Matthew H. Bonds

Poverty trap formed by the ecology of infectious diseases

While most of the world has enjoyed exponential economic growth, more than one-sixth of the world is today roughly as poor as their ancestors were many generations ago. Widely accepted general explanations for the persistence of such poverty have been elusive and are needed by the international development community. Building on a well-established model of human infectious diseases, we show how formally integrating simple economic and disease ecology models can naturally give rise to poverty traps, where initial economic and epidemiological conditions determine the long-term trajectory of the health and economic development of a society. This poverty trap may therefore be broken by improving health conditions of the population. More generally, we demonstrate that simple human ecological models can help explain broad patterns of modern economic organization.

Rwanda 20 years on: investing in life

Two decades ago, the genocide against the Tutsis in Rwanda led to the deaths of 1 million people, and the displacement of millions more. Injury and trauma were followed by the effects of a devastated health system and economy. In the years that followed, a new course set by a new government set into motion equity-oriented national policies focusing on social cohesion and people-centred development. Premature mortality rates have fallen precipitously in recent years, and life expectancy has doubled since the mid-1990s. Here we reflect on the lessons learned in rebuilding Rwandas health sector during the past two decades, as the country now prepares itself to take on new challenges in health-care delivery.

Host Life‐History Strategy Explains Pathogen‐Induced Sterility

Virulence is often equated with pathogen‐induced mortality, even though loss of fecundity is also common. But while the former may be understood as a simple consequence of lost host resources for the purposes of pathogen transmission, pathogen‐induced sterility is often not associated with changes in host mortality. As a result, a separate literature has emerged to explain fecundity effects of parasitism that has not been integrated into general theories of the evolution of virulence. Here, I present a model of pathogen‐induced sterility that is based on the assumption that hosts and pathogens vie for the same host resources for both reproduction and maintenance. Loss of host fecundity can then be explained by the host compensating for its future loss of resources, before infection. Such preinfection ‘‘fecundity compensation” may often cause preinfection investment in maintenance to be as low as postinfection levels, despite a loss of total host resources after infection. Thus, sterility is simply explained as a host life‐history strategy in a system where the pathogen necessarily steals host resources for its own transmission. In certain circumstances, the pathogen may even be able to manipulate the host to redirect resources away from reproduction and toward maintenance through castration, causing gigantism.

Disease Ecology, Biodiversity, and the Latitudinal Gradient in Income

Vector-borne and parasitic diseases are drivers of the latitudinal gradient in income, and the burden of these diseases is predicted to rise as biodiversity falls.

Economic Valuation of Subsistence Harvest of Wildlife in Madagascar

Wildlife consumption can be viewed as an ecosystem provisioning service (the production of a material good through ecological functioning) because of wildlifes ability to persist under sustainable levels of harvest. We used the case of wildlife harvest and consumption in northeastern Madagascar to identify the distribution of these services to local households and communities to further our understanding of local reliance on natural resources. We inferred these benefits from demand curves built with data on wildlife sales transactions. On average, the value of wildlife provisioning represented 57% of annual household cash income in local communities from the Makira Natural Park and Masoala National Park, and harvested areas produced an economic return of U.S.

Poverty, Disease, and the Ecology of Complex Systems

0.42 ha(-1) · year(-1). Variability in value of harvested wildlife was high among communities and households with an approximate 2 orders of magnitude difference in the proportional value of wildlife to household income. The imputed price of harvested wildlife and its consumption were strongly associated (p< 0.001), and increases in price led to reduced harvest for consumption. Heightened monitoring and enforcement of hunting could increase the costs of harvesting and thus elevate the price and reduce consumption of wildlife. Increased enforcement would therefore be beneficial to biodiversity conservation but could limit local peoples food supply. Specifically, our results provide an estimate of the cost of offsetting economic losses to local populations from the enforcement of conservation policies. By explicitly estimating the welfare effects of consumed wildlife, our results may inform targeted interventions by public health and development specialists as they allocate sparse funds to support regions, households, or individuals most vulnerable to changes in access to wildlife.

The impact of reducing financial barriers on utilisation of a primary health care facility in Rwanda

Coupled models of ecology and economic growth can provide key insights into the formation of poverty traps that arise from complex interactions between biosocial and biophysical processes.

HIGHER DISEASE PREVALENCE CAN INDUCE GREATER SOCIALITY: A GAME THEORETIC COEVOLUTIONARY MODEL

Abstract This study investigates the impact of subsidising community-based health insurance (mutuelle) enrolment, removing point-of-service co-payments, and improving service delivery on health facility utilisation rates in Mayange, a sector of rural Rwanda of approximately 25,000 people divided among five ‘imidugudu’ or small villages. While comprehensive service upgrades were introduced in the Mayange Health Centre between April 2006 and February 2007, utilisation rates remained similar to comparison sites. Between February 2007 and April 2007, subsidies for mutuelle enrolment established virtually 100% coverage. Immediately after co-payments were eliminated in February 2007, patient visits levelled at a rate triple the previous value. Regression analyses using data from Mayange and two comparison sites indicate that removing financial barriers resulted in about 0.6 additional annual visits for curative care per capita. Although based on a single local pilot, these findings suggest that in order to achieve improved health outcomes, key short-term objectives include improved service delivery and reduced financial barriers. Based on this pilot, higher utilisation rates may be affected if broader swaths of the population are enrolled in mutuelle and co-payments are eliminated. Health leaders in Rwanda should consider further studies to determine if the impact of eliminating co-payments and increasing subsidies for mutuelle enrolment as seen in Mayange holds at greater levels of scale. Broader studies to better elucidate the impact of enrolment subsidies and co-payment subsidies on utilisation, health outcomes, and costs would also provide policy insights.

A Randomized Trial of Ready-to-Use Supplementary Food Versus Corn-Soy Blend Plus as Food Rations for HIV-Infected Adults on Antiretroviral Therapy in Rural Haiti

Abstract There is growing evidence that communicable diseases constitute a strong selective force on the evolution of social systems. It has been suggested that infectious diseases may determine upper limits of host sociality by, for example, inducing territoriality or early juvenile dispersal. Here we use game theory to model the evolution of host sociality in the context of communicable diseases. Our model is then augmented with the evolution of virulence to determine coevolutionarily stable strategies of host sociality and pathogen virulence. In contrast to a controversial hypothesis by Ewald (1994), our analysis indicates that pathogens may become more virulent when contact rates are low, and their prevalence can ultimately induce greater sociality.

Herd immunity acquired indirectly from interactions between the ecology of infectious diseases, demography and economics

BACKGROUND The epidemics of food insecurity, malnutrition, and human immunodeficiency virus (HIV) frequently overlap. HIV treatment programs increasingly provide nutrient-dense ready-to-use supplementary foods (RUSFs) to patients living with HIV and food insecurity, but in the absence of wasting, it is not known if RUSF confers benefit above less costly food commodities. METHODS We performed a randomized trial in rural Haiti comparing an RUSF with less costly corn-soy blend plus (CSB+) as a monthly supplement to patients with HIV infection who were on antiretroviral therapy (ART) <24 months prior to study start. We compared 6- and 12-month outcomes by ration type in terms of immunologic response, body mass index (BMI), adherence to ART, general health quality of life, household food insecurity, and household wealth. RESULTS A cohort of 524 patients with HIV receiving ART was randomized and followed over time. Median CD4 cell count at baseline was 339 cells/µL (interquartile range [IQR], 197-475 cells/µL) for the CSB+ group, and 341 cells/µL (IQR, 213-464/µL) for the RUSF group. Measured outcomes improved from baseline over time, but there were no statistically significant differences in change for BMI, household wealth index, hunger, general health perception score, or adherence to ART by ration type at 6 or 12 months. The RUSF group had higher CD4 count at 12 months, but this was also not statistically significant. CONCLUSIONS In 12 months of follow-up, there was no statistically significant difference in outcomes between those receiving RUSF-based compared with CSB+-based rations in a cohort of HIV-infected adults on ART in rural Haiti.