During the 18th century the town had a reputation as being unhealthy and prone to frequent outbreaks of serious epidemics.
In 1764 the diarist William Thomas blamed the death of 40 residents in less than 14 days on the vapours emitting from the nearby coal mine, stating "Was buried in Lantrissent a young man from ye fever and about 200 have been buried in Llantrissent this 13 months last past as young Dr Bates reporteth…all yt die ar ym this side of yet Town and many of ym belonging to ye mine pits, except the mine pits were stoped the most of yet town and parts about will die. But in vain when God’s sweitch is beating.”
Asiatic cholera, spread by bacteria in contaminated water or food, swept across Europe in 1831 and 1832. The outbreak of 1848/49 was far more serious and over 3,000 people died in the county of Glamorgan.
In Cardiff there was a total of at least 350 deaths.6 Merthyr Tydfil was the worst affected town, suffering a total of 1,389 deaths from cholera, perhaps more The cholera epidemic gave a sense of urgency to the need to carry out sanitary improvements across Wales. The Public Health Act of 1848 permitted the establishment of local Boards of Health and the new position of Medical Officers of Health.
It was an enabling, not a compulsory act and implementation depended on the initiatives of local communities. The work of the local Boards of Health reflected the tensions in local politics and their actions and effectiveness varied.8 There was little central government direction and powers were limited.
Some 17 towns in south Wales petitioned to form Boards of Health around the time of the cholera epidemic, among them Cardiff and Swansea in 1848, Merthyr Tydfil in 1850, Aberdare in 1854 and Maesteg in 1858. All brought about some improvement in sanitation, but the effectiveness of reform depended greatly upon the balance of local interests. In Merthyr Tydfil, despite some opposition from local ironmasters concerned to safeguard their own industrial water needs, a public water supply was established. A reservoir was completed in 1863, and sewage pipes were laid underground.
There were many episodes of typhoid, dyptheria and measles affecting the population and in 1872 many residents died from smallpox. On this occasion a row of cottages to the rear of Swan Street, was named Glyn Terrace since the occupants were mostly miners who worked in the Glyn Colliery. When many of the families, probably Cornish settlers, succumbed to the disease, the houses were set alight in an effort to rid the town of smallpox. Some of the family graves are inscribed, “Not To Be Opened” in the parish church yard.
A newspaper report of the period stated: “This dreadful disease continues to a fearful extent in the town and neighbourhood, and we regret to state that five deaths occurred within the last week, and several fresh cases have broken out. There appears to be an impression abroad that the use of disinfectants has been greatly neglected. We believe that if small quantities of disinfecting matter were supplied by the medical profession to those persons who neglect making use of it, through total ignorance of its worth, it would certainly tend to have a very beneficial effect.”
Compulsory vaccination against smallpox was first introduced in 1852, yet in the period 1857 to 1859, a smallpox epidemic killed 14,244 people. In 1863 to 1865, a second epidemic claimed 20,059 lives. In 1867, a more stringent compulsory vaccination law was passed and those who evaded vaccination were prosecuted. After an intensive four year effort to vaccinate the entire population between the ages of 2 - 50, the Chief Medical Officer announced in May 1871 that 97.5% had been vaccinated. In the following year, 1872, the country experienced its worst ever smallpox epidemic which claimed 44,840 lives.
Between 1871-1880, during the period of compulsory vaccination, the death rate from smallpox leapt from 28 to 46 per 100,000 population. The need for better drainage and a sewerage system in Llantrisant was recognised as the reliance on a single Town Pump was considered inadequate and unhealthy. Investments were made into the drainage and water supplies and a Sanitation Board overseeing the public health concerns of the area.