Due to the general unsanitary conditions, the disease was difficult to contain.
There is a high rate of mortality among the natives, due to unsanitary habits and diet, and not to the climate.
The climate is healthy and agreeable, though the death-rate among the common people is abnormally high on account of personal habits and unsanitary surroundings.
T. pallidum subspecies endemicum is passed on mostly among children living in poverty in unsanitary environments and with poor hygiene.
In general body lice infestations occur in crowded, unsanitary facilities, such as prisons and military or refugee camps.