of mortality in the Antarctic region, and overall highlights the importance of considering avian cholera in the differential diagnoses during mortality events in Antarctica, even with the concurrent circulation of HPAIV.

microbiology↗

bioRxiv2025

New minimally invasive techniques for sample collection in Antarctic seals

Remote or minimally invasive sampling techniques are essential in wildlife research, particularly for Antarctic seals. These methods reduce handling time, minimize animal stress, and improve biosecurity by preventing pathogen transmission, especially relevant during the current outbreak of highly pathogenic avian influenza affecting Antarctic megafauna. Research on ice-dependent seals is logistically challenging and often requires chemical immobilization, which is costly, time-consuming, and poses risks to both animals and researchers. To overcome these limitations, we developed a simple, low-cost remote sampling device to collect nasal swabs from seals without physical contact. The device consists of a telescopic pole with a swab attached to its end. Researchers approached seals resting on ice floes or land using inflatable boats, without disembarking, thus minimizing field exposure. Over ten days, we collected ten nasal swabs from leopard seals (Hydrurga leptonyx, n=4), Weddell seals (Leptonychotes weddellii, n=4), and southern elephant seals (Mirounga leonina, n=2). All samples tested negative for avian influenza virus (INF-A) using RT-qPCR. This methodology is adaptable to various species and conditions, requires minimal equipment, and can be implemented by small teams. It provides a safe, efficient tool for disease surveillance in remote polar environments, advancing marine mammal research while minimizing disturbance to wildlife.

zoology↗

bioRxiv2025

The expanding avian influenza panzootic: skua die-off in Antarctica

High pathogenicity avian influenza virus of subtype H5 (H5 HPAIV), clade 2.3.4.4b, invaded Antarctica in 2023. Here we show that H5 HPAIV caused high mortality in a breeding colony of skuas at one of ten sites we visited in March 2024. By combined virological and pathological analyses, we found that H5 HPAIV caused multi-organ necrosis and rapid death in skuas. Taken together with recent data, skuas in Antarctica are at risk of continued mortality from H5 HPAIV infection, threatening their already small populations. Conversely, because of their wide distribution and ecological relevance, skuas may play a substantial role in spread of the virus across Antarctica. Transdisciplinary surveillance is needed in coming years to monitor the impact of this poultry-origin disease on Antarcticas unique wildlife.

microbiology↗

bioRxiv2021

Microneedle-mediated intratumoral delivery of anti-CTLA-4 promotes cDC1-dependent eradication of oral squamous cell carcinoma with limited irAEs

Head and neck squamous cell carcinoma (HNSCC) ranks 6th in cancer incidence worldwide and has a five-year survival rate of only 63%. Immunotherapies - principally immune checkpoint inhibitors (ICI), such as anti-PD-1 and anti-CTLA-4 antibodies that restore endogenous antitumor T-cell immunity - offer the greatest promise for HNSCC treatment. Anti-PD-1 has been recently approved for first line treatment of recurrent and metastatic HNSCC; however less than 20% of patients show clinical benefit and durable responses. In addition, the clinical application of ICI has been limited by immune-related adverse events (irAEs) consequent to compromised peripheral immune tolerance. Although irAEs are often reversible, they can become severe, prompting premature therapy termination or becoming life-threatening. To address the irAEs inherent to systemic ICI therapy, we developed a novel, local delivery strategy based upon an array of soluble microneedles (MN). Using our recently reported syngeneic, tobacco-signature murine HNSCC model, we found that both systemic and local-MN anti-CTLA-4 therapy lead to >90% tumor response, which is dependent on CD8 T cells and conventional dendritic cell type 1 (cDC1). However, local-MN delivery limited the distribution of anti-CTLA-4 antibody from areas distal to draining lymphatic basins. Employing Foxp3-GFPDTR transgenic mice to interrogate irAEs in vivo, we found that local-MN delivery of anti-CTLA-4 protects animals from irAEs observed with systemic therapy. Taken together, our findings support the exploration of MN-intratumoral ICI delivery as a viable strategy for HNSCC treatment with reduced irAEs, and the opportunity to target cDC1s as part of multimodal treatment options to boost ICI therapy.

cancer biology↗