While the Web of Causation was conceived to enhance understanding of noncommunicable chronic disease, this model also has application to communicable disease and injury. One interesting communicable disease example involves unanticipated consequences of economic development, and more particularly Trypanosymiosis or “sleeping sickness” that spread across Africa in the wake of new roads. The agent was carried behind trucks by its vector, the tsetse fly, with fly bites being the mode of disease transmission.