Papers by Pixley K I P T U I Kipsumbai
Zooplankton are important as they play a role in the food webs of aquatic ecosystem. However, ant... more Zooplankton are important as they play a role in the food webs of aquatic ecosystem. However, anthropogenic activities have potential hazardous impact on zooplankton. Zooplankton responds rapidly to chemical and physical changes in the water environment they occupy. Thus, their presence in a reservoir is an important biological indicator of its water quality. The present study aimed to determine spatial and seasonal variation of zooplankton community structure in relation to water quality in Chemususu dam and associated rivers. Samples were taken from six sampling sites, River Sawich (R1) and River Barain (R2), which are the two main in-flowing rivers, in the dam three selected stations (D1, D2 and D3) and the outlet, river Chemususu (R3). The study was carried out during the dry season (December 2016 to March 2017) and wet season (May to July 2017). Water quality parameters was evaluated using YSI multiparameter, nutrients were analyzed using Hach calorimeter, and zooplankton composition using microscopy. Further the data analysis was done using diversity indices, descriptive statistics, analysis of variance and canonical correspondence analysis. The physicochemical parameters displayed disparity in relation to with temperature, dissolved oxygen, total dissolved solids, total soluble solids, salinity, pH, nitrates, and carbonates showed significant spatial variation while, conductivity, turbidity, phosphates, and chlorides indicated significant seasonal variation (p<0.05). Species diversity and evenness (Shannon Wiener) differed significantly (p<0.05) among the sampling sites. The highest values of both diversity and evenness were recorded in D1 while lowest value was reported in R. Chemususu. The highest values of both diversity and evenness were recorded during wet season. Findings further showed that physicochemical parameters recorded significant positive interrelationships with zooplankton abundance, which have links to anthropogenic activities within the study area. Canonical correspondence analysis (CCA) demonstrated that the first and second components accounted for 91.6% of variance with NO3, DO, Cl, salinity and TDS influencing the abundance of Rotifera and Ostracoda in the wet season. Whereas turbidity, CO3, conductivity and TSS influenced the abundance of Cladocera and
Brachiaria grass is one of the most important grasses distributed throughout the tropics especial... more Brachiaria grass is one of the most important grasses distributed throughout the tropics especially in Africa. The quality of forage yields and biomass of brachiaria is negatively affected by diseases among which leaf spot, leaf blight and leaf rust are the most common. This research was conducted to characterize the rust pathogen of brachiaria grass infected selected genotypes in Kenya based on pathological and morphological characteristics. Leaves with leaf rust pustules were collected from improved cultivars and natural population from brachiaria production and demonstration plots at the International Livestock Research Institute, Nairobi, Kenya. Pathogenicity of rust isolates was determined on the brachiaria cultivars in glasshouse. The growth conditions of rust pustules were determined by exposing into different regimes of relative humidity, temperature and time to germ tube development were established under rust ideal environmental conditions. The cultivars tested (MG4, Piat...
Mycoses, 2010
Tinea capitis is endemic among schoolchildren in tropical Africa. The objective was to determine ... more Tinea capitis is endemic among schoolchildren in tropical Africa. The objective was to determine the prevalence of symptomatic tinea capitis in schoolchildren in Gabon. A cross-sectional study was conducted with 454 children aged 4-17 years, attending a rural school and an urban school. The diagnosis of tinea capitis was based on clinically manifest infection, direct microscopic examination using 20% potassium hydroxide (KOH) solution and fungal culture. Based on clinical examination, 105 (23.1%) of 454 children had tinea capitis. Seventy-four (16.3%) children were positive by direct examination (KOH) and/or fungal culture. The prevalence of tinea capitis depended on the school studied and ranged from 20.4% in the urban school with a higher socioeconomic status to 26.3% in the rural school with a lower socioeconomic status. Similarly, the spectrum of causative species varied between the different schools. Taken the schools together, Trichophyton soudanense (29.4%) was the most prominent species, followed by Trichophyton tonsurans (27.9%) and Microsporum audouinii (25.0%). Clinically manifest tinea capitis is endemic among schoolchildren in the Lambaréné region in Gabon. The prevalence of tinea capitis and the causative species depended on the type of school that was investigated.
Brachiaria grass is one of the most important grasses distributed throughout the tropics especial... more Brachiaria grass is one of the most important grasses distributed throughout the tropics especially in Africa. The quality of forage yields and biomass of brachiaria is negatively affected by diseases among which leaf spot, leaf blight and leaf rust are the most common. This research was conducted to characterize the rust pathogen of brachiaria grass infected selected genotypes in Kenya based on pathological and morphological characteristics. Leaves with leaf rust pustules were collected from improved cultivars and natural population from brachiaria production and demonstration plots at the International Livestock Research Institute, Nairobi, Kenya. Pathogenicity of rust isolates was determined on the brachiaria cultivars in glasshouse. The growth conditions of rust pustules were determined by exposing into different regimes of relative humidity, temperature and time to germ tube development were established under rust ideal environmental conditions. The cultivars tested (MG4, Piata, Xareas and Marandu) were susceptible to rust diseases in the field as well as in controlled environment. In the field the percent disease incidence of 100% was recorded while disease severity was higher in MG4 (7.5 and 8.5) in 2016 and 2017, respectively in a disease severity scale of 0 to 9. The disease was least severe in Piata (2.5) in 2016 and in Marandu (3.0) in 2017. Under artificial inoculation and controlled growth conditions MG4 proved more susceptible (6.5) while, Piata (1.7) was less severe in glasshouse. However, under growth chamber Xareas was most affected with a disease score of 6.5. The isolate from MG4 was more virulent on MG4 than isolates obtained from other bracharia cultivars followed by isolates from Xareas , which caused disease severity of (3.5) on MG4. When the isolates were subjected to different environmental conditions it was established that optimum relative humidity of 75 % and temperature of between 20-25 0 C was ideal for germ tube germination. Germ tube germination started after the 8 th hour but stopped extending at the 24 th hour. Morphologically the isolates varied in spore size from 20µm to79µm and in spore shape which were oval or globose, but all were yellow in colour. These findings indicated high occurrence of leaf rust disease in bracharia cultivars with varying tolerance levels which can provide a potential source of resistance genes. Further it is advisable to institute control measures against leaf rust whenever relative humidity is above 75% and temperature of 20-25 0 C prevails.
Ringworm of the scalp (Tinea capitis) is a superficial fungal infection primarily caused by derma... more Ringworm of the scalp (Tinea capitis) is a superficial fungal infection primarily caused by dermatophytes that invade the hair shaft. Effective elimination of the fungi is dependent on the identification of the species associated to achieve the greatest treatment of the disease. This study investigated the occurrence of dermatophytes species causing head Tinea capitis. A total of 267 pupils were sampled from nursery level to standard five (<5years to 14 years) in Marigat in Baringo County and examined for the presence of scalp disease. Infected specimens were collected from head scalps of infected children. Using sterile scalpels and forceps, infected epilated hair was cut around the scalp region, collected aseptically and wrapped in sterile aluminum foil paper. The collected samples were transported to the Kenya Medical Research Institute laboratory, Nairobi, for isolation and identification. The data on the demographic features was collected using a structured questionnaire. The data were analyzed using parametric tests employing analysis of variance test and correlation analysis. The prevalence of tinea capitis among the pupils in Marigat was 39.4%, which was found to significantly vary (p<0.05) with gender, age, class and previous history of antifungal treatments. There were significant differences in the prevalence of the fungal species causing tinea capitis among the pupils (χ 2 = 11.285, df = 3, p = 0.0027). The most predominant dermatophyte species causing tinea capitis was Trichophyton tonsurans (48.3%) followed by Trichophyton mentagrophytes (37.1%) while, Nannizia gysea (29.2%) was the least prevalent among the species. It is clearly indicated that there is high occurrence of tinea capitis caused by three dermatophyte species. Therefore, there is need to device mechanisms to manage tinea capitis in this area.
World Journal of Agricultural Research, 2019
Spinach diseases caused by Alternaria spp. are one of the most significant devastating pathogens ... more Spinach diseases caused by Alternaria spp. are one of the most significant devastating pathogens to spinach in Kenya and worldwide. Alternaria alternata has been associated with great losses in spinach both in total biomass yield and leaf quality. The pathogen has been traditionally controlled using synthetic fungicides which are expensive and harmful to both humans and environment. This study aimed at investigating the efficacy of the extracts of two plants; Curcuma longa (Tumeric) and Zingiber officinale (Ginger) against Alternaria alternata both in in vitro and in vivo conditions. Absolute ethanol, water, ethyl acetate and methanol were the solvents used in extraction of Curcuma longa and Zingiber officinale rhizome extracts. Decoctions were screened for antimycotic potential using the poisoned food technique. Results from this study revealed that Curcuma longa and Zingiber officinale extracts had varying degree of antifungal activity against the Alternaria alternata depending on...
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Papers by Pixley K I P T U I Kipsumbai