Drought that brought famine and flooded cities with poor, hungry people has been linked with typhus epidemics in Mexico dating back to the mid-17th century.
Researchers at the University of Arkansas in Fayetteville and the Universidad Nacional Autonóma de México in Mexico City established the association by comparing historical documents with tree-ring data representing soil moisture levels over the past 500 years.
They analyzed almanacs; diaries; personal accounts; and medical and death records from hospitals, physicians, cemeteries, and municipalities with information about 22 typhus epidemics that struck central Mexico between 1655 and 1918. The documents “leave no doubt that drought and famine were associated with some serious epidemics of typhus,” the researchers wrote (Burns JN et al. Emerg Infect Dis. 2014;20:442-447).
Drought’s Influence on Typhus. JAMA. 2014;311(17):1723. doi:10.1001/jama.2014.3903