In the last century most people lived along the river. There was an outbreak somewhere every year. Icterus melas is a form of jaundice in which the skin assumes a dirty dark brown color. Now, jaundice is a symptom of several diseases, so we are really just speculating about what might have been the Jones' disease, but simple hepatitis seems a likely candidate to me. I didn't check the freeze.
Malaria is another matter.
Stress brings out the serious episode, and cold could be the stress. The black water is from hemoglobin iron pigment in the urine due to the massive destruction of red cells in the blood. This only occurs in a few diseases. Jaundice neonatorum is the jaundice caused by Rh incompatibility at birth. Medicine has moved so dramatically in the last 40 years that the names and descriptions of classic diseases are given short shrift.