Endemic diseases are unknown and epidemics are rare.
The origin of these two epidemics was obscure.
The dissemination of plant parasites is favored by many circumstances not always obvious, whence an air of mystery regarding epidemics was easily created in earlier times.
Yellow fever epidemics are common on the Campeche coast, and sometimes appear at Progreso and Merida.
Epidemics rarely spread over any considerable tract of country, but are nearly always confined within local limits.