What country are you asking about? I'll assume the UK for now and that you are referring to the 19th century as a whole and not choice parts of it.
Major issues involved- Housing- lack of adequate sewers- unsanitary hospitals- lack of knowledge about the spread of disease- inadequate diet- poor working conditions.
During the first half of the 19th century Govt did very little to improve matters except set up the board of health in 1805 to try to prevent the spread of Spanish Fever to the UK. This was short lived and only lasted a year before it was disbanded. However after a major outbreak of Cholera in 1831 another board of health was set up, again only lasting a year but with far more far reaching effects. Medical Officers were appointed to most major cities to over see drainage issues and the Poor Law Commissioners survey of 1838-1842 identified key areas where action was needed to assist not only the poor but public health generally. 50 English towns became the subject of drainage and sanitary improvements thanks to the Health of Towns Commission 1843.
The first major Public Health Act was passed in 1848 and by 1870 there were over 700 local boards acting in the interest of public health.
A List of European conferences on Public Health.
Sanitary Conference in Paris, 1851-1853, 1859-1860
Cholera Conference in Constantinople, 1865-1867
International Sanitary Convention in Austria, 1874
Venice Sanitary Conference, 1891-1893, 1897
Dresden Sanitary Conference, 1893
Paris Sanitary Conference, 1893-1894
Venice Plague Convention, 1898
Paris Sanitary Conference 1902-1903
A list of epidemics can be found here:-
http://en.wikipedia.org/wiki/List_of_epidemics
If you read about your subject anything is interesting you know, try it yourself next time xx