Research Papers
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Item Age- and sex- specific differences in haematological abnormalities associated with HBB gene polymorphisms among patients infected with Plasmodium falciparum(Cellular, Molecular and Biomedical Reports, 2026) Kosiyo, Paul Mboya; Ayodo, George; Munde, Elly OchiengAge and sex influence haematological abnormalities in Plasmodium falciparum malaria, but their link to Beta sub-unit genes (HBB) gene polymorphisms is unclear. This study examined these factors in infected patients. In this analytical cross-sectional study of 234 participants in Kenya (90 infected with malaria, 144 non-infected; 20 with HbSS, 214 with HbAS/HbAA), individuals aged ≥6 months with fever >37.5°C were recruited. Participants were stratified by infection status, HBB genotype, and age groups (6–59, 60–120, >120 months). P. falciparum was detected via microscopy, hematological parameters with Celtac G MEK-9100K, and HBB genotyping by real-time PCR. Statistical tests compared proportions, laboratory features, and associations between age/sex and hematological abnormalities. Haemoglobin (Hb) was lower (p=0.002), while Mean cell volume (MCV) (p=0.036) and platelet count (p=0.046) were higher in those infected and have carriage of HbSS relative to those infected and have carriage of HbAS/HbAA, respectively. White blood cell count (WBC) was comparable between the two groups with p=0.076. Participants of age >120 months had increased odds of anaemia as shown by low Hb [OR=13.362, 95% CI=2.742-65.119, p=0.001], low HCT [OR= 3.132, 95% CI= 1.783-24.694, p= 0.002] and low RBC [OR=7.888, 95% CI=1.691-36.791, p=0.009]. Additionally, older patients had reduced risk of agranulocytosis [OR=0.208, 95% CI=0.056-0.778, p=0.002]. With respect to sex, platelets were higher (p=0.007) in infected females relative to infected males; none of the abnormalities was associated with sex within the context of this study's population and sample size. HBB polymorphisms modulate haematological abnormalities and older age (>120 months) is strongly associated with increased risk of anaemia, which is more pronounced in P. falciparum infection. Anaemia and related abnormalities are most evident in HbSS carriers compared to HbAS/HbAA, while sex shows no association with these haematological changes.Item Predictive analysis of criminal behavior based on age and height: A case study of inmate demographic in homabay prison kenya(International Journal of Professional Business Review, 2025-08-15) Okelo, Stephen LucasObjective: This study explored whether attributes such as —age and height—can help anticipate criminal behaviour among inmates in Homa Bay County, Kenya. It aimed to assess how effective age and height contributes to crime prediction. Theoretical Framework: The study was guided by criminology theories linking demographic variables to crime typologies, particularly the age–crime curve (Farrington, 2003; Ngugi & Mwangi, 2020) and studies associating physical traits such as height with aggressive crimes (Adeyemi & Olatunji, 2019). These frameworks supported the hypothesis that age and height jointly influence the likelihood and type of criminal activity. Conceptual Framework: The study was anchored on hypothesized relationships between inmate demographic variables (age and height) and the type of crime committed, as well as how these variables can be used to build predictive models for criminal behavior. Method: a desktop review and quantitative data analysis design was adopted. Target population include 290 records of inmate prisoners from Homa Bay prison. Data collection tools included a record of reported crimes. Quantitative data were analyzed using descriptive statistics and visualizations to examine how offences are distributed across age and height groups. Results and Discussion: the study showed a positive relationship between age and height, whereby age proved to be a stronger predictor, with offences peaking around age 28, while height plays a secondary role, showing modest associations with violent crimes at certain ranges (notably around 6.8 feet). Research Implications: The results provide valuable insights for law enforcement profiling, youth-focused preventive interventions, and rehabilitation planning in Kenya. Predictive models incorporating age and height could help reduce mistaken identity, strengthen criminal investigations, and guide correctional programming. Originality/Value: This study contributes original empirical evidence from a developing county, addressing gaps in criminal identification and supporting strategic decision-making in crime prediction and rehabilitation measures.Item Hydrology-Based Evaluation of Irrigation and Cropping Practices in Relation to Malaria Transmission in Western Kenya(2026-07-13) Jiang, Ai-Ling; Lee, Ming-Chieh; Atieli, Harrysone; Yan, Guiyun; Hsu, Kuo-linIrrigation is widely linked to increased malaria vector population and transmission in rural Africa, yet it remains essential for improving food security. Balancing agricultural productivity with public health therefore requires approaches that consider malaria risk. In this study, we integrated a hydrologic model with an agent-based malaria model to evaluate the impacts of cropping practices, irrigation strategies, and human and mosquito mobility on malaria transmission in Homa Bay, Kenya. We examined scenarios with single crops (either staple or cash crops) and mixed cropping systems, alongside irrigation methods including flood, intermittent, and drip irrigation. The modelling framework captures spatiotemporal dynamics of mosquito breeding habitats driven by crop water demands and irrigation scheduling. Results show that staple crops such as rice required approximately 12% more irrigation than vegetables but were associated with 3-7% lower transmission metrics. This suggests that the timing and spatial distribution of water application are more important than total irrigation volume in determining larval habitat conditions. Combining intermittent and drip irrigation reduced malaria prevalence by 44% relative to flood irrigation, as it limited the extent and persistence of larval habitats. Water-efficient irrigation strategies also concentrated transmission into smaller areas, making targeted interventions more feasible. Under these more heterogeneous risk patterns, human movement and vector dispersal played a critical role in shaping malaria prevalence. Overall, the integrated modelling approach provides a framework for evidence based agricultural planning that meets crop water demands while reducing malaria risk.Item Anopheles larval ecology and physicochemical characterization of larval habitats in Dire Dawa: an area colonized by Anopheles stephensi in Eastern Ethiopia(BioMed Central, 2026-08-01) Abiy, Ephrem; Degefa, Teshome; Balkew, Meshesha; Merga, Hailu; Zewdu, Deneke; Ayala, Alamayo; Atieli, Harrysone; Lee, Ming-Chieh; Zhou, Guofa; Yan, Guiyun; Yewhalaw, DelenasawBackground: Understanding mosquito larval ecology is crucial for effective vector control strategies. While much is known about Anopheles larval habitat distribution, the impact of landscape (urban vs. rural) on Anopheles stephensi larval distribution and population dynamics in Ethiopia remains unclear. Methods: A longitudinal study was conducted from February 2023 to December 2024 in aquatic habitats in urban, peri-urban, and rural areas of Dire Dawa city administration, eastern Ethiopia. Mosquito larvae and pupae were collected and reared in a field insectary until adult emergence. The female Anopheles were morphologically identified and further confirmed via polymerase chain reaction (PCR). The physicochemical parameters of the larval habitats were measured via a HANNA multiparameter water probe. Statistical analyses included general linear models, ANOVA, logistic regression, paired sample t tests, chi-square tests, principal component analysis and correlation analyses to assess larval presence, density, and distribution in relation to water physicochemical parameters across the three ecological settings. Results: A total of 23,526 larvae and 1,808 pupae of Anopheles mosquitoes were collected from 856 man-made habitats (bricks, plastic sheets, steel drums, tire tracks, canal ditches, and barrels) and 53 natural habitats (river edges, animal hoof prints , ponds, and swamps) in urban, periurban, and rural areas. Uncovered cemented cisterns were the main human-made larval habitats; river edges were the main natural habitats. Anopheles larvae were absent in the steel drums and plastic barrels at the rural sites. Anopheles larval density significantly differed across the different ecological settings (F=7.8, df =1, 908, p=0.005) and among the different larval habitat types (F= 326.2, df = 1, 907, p< 0.001), land use/surrounding environment (χ2 = 32.6, df = 13, p = 0.002), vegetation (χ2 = 27.1, df =12, p=0.008), shade coverage (χ2 = 25.9, df = 15, p=0.039), substrate type (χ2 = 34.1, df = 6, p < 0.001), and competitor/predator presence (χ2 = 14.6, df = 1, p = 0.001). However, larval presence was not associated with the presence of larval interventions (χ2 = 1.3, df = 1, p = 0.250). Water pH (r = 0.26, n =102, p < 0.050) and water pressure (r = 0.21, n= 102, p < 0.050) were the only water physicochemical parameters that were positively correlated with An. stephensi presence. Conclusion: An. stephensi was dominant in urban areas but was also present in rural areas. Existing larval source management methods do not prevent Anopheles from occurring in many habitats, indicating an urgent need for improved strategies.Item Reduced bio-efficacy of aged PermaNet® 3.0 Nets against local pyrethroid-resistant Anopheles arabiensis in Western Kenya(Frontiers in Tropical Diseases, 2026-01-30) Machani, Maxwell G.; Zhou, Guofa; Oyweri, Job; Nzioki, Irene; Githure, John; Atieli, Harrysone; Wang, Chloe; Zhong, Daibin; Lee, Ming-Chieh; Afrane, Yaw A.; Yan, GuiyunBackground: Long-lasting insecticidal nets (LLINs) are central to malaria control and designed to protect for up to three years; however, increasing pyrethroid resistance undermines their effectiveness. Piperonyl butoxide (PBO) LLINs, designed to enhance pyrethroid efficacy, are recommended in high-resistance areas, yet their long-term operational bio-efficacy remains unclear. This study evaluated the killing efficacy of PBO LLINs over three years of field use compared to standard LLINs and monitored insecticide resistance in local Anopheles gambiae s.l. populations. Methods: During a trial in Muhoroni, western Kenya (2021–2024), standard and PBO LLINs were collected at 6, 18, and 36 months of use. Residual bio-efficacy was assessed using WHO cone bioassays against a susceptible Anopheles gambiae s.s. Kisumu strain and field An. gambiae s.l. populations. WHO tube and bottle assays determined insecticide resistance, while synergist assay assessed metabolic resistance. Quantitative polymerase chain reaction detected target-site mutations (kdr-1014 F/S and Ace-1 G119S). Results: Molecular identification confirmed all An. gambiae s.l. were Anopheles arabiensis, showing increasing pyrethroid resistance, with deltamethrin mortality declining from 96.3% (2021) to 22.7% (2024) while remaining susceptible to pirimiphos-methyl and clothianidin. PBO pre-exposure restored deltamethrin mortality from 22.7% to 98.9%. The frequency of 1014F increased from 0.09 to 0.17 and 1014S from 0.04 to 0.06, with no Ace-1 mutations detected. Standard LLINs retained >80% efficacy against the susceptible strain for 18 months but were below threshold against field mosquitoes even when new. PBO LLINs were effective at baseline against field populations but declined sharply, with mortality dropping to 24% by 6 months. Overall, both net types exhibited a marked decline in killing efficacy over time against field mosquitoes, with mortality falling < 20% within six months. Conclusion: Anopheles arabiensis showed increasing pyrethroid resistance, driven largely by metabolic mechanisms. Standard LLINs showed suboptimal killing efficacy against field populations, while PBO LLINs achieved high baseline efficacy but declined significantly by six months. These findings indicate that PBO LLINs can improve protection against resistant vectors but may be insufficient in high-resistance areas, underscoring the need for alternative non-pyrethroid interventions, strategic deployment, and revised LLIN re-distribution cycles aligned with their functional lifespan.Item Comparative Economic Analysis of Clonal Tea Yield Response to Nitrogen Fertiliser Rates within Selected Geographical Areas in Kenya(International Journal of Tea Science, 2020-09-09) Rosebell A. Owuor; Alphonce J. Odondo; P. Okinda Owuor; David M. KamauTea sector contributes approximately 30% of export earnings in Kenya. Despite the industry continuing to realize positive gross margins, high costs of production coupled with weak trends in export prices threaten its future contributions. Nitrogen fertiliser is mandatory in tea production and its appropriate use promotes tea growth rate and yields. Previous studies using different tea cultivars established that optimal fertiliser rates varied with clones and geographical area of production. However, economics of nitrogenous fertilisers use on same tea cultivar in different tea growing regions in Kenya remains undefined. This study evaluated response of NPKS 25:5:5:5 fertiliser applied at 0, 75, 150, 225 and 300 kg N/ha/year on clone BBK35 to determine the viable economic rate under uniform management in different locations (Karirana, Timbilil, Changoi, Sotik Highlands and Kipkebe) within Kenya. The study used time series tea yield data and corresponding variable costs from field experiments running from 1997 to 2007. The data were subjected to Partial Budget Analysis (PBA) procedures for economic analysis of on-farm experiments. The economic returns varied with rate of nitrogen and region of production. Maximum marginal rate of return (MRR) were achieved at 75 kg N/ha/year at Kipkebe, Changoi and Timbilil, and 150 at Sotik Highlands and Karirana. However best economic returns were recorded at 300 kg N/ha/year in Kipkebe and Sotik Highlands, 225 kg N/ha/year in Changoi, and at 150 kg N/ha/year in Timbilil and Karirana. These results demonstrate that current uniform fertiliser recommendation rate of 100 to 220 kg N/ha/year may not be suitable for all regions. There is need to develop region specific nitrogen fertiliser requirements for tea growing areas in Kenya.Item Effects of Strategy Control Measures on Strategy Implementation at the Lake Victoria North Water Services Board, Homabay County,Kenya(2020-07) Belyndah Shitakwa Ligare; Thomas Okoth Otieno; Dr. Victor AliataThe Lake Victoria North Water Services Board (LVNWSB) in Homabay initiated a project with the aim of improving and expanding the network and infrastructure for drinking water and its sanitation in the county of Homabay. At that time, about 92% of the population had no access to piped water which was also of poor quality and high cost. Only 8% of the residents benefited from a continuous water supply. The Homabay Project is worth Ksh 300M which was to be completedby 2017 but up to date it has not been completed. The objective of this study was to establish the effect of strategy control measures on strategy implementation at the LVNWSB, in Homa Bay County, Kenya. The stakeholder theory was used in the study that suggests that an organization is a social construction made of interaction of various stakeholders. This study used correlation survey design.The target population for this study was 50 employees of LVNWSB. Census method was used to survey the target population. The respondents were given questionnaires that were administered through drop and pick method.The questionnaires were pre-tested by conducting a pilot survey from 5 respondents taken from the 50 employees using the internal consistency technique by employing Cronbach Coefficient Alpha test for reliability. Validity was determined using Content Validity Index (CVI). The research instrument was designedto collect qualitative and quantitative data. The researcher used multiple regression analysis using SPSS so as to determine the effects of independent variables on dependent variable.The study findings revealed that strategic control systems have a positive significant effect on strategy implementation (β=.389, p=.000). The study concluded that strategic control systems have positive effect on strategy implementation. The study therefore recommends that the government improves the strategic control measures to enhance strategy implementation at LVNWSB.Findings from this study will be valuable to a number of stakeholders in and outside thewater sector: expanding existing knowledge, referencing and finding comparisons in the quest of getting an ideal strategy-ethics composition and policy approach to stakeholder involvement that would improve service delivery.Item COMPOSITION-DIFFERENTIATION OPERATOR ON THE BERGMAN SPACE(Pan-American Journal of Mathematics, 2023) K. O. ALOO1; J. O. BONYO2; I. OKELLO1We investigate the properties of composition-differentiation operator Dψ on the Bergman space of the unit disk L2 a(D). Specifically, we characterize the properties of the reproducing kernel for the derivatives of the Bergman space functions. Moreover, we determine the adjoint properties of Dψ whenever ψ is self analytic map of the unit disk D.Item Structural Characteristics and Conduct of Sweet Potato Market in Rachuonyo Region, Kenya: Perception of Sweet Potato Farmers and Traders(East African Journal of Business and Economics, 2023-07-31) Dr. Alphonce Juma Odondo, PhD1*Myriad studies have been conducted on commodity markets in different parts of the world. However, such studies have yielded inconsistent results on various facets of market structure and market conduct, implying that each market may have its distinctive characteristics which impact on its performance. In SubSaharan Africa, the growth of sweet potato industry is hindered by lack of information on sweet potato market structural characteristics. Kenya’s sweet potato industry is facing a similar challenge. This scenario calls for a baseline survey on the sweet potato market structural characteristics and conduct as a basis for subsequent robust studies on the possible nexus between the market structure, conduct and performance of the industry. The study adopted a descriptive survey design based on interpretivism research paradigm. A sample size of 384 farmers, 166 retailers and 55 wholesalers were taken. Pretested questionnaires were used to gather perception of the respondents on various parameters based on a fivepoint Likert scale. The views were then summarized in terms of means scores. It was established that the sweet potato market was imperfect since there were notable elements of potato differentiation and barriers to entry into the market. Such barriers included competition from other traders and uncertainties in the demand for sweet potato. The situation was exacerbated by lack of suitable storage facilities given the perishable nature of the commodity. High market concentration was noted at the wholesale level, a likely indicator of price collusion and exploitation by the few large sellers that dominated the market. In this regard, there is need to enhance value addition activities that can enable the market players especially the farmers to be more competitive within the supply chain. Efforts should also be made to eliminate the identified market barriers.Item Job Promotion and Employee Performance among the Administration Police in Bungoma County, Kenya(Cross Current International Journal of Economics, Management and Media Studies, 2020) Belyndah Shitakwa Ligare; Dr. Kadian Wanyonyi Wanyama; Dr. Victor Lusala AliataAccording to Kenya Police Service Annual Crime Reports (KPSACR) of 2016, the number of criminal offences is still on the increase with the 2013, 2014 and 2015 reports evidencing an offence number of 71832, 72,490 and 73,376 respectively. Based on this upward trend, it is still unclear if the trend is related to human resource practices such as job promotion as applied in the administration police which in turn have an effect on the performance of the administration police. In the service industry, especially the Kenya National Police Service, little research has been conducted on job promotion and employee performance especially in Bungoma County. The purpose of this study was to establish the influence of job promotion on the performance of administration police. The study adopted a descriptive survey design. The target population was 1,318 administration police officers in Bungoma County rom which a sample size of 384 respondents was used. Questionnaires were the main instruments used to collect primary data. Stratified random sampling, simple random sampling and systematic random sampling techniques were used. Data was analyzed using both descriptive and inferential statistics. Reliability analysis gave an average Cronbach alpha value of 0.8034 which indicated that the instruments were reliable. Results of the study showed that there was a statistically significant positive relationship between job promotion and employee performance and that job promotion accounted for 71.3% (R2 = 0.713) variations in the employee performance. It was concluded that if job promotion was well executed in the administration police, the performance of the staff would be enhanced. The following were the recommendations of the study: organizations should adhere strictly to its promotion policy, ensure promotion process is fair and that employees are promoted based on merit. The findings of this study is expected to inform administration police management policy makers, the government and other stakeholders on relevance and implications of on job promotion in the administration police aimed at improving the performance of staff