Browsing by Author "Lee, Dong-Kyu"

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    Effects of Temperature on the Growth and Development of Culex pipiens Complex Mosquitoes (Diptera: Culicidae)
    (IOSR Journal of Pharmacy and Biological Sciences, 2015) Lee, Dong-Kyu; Kiarie, Martha; Ngumbi, Philip
    This study sought to establish the direct effects of varying temperatures on the growth and development of the two members of the domestic mosquito, Culex pipiens complex; Culex pipiens pallens Coquillett and Culex pipiens molestus Forskal. The methods used were similar to those used by [18]. The mosquitoes used were obtained from colonies reared at the Kosin University; south Korea, Insectary at a temperature and relative humidity regime of 27 ± 1 oC and 75 ± 5% RH, respectively and a 13:11 light and dark photoperiod. The effects were evaluated in terms of embryonation times, length of the larval and pupal stages, the survival rates and maximum longevity of the female. Varying temperatures were found to have effects on egg embryonation, the lengths of the pupal and larval periods and the survival and longevity of the female mosquitoes. The results showed that in lower temperatures embryonation took longer among the 20oC and 24oC the larval and pupal stages were longer and the female mosquitoes lived longer. In higher temperatures (28oC), embryonation was faster, the larval and pupal stages were shorter and the females did not live for as long as they did at 20oC and 24oC. There were no significant differences (p > 0.05) in egg embryonation times between the two subspecies, at the three temperatures used in the study. There were no significant differences in the larval period between the two subspecies between 24oC and 28oC. However, the length of the pupal period in the two subspecies differed significantly (p < 0.05), at the three experimental temperatures. The pupal period of Cx. Pipiens pallens averaged 5.5, 6.5 and 2.7 days while that of Cx. pipiens molestus averaged 6.4, 4.3 and 2.28 days at 20oC, 24oC and 28oC temperatures, respectively.
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    Field efficacy and non-target effects of temephos granules against Culex pipiens (Diptera: Culicidae) and microorganisms in septic tanks, Republic of Korea
    (Entomological Research, 2011-01) Kang, Joo-Oh; Jeong, Dong Kwan; Lee, Dong-Kyu; Kang, Hyesook; Kiarie, Martha
    A granular formulation of 1.0% temephos (temephos G) was tested for its efficacy in mosquito larval control, residual effects and effects on non-target microorganisms. Culex pipiens complex in septic tanks in Yangsan, Republic of Korea were used for this study. Microorganisms in the same septic tanks were used for study of non-target organisms. After the application of temephos G at the rates of 2.0 and 5.0 mg/L to selected septic tanks, mortalities were recorded for 50 days. The effect of temephos G on non-target organisms was studied by evaluating its effects on the bacterial populations in the treated septic tanks. It was observed that using 1.0% temephos G at a rate of 2.0 mg/L resulted in 100% mortality against Cx. pipiens larvae by the eighth day after treatment. The residual activity of temephos G was observed to continue for a time; for example 29 days after treatment, average larval mortality rates of >68.0% were observed for both concentrations. At the 50th day after treatment, the mortality rates of the Cx. pipiens larvae were observed to decrease to below 42.7% for both concentrations. Application of temephos G did not have significant effects on the bacteria populations in the septic tanks. Since temephos did not seem to have any major effects on the microorganisms, it was concluded that it is a safe and effective larvicide to use in the septic tanks at a rate of 2.0–5.0 mg/L of 1.0% temephos G.
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    Relationship between Infections and poverty levels in Njoro District in Kenya - Kosin Journal of Health Sciences
    (Daystar University, Kenyatta University, Kosin University, 2020-05-23) Kinuthia, Geoffrey K.; Kiarie, Martha; Gicheru, Michael Muita; Kabiru, Ephantus Wanjohi; Lee, Dong-Kyu
    A cross-sectional study was conducted in selected rural areas of Njoro in Kenya to determine the socio-economic variables, poverty levels and disease control practices among the residents in 336 homesteads. The objective was to establish the relationship between parasitic diseases control practices, lifestyles and poverty levels among the residents in the rural areas. In addition, a retrospective study that involved recording of the frequency of parasitic and bacterial diseases diagnosed and treated in four randomly selected health centres, in the study area, from 2004 to 2009 was carried out. The results showed that the rural residents in the study area tended to have large families (68%), low education level (67%), high responsibility burden (67%) and a large number were living below poverty line (81%). The low economic status of residents coupled with certain lifestyles and practices pre-disposed the residents to infectious diseases. It was observed that ‘not boiling drinking water’ had a higher probability of occurring among the lower economic cadre of residents than in medium economic cadre [Odds Ratio (OR) = 2.36; 95% Confidence Interval (CI) of 1.38 – 4.03]. Occurrences probability of ‘not using a mosquito net’ (OR = 1.44) and ‘not using a toilet paper always’ (OR = 2.60) were higher in residents of low economic cadre. Retrospective survey showed that malaria had a higher frequency (42.75%), followed by typhoid fever (24.14%), Entamoeba histolytica (20.83%), Giardia lamblia (20.32%), intestinal worms (4.57%), Escherechia coli (3.35%) and Trichomonas hominis (1.63%). It was concluded that a combination of large family size, low education levels, high responsibility burdens, and low economic status contributed significantly to occurrence of infectious health conditions among rural residents in the study area.