Following the abolition of the slave trade in the British Empire in 1833, it can be argued that emigrants and indentured labourers saw an improvement in their living conditions on board ships. While Gaiutra Bahadur and earlier, Hugh Tinker have suggested that indentured labourers were abused and exploited on board these ships as well, it would seem as though shipboard conditions were ameliorated across the nineteenth century (Northrup, Indentured Labor...Imperialism).

On board most ships sailing from Calcutta to the West Indies, the living area was one big room between decks, with each passenger allocated up to ‘15 superficial feet’ (1 superficial foot= 1 ft x 1ft x 1in) to live in. On slave ships, the space allocated was approximately 3-5 superficial feet. One ship surgeon’s account from the time can be used as a model for the improvement in the conditions of shipping. Theophilus Richmond, on his first voyage as a surgeon on a coolie ship to Demerara (that set out on June 23rd 1837) claimed that the living space for the passengers were far more ‘roomy and comfortable than (he) ever thought it could be’. Furthermore, the coolies had been given clean, new clothes, establishing some sanitary measures on the outset of the voyage.

However, while indentured workers had more space compared to slaves, allowing for slightly more separated living quarters, the shared living area could have made it easier for cholera to travel, through tainted hands or soiled clothes. The prevalence of the disease on these voyages seems to be supported by the dedication of a section to ‘Cholera on Emigrant Ships’ in the Proceedings of the Sanitary Commissioner with the Government of India. Here, excerpts from letters and observations discussing cases of cholera, the interaction between the captain and surgeon during outbreaks and number of cases in vessels can be found. For instance, the ship John Scott had 20 cholera deaths between 1869-70.

Furthermore, ventilation was given utmost priority, with lots of hatches and openings placed to allow ‘foul, warm air’ to escape from in between the decks, thus giving the passengers frequent exposure to fresh air. However, while this in general was a healthy practice, it was ineffective in preventing cholera. This was because it was falsely assumed by some medical experts of the time, that “the highways by which cholera travels are...aerial highways, and not routes of human communication”(William Pearse, Notes...Disease). It wasn't until 1849, when William Budd discovered microscopic bodies in cholera excreta, that earlier theories, such as that of Pearse, were disputed with scientific evidence.

Instead, the proportion of cholera outbreaks was doubled during wet and rainy weather, as opposed to dry weather, and also very high during summer months, due to the pervasiveness of waterborne diseases in such conditions.

Sources:

Pearse, William Henry. Notes on Health in Calcutta and British Emigrant Ships, Including Ventilation, Diet, and Disease. London: Churchill, 1866. Print.
Balfour, Edward. Statistics of Cholera. Madras: Printed by C.D'Cruiz at the M.A. &. P., 1870. Print.
Emmer, P. C. The Dutch Slave Trade: 1500-1850. New York: Berghahn, 2006. Print.