A wide range of research has promised new tools for forecasting infectious disease dynamics, but little of that research is currently being applied in practice, because tools do not address key public health needs, do not produce probabilistic forecasts, have not been evaluated on external data, or do not provide sufficient forecast skill to be useful. We developed an open collaborative forecasting challenge to assess probabilistic forecasts for seasonal epidemics of dengue, a major global public health problem. Sixteen teams used a variety of methods and data to generate forecasts for 3 epidemiological targets (peak incidence, the week of the peak, and total incidence) over 8 dengue seasons in Iquitos, Peru and San Juan, Puerto Rico. Forecast skill was highly variable across teams and targets. While numerous forecasts showed high skill for midseason situational awareness, early season skill was low, and skill was generally lowest for high incidence seasons, those for which forecasts would be most valuable. A comparison of modeling approaches revealed that average forecast skill was lower for models including biologically meaningful data and mechanisms and that both multimodel and multiteam ensemble forecasts consistently outperformed individual model forecasts. Leveraging these insights, data, and the forecasting framework will be critical to improve forecast skill and the application of forecasts in real time for epidemic preparedness and response. Moreover, key components of this project—integration with public health needs, a common forecasting framework, shared and standardized data, and open participation—can help advance infectious disease forecasting beyond dengue.

Sub-Saharan Africa (SSA) is facing a double burden of disease with a rising prevalence of non-communicable diseases (NCDs) while the burden of communicable diseases (CDs) remains high. Despite these challenges, there remains a significant need to understand how or under what conditions health interventions implemented in sub-Saharan Africa are sustained. The purpose of this study was to conduct a systematic review of empirical literature to explore how health interventions implemented in SSA are sustained. We searched MEDLINE, Biological Abstracts, CINAHL, Embase, PsycInfo, SCIELO, Web of Science, and Google Scholar for available research investigating the sustainability of health interventions implemented in sub-Saharan Africa. We also used narrative synthesis to examine factors whether positive or negative that may influence the sustainability of health interventions in the region. The search identified 1819 citations, and following removal of duplicates and our inclusion/exclusion criteria, only 41 papers were eligible for inclusion in the review. Twenty-six countries were represented in this review, with Kenya and Nigeria having the most representation of available studies examining sustainability. Study dates ranged from 1996 to 2015. Of note, majority of these studies (30 %) were published in 2014. The most common framework utilized was the sustainability framework, which was discussed in four of the studies. Nineteen out of 41 studies (46 %) reported sustainability outcomes focused on communicable diseases, with HIV and AIDS represented in majority of the studies, followed by malaria. Only 21 out of 41 studies had clear definitions of sustainability. Community ownership and mobilization were recognized by many of the reviewed studies as crucial facilitators for intervention sustainability, both early on and after intervention implementation, while social and ecological conditions as well as societal upheavals were barriers that influenced the sustainment of interventions in sub-Saharan Africa. The sustainability of health interventions implemented in sub-Saharan Africa is inevitable given the double burden of diseases, health care worker shortage, weak health systems, and limited resources. We propose a conceptual framework that draws attention to sustainability as a core component of the overall life cycle of interventions implemented in the region.

Cholera outbreak following the earthquake of 2010 in Haiti has reaffirmed that the disease is a major public health threat. Vibrio cholerae is autochthonous to aquatic environment, hence, it cannot be eradicated but hydroclimatology-based prediction and prevention is an achievable goal. Using data from the 1800s, we describe uniqueness in seasonality and mechanism of occurrence of cholera in the epidemic regions of Asia and Latin America. Epidemic regions are located near regional rivers and are characterized by sporadic outbreaks, which are likely to be initiated during episodes of prevailing warm air temperature with low river flows, creating favorable environmental conditions for growth of cholera bacteria. Heavy rainfall, through inundation or breakdown of sanitary infrastructure, accelerates interaction between contaminated water and human activities, resulting in an epidemic. This causal mechanism is markedly different from endemic cholera where tidal intrusion of seawater carrying bacteria from estuary to inland regions, results in outbreaks.

Phytoplankton abundance is inversely related to sea surface temperature (SST). However, a positive relationship is observed between SST and phytoplankton abundance in coastal waters of Bay of Bengal. This has led to an assertion that in a warming climate, rise in SST may increase phytoplankton blooms and, therefore, cholera outbreaks. Here, we explain why a positive SST-phytoplankton relationship exists in the Bay of Bengal and the implications of such a relationship on cholera dynamics. We found clear evidence of two independent physical drivers for phytoplankton abundance. The first one is the widely accepted phytoplankton blooming produced by the upwelling of cold, nutrient-rich deep ocean waters. The second, which explains the Bay of Bengal findings, is coastal phytoplankton blooming during high river discharges with terrestrial nutrients. Causal mechanisms should be understood when associating SST with phytoplankton and subsequent cholera outbreaks in regions where freshwater discharge are a predominant mechanism for phytoplankton production.