Detection of infectious disease outbreaks in twenty-two fragile states, 2000-2010: a systematic review.

Fragile states are home to a sixth of the world's population, and their populations are particularly vulnerable to infectious disease outbreaks. Timely surveillance and control are essential to minimise the impact of these outbreaks, but little evidence is published about the effectiveness of existing surveillance systems. We did a systematic review of the circumstances (mode) of detection of outbreaks occurring in 22 fragile states in the decade 2000-2010 (i.e. all states consistently meeting fragility criteria during the timeframe of the review), as well as time lags from onset to detection of these outbreaks, and from detection to further events in their timeline. The aim of this review was to enhance the evidence base for implementing infectious disease surveillance in these complex, resource-constrained settings, and to assess the relative importance of different routes whereby outbreak detection occurs.We identified 61 reports concerning 38 outbreaks. Twenty of these were detected by existing surveillance systems, but 10 detections occurred following formal notifications by participating health facilities rather than data analysis. A further 15 outbreaks were detected by informal notifications, including rumours.There were long delays from onset to detection (median 29 days) and from detection to further events (investigation, confirmation, declaration, control). Existing surveillance systems yielded the shortest detection delays when linked to reduced barriers to health care and frequent analysis and reporting of incidence data.Epidemic surveillance and control appear to be insufficiently timely in fragile states, and need to be strengthened. Greater reliance on formal and informal notifications is warranted. Outbreak reports should be more standardised and enable monitoring of surveillance systems' effectiveness

Performance of Coffea arabica F1 hybrids in agroforestry and full-sun cropping systems in comparison with American pure line cultivars

Coffea arabica F1 hybrids derived from crosses between wild Sudan-Ethiopian and American cultivars and propagated by somatic embryogenesis have been obtained in Central America. These new hybrids considerably enhanced the genetic diversity of coffee in the region. We conducted 15 trials to assess whether using hybrids represents substantial genetic progress in terms of productivity in agroforestry and full-sun cropping systems. The new germplasm was grown in the same conditions as the best American cultivar (homozygous pure lines). The results showed that yields of hybrids were earlier and superior to those of American cultivars. The hybrids were also more stable than the American cultivars in all environments. In the agroforestry system, the mean yield of hybrids was 58% higher than that of the American cultivars, while the mean yield of hybrids in the full-sun system was 34% higher. Coffee-based agroforestry systems (AS) are considered effective in protecting the environment in the volcanic cordilleras of Central America. We found that introducing hybrids in coffee-based AS can considerably increase productivity. This finding could be a convincing argument to encourage coffee growers who have adopted the full-sun cropping system to return to agroforestry cropping systems. Finally, the conditions for large-scale dissemination of those new hybrids—which represent a major innovation for C. arabica cropping—was analysed

Environmental impacts of nitrification and nitrate adsorption in fertilized andisols in the Valle Central of Costa Rica

A major scientific challenge for modern agriculture is control of off-site effects on the water resource. In the Valle Central of Costa Rica, coffee plantations may leach fertilizer-derived (Equation presented) to groundwaters, as a result of high fertilization rates (annually ~270 kg/ha as N), highly permeable and well structured Andisols, and high rates of annual runoff (>1000 mm). The objective of this study was to examine several aspects of the nitrification and (Equation presented) adsorption that control (Equation presented) leaching from these highly productive soils. Monthly collections from four Andisols indicated that soil (Equation presented) varied seasonally, with (Equation presented) accumulating to about 280 kg/ha in the upper meter of soil during the 5-month dry season. Soil (Equation presented) was reduced during wet season months, even though fertilization was confined to the wet season. During these months, soil (Equation presented) averaged about 140 kg/ha as N in the upper meter of soil, apparently reduced by wet season leaching, root uptake, and, possibly, dentrification. Field and laboratory incubations at different soil moisture and temperature regimes demonstrated how soil microflora mineralized N and nitrified (Equation presented) at relatively high rates, even at low water potentials, e.g., 1000 mm). El objetivo de este estudio fue examinar varios aspectos de la nitrificación y (Ecuación presentada) adsorción que controlan (Ecuación presentada) la lixiviación de estos suelos altamente productivos. Las recolecciones mensuales de cuatro Andisoles indicaron que el suelo (Ecuación presentada) varió estacionalmente, con (Ecuación presentada) acumulando alrededor de 280 kg/ha en el metro superior del suelo durante la estación seca de 5 meses. El suelo (ecuación presentada) se redujo durante los meses de la estación húmeda, aunque la fertilización se limitó a la estación húmeda. Durante estos meses, el suelo (Ecuación presentada) promedió alrededor de 140 kg/ha como N en el metro superior del suelo, aparentemente reducido por la lixiviación de la estación húmeda, la absorción de raíces y, posiblemente, la desnitrificación. Las incubaciones de campo y de laboratorio a diferentes regímenes de humedad y temperatura del suelo demostraron cómo la microflora del suelo mineralizaba el N y nitrificaba (ecuación presentada) a tasas relativamente altas, incluso con potenciales hídricos bajos, por ejemplo, <−1,5 MPa. Durante la estación seca, las incubaciones de campo sugirieron que las tasas de nitrificación eran de alrededor de 30 kg/ha por mes como N en los 20 cm superiores del suelo. Contenidos relativamente grandes de (Ecuación presentada) pueden ser adsorbidos por estos andisoles alófanos, especialmente a pH bajo (hasta alrededor de 5 cmol/kg a pH <3). La adsorción de nitrato retarda potencialmente la lixiviación de (Ecuación presentada) a las aguas subterráneas; sin embargo, la eficacia de la adsorción como protección de la calidad del agua subterránea probablemente sea limitada debido a los altos aportes de N fertilizante y al manejo del encalado de los suelos cafetaleros que mantiene un pH del suelo relativamente alto. Se necesita investigación adicional sobre el ciclo del N del café y la eficiencia de los fertilizantes en el café para garantizar una alta productividad del café y proteger la calidad del agua del acuífero en el Valle Central. © 1994 Williams y Wilkins.Universidad Nacional, Costa RicaEscuela de Ciencias Biológica