State-space forecasting of Schistosoma haematobium time-series in Niono, Mali

Background

Much of the developing world, particularly sub-Saharan Africa, exhibits high levels of morbidity and mortality associated with infectious diseases. The incidence of Schistosoma sp.—which are neglected tropical diseases exposing and infecting more than 500 and 200 million individuals in 77 countries, respectively—is rising because of 1) numerous irrigation and hydro-electric projects, 2) steady shifts from nomadic to sedentary existence, and 3) ineffective control programs. Notwithstanding the colossal scope of these parasitic infections, less than 0.5% of Schistosoma sp. investigations have attempted to predict their spatial and or temporal distributions. Undoubtedly, public health programs in developing countries could benefit from parsimonious forecasting and early warning systems to enhance management of these parasitic diseases.

Methodology/Principal Findings

In this longitudinal retrospective (01/1996–06/2004) investigation, the Schistosoma haematobium time-series for the district of Niono, Mali, was fitted with general-purpose exponential smoothing methods to generate contemporaneous on-line forecasts. These methods, which are encapsulated within a state–space framework, accommodate seasonal and inter-annual time-series fluctuations. Mean absolute percentage error values were circa 25% for 1- to 5-month horizon forecasts.

Conclusions/Significance

The exponential smoothing state–space framework employed herein produced reasonably accurate forecasts for this time-series, which reflects the incidence of S. haematobium–induced terminal hematuria. It obliquely captured prior non-linear interactions between disease dynamics and exogenous covariates (e.g., climate, irrigation, and public health interventions), thus obviating the need for more complex forecasting methods in the district of Niono, Mali. Therefore, this framework could assist with managing and assessing S. haematobium transmission and intervention impact, respectively, in this district and potentially elsewhere in the Sahel.     

Effects of growth conditions on the oxygen equivalence of microbial cells

A natural microbial population of sewage origin was grown at four temperatures (10, 20, 30, 40°C) and five mean residence times (3, 6, 12, 18, 24 hr) in a continuous stirred tank reactor. Samples of cells were removed during steady-state operation and analyzed for chemical oxygen demand (COD), ash content, protein, carbohydrate, and nucleic acids. The oxygen equivalence (OE) of the cells was measured directly as g COD/g ash-free cells and was determined indirectly by calculating the calorific content from the macromolecular composition. The results indicate that OE is a function of growth conditions. Furthermore the COD test is a poor measureof OE because of a high level of variation associated with the test. Additional studies should be performed using bomb calorimetry to establish a quantitative relationship between growth conditions and OE.     

Anaerobic power performance of incumbent female firefighters

Prior studies have indicated that anaerobic power tests correlate highly with firefighting performance tasks. This investigation measured peak power and mean power of 10 incumbent female firefighters (age, 29.8 +/- 2.1 years; height, 169.7 +/- 7.9 cm; weight, 66.8 +/- 9.9 kg) who underwent a 30-second Wingate anaerobic power test. Peak power and mean power were recorded as 451.6 +/- 69.6 W and 314.1 +/- 32.7 W, respectively, compared with a control group. Results revealed that incumbent female firefighters did not score significantly greater than the control group in either peak power or mean power. Although the level of anaerobic power needed to perform firefighting tasks is unknown at this time, it does not appear that incumbent female firefighters are reliant on anaerobic power as operationalized in this study.     

Avian biodiversity in the coastal wetlands of the Okahukura Peninsula

The Tapora Landcare Group, operating on the Okahukura Peninsula, has the long-term goal of making this region predator fenced. The aim of this study was to obtain information on the current status of avian biodiversity and the bird community across the band of coastal wetlands on the Okahukura Peninsula. Bird counts were conducted and playback lures used to detect three cryptic wetland species: fernbirds (Bowdleria punctata); spotless crakes (Porzana tabuensis); and banded rails (Gallirallus philippensis). Fernbirds and banded rails were detected at seven of the eight wetland sites sampled whereas spotless crakes were detected at two sites. The native species with the highest relative abundance across the eight sites were silvereyes (Zosterops lateralis) and South Island pied oystercatchers (Haematopus finschi). Changes in avian biodiversity over time in the region can now be monitored, and comprehensive long-term data on the status of avian biodiversity over time obtained.     

Production of an MHC class II B molecular probe in the turkey,Meleagris gallopavo

Genetic selection for disease resistance may be facilitated by molecular markers of the major histocompatibility complex (MHC) of poultry. We describe the first sequence variation documented at the MHC Class II B region of turkeys, and provide specific probe optimization conditions for studying RFLP polymorphisms in this species.