Browsing by Author "Gebresilassie, Araya (PhD)"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Larvicidal and Adulticidal Effects of Some Selected Plant Extracts Against Anopheles Stephensi Liston (Culicidae: Diptera) Under Laboratory Condition
    (Addis Ababa University, 2021-09-21) Muhammed, Merdya; Gebresilassie, Araya (PhD); Dugassa, Sisay (PhD)
    Mosquitoes that belong to the genus Anopheles are among the major vectors of vector-borne diseases (VBDs). Among VBDs, malaria plays a crucial role in public health challenges worldwide. The use of synthetic insecticides to control malaria vectors causes resistance, environmental toxicity and kills non-target animals. Thus, it is imperative to seek a relatively safe and effective alternative tool to the currently available mosquitocidal products. Natural herbal products with insecticidal properties would play an important role in resolving this problem. Therefore, the current study aimed to assess the effects of crude leaf solvent extracts of Calpurnia aurea, Momordica foetida, and Zehneria scabra against the laboratory colony of larvae and adults of An. stephensi. Fresh leaves of test plants were collected, air dried, and then separately ground to powder. The powders were soaked in aqueous, hexane, and methanol solvents. The extracts were concentrated, and a stock solution was prepared to desired test concentration. For comparison, temephos (larvicide) and untreated solutions were used as the standard and negative controls, respectively. Mortality was observed after 24 hrs recovery period. The statistical analyses were performed using SPSS software (Kruskal-Wallis test), and R software (a generalized linear model was used to determine LC50 and LC90 values of the extracts). Larvicidal activity between treatments, negative control, and standard groups were significant differences (P < 0.05). Among the test extracts, the lowest LC50 and LC90 values were recorded in larvae treated with aqueous extract of M. foetida with 34.61 ppm and 57.61 ppm, respectively followed by Z. scabra (LC50 = 35.85 ppm; LC90 = 68.26 ppm) and C. aurea (LC50 = 38.69 ppm; LC90 = 108.28 ppm). Larval mortality was not observed from the hexane and control treatments, while the temephos achieved 100%. In addition, aqueous extract of Z. scabra showed the most effective adulticidal action in An. stephensi with LC50 and LC90 values of 176.20 ppm and 425.13 ppm, respectively. The results suggest that the leaf extracts of the three test plants have the potential of being used for the control of An. stephensi instead of synthetic mosquitocides. Further studies need to be conducted to identify the active ingredients and their mode of action.
  • No Thumbnail Available
    Item
    Prevalence of Giardia and Amoebia Infections Among Diarrhoeal Patients Attending Nebelet Health Center in Tigray ,Ethiopia
    (Addis Ababa University, 2019-09-09) Hailu, Mulu; Gebresilassie, Araya (PhD)
    Parasitic infections including intestinal parasites are considered as the most common communicable diseases Worldwide, especially in developing countries Ethiopia, like other developing countries, intestinal parasitic infections are the major public health problems affecting millions annually. With this in mind, this study was designed with the objective of identifying the prevalence of protozoan infections among diarrheal patients attending Nebelet Health Center in Tigray Regional State, northern Ethiopia. Retrospective analysis was conducted to determine the prevalence of intestinal parasitic protozoan infection in patients attending Nebelet Health center from September 2013 to August 2018 from records of stool examination. Stool samples collected from the patients were examined using direct wet mount and formal Ether concentration techniques by experienced laboratory technologists of the health center. All cases intestinal protozoan parasitic infection reported between 2013 and 2018 were reviewed and analyzed. In the past five years, a total 2,928 stools sample was examined for various intestinal parasitic infections. Out of these, 489 (16.7%) were positive to intestinal protozoan parasitic infections. The only protozoan parasites detected in the examined stool samples in the health center were Entamoeba histolytica/-dispar and Giardia lamblia. In particular, G lamblia was the most prevalent parasite (56.4%) followed by E. histolytica with an infection of (43.6%). The result also showed that there was difference in the overall prevalence rate of the parasitic infection in different age groups: <5yr 172 (35.17%), 5-14yr 127 (25.97%), 15-29yr 91 (18.60%), 30-44yr, 68 (13.90%),>44yr, 31 (6.36%). Higher infection was observed among males (55.2%) than females (44.8%). In overall, the study revealed that protozoan parasitic infections represent a major public health problem amongst patients attending the health center in Nebelet Town. Therefore, in order to minimize the risk and exposure of the community to these intestinal parasites all the concerned government and non- government sectors should design appropriate and cost-effective control methods that improve the quality of personal hygiene and environmental sanitation in the study area.