We propose an economic theory of infectious disease transmission and rational behavior. Diseases are costly due to mortality (premature death) and morbidity (lower productivity and quality of life). The theory offers three main insights. First, higher disease prevalence implies lower saving-investment propensity. Preventive behavior can partially offset this when the prevalence rate and negative disease externality are relatively low. Secondly, infectious diseases can generate a low-growth trap where income alone cannot push an economy out of underdevelopment, a result that differs from development traps in the existing literature. Since income per se does not cause health in this equilibrium, successful interventions have to be health specific. Thirdly, a more favorable disease ecology propels the economy to a higher growth path where infectious diseases are eradicated. Even so, diseases can significantly slow down convergence to this growth path. Taken together, our results suggest that the empirical relationship between health and income at the aggregate level may be more nuanced than realized.

We study the dynamics of poverty and health in a model of endogenous growth and rational health behavior. Population health depends on the prevalence of infectious diseases that can be avoided through costly prevention. The incentive to do so comes from the negative effects of ill health on the quality and quantity of life. The model can generate a poverty trap where infectious diseases cycle between high and low prevalence. These cycles originate from the rationality of preventive behavior in contrast to the predator-prey dynamics of epidemiological models. We calibrate the model to reflect sub-Saharan Africa's recent economic recovery and analyze policy alternatives. Unconditional transfers are found to improve welfare relative to conditional health-based transfers: at low income levels, income growth (quality of life) is valued more than improvements to health (quantity of life). JEL Classification: O11, O40, O47.

This paper studies the effect of sovereign risk on capital flows from rich to poor nations in the context of a two-country model, where Foreign Direct Investment (FDI) creates positive externalities in domestic production. We show that if externalities are large, a developing country never expropriates foreign assets, and behaves as under perfect enforcement of foreigners' property rights, jumping to the steady state in one period. If externalities are absent, a developing country always expropriates foreign assets and, then, there are no capital flows in equilibrium, as occurs in autarky. If externalities are of a medium size, our model can account for scarce capital flows from rich to poor nations, as well as other key features of the data, such as rising-over-time patterns of foreign capital and FDI in developing countries. In addition, the model offers an economic rationale for the FDI restrictions observed across nations. Copyright � 2008 The Authors. Journal compilation � 2008 Blackwell Publishing Ltd.

This study argues that public infrastructure is an important though previously neglected driving mechanism of the structural transformation process. To assess its significance quantitatively, this study first develops a multisector neoclassical growth model with heterogeneous firms, where public infrastructure contributes to firms' production and mitigates the barriers to firms' entry. The model is calibrated using data from Brazil, a country that has significantly expanded its infrastructure in recent decades, yet remains in deep need of further infrastructure improvements. The accumulation of infrastructure accelerates the structural transformation through generating higher returns and lowering entry costs in sectors with greater public capital intensity. In the simulations, public capital formation explains about 15 percent of the process. The paper also shows the effects of different barriers to public capital formation on the structural transformation and GDP per capita.