The underlying reason for this was the tuberculosis epidemic, which traumatized much of Europe, though was less pronounced in the US.
Generally called Consumption, phthisis, scrofula, Pott’s disease, and the White Plague, tuberculosis was peculiar because it behaved so differently from most other diseases.
Its closest commonly known relative is leprosy. Unlike other bacteria, that reproduce on average about each half hour, they reproduce slowly, only once or twice a day. Even today, this means that treatment for those diseases can last from six months (for just infection that is not active) to years.
In any event, tuberculosis terrified people for several reasons. First because it could kill quickly, with very few obvious symptoms, or it could drag on for years or decades. A person could be infected yet not show symptoms for years, either.
Second, it could attack any organ in body, with very different results. When it hit the brain, a person could become wildly creative (which resulted in some calling it “the artists disease”), or they could become hyper-sexual, or they could become demented or insane.
Often people became very pale and gaunt as their body wasted away, which was actually adopted as a fashion, “the Victorian look”. Many had their spinal cords damaged by the disease, forcing them to use wheelchairs.
What we think of today as morbid and Gothic fashion sense was because of the fascination with death and dying and fatalism found at that time. The horror genre became very popular, with themes such as premature burial. Many novels would have characters suddenly vanish from the plot because they just up and died.
At the end of the 19th Century and in the first part of the 20th Century, effective treatments were finally developed. Then with the development of antibiotics the disease was almost eradicated in the US. The last tuberculosis sanitariums were finally closed in the 1960s, having run out of patients. They were distinguishable by their smokestacks, since they always burned their mattresses and linens.
Unfortunately, tuberculosis is coming back. At first, the disease developed drug resistance to some of the more common antibiotics. So it is identified as DR-TB.
The real problem began with multiple drug resistant, or MDR-TB. Because people with MDR-TB were given ordinary antibiotics to treat it, it would progress further before effective treatment, and in some cases it was too late, so the mortality rate increased.
Even worse is extensively drug resistant XDR-TB, which if you catch it, you must be quarantined, and you have at least a 50% chance of death. In the United States, 63 cases of XDR TB have been reported between 1993 and 2011.
There has now been two reports of totally drug resistant TDR-TB outbreaks, but they were so fast and lethal that everyone infected has died, stopping the disease from spreading.
Importantly, each of these varieties of TB coexist, so the vast majority of infections are not drug resistant.
TB is second only to HIV/AIDS as the greatest killer worldwide due to a single infectious agent. In 2011, 8.7 million people fell ill with TB and 1.4 million died from TB. Over 95% of TB deaths occur in low- and middle-income countries, and it is among the top three causes of death for women aged 15 to 44.
TB is a leading killer of people living with HIV causing one quarter of all deaths. Multi-drug resistant TB (MDR-TB) is present in virtually all countries.
Novels written in the 18th and 19th centuries are pervaded by the fear or the experience of tuberculosis. Historical novels written in the anti-biotics era, no matter how well-researched otherwise, rarely mention it.