Though Scarlet fever has been around for millennia, there seems have been a more deadly presentation of the disease in the 19th century. Epidemics popped up around Europe with dramatically increased fatality rates with children being the primary victims.
Scarlet fever, which is caused by a streptococcus bacteria, usually presents with a high fever, sore throat, characteristic rash and a really weird-looking tongue. For those who survived their bout of scarlet fever like Beth in Little Women, Thomas Edison, and possibly Helen Keller, complications could be severe and long-lasting. They include damage to complete loss of hearing, Rheumatic fever and Glomerulonephritis (Bright disease). Rheumatic fever can lead to damage to the heart which ostensibly is what permanently debilitated poor Beth.
There’s no vaccine but it is now treatable with antibiotics. We don’t typically think of diseases like this as troublesome now on account of the availability of treatment, though strangely, the UK seems to be experiencing a spike in cases.
other source: CDC