Plague Ports is a comparative study of the impact of bubonic plague on ten ports around the world during the third plague pandemic from about 1894. The ten ports are: Hong Kong (1894), Bombay (1896), Alexandria (1899), Porto (1899), Buenos Aires (1900), Rio de Janeiro (1900), Honolulu (1899–1900), San Francisco (1900–1), Sydney (1900) and Cape Town (1901). The book underscores the global impact of the third pandemic, when empire and global trade had connected ports around the world and transformed an epidemic that began in Asia into a world-wide health concern across five continents. The book examines the responses to the pandemic of medical and public health authorities, politicians, the print media and the general population in these urban ports.

The book's introduction (Part 1) provides a discussion of medical developments in the second half of the nineteenth century that would frame medical knowledge and the response to bubonic plague. It gives a short overview of the three historic plague pandemics, outlines the epidemiology and ecology of the disease, and the transmission links between fleas, rats and people. Hong Kong was one of the first ports to experience plague in 1894, whence the disease had made its way from the mainland city of Canton. It was in Hong Kong in 1894 that bacteriologists Kitasato Shibasaburō and Alexandre Yersin independently discovered the plague bacillus that would later bear Yersin's name. From Hong Kong, British commercial links would facilitate the introduction of plague to Bombay. During the Bombay epidemic, a Jewish Ukrainian bacteriologist, Waldemar Mordechai Haffkine, would produce and successfully test an anti-plague vaccine. Haffkine's vaccine would be in demand around the world during the third plague pandemic. An important theme in the book is the rivalry between the sanitarians and the bacteriologists – the latter, proponents of germ theory – and how these theories of medicine overlapped in the late nineteenth century. In both Hong Kong and Bombay, plague severely affected those who worked at docks or lived close to ports, and dwellers in slum areas. The outbreak of plague in Alexandria would bring the disease to the doors of Europe. Plague made its appearance in Porto, Portugal, in 1899, causing great concern among its neighbors – especially France and Spain – who feared the permeability of boundaries to disease. Plague struck Honolulu and San Francisco in the United States, two cities with large Chinese immigrant populations, who lived in poor housing close to the ports. Plague incidence would be notable among Asian immigrants, who also bore the brunt of official anti-plague measures. Echenberg points out that plague mortality in Honolulu was among the lowest of the third pandemic, despite the low standard of public health practice there, though the relevant chapter does not really explain why. Plague entered Sydney between October 1899 and January 1900, introduced probably through its close ties to Hong Kong and Bombay. Sydney displayed one of the best public health responses to plague during the third pandemic, recording the lowest case fatality rate. The final plague case study in the book is of Cape Town in South Africa in 1901, where the overlap of the epidemic with the Boer War further complicated official response, as military contingents were beyond the control of civilian public health personnel. Cape Town's epidemic was significant in the high mortality rate among health workers. Plague measures targeted Africans and resulted in the relocation of Africans from Districts 1 and 6 to Uitvlugt, formerly designated as a sewage farm. So plague provided the occasion for Cape Town to create the first African relocation in South Africa.

Plague Ports highlights how international trade had connected ports in different continents by the end of the nineteenth century, with the potential to transform local epidemics into global pandemics. The book also underscores international collaboration in the face of epidemics such as bubonic plague. Even when epidemics occurred in far-flung locations such as Hong Kong, Bombay or Portugal, medical teams arrived from several countries to study disease epidemiology. The third plague pandemic forced many cities and national governments to take modern public health seriously. The presence of immigrant Chinese populations in Honolulu, San Francisco and Sydney, places in close connection with Hong Kong, the original port of infection, suggests that Chinese immigration and trading networks may have played a role in the widespread transmission of plague. All three cities displayed pronounced anti-Chinese sentiment, even when the link between the Chinese population and the plague epidemic seemed tenuous. For the Africanist, Plague Ports places in a larger context single-country studies by Maynard Swanson on South Africa, and Echenberg on Senegal. It reveals the fragility of disease boundaries in an era of European empires and European-dominated international trade.