Mosquito Empires: Ecology and war in the Greater Caribbean, 1620–1914 (review)

In this impressive book, accomplished environmental historian J.R. McNeill seeks to answer how yellow fever and malaria shaped geopolitics in the Greater Caribbean over a period of three centuries. McNeill defines the Greater Caribbean as the low-lying coastal regions from the Guyanas to the Chesapeake Bay, including the Caribbean islands and Central America. From the mid-seventeenth century the Greater Caribbean was shaped by a plantation system that relied on the constant importation of large numbers of African slaves as a work force. The transformation of the Greater Caribbean enabled the emergence in the region of malaria and yellow fever, two deadly mosquito-borne diseases from tropical Africa. According to McNeill, this ecological process has been underappreciated by historians as a major factor shaping the outcome of European imperial rivalries in the Greater Caribbean as well as the independence struggles of Haiti, the United States, Colombia, and Venezuela.

The book is organized in three parts and an introductory chapter where McNeill discusses his main argument. The first part details the origins of the deadly disease environment in the Greater Caribbean, the development of European rivalries, and the sad state of medical care available to victims of yellow fever and malaria. McNeill’s discussion of the rise of yellow fever, the deadlier of the two diseases, in the Greater Caribbean is complex but fascinating. The rapid growth of sugar plantations in the region during the first half of the seventeenth century created the perfect conditions for yellow fever. The virus itself arrived in the Caribbean with West African slaves. Traveling with the virus and the slaves were the African mosquito species Aedes aegypti, the female of which infects humans with yellow fever. Conditions for yellow fever further improved with widespread deforestation due to the large amounts of firewood needed to boil cane for the sugar mills. This resulted in the loss of habitat for birds, the main predators of the mosquitoes. Additionally, mosquitoes such as the Aedes aegypti found abundant breeding grounds in the standing water held in numerous clay-pots essential for boiling sugar cane. To make matters worse, sugarcane itself was an attractive food source for mosquitoes. The Greater Caribbean port-cities at which African slaves arrived and from where sugar was shipped were also conducive for the outbreak of yellow fever. Many water containers were kept in the ports, ensuring a large mosquito population, and a constant stream of newly arrived European soldiers and African slaves supplied a large pool of potential victims for the female Aedes aegypti. Finally, El Niño weather patterns influenced the growth of mosquito populations. Whenever rainfall and humid temperatures were unusually high, mosquitoes multiplied enormously, increasing the chance for the outbreak of yellow fever.

A critical component of McNeill’s argument is that yellow fever and malaria were selective killers. While yellow fever conferred full immunity to survivors, malaria supplied biological resistance to people who survived the disease. Since yellow fever and malaria were both endemic in West Africa, slaves imported from that region did usually not fall victim to the two tropical diseases. In contrast, adult Europeans who had never been exposed to the diseases were the most vulnerable. European soldiers and sailors who arrived in the Greater Caribbean during an outbreak of yellow fever or malaria suffered catastrophic casualty rates. At the same time, survivors of the epidemics developed immunity or biological resistance, giving them a significant tactical advantage in the geopolitical struggles for the Greater Caribbean.

In the second part entitled “Imperial Mosquitoes,” McNeill examines the impact of yellow fever, and, to a lesser extent malaria, on the imperial rivalries in the Greater Caribbean from the mid-seventeenth century until the end of the Seven Years’ War. Surprisingly, the soldiers of the Dutch West India Company did not suffer from yellow fever during their campaigns against the Portuguese in northeastern Brazil during the first half of the seventeenth century. The absence of yellow fever in this part of Brazil remains mysterious as...