What was the main diseases in Merthyr Tydfil in the 1840s?

The supply of fresh water was extremely poor in Merthyr Tydfil. Although the River Taff ran through the town, the ironmasters diverted the water to supply their steam-engines and cooling plant. The Taff became an open sewer and the contaminated water supply resulted in several outbreaks of cholera and typhoid. By 1848 Merthyr Tydfil's mortality rate was the highest in Wales and the third highest in Great Britain. Sadly, the young children were particularly vulnerable to disease caused by unhealthy living conditions. In the first half of the 19th century, over 60% of all burials in Merthyr Tydfil were of children under the age of five. Despite this high mortality rate, the population reached 40,000 in 1845.