The impact of vector migration on the effectiveness of strategies to control gambiense human African trypanosomiasis

BACKGROUND: Several modeling studies have been undertaken to assess the feasibility of the WHO goal of eliminating gambiense human African trypanosomiasis (g-HAT) by 2030. However, these studies have generally overlooked the effect of vector migration on disease transmission and control. Here, we evaluated the impact of vector migration on the feasibility of interrupting transmission in different g-HAT foci. METHODS: We developed a g-HAT transmission model of a single tsetse population cluster that accounts for migration of tsetse fly into this population. We used a model calibration approach to constrain g-HAT incidence to ranges expected for high, moderate and low transmission settings, respectively. We used the model to evaluate the effectiveness of current intervention measures, including medical intervention through enhanced screening and treatment, and vector control, for interrupting g-HAT transmission in disease foci under each transmission setting. RESULTS: We showed that, in low transmission settings, under enhanced medical intervention alone, at least 70% treatment coverage is needed to interrupt g-HAT transmission within 10 years. In moderate transmission settings, a combination of medical intervention and a vector control measure with a daily tsetse mortality greater than 0.03 is required to achieve interruption of disease transmission within 10 years. In high transmission settings, interruption of disease transmission within 10 years requires a combination of at least 70% medical intervention coverage and at least 0.05 tsetse daily mortality rate from vector control. However, the probability of achieving elimination in high transmission settings decreases with an increased tsetse migration rate. CONCLUSION: Our results suggest that the WHO 2030 goal of G-HAT elimination is, at least in theory, achievable. But the presence of tsetse migration may reduce the probability of interrupting g-HAT transmission in moderate and high transmission foci. Therefore, optimal vector control programs should incorporate monitoring and controlling of vector density in buffer areas around foci of g-HAT control efforts

Contributions of organic amendments to exchangeable potassium percent and soil nitrate concentration in an ultisol and their effect on maize(zea mays l) grain yield

No Abstract

Determining the Field Capacity, Wilting point and Available Water Capacity of some Southeast Nigerian Soils using Soil Saturation from Capillary Rise

Water is a unique material resource which plays a vital role in nature and in agriculture. The objective of this study was to find out the applicability of saturation percentage (SP) to estimate field capacity (FC) and permanent wilting point (PWP) of soils across different texture in southeast Nigeria. Top 0-20 cm soil sample were randomly collected from 28 points in different parts of southeast Nigeria and analyzed for particle size distribution, organic carbon (OC %) and moisture constants. Simple correlations and regression models were used to relate the moisture constants at various suctions to saturation percentage (SP).Results of the study showed that sand, silt and clay contents of the soils ranged between 2-73%, 2-48% and 8-76%, respectively. Similarly, OC % ranged between 0.08- 3.03 % while the ranges of 24.3-75.7, 8.3-50.5% and 2.3-32.6% were observed for SP, FC and PWP, respectively. Results showed strong linear relationship between SP and the moisture constants (FC, PWP) and that the readily available water capacity (RAWC) and total available water capacity (TAWC) cannot be estimated from SP across the texture of the studied soils.Keywords: Moisture constants, Agriculture, Saturation percentage, texture, WaterNig J. Biotech. Vol. 24 (2012) 41-4

Influence of organic waste on plant growth parameters and nutrient uptake by maize (Zea may L)

No Abstract.Nigerian Journal of Soil Sciences Vol. 16 (1) 2006: pp. 104-10

Effect of animal waste on physicochemical properties of a dystric leptosol and maize yield in Southeastern Nigeria

No Abstract.Nigerian Journal of Soil Sciences Vol. 16 (1) 2006: pp. 96-10

Changes in Rheological Properties and Heavy Metal Content of an Ultisol Amended with Ash and its Effect on Maize Yield

This study investigated the effect of ash from wood (WA), rice husk (RHA) and coconut (CA) on soil liquid limit (LL), plastic limit (PL), sodium absorption ratio (SAR), exchangeable sodium percent (ESP), exchangeable potassium percent (EPP) and contents of Cu, Fe, Bo and Pb in an Ultisol in Southeastern Nigeria. The experiment was laid out as completely randomized block design with four treatments and five replications. The treatments were applied at the rate of 4t ha-1 and maize used as a test crop. Results of the study showed significant increase (p=0.05) in LL,PL, EPP and ESP. Observed LL values were 6%,12% and 11% higher in CA, RHA and WA amended plots, respectively, relative to the control. Results of the study also showed decreased soil contents of Bo and Cu and increased Pb content to non-toxic level. Results also showed significantly (p=0.05) higher maize height and yield in ash amended plots relative to the control. Ash application is recommended since it improves soil properties and increase maize yield.Keywords: Ash, rheological properties, heavy metal, maize yieldNig J. Biotech. Vol. 25 (2013) 53 -5

Effect of Ground Cover by Different Crops on soil Loss and Physicochemical Properties of an Ultisol in South Eastern Nigeria.

Of all hazard factors, soil cover and cover management for conservations have the most important influences on the rain erosion hazard. The effects of ground cover by various crops on the soil physico-chemical properties and soil loss of an Ultisol in southeastern Nigeria were studied. Five experimental plots containing groundnut (Arachis hypogeal), maize (Zea mays), soyabean (Gylcine max), bambara groundnut (Vigna subterranean) and bare plot (control) were laid out in randomized complete block design (RCBD) and replicated three times. Five 15cm nails were randomly driven into the soil perpendicular to and leveled off with the soil surface to monitor soil removal by erosion. Results from this study showed that bare plots (no cover) had the highest topsoil loss of 2.40cm or 372 t ha-1 when compared with the plot with least topsoil loss (groundnut) which had 0.87cm of 134.8t ha-1. Similarly, plots planted with bambara groundnut and soyabean lost 1.95 and 1.83cm of topsoil corresponding to 302 and 283.6t ha-1 of topsoil loss respectively at 30days after planting (DAP). Similar trends were observed at 60 and 90 DAP. The least clay content was found in bare and bambara groundnut plots. Bare soil also had the least soil pH.Nigerian Journal of Soil Science Vol. 17 2007: pp. 94-9