MST-Zoological Sciences
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Browsing MST-Zoological Sciences by Author "Aloo, P. A."
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Item Characterization of coase particulate organic matter (CPOM) standing crop and its retentive structures along a low order tropical stream: Sagana river, Kenya(2012-01-09) Odhiambo, Charles Oduor; Mwangi, B. M.; Aloo, P. A.Retention capacity of coarse particulate organic matter (CPOM) was studied in a low order forested tropical stream, Sagana River, Kenya from February to October 2003. Sampling was carried out bi-weekly along a 100 metres stream stretch. Retentive features were examined for their abudance, type, size and distribution along the stream reach. The characteristics (length, breadth, area and volume) of the retentive features were measured and related to the amount of CPOM retained. A Hess sampler (area = 0.0299m2) was used for collecting benthic organic matter (BOM), which was then sorted into leaves barks, twigs, fruits, roots, wood debris and others. Prior to sorting, all associated macroinvertebrates were picked, identified, enumerated and classified to functional feeding group categories. The distribution and abudance was determined and related to the amount of CPOM retained by the retentive features. Materials from retentive features were ashed and weighed. The horizontal projection area (HPA) ranged from 0.64m2 to 3.76m2 and the volume of debris dam from 0.38m3 to 3.7m3. At the exposed riffle gravel bar (ERGB), the HPA varied greatly from 0 to 32.62m2. Large woody debris (LWD) retained the highest amount of BOM totaling 68.89g AFDWm-2 followed by ERGB with 65.34g AFDWm-2 and debris dam with a total of 58.83g AFDWm-2. Leaf litter dominated the BOG inputs accounting for over 47% at the debris dam Ficus thorningii leaves dominated the leaf inputs accounting for upto 44% of the total BOM. Correlation analysis showed that the most important factor influencing the accumulation of leaf litter was the volume of the debris dam (r = 0.83; p < 0.01). The highest microinvertebrate abudance was recorded at the exposed riffle gravel bar totaling to 675 individuals followed by LWD with 671 individuals and debris dam with a total of 537 individual. However, diversity and evenness was highest at the debris dam (H1 = 1.96; E = 0.67). Among the retention structures the main functional feeding groups were the collector-gatherers. The abundance increased greatly due to increased abudance of midges (Chironomids) and collector gathering mayflies (Baetis sp. Caenis sp. Afronurus sp. and Choroterpes sp.) Contrary to the predictions of the River Continuum Concept (RCC), macroinvertebrates belonging to the shredding functional group that were dominated by Scitidae (Coleoptera) and Tipulidae (Oligochaeta) constituted a small proportion of the total faunal abudance among the retentive structures. Organic debris dams and LWD, therefore, are extremely important components of the stream ecosystem. The present study showed that debris dam supported high diversity of rare macroinvertebrate taxa which is due to the highly heterogeneous architecture of dam, that offers a multitude of microhabitats for many functional feeding groups. They retain and regulate the size and amount of organic matter input within the system, thereby allowing it to be processed into finer size fractions rather than transported downstream in a coarse particulate form, which in turn affect the community structure of the stream ecosystem. It is therefore concluded that most of the relationships between macroinvertebrate assemblages and the BOM accumulation among the retentive features were due to the existence of good substrate grounds for refuge or attachment and as habitats for prey insects which various taxa feed upon and not BOM as food source.Item The risk of intestinal parasitic infections in Kisii municipality, Kenya(2011-12-08) Nyarango, Morerwa Robert; Aloo, P. A.; Kabiru, Ephantus W.Risk is a probability of an adverse outcome or a factor that raises the probability of outcome Intestinal parasites usually inhabit the gastro-intestinal tract during part or the whole of their life cycle. In human beings, intestinal parasites are often associated with poor personal hygiene and environmental conditions such as contamination of soil and water sources with human faeces resulting from poor sewage disposal hence a major source of intestinal parasite transmission. The study was carried out between December 2006 and June 2007 in Kisii Municipality. The main objective of this study was to establish the risk of infections by intestinal parasites in Kisii Municipality. Random sampling using lottery method was used to select specimens for the study. Parasitological analysis of foodstuffs and stool samples was done at Kisii level -5 Hospital. The Parasitological profile of stool samples was done by direct saline smear and formalin-ethyl acetate sedimentation while for food stuffs concentration of the suspension was used. A light microscope was used for the examination of trophozoites, ova and cysts of intestinal parasites. Food handling practices were observed using a check list and recorded during each sampling day. A computer program (SPSS 11.5 for Windows) was used for data analysis. Multiple logistic regression analysis was used to establish the relationship of various variables with intestinal parasites. The differences were considered to be statistically significant when the p-value obtained was less than 0.05. In all vegetables sampled, spider flower tested highly positive 17 (81.0%) for intestinal parasites while Kales tested least positive 11(52.4%). Out of 84 vegetables sampled 55(65.5%) were infested with intestinal parasites. There was a statistically significant difference observed between infestation rates of intestinal parasites and types of vegetables (x2 =179.12, df = 3 , p =0.000). The prevalence of intestinal parasites was significantly high in the meat samples stored in the open surface compared to those stored in the refrigerator (x2 = 37.628' df = 2, p=0.000). Additionally, high prevalence of intestinal parasites was observed in meat samples obtained from butcheries where the vendors served dual roles as cashier compared to the butcheries where there were vendors handling meat and cashier handling cash (x2 =65.737, df = 2, p=0.000). There was a significantly high prevalence of intestinal parasites on meat samples whose surfaces had houseflies (x2 =65.737, df = 2, P=0.000). Prevalence of intestinal parasites was high among food handlers of Kisii Municipality where out of 168 food handlers, 69 (41.1%) were infected with one or more intestinal parasites. Of the positive food handlers, 27 (13.1%) were infected with one species of protozoa while 37 (22.0%) were infected with one species of helminth and 5 (3.0%) had mixed infections. This study has shown that there were risks of acquiring intestinal parasitic infections from various sources with meat posing the highest risk of intestinal parasite transmission (75.9 %), followed by vegetables (65.5 %) and food handlers (41.1%) Out of 692 samples of various specimens examined 458 (66.2%) were infested with intestinal parasite, indicating a high overall risk of infections from various sources. The risk of infections by intestinal parasites from various sources indicated a statistically significant difference between various sources (x2 = 214.966, df = 2, p<0.00). The findings can be used to sensitize the public on the risk of acquiring intestinal parasites as a result of unhygienic food handling practices and can be adopted by municipal authorities to step up control measures for risk factors favouring intestinal parasitic infections.