Víctor Martín and Joan Navarro talk us through how gulls tagged with GPS and tested for pathogens can be used as tools to detect early pathogen circulation and pollution sources in the environment. This is explored further in their new research article.
Antimicrobial resistance is a global health challenge, exacerbated by the overuse of antibiotics in both human and veterinary medicine. The emergence and spread of antibiotic-resistant bacteria not only threaten human health but can also impact agriculture, livestock, and food production. Understanding the dynamics of ARB in the environment is crucial, especially in areas where anthropogenic activities create favourable conditions to their proliferation. Can we early detect agents that impact agriculture and human health? YES!
Our study
This study investigates the role of yellow-legged gulls (Larus michahellis) as both sentinels and vectors of resistance and pathogens in an intensive agricultural landscape in northeastern Spain. The researchers focused on Ivars i Vila-sana shallow lake, a Natura 2000 site surrounded by farmland, livestock farms, and waste management facilities. By employing advanced bio-logging technology such as GPS tracking devices, the study aimed to track gull movements and assess the potential pathways for pathogen dispersal.
During the breeding seasons of 2022, 2023, and 2024, 26 adult gulls were captured, and their faecal samples were collected to analyse for the presence of pathogenic bacteria that can be harmful for humans, such as Escherichia coli, and develop resistance to antibiotics commonly used to treat human infections.
Our results
Overall, the study reveals that while yellow-legged gulls can be viewed as “evils” due to their potential role in pathogen transmission, they also serve as valuable “allies” in early monitoring pathogen dynamics. Their movements and infection status can provide critical insights into the circulation of pathogens in the environment, thereby aiding in the development of management strategies and surveillance.
Gulls as ‘evils’: In terms of pathogen risk, the analysis indicated that gulls could spread faecal matter containing bacteria up to 23 km away from their breeding colony, with a significant concentration of bacteria spread occurring within a 1 km from the colony.
Gulls as ‘allies’: The study developed a connectivity network – how easily pathogens and animals can move through the landscape – based on the GPS tracking data and identified 54 sites, including dumps, irrigation ponds, and livestock farms that can be sources and hotspots for pathogen pollution. The strong connectivity between these places underscores the role of gulls in linking several habitats, facilitating the potential transmission of pathogens and resistances within the agricultural landscape. This finding emphasizes the role of gulls not only as carriers of pathogens but also as potential early warning indicators for environmental monitoring.
Implications
The implications of this research extend beyond ecological understanding; they highlight the urgent need for integrated monitoring programs that address pathogen dissemination in human-altered ecosystems. Such programs should focus on identifying pollution sources, implementing effective waste management practices, and promoting sustainable agricultural practices to mitigate the impact of pathogen and resistance to antibiotics on public health and food safety.
In conclusion, this study demonstrates the importance of utilizing wildlife, particularly gulls, as sentinels for pathogen monitoring in agricultural landscapes. By combining GPS tracking, networks, and pathogen detection, researchers can create spatial risk maps that inform management practices aimed at reducing the spread of antibiotic resistance. This approach aligns with the One Health framework, which recognizes the interconnectedness of human, animal, and environmental health, and is essential for tackling the multifaceted challenges posed by antimicrobial resistance.
Read the full article “Evil and allies: Opportunistic gulls as both spreaders and sentinels of antibiotic-resistant bacteria in human-transformed landscapes” in Journal of Applied Ecology.
