Mallorca 1820 plague likely not only bubonic, study finds

A new study published in PNAS suggests that the plague that struck Mallorca in 1820 was not solely bubonic, as long believed. Researchers used daily mortality records from Son Servera and Capdepera to model the outbreak, concluding that pneumonic and septicemic forms likely played a substantial role in transmission. The overall case fatality rate was 78%, with short infectious periods and rapid clinical deterioration, pointing to human-to-human spread rather than rat-flea transmission Source: ABC, Infobae.

The evidence

• The study analyzed daily tallies of cases, deaths, and recoveries, ordered by the Junta Superior de Sanidad and preserved in the Real Academia de Medicina de las Islas Baleares Source: Infobae.
• In Son Servera, the transmission potential reached 1.3 before containment, while in Capdepera it was 1.0, indicating a "very controlled" epidemic Source: Infobae.
• Historical accounts note that some physicians saw no buboes, supporting the hypothesis of non-bubonic forms Source: ABC.

Disagreement and caution

While the researchers argue that pneumonic and septicemic transmission were significant, they acknowledge limitations. Pujadas-Mora cautions that the team "has not touched bone" and relies on mathematical models, urging caution Source: Infobae. Puig adds that they do not believe the rat-human cycle existed, but the evidence is indirect Source: Infobae.

What's next

The findings could reshape understanding of historical epidemics and inform modern responses to similar pathogens. Further research may examine other outbreaks with similar data to validate the models Source: ABC.