Emerging Issues in Sanitation: Herd Protection, Sharing Between Households, and Joint Effects.

Abstract

Sanitation (toilets and latrines) is considered one of the most important health advancements of modern times, yet over one third of the world still lacks basic access to sanitation services. In the coming year, the international community will likely adopt a global goal of reaching universal access by the year 2030. While much is known about the health benefits of improved sanitation, this dissertation seeks to address three emerging issues related to sanitation coverage: herd protection, sharing between households, and the joint effects of drinking water and sanitation. In chapter two, we explore the concept of herd protection, which occurs when an infectious disease intervention indirectly benefits those that do not receive it. We review the literature and highlight herd protective effects from interventions such as vaccines, insecticide treated bednets, and deworming drugs. We then use a mathematical model to highlight the mechanisms through which improving sanitation in some households can provide herd protection to the entire community. In chapter three, we build off of the conceptual work of chapter two by assessing herd protection from sanitation in 24 rural villages in northern coastal Ecuador. We find that children from neighborhoods with higher sanitation coverage were taller than children from areas with lower levels of coverage. In chapter four, we address the topic of sanitation facilities that are shared by multiple households, which is an increasingly common practice in urban slums and rural communities. Using data from, 51 Demographic and Health Surveys, we show that using such a facility is associated with an modest increase in diarrhea prevalence, but the effect varied across countries. In chapter five, we investigate the independent and joint effects of drinking water and sanitation. Using data from 217 Demographic and Health Surveys, we find that these services are largely independent, suggesting that they should be combined to maximize the benefit. We observe that the effect of water and sanitation varies across countries, and the effect of sanitation has diminished over time. This dissertation uses a variety of methods to highlight the importance of access to adequate sanitation at the household and at the community level.