Agricultural Engineering and Land Planning Collection

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A ‘Smart’ approach on fluoride removal: detection in water sources and removal with biomass
(Sokoine University of Agriculture, 2020-01) Mwakabona, Hezron
Fluoride is one of the common minerals found in natural water, ingestion of which, at moderate concentration, is linked to good dental health. However, ingestion of higher concentrations of this mineral over a period is responsible for fluorosis, a disorder characterised by mottling of teeth and skeletal deformations. Therefore, the WHO sets the highest permissible level of this mineral in drinking water at 1.5 mg/L to limit its effect on public health. Consequently, a water source with fluoride concentration above this highest permissible level is regarded as unfit for human consumption, hence, requiring a treatment before consumption. As such, several studies have explored different low-cost methods to detect and remove this contaminant from drinking water. These include defluoridation and detection of fluoride by plant biomass and iron-based materials, respectively. These materials arc attractive because they have a potential for providing efficacious and cost-effective methods to deal with this water contaminant. In this thesis, the challenges delaying their field application (in detection and removal) of fluoride arc identified and suitable solutions are presented. Furthermore, the properties of iron that make it suitable for fluoride detection and removal enhancement in aqueous media arc presented. A critical review of the studies published over the past three decades on water defluoridation by non-aciivated biomass reveals that, most studies explorc extensively only the defluoridation efficiency/capacily ofthese materials. This bias in studied properties is shown to be due to inadequacy in selection of study parameters, where, the defluoridation mechanisms are poorly studied. This could have resulted in the current poor understanding of their defluoridation mechanisms. Therefore, lessons from these studies were used to identify and propose the “must include” parameters to direct the future studies for better understanding of their defluoridation properties, especially, the defluoridation mechanisms. These are: effect of solution pH, point of zero charge and surface functional groups characterisation before and after material use. For plant biomass ash, the major challenge associated with its application in water defluoridation was found to be related to media-induced contamination of the treated water, notorious being the elevation of the pH of the treated water. This challenge could have repelled many possible applications of this material in water treatment besides its great potentials as water treatment material. In this study, the Cyperus plants were successfully
Effect of grating, chipping, dry fermentation and sun drying on cyanide level of cassava in Tongwe village.
(Sokoine University of Agriculture, 2009) Khatib ,M. A.
This study was conducted to evaluate effectiveness in cyanide reduction by four different methods of processing cassava roots, two traditional (dry fermentation and direct sun drying) and two improved methods (grating and chipping) and also assess losses due to cassava processing in Tongwe village (Muheza District). Presence of mycotoxin-producing organisms in fermented cassava flour was examined. Cyanogens were determined using the AOAC alkaline titration method. The microbial growth was done on plate using Sabouraud’s Dextrose Agar (SDA). The cyanide level, in the processed cassava differed significantly (p<0.05). Improved methods were more effective than traditional. The mean cyanide was; 6.79, 7.96, 8.96 and 9.90 mg HCN/kg DWB for grating, chipping, dry fermentation and direct sun drying, respectively. Identification of mould revealed the absence of mycotoxin producing organisms and therefore ruled out the possibility of presence of mycotoxins in the dry fermented cassava flours collected from 60 households in Tongwe and 10 samples prepared in Tongwe cassava processing unit. Losses due to processing in all four methods were determined by calculating the difference between peeled fresh cassava weight and the weight of flour produced after processing. Results showed significant differences (p<0.05) between the traditional and improved methods studied. The mean percentage losses were; 67.28, 69.73, 51.83 and 54.14 for grating, chipping, dry fermentation and direct sun drying, respectively. Sensory evaluation done at SUA and Tongwe showed significant differences (p<0.05) in preferences between the stiff porridge prepared using flour from all four methods of processing cassava, the most preferred product being ugali from chipped cassava flour. This experiment has indicated that improved methods are more effective in cyanide reduction than traditional ones. However, traditional methods were more economical in processing losses and that there were no mycotoxin-producing organisms in fermented cassava flour. Both methods produce acceptable products worth encouraging if losses are minimized.
Land use systems change and its influence on people’s livelihood in South Eastern Tanzania
(Sokoine University of Agriculture, 2006) Tenga, John Jasper
A study was carried out in South Eastern Tanzania to evaluate spatial and temporal changes that have occurred over a period of 40 years in land use systems and their influence on people’s livelihood. Field survey, remote sensing and GIS techniques were employed to assess land use systems dynamics. A questionnaire survey was conducted to collect information on socio-economic activities related to land use systems change. Statistical analysis was done using SPSS and EXCEL programmes. The results indicate that land use systems in the study area vary spatially across geomorphic units in terms of patterns and degree of change. Between 1965 and 2004 areas under fallow bushland, fallow bushed grassland, reserved wooded grassland and reserved woodland decreased as a result of increasing area under agricultural land use systems. Geomorphic and soil characteristics are the major biophysical factors influencing dominant land use system pattern and change in the study area. Demographic change, land tenure and farming practices were the socio-economic drivers of the observed land use systems change. Land use systems change has influenced the people’s livelihood in the study area by increased household income. Increase of cultivated land with tree crops correlated significantly with price of cashewnut (R = 0.8582, P<0.05) and gross income (R = 0.8396, P<0.05) whereas cultivated land with annual crops correlated negatively with market accessibility (R = 0.8906, P<0.05). In view of observed land use systems dynamics, further research is recommended to come up with comprehensive policy guidelines to check the imbalance between the cashewnut and annual crop production to safeguard food security while at the same time conserving the environment.
Evaluation of Irrigation Water Quality for Paddy Production at Bumbwisudi Rice Irrigation Scheme, Zanzibar
(TAJAS, 2016) Kahimba, F.C; Ali, R. M; Mahoo, H.F
Human activity spaces and plague risks in three contrasting landscapes in Lushoto District, Tanzania
(Tanzania Journal of Health Research, 2014-07-14) Hieronimo, P.; Gulinck, H; Kimaro, D.N; Mulungu, L.S; Kihupi, N.I; Msanya, B.M; Leirs, H; Deckers, J.A
Since 1980 plague has been a human threat in the Western Usambara Mountains in Tanzania. However, the spatial-temporal pattern of plague occurrence remains poorly understood. The main objective of this study was to gain understanding of human activity patterns in relation to spatial distribution of fleas in Lushoto District. Data were collected in three landscapes differing in plague incidence. Field survey coupled with Geographic Information System (GIS) and physical sample collections were used to collect data in wet (April to June 2012) and dry (August to October 2012) seasons. Data analysis was done using GIS, one-way ANOVA and nonparametric statistical tools. The degree of spatial cooccurrence of potential disease vectors (fleas) and humans in Lushoto focus differs significantly (p ≤ 0.05) among the selected landscapes, and in both seasons. This trend gives a coarse indication of the possible association of the plague outbreaks and the human frequencies of contacting environments with fleas. The study suggests that plague surveillance and control programmes at landscape scale should consider the existence of plague vector contagion risk gradient from high to low incidence landscapes due to human presence and intensity of activities.
Influence of irrigation water quality on soil salinization in semi-arid areas: a case study of Makutopora, Dodoma-Tanzania
(International Journal of Scientific & Engineering Research, 2015) Batakanwa, F.J; Mahoo, H.F; Kahimba, F.C
This research was carried out in Dodoma, at Makutopora Agricultural Research Institute. The main objective was to determine the influence of irrigation water on soil salinization in semi-arid areas. A total of 80 representative soil samples were randomly collected from study area. Two water samples were also collected from the study area. The samples were treated and analyzed for physical and chemical related indices. The results are grouped into general quality parameters, which included salinity and salt inducing cations and anions. The findings indicated that the mean pH was 7.53 while the mean EC value was 944.5 μS/cm. The mean cations in the water were 3.97, 4.32, 2.57, and 11.39 meq/l for Ca2+, Mg2+, K+, and Na+, respectively. The Sodium Adsorption Ratio (SAR) was 5.60. The mean carbonates concentration detected in the irrigation water was 9.05 meq/l, while the mean chloride and sulfide were 17.20 and 3.6 meq/l, respectively. Soil samples were grouped into three major groups namely non-irrigated, half irrigated, and full irrigated soils. For the non-irrigated, half irrigated, and full irrigated soils: the mean pH in the soil was 6.59, 6.89 and 7.04, respectively; the mean ECe were 94.35, 338.5, and 344.72, mS/cm, respectively; SAR was 0.76, 2.64, and 4.82, respectively; exchangeable cations and anions as shown in Table 4, 6 and 8. The results reveal that water may have the potential to be hazardous to the soil as well as to the crop grown because most parameters were above safe limits. The linear regression model showed high correlation of soil salinity with exchangeable bases with R2 =0.776 and significant at p≤0.04 for non-irrigated soil, R2=0.627 at p≤0.001 for half irrigated soil, and R2=0.597 at p≤0.003 for full irrigated soil. For all soil samples the linear regression model shows strong relationships that exist between the soil salinity and exchangeable bases present in the soil. It is recommended that adequate drainage with emphasis on surface drainage should be provided and salt and sodium build up should be monitored regularly
Risk Factors Associated with Elevated Blood Glucose Among Adults in Mwanza City, Tanzania
(2015) Ruhembe, C. C.; Mosha, T. C. E.; Nyaruhucha, C. N. M.
Type 2 diabetes mellitus (T2DM) prevalence is increasing at alarming rates posing significant health problem in Tanzania. Urbanization with economic advancement has led to lifestyle behaviors such as high intake of dense caloric foods, sedentary lifestyle, smoking, and limited intake of fruits and vegetables. All these have been associated with higher prevalence of cardiovascular diseases, hypertension and T2DM. This cross-sectional study was conducted to assess the risk factors and lifestyles characteristics associated with type 2 diabetes mellitus among adults in Mwanza city, Tanzania. A multistage random sampling technique was used to obtain 640 male and females respondents aged 30 and above years. Data were collected through face to face interview by using a structured questionnaire which was constructed to solicit information about risk factors and lifestyle characteristics of the respondents. Anthropometric measurements such as height, weight, waist and hip circumferences and total fat and fat free mass were also taken. Random blood glucose and blood pressure levels were measured. Prevalence of overweight in the studied population was 10.5% in males and 18.1% in females. Most females (60.8%; n=79) had waist hip ratio of ≥ 0.85. BMI and body fat were significantly (p˂0.05) related to elevated blood glucose. It was further noted that, relationship between diabetic respondents with their first degree relatives with diabetes was significant (p˂0.05). The relative risk for developing type 2 diabetes mellitus by having first class relative with the disease was RR 2.11, (95% CI: 1.4-3.1). There was a strong (p˂0.05) association between smoking and elevated blood glucose. It can be concluded that it is of utmost importance to intervene, and modify lifestyle behaviours of adults so as to reduce the risks of developing T2DM.
Maize cultivar specific parameters for decision support system for agrotechnology transfer system (DSSAT) application in Tanzania
(2013) Mourice, S. K.; Rweyemamu, C. L.; Tumbo, S. D.; Amuri, N.
In order to develop basis for tactical or strategic decision making towards agricultural productivity improvement in Tanzania, a new approach in which crop models could be used is required. Since most crop models have been developed elsewhere, their adaptation, improvement and/or use outside their domain of development requires a great deal of data for estimating model parameters to allow their use. Cultivar specific parameters for maize varieties in Tanzania have not been determined before and consequently, crop modelling approaches to address biophysical resource management challenges have not been effective. An overall objective of this study was to evaluate DSSAT (v4.5) Cropping System Model (CSM) using four adapted maize cultivars namely Stuka, Staha, TMV1 and Pioneer HB3253. The specific objectives were; to determine maize crop growth and development indices under optimum conditions, to estimate maize cultivar parameters, and to evaluate DSSAT CSM for simulating maize growth under varied nitrogen fertilizer management scenarios. The results indicate that maize cultivars did not differ significantly in terms of the number of days to anthesis, maturity, or grain weight except final aboveground biomass. Also there was no difference between variables with respect to growing seasons. The cultivar specific parameters obtained were within the range of published values in the literature. Model evaluation results indicate that using the estimated cultivar coefficients, the model simulated well the effects of varying nitrogen management as indicated by the agreement index (d-statistic) closer to unity. Also, the cultivar coefficients which are difficult to measure physically were sensitive to being varied indicating that the estimated values were reasonably good. Therefore, it can be conclude that model calibration and evaluation was satisfactory within the limits of test conditions, and that the model fitted with cultivar specific parameters that can be used in simulation studies for research, farm management or decision making.
Accuracy of Giovanni and Marksim software packages for generating daily rainfall data in selected bimodal climatic areas in Tanzania
(Tanzania Journal of Agricultural Sciences, 2014) Kahimba, F. C.; Tumbo, S. D.; Mpeta, E.; Yonah, I. B.; Timiza, W.; Mbungu, W.
Agricultural adaptation to climate change requires accurate, unbiased, and reliable climate data. Availability of observed climatic data is limited because of inadequate weather stations. Rainfall simulation models are important tools for generating rainfall data in areas with limited or no observed data. Various weather generators have been developed that can produce time series of climate data. Verification of the applicability of the generated data is essential in order to determine their accuracy and reliability for use in areas different from those that were used during models development. Marksim and Giovanni weather generators were compared against 10 years of observed data (1998-2007) for their performance in simulating rainfall in four stations within the northern bimodal areas of Tanzania. The observed and generated data were analyzed using climatic dialog of the INSTAT program. Results indicated that during the long rain season (masika) Giovanni predicted well the rainfall amounts, rainy days, and maximum dry spells compared to Marksim model. The Marksim model estimated seasonal lengths much better than the Giovanni model during masika. During short rain season (vuli), Giovanni was much better than Marksim. All the two software packages had better predictions during masika compared to vuli. The Giovanni model estimated probabilities of occurrence of rainfall much better (RMSE = 0.23, MAE = 0.18, and d =0.75) than Marksim (RMSE = 0.28, MAE = 0.23, and d = 0.63). The Marksim model over-predicted the probabilities of occurrence of dry spells greater than seven days (MBE = 0.17) compared to the Giovanni model (MBE = 0.01). In general the Giovanni model was more accurate than the Marksim model in most of the observed weather variables. The web based Giovanni model is better suited to the northern bimodal areas of Tanzania. The Marksim model produced more accurate climatic data when the long-term average climate data are used as input variables. This study recommends the use of rainfall data generated using Giovanni software over Marksim, for areas receiving bimodal rainfall regimes similar to the northern bimodal areas of Tanzania.
Enhancing response farming for strategic and tactical management of risks of seasonal rainfall variability
(2014) Admassu, H.; Mahoo, H. F.; Rwehumbiza, F. B. R.; Tumbo, S. D.; Mogaka, H.
Seasonal rainfall variability, particularly the uncertainty with respect to the direction and extent that variability will assume in a given season, forms the greatest source of risk to crop production in semi-arid areas of Ethiopia. Equipping vulnerable communities, in advance, with the expected date of onset of a cropping season, is crucial for smallholder farmers to better prepare to respond and manage the uncertainties. Therefore, rainfall prediction, particularly development of models that can foretell the date of onset of next cropping season is crucial in facilitating strategic agronomic planning and tactical management of in-season risks. A twenty-four-year climatic data study was conducted for Melkassa Agricultural Research Centre (MARC) in semi arid Ethiopia, to develop onset date prediction models that can improve strategic and tactical response farming (RF). A sequential simulation model for a build up of 15 to 25 mm soil water by April 1st, was conducted. Simulation results revealed a build up of soil water up to 25 mm, to be the most risk-wise acceptable time of season onset for planting of a 150-day maize crop. In the context of response farming, this was desirable as it offers the opportunity for farmers to consider flexible combination production of maize (Zea mays L.) varieties of 120 and 90 days in the event of failure of earliest sown 150-day maize crop. Thus, to allow for flexible combination production of the three maize varieties, predictive capacity was found crucial for April onset of the next crop season. Accordingly, based on the consideration of pre-onset rainfall parameters, the first effective rainfall date varied considerably with the date of onset of rainfall. Regression analyses revealed the first effective rainfall date to be the best predictor of the date of onset (R2 = 62.5%), and a good indicator of the duration of next season (R2 = 42.4%). The identified strategic predictor, the first effective rainfall date, enabled prediction of time of season onset and season length by a lead time of two to three months. This markedly improved Stewart’s RF. The date of onset of the next crop season was also found to be a useful predictor of season duration (R2 = 87.3%). Strategic agronomic planning should be adjusted according to the first effective rain date, and tactically according to what date of rainfall onset informs us about expectations in the duration and total season water supply.
Tanzania CMIP5 Climate Change Projections
(2016) Tumbo, S. D.; Ngongolo, H.; Sangalugembe, C.; Wambura, F.; Mlonganile, P.
This paper presents updated climate change projections for Tanzania based on Coupled Model Intercomparison Project phase 5 (CMIP5) using Mid-Century Representative Concentration Pathway (RCP) 8.5. A total of twenty global circulation models (GCMs) were downscaled based on the eleven Tanzania climatological zones using thirteen synoptic weather stations. For each climatological zone, the skill score test of the 20 GCMs was done against the observed rainfall and the threshold of 80% except for one zone, which used threshold of 75%, to select GCMs for projecting future rainfall and temperature. It was found that in all the climatological zones the number of GCMs which performed above the threshold ranged between five and twelve. Rainfall and temperature of skilled GCMs were then downscaled by Delta method and then evaluated for uncertainty. The skill score test showed that climatological zones in the western part of Tanzania had higher skills and higher agreement compared to zones located in the eastern side. Stations in the bimodal rainfall zones such as Musoma and Same showed high level of uncertainty in the projected future rainfall and temperature. Temperature uncertainty was ± 0.4oC for Same, Musoma and Dodoma stations followed by Songea and Mbeya at ± 0.3oC. On average, temperature was projected to increase by about 0.9oC and also rainfall to increase but mainly in the month of April in the central and southern zones.
Integrated catchment characteristics, runoffwater reservoir capacities and irrigation - requirement for bean productivity
(2013) Singa, D. D.; Tumbo, S. D.; Mahoo, H. F.; Rwehumbiza, F. B. R.; Lowole, M. W.
Crop production in semi-arid Sub-Saharan Africa (SSA) is limited by over-reliance on rainfall, which is erratic and inadequate. Rainwater conservation and irrigation are needed to avert drought effects and dry spells, and extend crop production activities to dry seasons. A study was conducted from 2011 to 2013 at Ukwe area in Malawi, to determine the size of seasonal open surface reservoir and crop field in relation to catchment characteristics among smallholder farming communities, using beans as a case study crop. There is positive linear relationship between seasonal harvested watershed runoff and rainfall (over 75%). Based on the catchment characteristics and crop water requirement, catchment/cultivated area ratio was 2.1. Harvested runoff water is linearly related to seasonal rainfall amount. About 6000 m3 of water was required to irrigate a hectare of beans. Total volume harvested was estimated to support six-fold the current field area at bean water productivity of 0.7 g L-1. It is possible to determine dry season bean water productivity based on integrated effects of catchment characteristics, runoff water reservoir capacities and irrigation water requirement.
Investigation of sorghum yield response to variable and changing climatic conditions in semi-arid central Tanzania: Evaluating crop simulation model applications
(2013) Msongaleli, B.; Rwehumbiza, F. B. R.; Tumbo, S. D.; Kihupi, N.
Combination of global circulation models (GCMs), local-scale climate variability and crop simulation models were used to investigate rain-fed sorghum yield response under current and future climate in central Tanzania. Decision Support System for Agrotechnology Transfer (DSSAT) v.4.5 and Agricultural Production Systems Simulator (APSIM) v 7.4 were calibrated and evaluated to simulate sorghum (Sorghum Bicolor L. Moench) var. Tegemeo in 2050s compared to baseline. Simulated median yields from both crop models for the baseline (1980-2010) agree with the trend of yield over the years realistically. The models predicted yields of sorghum in the range from 818 to 930 kg ha-1 which are close to the current national average of 1000 kg ha-1. Simulations by both models using downscaled weather data from two GCMs (CCSM4 and CSIRO-MK3) under the Fifth Coupled Model Intercomparison Project (CMIP5) and Representative Concentration Pathway (RCP 4.5) by mid-century show a general increase in median sorghum yields. Median sorghum yields will increase by 1.1% - 7.0% under CCSM4 and by 4.0% - 12.5% under CSIRO-MK3. Simulations for both current and future periods were run based on the present technology, current varieties and current agronomy packages. This examination of impacts of climate change revealed that increase in sorghum yield will occur despite further projected declines or increase in rainfall and rise in temperature. Modifying management practices through adjustment of sowing dates and the choice of cultivars between improved and local are seemingly feasible options under future climate scenarios depending on the GCM and the direction of the management practice. Our simulation results show that current improved sorghum cultivars would be resilient to projected changes in climate by 2050s, hence bolstering the evidence of heat and drought tolerance in sorghum crop, thus justifying its precedence as an adaptation crop under climate change. We conclude that despite the uncertainty in projected climate scenarios, crop simulation models are useful tools for assessing possible impacts of climate change and management practices on sorghum.
Simulation of water productivity for Maize under drip irrigation
(Tropentag, 2011) Festo, R.; Bobert, J.; Mahoo, H.; Kashaigili, J.
Water has become increasingly scarce in most of the countries in the world. To use the available water efficiently in crop production, agricultural water productivity (WP) need to be improved. Drip irrigation systems and deficit irrigation practices are the most ef- ficient methods in improving WP. Availability of soil-water-crop simulation and climatic models can also help in the efforts to improve WP. A study was conducted in Morogoro using CROPWAT model to simulate water productivity of maize under drip irrigation by supplying different water deficits. A completely randomised block design was used with three replications and four treatments. The treatments were T1, T2, T3 and T4 represen- ting 60, 40, 20, 0 percent deficit of ETC (crop evapo-transpiration) respectively. Biomass accumulation (at 45 and 75 days after planting; DAP), grain yield and harvest index we- re determined for each treatment and experimental yield reductions were calculated. The CROPWAT simulation was done for each water deficit level and yield reductions were recorded. A comparison was made between experimental and simulated yield reductions. The mean biomass production between the treatments at 45 DAP were not significant dif- ferent (p < 0.05). At 75 DAP mean biomass production (0.684, 0.728, 1.049, 1.378 kg m-2 for T1, T2, T3 and T4 respectively) were highly significant different (p < 0.05). The mean grain yield between treatments, mean water productivity (1.67, 2.2, 1.78, 1.72 kg m-3 for T1, T2, T3 and T4 respectively) and harvest index values were significant different (p < 0.01). Experimental and CROPWAT simulated yield reductions were not significant different (p < 0.01) at all stages for all the treatments. The CROPWAT model adequately simulated the experimental yield response to water for maize (maize water productivity).
Major factors influencing the occurrence of landslides in the northern slopes of the Uluguru mountains, Tanzania
(2000) Kilasara, M.; Mtakwa, P. W.; Poesen, J.; Deckers, J. N.
Landslide mitigation largely depends on the understanding of the nature of the factors that have direct bearing on the occurrence oflandslides. Identification of these factors is of paramount importance in setting out appropriate and strategic landslides control measures. The present study focused on the identification of the major factors influencing the occurrence oflandslides in the Northern slopes of the Uluguru Mountains, Tanzania. The main objective was to establish relationship between spatial distribution of landslides and their causative factors. Such information would enable the planning of appropriate and strategic control measures. Aerial photographs, field survey and Geographic Information System (GIS) techniques were employed to identify the landslides features which occurred during EL NINO rains, spatial distribution and their corresponding factors. The results show that landslides dominate the geomorphic units with slope gradient ranging from 25% to over 80%. The most affected geomorphic units are in the order: debris slopes> incisions and V-shaped valleys > amphitheatres. Factors which cause theoccurrence of landslides are both soil and terrain related. The most important soil characteristics are presence of shallow soil solum with low bulk density and high macro porosity overlying a relatively less porous saprolite or hard bed rock. The terrain related factors include: undercutting of slopes by roads and pathways and presence of very steep concave side slopes. Water flow from roads and pathways and seepage from irrigation channels are precursors for the triggering oflandslides in the study area.
Small mammals distribution and diversity in a plague endemic area in West Usambara Mountains, Tanzania
(Tanzania Journal of Health Research, 2014-07-03) Ralaizafisoloarivony, Njaka A.; Kimaro, D. N.; Kihupi, Nganga I.; Mulungu, Loth S.; Leirs, Herwing; Deckers, J.; Msanya, B. M.; Gulinck, Hubert
Small mammals play a role in plague transmission as hosts in all plague endemic areas. Information on distribution and diversity of small mammals is therefore important for plague surveillance and control in such areas. The objective of this study was to investigate small mammals’ diversity and their distribution in plague endemic area in the West Usambara Mountains in north-eastern Tanzania. Landsat images and field surveys were used to select trapping locations in different landscapes. Three landscapes with different habitats were selected for trapping of small mammals. Three types of trap were used in order to maximise the number of species captured. In total, 188 animals and thirteen species were captured in 4,905 trap nights. Praomys delectorum and Mastomys natalensis both reported as plague hosts comprised 50% of all the animals trapped. Trap success increased with altitude. Species diversity was higher in plantation forest followed by shrub, compared to other habitats, regardless of landscape type. It would therefore seem that chances of plague transmission from small mammals to humans are much higher under shrub, natural and plantation forest habitats.
Land use determinants of small mammal abundance and distribution in a plague endemic area of Lushoto District, Tanzania
(Tanzania Journal of Health Research, 2014-07) Hieronimo, Proches; Kimaro, D. N.; Kihupi, Nganga I.; Gulinck, Hubert; Mulungu, Loth S.; Msanya, B. M.; Leirs, Herwing; Deckers, J.
Small mammals are considered to be involved in the transmission cycle of bubonic plague, still occurring in different parts of the world, including the Lushoto District in Tanzania. The objective of this study was to determine the relationship between land use types and practices and small mammal abundance and distribution. A field survey was used to collect data in three landscapes differing in plague incidences. Data collection was done both in the wet season (April-June 2012) and dry season (August- October 2012). Analysis of variance and Boosted Regression Trees (BRT) modelling technique were used to establish the relationship between land use and small mammal abundance and distribution. Significant variations (p ≤ 0.05) of small mammal abundance among land use types were identified. Plantation forest with farming, natural forest and fallow had higher populations of small mammals than the other aggregated land use types. The influence of individual land use types on small mammal abundance level showed that, in both dry and wet seasons, miraba and fallow tended to favour small mammals’ habitation whereas land tillage practices had the opposite effect. In addition, during the wet season crop types such as potato and maize appeared to positively influence the distribution and abundance of small mammals which was attributed to both shelter and food availability. Based on the findings from this study it is recommended that future efforts to predict and map spatial and temporal human plague infection risk at fine scale should consider the role played by land use and associated human activities on small mammal abundance and distribution.
Integrating land cover and terrain characteristics to explain plague risks in Western Usambara Mountains, Tanzania: a geospatial approach
(Tanzania Journal of Health Research, 2014-07) Hieronimo, Proches; Meliyo, Joel; Gulinck, Hubert; Kimaro, D. N.; Mulungu, Loth S.; Kihupi, Nganga I.; Msanya, B. M.; Leirs, Herwing; Deckers, J.
Literature suggests that higher resolution remote sensing data integrated in Geographic Information System (GIS) can provide greater possibility to refine the analysis of land cover and terrain characteristics for explanation of abundance and distribution of plague hosts and vectors and hence of health risk hazards to humans. These technologies are not widely used in East Africa for studies on diseases including plague. The objective of this study was to refine the analysis of single and combined land cover and terrain characteristics in order to gain an insight into localized plague infection risks in the West Usambara Mountains in north-eastern Tanzania. The study used a geospatial approach to assess the influence of land cover and terrain factors on the abundance and spatial distribution of plague hosts (small mammals) and plague vectors (fleas). It considered different levels of scale and resolution. Boosted Regression Tree (BRT) statistical method was used to clarify the relationships between land cover and terrain variables with small mammals and fleas. Results indicate that elevation positively influenced the presence of small mammals. The presence of fleas was clearly influenced by land management features such as miraba. Medium to high resolution remotely sensed data integrated in a GIS have been found to be quite useful in this type of analysis. These findings contribute to efforts on plague surveillance and awareness creation among communities on the probable risks associated with various landscape factors during epidemics.
Contribution of land use to rodent flea load distribution in the plague endemic area of Lushoto District, Tanzania
(Tanzania Journal of Health Research, 2014-07) Hieronimo, Proches; Kihupi, Nganga I.; Kimaro, D. N.; Gulinck, Hubert; Mulungu, Loth S.; Msanya, B. M.; Leirs, Herwing; Deckers, J
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.
Vegetation habitats and small mammals in a plague endemic area in Western Usambara Mountains, Tanzania
(Tanzania Journal of Health Research, 2014-07) Ralaizafisoloarivony, Njaka A.; Kimaro, D. N.; Kihupi, Nganga I.; Msanya, B. M.; Mulungu, Loth S.; Leirs, Herwing; Deckers, J.; Gulinck, Hubert
Human plague still exists in different parts of the world, including some landscapes in north- eastern Tanzania. Wherever the hotspot of plague, small mammals seem to play a key role as host. The objective of this study was to investigate the relationship between vegetation habitats types and small mammals in a plague endemic area of Lushoto District in Tanzania. A combination of field survey and Landsat images was used to identify the vegetation habitats. Small mammals were trapped in the mapped vegetation units, and identified. In total, six main types of vegetation habitats were investigated. A total of 13 small mammal species, potentially related to plague were trapped. Results show that annual cultivated crops habitat accounted for 80% of Mastomys natalensis while natural forest accounted for 60% of Praomys delectorum. These findings have shed new light on the diversity of rodents in different habitats of natural and semi-natural vegetations, and agricultural crops in the study area, which is an important intermediate step in unravelling the complex human plague system.

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