Department of Biological Sciences
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Item Effectiveness of albendazole on soil transmitted nematodes among school children-: a case of Kakamega County, Kenya(2019-03-25) Ngonjo, T.W.; Okoyo, Collins; Simiyu, Elses; Kihara, Jimmy; Lelo, Agola Eric; Kabiru, Ephantus; Mwandawiro, CharlesBackground: Recent assessment by WHO on Soil Transmitted Nematodes (STN) point that their morbidity is still high in people mainly in children. A. lumbricoides globally infects 1.2 billion people and T. trichiura 795 million worldwide. Infections with Ancylostoma duodenale and Necator americanus 740 million leading to 135,000 deaths per year. It became necessary to find out the effectiveness of Albendazole on soil transmitted Nematodes among school children- a case of kakamega county, kenya. Methodology: Study respondents were selected fom public primary school children in Kakamega County. A total of 731 and 665 (pre & post) children in 7 primary schools in three sub counties of Kakamega County were recruited in the study. Pre-treatment survey was done in March, 2014 and follow up in September 2014. Fecal samples were examined for the presence of STN . 14 days after treatment using Kato- Katz method. The total number of eggs were expressed as eggs/gm of feaces (epg). Pretreatment prevalence was 43.5% for Ascaris lumbricoides, 1.8% for hookworm and 0.9% for Trichuris trichiura. Results: Mean intensity of hookworm, A. lumbricoides and T. trichiura infections in the pre-and post-surveys were reduced by 1.2%, 98.4% and 100% respectively. Prevalence decreased to 2.3% for Ascaris lumbricoides and 0 % for T. trichiura. Post treatment prevalence of A. lumbricoides and T. trichiura infections were significantly reduced by 94.8% and 100% respectively. A slight increase in hookworm prevalence was observed. However, this increase was not significant (p=0.993). Conclusion: The therapeutic efficacy of Albendazole indicated a good reduction in parasite burden. Albendazole satisfactorily reduced STN infection while for hookworm there was a non-significant increase in prevalence.Item Plasmid mediated penicillin and tetracycline resistance among Neisseria gonorrhoeae isolates from Kenya(2020) Kivata, Mary Wandia; Mbuchi, Margaret; Eyase, Fredrick; Bulimo, Wallace Dimbuson; Kyanya, Cecilia Katunge; Oundo, Valerie; Mbinda, Wilton Mwema; Sang, Willy; Andagalu, Ben; Soge, Olusegun O.; McClelland, Raymond Scott; Distelhorst, JohnBackground: Treatment of gonorrhea is complicated by the development of antimicrobial resistance in Neisseria gonorrhoeae (GC) to the antibiotics recommended for treatment. Knowledge on types of plasmids and the antibiotic resistance genes they harbor is useful in monitoring the emergence and spread of bacterial antibiotic resistance. In Kenya, studies on gonococcal antimicrobial resistance are few and data on plasmid mediated drug resistance is limited. The present study characterizes plasmid mediated resistance in N. gonorrhoeae isolates recovered from Kenya between 2013 and 2018. Methods: DNA was extracted from 36 sub-cultured GC isolates exhibiting varying drug resistance profiles. Whole genome sequencing was done on Illumina MiSeq platform and reads assembled de-novo using CLC Genomics Workbench. Genome annotation was performed using Rapid Annotation Subsystem Technology. Comparisons in identified antimicrobial resistance determinants were done using Bioedit sequence alignment editor. Results: Twenty-four (66.7%) isolates had both β-lactamase (TEM) and TetM encoding plasmids. 8.3% of the isolates lacked both TEM and TetM plasmids and had intermediate to susceptible penicillin and tetracycline MICs. Twenty-six (72%) isolates harbored TEM encoding plasmids. 25 of the TEM plasmids were of African type while one was an Asian type. Of the 36 isolates, 31 (86.1%) had TetM encoding plasmids, 30 of which harbored American TetM, whereas 1 carried a Dutch TetM. All analyzed isolates had non-mosaic penA alleles. All the isolates expressing TetM were tetracycline resistant (MIC> 1 mg/L) and had increased doxycycline MICs (up to 96 mg/L). All the isolates had S10 ribosomal protein V57M amino acid substitution associated with tetracycline resistance. No relation was observed between PenB and MtrR alterations and penicillin and tetracycline MICs.Item Barriers to Implementation of Green ICT in Kenya(2012) Wabwoba, F.; Wanyembi, Gregory W.; Omuterema, StanleyABSTRACT Information and Communication Technology (ICT) is playing an increasingly important role in both business and private undertakings. Its use in several areas in the world economy has brought about increased demand for electronic equipment. The rapid pace of technology advancement and the drop in hardware prices has led to increased demand and acquisition resulting in increased production and use of hardware. However, the increased ICT uptake has increased costs and demand for energy where electricity is the main power source. Electricity notably is a major contributor to climatic change because the coal or oil that helps generate it does releases carbon dioxide, pollutants, and sulphur into the atmosphere. With environmental degradation, rising costs of doing business and power demand and demand for social responsibility, going green is no longer an option. There are green ICT technologies in the market to mitigate the concerns but unfortunately they are not bearing fruit that calls for an understanding of barriers to implementation of the same in developing nations like Kenya. The study used multiple case study approach. The study population included ICT managerial, technical and end user human resource and public university ICT graduate students. The multiple study was conducted in one leading sugar manufacturing industry, a communication commission regulatory body and one public university offering ICT from certificate to PhD level. Respondents were either interviewed or responded to a questionnaire. The study established that green ICT technologies are available in Kenya and are not barriers to its implementation. The paper highlights the barriers to implementing green ICT in Kenya. The paper recommends alignment of ICTItem Green synthesis of copper oxide nanoparticles and its efficiency in degradation of rifampicin antibiotic.(Springer, 2023-08-28) Nzilu, Dennis Mwanza; Madivoli, Edwin Shigwenya; Makhanu, David Sujee; Wanakai, Sammy Indire; Kiprono, Gideon Kirui; Kareru, Patrick GachokiIn recent ages, green nanotechnology has gained attraction in the synthesis of metallic nanoparticles due to their cost-effectiveness, simple preparation steps, and environmentally-friendly. In the present study, copper oxide nanoparticles (CuO NPs) were prepared using Parthenium hysterophorus whole plant aqueous extract as a reducing, stabilizing, and capping agent. The CuO NPs were characterized via UV–Vis Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), powder X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Dynamic Light Scattering (DLS). The UV–Vis spectra of CuO NPs showed a surface plasmonic resonance band to occur at 340 nm. FTIR analysis revealed the presence of secondary metabolites on the surface of CuO NPs, with a characteristic Cu–O stretching band being identified at 522 cm−1. Scanning electron micrographs and transmission electron micrographs showed that CuO NPs were nearly spherical, with an average particle of 59.99 nm obtained from the SEM micrograph. The monoclinic crystalline structure of CuO NPs was confirmed using XRD, and crystallite size calculated using the Scherrer-Debye equation was found to be 31.58 nm. DLS showed the presence of nanoparticle agglomeration, which revealed uniformity of the CuO NPs. Furthermore, the degradation ability of biosynthesized nanoparticles was investigated against rifampicin antibiotic. The results showed that the optimum degradation efficiency of rifampicin at 98.43% was obtained at 65℃ temperature, 50 mg dosage of CuO NPs, 10 mg/L concentration of rifampicin solution, and rifampicin solution at pH 2 in 8 min. From this study, it can be concluded that CuO NPs synthesized from Parthenium hysterophorus aqueous extract are promising in the remediation of environmental pollution from antibiotics. In this light, the study reports that Parthenium hysterophorus-mediated green synthesis of CuO NPs can effectively address environmental pollution in cost-effective, eco-friendly, and sustainable ways.Item Functional response of Orius albidipennis (Hemiptera: Anthocoridae) to Megalurothrips sjostedti (Thysanoptera: Thripidae)(Karatina University, 2002-05-02) Gitonga (a), Linus M.; Löhrb (b), B.; Magambo (a), J. K.; Mueke (c), J. M.A locally available anthocorid predator, Orius albidipennis Reuter, was evaluated as a candidate biocontrol agent for Megalurothrips sjostedti Trybom, a major pest of French beans, Phaseolus vulgaris (L), in Kenya. The functional response of adult O. albidipennis to larval and adult M. sjostedti was studied at 15, 25, and 28 °C and densities of 5, 10, 20, and 30 larval and adult M. sjostedti per cage, over 24 h. More larvae and adult M. sjostedti were killed at the higher densities and with an increase in temperature. The data provided good fit to both type I and II functional response models. Attack rates increased with temperature for both the second instar larva and adult M. sjostedti. Handling times for the larvae decreased with an increase in temperature while those for the adults increased with increase in temperature. The implications of these results are discussed.Item Current Status of Soil-Transmitted Helminths among School Children in Kakamega County, Western Kenya Prevalence and Intensity of Intestinal Parasites in School age Children in Thika District, Kenya(Hindawi Publishing Corporation, 2016-02-17) Ngonjo, Teresia; Okoyo, Collins; Andove, Julius; Simiyu, Elses; Lelo, Agola Eric; Kabiru, Ephantus; Kihara, Jimmy; Mwandawiro, CharlesBackground. School age children are at high risk of soil-transmitted helminth (STH) worldwide. In Kenya, STH infections in children remain high despite the periodic administration of anthelmintic drugs. Our study assessed the prevalence and intensity of STH in primary school-aged children in Kakamega County, western Kenya. Methodology. We carried out a cross-sectional study on a population of 731 children attending 7 primary schools in March 2014. Children aged 4–16 years were examined for STH by the quantitative Kato-Katz technique. Infection intensities were expressed as eggs per gram (epg) of faeces. Findings. Among 731 school children examined for STH, 44.05% were infected. Highest prevalence of STH was in Shitaho primary school where 107 participants were examined and 62.6% were infected with mean intensity of 11667 epg. Iyenga had the least prevalence where 101 participants were examined and 26.7% were infected with mean intensity of 11772 epg. A. lumbricoides was the most prevalent STH species with 43.5% infected, while hookworm infections were low with 1.8% infected. Conclusion. Prevalence of STHs infections in Kakamega County remains high. We recommend guidelines and other control strategies to be scaled up to break transmission cycles.Item A new mite IPM strategy: predator avoidance behaviour resulting from the synergetic effects of predator release and acaricide‐treated nets(Wiley, 2018-10-26) Kungu, Miriam; Deletre, Emilie; Subramanian, Sevgan; Fiaboe, Komi Km; Gitonga, Linus; Lagat, Zipporah Osiemo; Thibaud, MartinBackground: Tetranychus evansi and T. urticae spider mites are known major pests of Solanaceae. Smallholders in Africa rely heavily on pesticide treatments. However, farmers claim that pesticides are generally ineffective despite high-frequency sprays. New management solutions are thus urgently needed. This study assessed the efficacy of using acaricide-treated nets combined with predatory mite release for controlling spider mites. Results: The results showed the acaricide-treated net alone was more effective at reducing numbers of T. urticae than T. evansi. We observed the opposite for release of the predatory mite Phytoseiulus longipes. This difference could be explained by the specific dispersion strategies of the two spider mite pests; T. evansi is gregarious, whereas T. urticae dispersed rapidly. Joint application of both techniques resulted in a synergetic effect that reduced T. evansi and T. urticae spider mite numbers close to zero. The synergetic effect could be explained by predator avoidance behaviour of the prey spider mites, resulting in higher prey trapping and killing rates on acaricide-treated nets, while P. longipes fed on spider mite eggs. Conclusion: These techniques are profitable for smallholders as they are not expensive and avoid residues on the crop. © 2018 Society of Chemical Industry.Item Bioecology of thrips in French bean growing ecosystem in Kenya(2012-10-31) Gitonga, Linus MuthuriStudies on the bioecology ofthrips on French beans were carried out at Machakos, Kaguru and JKUAT. The general objectives of this study were twofold, namely to study the biology and population dynamics of thrips on French beans and to identify and evaluate indigenous natural enemies of the thrips. Two thrips species, M sjostedti and F occidentalis were found throughout the year on French bean crops in all localities of the study. Their population peaks occurred at different times in the course of the year. Populations of M sjostedti peaked after the rains while those of F occidentalis occurred during the hot and dry months of the year at all the localities. Studies on the movements of thrips, into and out of the French bean crops showed that colonization by both species begins soon after germination and that both species preferred the flowers to other plant parts. F occidentalis was found to thrive equally well on the leaves, unlike M sjostedti which only inhabited flower buds and flowers. During the pre-flowering phase ofthe crop, M sjostedti were found on the terminal buds from where they moved to the flowers immediately after the onset of flowering. Most first instar larvae emerged from the pods and flowers. Petioles, leaves, flower buds, flowers and pods were used as oviposition substrates by the thrips.to varying extents. Analysis of the spatial distribution showed both species to be significantly aggregated in the respective plant parts. Laboratory studies indicated that developmental period decreased with an increase in temperature for all the stages of M sjostedti and F. occidentalis. Developmental threshold temperatures were calculated as 9.6 and 9.0 for M sjostedti and F. occidentalis respectively. Development from egg to adult required 212.0 and 256.8 Degree Days for M sjostedti and F. occidentalis respectively. However, at 15?C and 300C, mortality rates for all the developmental stages were higher for M sjostedti than F. occidentalis. The highest mortalities were recorded for the first instar larvae for both species, ranging from 15% to 42% and 11 % to 30% for M sjostedti and F. occidentalis respectively. Pre-pupae and pupae had the lowest mortality rates. An indigenous anthocorid bug, Orius albidipennis was found throughout the year in all the three field sites. Studies on the functional responses of 0. albidipennis to M sjostedti showed that more second instar larvae than adult M sjostedti were killed at all the temperature profiles and densities. With increase in temperature, more second instar larvae and adult M sjostedti were killed. High f2 values shows that both Types I and IT functional responses provided good fit for the data at 15?C, 25?C and 28?C. Attack rates also increased with an increase in temperature. Mortality rates of the 0. albidipennis nymphal instars decreased from the first to the 5th instar at all the temperatures. The mortality rates at 25?C were lower than at 20?C and 30?C for all the nymphal instars except the first instar. Temperatures had a significant effect on the pre-oviposition period, which decreased with an increase in temperature. The eggs took long to hatch at 20?C. Developmental periods of each of the nymphal instars decreased with an increase in temperature. An indigenous larval endoparasitoid of thrips, Ceranisus menes, was found throughout the year in the three localities and its population peaks occurred in the late and early months of the year, from October to April. A closer correlation was found between C. menes and F. occidentalis than with M sjostedti. At JKUAT, percentage parasitism, over the entire crop cycle, ranged from 3.5% to 19.5% and peaked in the months of Marchi April. The lowest percentage parasitism coincided with the period of the highest M sjostedti infestation on French beans. Linear regression analysis showed a density dependence relationship between parasitism and larval density. Laboratory experiments showed that C. menes successfully parasitized and completed development in both M sjostedti and F. occidentalis. Developmental times of C. menes in M sjostedti and F. occidentalis were not significantly different.Item Temperature-dependent development of Megalurothripssjostedti and Frankliniellaoccidentalis (Thysanoptera: Thripidae)(2002-09) Gitonga, Linus; Lohr, B.; Overholt, Bill; Magambo, J. K.Megalurothrips sjostedti (Trybom) and Frankliniella occidentalis (Pergande) (Thysanciptera: Thripidae) are among the most serious pests of French beans, Phaseolus vulgaris var. Monel in Kenya and occur in all major growing areas. The former seems to be prevalent during cold and rainy periods while the latter is mainly a problem during hot and dry conditions. The development of the two species was studied at temperatures ranging from 15 degreesC to 30 degreesC. The average developmental times of each stage are given. For both species, the developmental times decreased with an increase in temperature. The degree-days required to complete development from egg to adult were 212 and 256 above the estimated threshold temperatures of 9.6 degreesC and 9.0 degreesC for M. sjostedti and F.occidoitalis, respectively. Between 19 and 23 generations of M. sjostedti and between 17 and 20 generations of F. occidentalis; could possibly develop under Kenyan field conditions in one year. Overall mortality was lowest at 25 degreesC. Mortality rates for both species decreased from larval instars to adult and were higher for M. sjostedti than for F. occidentalis. Since the developmental times were not different, the differential pest status of M. sjostedti and F. occidentalis must be a result of other factors.Item Antimicrobial acitivity of extracts from Tephrosiavogelii Hook F.(Jomo Kenyatta University of Agriculture & Technology (JKUAT), Kenya, 2006) Wanga, B. N.; Akenga, T.; Imbuga, M.; Gitonga, L.; Olubayo, F.; Namungu, P.The dichloromethane extracts of the root and leaf of Tephrosia vogelii Hook F. (Family: Papilionaceae) grown in Kenya, were subjected to antimicrobial assays against Staphylococcus aureus, Escherichia coli and Fusarium phoseolida. The minimum inhibition concentrations (MIC) ranged between 0.25 to 6.4 μg/ml for all the microorganisms tested. The crude root and leaf extracts were also toxic to the brine shrimps, organisms used as indicators of toxicity (LC50: 0.960; 0.958μg/ml,respectively). Chromatographic separation led to the identification of (6aß, 12aß, 5'ß)-6a, 12a, 4',5'-tetra hydro-2,3-dimethoxy 5'-ß- isopropenyl–furano (3',2': 8,9)-6H-rotoxen-12-one, (rotenone) in 9.75% yield, (roots), and 11.75% (leaves). Characterisation was achieved by use of spectroscopic techniques and comparison with rotenone standard and literature data. Novel HPLC conditions for purification of rotenoids were established. The MIC of rotenone against the tested microbes was found to be 5.2 and 1.0 μg/ml for Staphylococcus aureus and Escherichia coli respectively, while the LC50 against the brine shrimps was found to be 3.20 μg/ml. The findings indicate that the extracts of T. vogelii contain metabolites that have antimicrobial activity comparable to other medicinal plants.