Browsing by Author "Deckers, Jozef A."
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Item Contribution of land use to rodent flea load distribution in the plague endemic area of Lushoto District, Tanzania(Sokoine University of Agriculture,, 2014-07-01) Hieronimo, Proches; Kihupi, Nganga I.; Kimaro, Didas N.; Gulinck, Hubert; Mulungu, Loth S.; Msanya, B. M.; Leirs, Herwing; Deckers, Jozef A.Fleas associated with different rodent species are considered as the major vectors of bubonic plague, which is still rampant in different parts of the world. The objective of this study was to investigate the contribution of land use to rodent flea load distribution at fine scale in the plague endemic area of north-eastern Tanzania. Data was collected in three case areas namely, Shume, Lukozi and Mwangoi, differing in plague incidence levels. Data collection was carried out during both wet and dry seasons of 2012. Analysis of Variance and Boosted Regression Tree (BRT) statistical methods were used to clarify the relationships between fleas and specific land use characteristics. There was a significant variation (P ≤ 0.05) of flea indices in different land use types. Fallow and natural forest had higher flea indices whereas plantation forest mono-crop and mixed annual crops had the lowest flea indices among the aggregated land use types. The influence of individual land use types on flea indices was variable with fallow having a positive effect and land tillage showing a negative effect. The results also demonstrated a seasonal effect, part of which can be attributed to different land use practices such as application of pesticides, or the presence of grass strips around fields. These findings suggest that land use factors have a major influence on rodent flea abundance which can be taken as a proxy for plague infection risk. The results further point to the need for a comprehensive package that includes land tillage and crop type considerations on one hand and the associated human activities on the other, in planning and implementation of plague control interventions. ________________________________________________________________________________Item Status and variability of soil micronutrients with landforms in the plague focus of Western Usambara Mountains, Tanzania(International Journal of Plant & Soil Science, 2014-11-13) Meliyo, Joel L.; Massawe, Boniface H. J.; Brabers, Leon; Msanya, B. M.; Kimaro, D. N.; Kihupi, N. I.; Deckers, Jozef A.; Gulinck, Hubert; Leirs, HerwigA study was carried out in Western Usambara, Tanzania to assess the status of soil micronutrients across three geomorphic units viz., plain, escarpment and plateau in order to provide essential information for on-going studies on plague epidemiology. Nineteen soil profiles were opened, described and 54 samples collected for laboratory analysis. Standard methods were employed to analyse soil physical and chemical properties. Micronutrients Fe, Mn, Cu and Zn were extracted by DTPA and quantities estimated spectrophotometrically. Spatial distribution of micronutrients along the geomorphic units and within pedons was studied using descriptive statistics, correlation, ANOVA and means separation was done by Tukey’s test at 95 % confidence interval in Minitab 14 software. Relationships between small mammal and flea abundance and micronutrients were established by regression analysis using R-software. Results showed that DTPA extractable Fe, Mn, Cu and Zn were variable. Fe ranged from 2.13 to 399.4 mg/kg soil, with a mean of 65.3 mg Fe/kg soil across the geomorphic units. Mn ranged from 0.59 to 266.28 mg Mn/kg soil while Cu ranged from 0.25 to 8.19 mg/kg soil with a mean of 2.98 mg Cu/kg soil. Results show that Zn ranged from 0.08 to 19.6 mg Zn/kg soil, with a mean of 1.16 mg Zn/kg soil. Generally, micronutrients declined with soil depth. The micronutrient levels were high in the geomorphic units with the trend: plateau > escarpment > plain. Iron was found to significantly P<.01 and P<.05 influence plague hosts and vectors. The study concludes that micronutrients vary with soils and geomorphic units. Iron had positive influence on plague hosts and vectors. Further research on the relationships between micronutrients, and plague hosts and vectors in different plague foci in the country is recommended.