As a public health researcher, this sounded like my sort of query! During 1873 there was a peak in smallpox and scarlet fever in the Midlands and other places around Europe. http://dictionary.reference.com/browse/epidemiology
1870 to 1873
The term "epidemiology" came into use around this time and there were huge public works funded, aimed at preventing the spread of disease, eg. the great London Sewer in response to outbreaks of cholera around drinking water sources.
There are some nice little potted history pages by Tim Lambert on Axholme cities and nearby places:http://www.localhistories.org/liverpool.htmlhttp://www.picturesofengland.com/history/york-history.html
There was also a tremendous amount of tuberculosis/TB among the people living on the low-lying reclaimed lands of Axholme and it used to kill approximately 1 in 7 people! Some of my ancestors from the area were still dying from it in New Zealand, after emigrating, including my father's only sister who died at 30 years of age. TB also made people very vulnerable to dying from influenza & the common cold. The list goes on! So a bad winter meant reduced resistance to disease, lesser availability of fresh food; water & sewerage pipes frozen and people crowded together indoors, all creating ideal conditions for epidemics.
People in public health epidemiology are still analysing data from the great 19th century epidemics in a bid to understand how we might prevent similar ones of different diseases nowadays.