Department of Zoological Sciences

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    The risk of pathogenic intestinal parasite infections in Kisii Municipality, Kenya
    (Karatina University, 2008-07-14) Nyarango, Robert M; Aloo, Peninah A; Kabiru, Ephantus W; Nyanchongi, Benson O
    Background: Intestinal parasitic infections are among the most common infections worldwide. Various epidemiological studies indicate that the prevalence of intestinal parasites is high especially in developing countries, although in many of these, the environmental risk factors have not been clearly elucidated. The objective of this study was to determine the risk of pathogenic intestinal parasites infections in Kisii Municipality. Methods: Random sampling was used in the selection of the study samples. Stool parasitological profiles of food handlers were done by direct smear and formalin-ethyl acetate sedimentation method. Both vegetable and meat samples were examined for the presence of intestinal parasites. The storage and meat handling practices of the various butcheries were observed. Results: Types of samples examined for occurrence of intestinal parasites includes, a total of 84 vegetable, 440 meat and 168 stool samples. Fifty five (65.5%) vegetable, 334 (75.9%) meat and 69 (41.1%) of the stool samples were found positive for intestinal parasites indicating a high overall risk (66.18%) for intestinal parasite infections. Of the parasites detected, the most common parasites infesting the foodstuffs and infecting the food handlers were Ascaris lumbricoides and Entamoeba histolytica. Parasites were significantly less likely to be present on meat that was refrigerated during display than meat that was displayed at ambient temperature. Conclusion: There is a high risk of infection with intestinal parasites in the sampled Municipal markets. About half of the food handlers surveyed (41.1 %) at the Municipal Hospital had one or more parasitic infections. Furthermore, meat (65.5%) and vegetables (75.9%) sold at the Municipal market were found to be contaminated with parasites hence the inhabitants requires a need for education on food safety, good distribution practices and improvement on sanitary conditions.
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    Lake Baringo: Addressing threatened biodiversity and livelihoods
    (2006-12-08) Odada, Eric O.; Onyando, Japheth O.; Obudho, Peninah A.
    Lake Baringo is a shallow, internal drainage, freshwater lake located in the Kenyan Rift Valley. The lake is an important source of water for humans and livestock, as well as a significant income source for local communities through activities such as tourism, biodiversity conservation, and fish sold in local markets. The lake has been subject to overfishing, as well as to greatly enhanced sedimentation as a result of land use changes in the drainage basin. This paper provides an analysis of the conditions prevailing at Lake Baringo, and examines in detail the management response to the problems facing the lake. The roles of the many and varied institutions in the lake basin's management are discussed, and an analysis of internationally funded projects designed to ameliorate the situation is provided
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    Biological diversity of the Yala Swamp lakes, with special emphasis on fish species composition, in relation to changes in the Lake Victoria Basin (Kenya): threats and conservation measures
    (2003-05) Aloo, P.A.
    During the second half of the last century, the Lake Victoria ecosystem has undergone drastic ecological changes. Most notable has been the decline in the populations of many endemic cichlid fishes. The lake has lost nearly 200 haplochromines and one tilapiine, Oreochromis esculentus. The above changes have been attributed to effects of species stocking and, in particular, from predation pressure by the introduced Nile perch, Lates niloticus. Other factors that have led to the decline of the endemic species include intensive non-selective fishing, extreme changes in the drainage basin, increased eutrophication, and the invasion of the lake by the water hyacinth, Eichhornia crassipes. However, the remnants of some species that had disappeared from Lake Victoria occur abundantly in the Yala Swamp lakes (Kanyaboli, Sare and Namboyo). This paper discusses the biodiversity of the swamp and the three lakes and gives suggestions for their conservation
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    Ecological studies of the Helminth parasites of fish in Lake Naivasha, Kenya
    (Karatina University, 1999) Aloo, P. A.
    In many parts of the world, wild stocks of fish are dwindling especially in Africa where drought, pollution and over-exploitation are some of the causative factors. The continent is not spared other climatic catastrophies such as global warning with its effects on the flora and fauna (both terrestrial and aquatic). This may lead to the manifestation of diseases caused by parasitic organisms, which have been known to co-exist with their hosts. The work reported here attempted to highlight the importance of studying the ecological relationship between parasites and their hosts in their wild environments i.e. the microhabitats (fish) and the macrohabitat (the lake). This work aimed at determing the distribution of four teleostean fishes Oreochromis leucostictus (Trewavas), Micropterus salmoides (Lacepede). Tilapia zillii (Gervais) and Barbus amphigrama (Boulenger) as hosts of the parasites, to establish the occurrence and prevalence of helminth parasites in each of the four species and to determine and quantify the relationships between the helminth parasites and the teleostean hosts. The distribution of the four fish species as hosts of the helminth parasites was studied for a period of two years. The occurrence of the helminth parasites, intensity of infection in each species, prevalence of each parasite on each host, differential establishment, seasonal variation in prevalence and intensity of infection and the effects of these parasites on their hosts were determined. The effect of water chemistry on the intensity of infection was established by comparing the main Lake Naivasha which is fresh and the more saline Oloidien Bay. Statistical tests used to establish the relationship between the parasites and their hosts were the chi-square, analysis of variance, split-plot technique and regression analysis. The results showed a significant variation in the monthly distribution of the fish species within the lake (F11,32=4.07, P<0.001). Fish abundance also varied within the sampling sites with Oreochromis leucostictus being the most abundant. Depth was found to be the only single factor influencing the distribution of fish in the lake with fish numbers decreasing with depth (b=3.04; t11=4.15, P<0.01). It was established that there are four helminth parasites whose larval stages infect Lake Naivasha fishes viz: a nematode, Contracaecum sp.; an acanthocephalan Polyacanthorhynchus kenyensis, a trematode Clinostomum sp and a dilepidid cestode of the genus Amirthalingamia. A differential establishment of these parasites on the hosts was observed. (F5,2860 =14.044; P<0.001). No significant variation was observed in the monthly occurrence of the parasites (F11,132=1, P>0.05). Host specificity was also revealed among the parasites with two parasites Clinostomum and Amirthalingamia being very specific on O. leucostictus and T. zillii respectively (F15,2860=21.63; P<0.001). A strong relationship between the intensity of infection and the sex of the fish was also revealed (X2(1)=64.43; P<0.001). Although the relationship between the age of the fish and the intensity of infection with Contracaecum sp. was not significant (t4=0.425;P>0.05), the intensity of infection of O. leucostictus with P. kenyensis increased with age (t4=7.061; P>0.01). These parasites showed no harmful effects no harmful effects on their host from the observation of the relationship between intensity with Contracaecum and the condition factor of the fish (F3,33=0.02; P>0.05). In conclusion, Lake Naivasha fish species do not harbour any ectoparasites but they are infected by larval stages of four endoparasites