I can enlighten you folks on Dryditch Fever. In older times, epidemics of various diseases would often occur in the summertime- often June-September, until frosts started killing the disease germs. These were usually some variation of fever, including malaria and scarlet or yellow fever. For example, yellow fever has symptoms which include fever, chills, sever head and body aches, nausea, vomiting, fatigue and weakness. In late stages, it causes spike fevers, jaundice, and multiple organ failure resulting in death. These are all common to Dryditch Fever. The name, then, would come from its summer occurrence, when dry weather caused the evaporation of water in the ditch. Epidemics were also especially common in times of drought, because there was not enough water to treat sicknesses well. This is a probable additional factor.