Vaccination of household chickens results in a shift in young children's diet and improves child growth in rural Kenya.

Childhood growth faltering remains unacceptably high in sub-Saharan Africa. Rural communities dependent on household food production with limited off-farm income or liquid assets to bridge seasonal food availability are especially vulnerable. A cross-sectional survey in Siaya County, Kenya identified 23.5 and 4.8% of children under 5 y of age as stunted and wasted, respectively, using height-for-age Z (HAZ) scores to detect stunting and weight-for-height Z (WHZ) scores for wasting. Although these households are classified as living in poverty or extreme poverty with very limited off-farm income, households commonly have on-farm resources that could be developed to improve nutrition. While 95% of these households have chickens and consumption of eggs was shown to increase childhood growth by an average of 5%, the average flock size is small and constrained by high mortality due to infectious disease. We hypothesized that interventions to relieve this constraint would translate into household decisions influencing the diets and growth of children. Here, we show that vaccination of chickens against Newcastle disease has a causal impact on children's consumption of animal source foods rich in protein and micronutrients relative to a high-carbohydrate, grain-based diet. Children in treatment households (chicken vaccination) showed overall increases in scores for both HAZ and WHZ relative to control households, benefiting both girls and boys. The findings demonstrate the impact of directing interventions at common on-farm assets managed by women in rural communities and support programs to enhance productivity at the household level.

Conflict and Risky Health Behavior: Evidence from Mexico's Drug War.

Risky health behaviors contribute to a large share of disease in developing countries, yet few papers have studied the effect of conflict on these behaviors. The canonical health capital model predicts that conflict should increase risky health behaviors: as the likelihood of survival falls, incentives to invest in preventive measures also fall, increasing risk-taking. However, recent findings from various violent contexts, including the drug war in Mexico, suggest the behavioral response to conflict may reduce risk-taking. In this paper, I identify the effect of insecurity on sexual risk-taking using unique panel data on female sex workers in Ciudad Juarez, Mexico. I show that more intense conflict generates a large reduction in risky sex transactions. I rule out several alternate explanations, including compositional changes in sex markets and changes in drug use. The results suggest that the behavioral response to insecurity can mitigate the negative effects of conflict on health.

The effect of HIV prevention products on incentives to supply condomless commercial sex among female sex workers in South Africa.

Evidence suggests that economic factors play an important role in commercial sex work, in particular that condomless sex commands a price premium relative to condom-protected sex. This paper explores whether the use of a new HIV prevention product, with 100% efficacy but modeled after pre-exposure prophylaxis (PrEP), could change the price and quantity of condomless commercial sex supplied. We collected stated preference data from 122 HIV-negative female sex workers in urban South Africa, using a repeated choice experiment to simulate the impact of using PrEP on choices. Results suggest that the price premium for condomless sex would decrease by 73% with PrEP use and the quantity of condomless sex is predicted to increase by a factor of 2.27. Act price does not significantly affect choices without protection but strongly influences choices under full HIV protection. The utility offered by condoms reduces by around 15% under PrEP use. Because new HIV prevention products do not protect against other STIs or pregnancy, the unintended consequences of introducing HIV prevention products should be closely monitored, whereas users should not face stigma or blame for reacting rationally to exogenous changes to market conditions.

Economics of East Coast fever: a literature review.

East Coast fever (ECF) is a cattle disease caused by a protozoan parasite called Theileria parva (T. parva). Theileria parva is transmitted among cattle by ticks. It is endemic in parts of central, eastern, and southern Africa and imposes an economic burden through illness and death of approximately a half of a billion U.S. dollars annually. This paper reviews existing science on the economics of ECF. We utilize a conceptual model that defines primary categories of economic costs due to ECF and use it to organize a synthesis of the literature on aggregate and micro level direct costs of the disease and the costs and benefits related to various ECF management strategies. We then identify knowledge gaps to motivate for future research.

Evaluation of large-scale combination HIV prevention programs: essential issues.

HIV prevention research has shifted to the evaluation of combination prevention programs whereby biomedical, behavioral, and structural interventions are implemented concurrently to maximize synergies among interventions. However, these kinds of combination prevention packages, particularly when implemented at scale, pose significant evaluation challenges, including how best to determine impact and how and whether to measure the effectiveness of component strategies. In addition, methodological challenges unique to HIV infection such as the absence of a reliable incidence assay, the lack of naive control groups, and no suitable surrogates further complicate rigorous evaluation. In this commentary, we discuss the key considerations for planning impact evaluations of combination HIV prevention programs in light of these challenges, including defining the evaluable package, determining which component programs require independent assessment of impact, choosing study designs with valid counterfactuals, selecting appropriate outcomes of interest, and the importance of mid-course program corrections.