Around sixty percent of human diseases originate in animals, whether from domestic or wild species. In fact, three of every five new diseases detected globally each year come from animal sources, a point stressed by Santiago Vega, a professor in Animal Health at the Faculty of Veterinary Medicine of the CEU Cardenal Herrera University. This assertion was shared during the MSD Dialogues Journalist Seminar Exploring for Life: One World, One Health, organized by MSD and the One Health Platform in Spain. It was noted there that about 75 percent of emerging infectious diseases in humans show resistance to antibiotics, underscoring the animal origin of many health threats.
During the gathering, the researchers highlighted the essential role of the One Health approach, which links human, animal, and environmental health to find viable solutions for public health problems. An illustration of this interconnection is how viruses, which account for roughly 44 percent of infectious disease agents, gain strength as temperatures rise. Increasingly, disease-transmitting vectors, such as mosquitoes, stay active for longer periods in many regions, expanding contact with people from about four months to twelve months of the year. This shift creates opportunities for cross-species transmission, as seen with Covid-19.
ECODES Climate Action Director Pablo Barrenechea commented on the urgency of accelerating climate actions within health care settings. He warned that the healthcare sector, if treated as a country, would rank fifth in global emissions. Vega echoed the sentiment, pointing out that aerosols contribute around 450,000 tons of CO2 annually, while criticizing the insufficient use of substitute therapies and patient reluctance to embrace them.
Raquel Sánchez, advisor to the Spanish Patient Forum, emphasized that the term One Health remains largely unfamiliar to many citizens. She argued that health messaging should speak in everyday language so that the average person on the street can grasp the concept.
Vaccination and combating antimicrobial resistance
Antimicrobial resistance (AMR) is widely recognized as a major global health threat and a central pillar of One Health strategies. A 2022 study published in The Lancet estimated that 1.27 million people died from infections related to resistant pathogens in 2019, and without urgent action, future costs to health systems could rise dramatically by 2050. Vaccination is framed as a key preventive measure because it reduces the need for antibiotics. Jaime Pérez, president of the Spanish Vaccinology Association, described vaccines as a foundational component of the One Health approach.
Vaccines have three primary roles: they prevent infections, they help reduce antibiotic use as seen with influenza vaccines, and certain vaccines like pneumococcal conjugate vaccines can curb resistance. In the United States, vaccination programs have contributed to substantial reductions in antibiotic-resistant pneumococcal strains. Yet there remains a disconnect between vaccine initiatives and the broader antimicrobial resistance crisis.
Rafael Cantón, the European Committee on Antimicrobial Susceptibility Testing coordinator, highlighted the economic burden of antibiotic resistance. Patients with multi-drug resistant bacteria tend to stay longer in hospitals, driving up costs, and the likelihood of mortality from resistant infections is higher than with susceptible strains. He noted that in Spain alone about 30,000 deaths are attributed to multidrug-resistant bacteria.
Bruno González-Zorn, a professor at the Complutense University of Madrid and head of the Antimicrobial Resistance Unit, stressed that One Health is essential in combating the silent epidemic of antibiotic resistance. He lamented the public’s low awareness—nearly all Spaniards have antibiotics at home, yet many do not recognize the seriousness of this issue. He urged more resources to promote research and education.
“We are transitioning into a post-antibiotic era that threatens modern medicine,” he warned. The field has built bridges for years, but greater collaboration is needed, including involvement from nurses and other professionals, because curbing antibiotic use is beneficial for patient care and can shorten waiting times.