Deadly virus could trigger next pandemic as doctors warn Spain faces new infection threats

A potentially deadly virus known as Lassa fever could pose a new infection threat to Spain, according to infectious disease specialists. This warning comes as concerns grow over changing environmental conditions that may allow pathogens and their carriers to spread more rapidly. At a meeting organized by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) and the National Association of Health Journalists, experts discussed how warming temperatures, altered rainfall patterns, deforestation, and increased global movement are creating new opportunities for infections to emerge and spread beyond their traditional regions.

Lassa fever, primarily found in parts of West Africa, is carried by rodents whose urine and droppings can contaminate food and household items. People can contract the virus through contact with contaminated materials or infected rodents, and it can also spread within healthcare settings if proper infection-control measures are not in place.

While most Lassa fever cases are mild or asymptomatic, the disease can lead to severe complications affecting multiple organs and increasing the risk of bleeding, respiratory issues, and shock. There is currently no licensed vaccine, and early detection along with supportive medical care are crucial for improving survival rates.

The experts emphasized that Lassa fever should be considered a high-priority threat due to its potential to cause a major international health crisis. They cited the recent spread of monkeypox (mpox) as a cautionary example, highlighting how infections can cross borders quickly, especially with the ease of international travel. Animals such as mosquitoes, sandflies, and rodents serve as vectors for various diseases, including dengue, Zika, chikungunya, West Nile virus, and Toscana virus, all of which have established populations in the Iberian Peninsula and can thrive under changing climate conditions.

Spain has been monitoring West Nile virus, which has resulted in 149 locally acquired human cases reported in 2026. However, the country is now also on alert for Lassa fever and other emerging infections. Veterinary virologist Antonio Rivero stressed the importance of a holistic “One Health” approach that integrates human, animal, and environmental health to better understand and manage the emergence of infectious diseases.

He called for greater preparedness and scientific readiness among health services to effectively identify and manage unfamiliar infections, urging clear and responsible public communication to keep people informed without inducing unnecessary fear or panic.