Standard methods for the examination of water and wastewater: including bottom sediments and sludges , Standard methods for the examination of water and wastewater: including bottom sediments and sludges , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Standard methods for the examination of water and wastewater: including bottom sediments and sludges

Basic Laboratory Methods in Medical Parasitology

The cyanobacterial genus Arthrospira appears very conserved and has been divided into five main genetic clusters on the basis of molecular taxonomy markers. Genetic studies of seven Arthrospira strains, including genome sequencing of seven strains, have enabled a better understanding of those photosynthetic prokaryotes. Even though genetic manipulations have not yet been performed with success, many genomic and proteomic features such as stress adaptation, nitrogen fixation or biofuel production have been characterized. Many of above-mentioned studies aimed to optimize the cultivation conditions. Factors like the light intensity and quality, the nitrogen source or different modes of growth (auto-, hetero- or mixotrophic) have been studied in detail. The scaling-up of the biomass production using photobioreactors, either closed or open, was also investigated to increase the production of useful compounds.. The richness of nutrients contained in the genus Arthrospira can be used for promising applications in the biomedical domain. Ingredients such as the calcium spirulan, immulina, C-phycocyanin and γ-linolenic acid (GLA) show a strong biological activity. Recently, its use in the fight against cancer cells was documented in many publications. The health-promoting action of 'Spirulina' has been demonstrated in the case of cardiovascular diseases and age-related conditions. Some compounds also have potent immunomodulatory properties, promoting the growth of beneficial gut microflora, acting as antimicrobial and antiviral. Products derived from Arthrospira were shown to successfully replace biomaterial scaffolds in regenerative medicine. Supplementation with the cyanobacterium also improves the health of livestock and quality of the products of animal origin. They were also used in cosmetic preparations.

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Edible Cyanobacterial Genus Arthrospira: Actual State of the Art in Cultivation Methods, Genetics, and Application in Medicine.

The ability of 27 algae belonging to 11 taxonomic divisions to grow at the expense of organic nitrogen was tested in axenic culture. Experiments were carried out in buffered media: morpholine propanesulphonic acid (MOPS) was used successfully for all fresh water strains except diatoms. It was not used as a nitrogen source by any strain examined but served as a good source of sulphur for four strains. The range of substrates used was extensive and included amino acids, urea, acetamide, urate and some nucleosides. Growth rates varied widely but growth yields were generally comparable to those attained with nitrate or ammonia except for substrates containing more than one utilizable nitrogen atom. Limited experiments were carried out in the dark, and it was found that a given substrate was equally suitable for both dark heterotrophic and photolithotrophic growth. Levels of chlorophyll a were measured during growth of two algae with nitrate, glycine and urate. With nitrate, levels of specific chlorophyll a declined some ten-fold during growth: with poor substrates supporting only slow growth, levels were more uniform but were only 10–15% of those attained during growth with good substrates. One strain grown with MOPS as sole source of sulphur produced cultures with levels of chlorophyll a about half those found in sulphate-grown cultures. Tolerance of sodium chloride was examined in a few strains and even putatively fresh water strains were found to be appreciably tolerant.

The utilization of organic nitrogen for growth of algae: physiological aspects [cyanobacteria, nitrogen sources, sulphur sources, chlorophyll a]

Diarrheal diseases caused by intestinal protozoan parasites are a major food-borne public health problem across the world. Vegetables and fruits provide important nutrients and minerals, but are also common sources of some food-borne human pathogenic microorganisms. The contamination of raw vegetables and fruits with human pathogenic parasites are now a global public health threat, despite the health benefits of these foods in non-pharmacological prophylaxes against diseases. A large number of reports have documented the contamination of vegetables or fruits with human pathogenic microorganisms. In this paper, we reviewed the contamination and detection methods of human pathogenic intestinal protozoans that are frequently recovered from raw vegetables and fruits. The protozoan parasites include Cryptosporidium spp., Giardia duodenalis, Cyclospora cayetanensis, Entamoeba spp., Toxoplasma gondii, Balantioides coli, Blastocystis sp., Cystoisospora belli and Enterocytozoon bieneusi. The risk factors involved in the contamination of vegetables and fruits with parasites are also assessed.

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Detection of human intestinal protozoan parasites in vegetables and fruits: a review.

Intestinal parasitic infections (IPIs) have been major public health problems in low income countries primarily affecting school children. Previous studies in Ethiopia have shown high burden of intestinal parasitic infections in most children. In order to gain a deeper insight into the magnitude of the problem more information is needed from different localities where similar studies have not been conducted. The aim of this study was to assess the prevalence of IPIs and associated risk factors among school children in Jawi Primary School, Jawi town, north -west Ethiopia. A cross-sectional study was conducted from April to June 2017 to assess the prevalence of IPIs and associated risk factors among Jawi Primary School children, Ethiopia. A total of 422 children were selected using age-stratified systematic random sampling technique. Stool samples were examined microscopically using direct wet-mount and formal-ether concentration techniques. A structured questionnaire was used to obtain information regarding the associated risk factors. Data were analyzed using SPSS version 20 and p value < 0.05 was taken as statistically significant. Of 406 students examined for IPIs, 235 (57.88%) were positive for one or more intestinal parasites. Single, double and triple infections were 41.9, 6.2 and 1.2%, respectively. Overall infection rate was slightly higher in males (51.85%) than in females (45.30%) though the difference was not significant. Higher prevalence rate (about 51–53%) was recorded among 6 to 18 years old children. Prevalence of Giardia lamblia was the highest (19.95%), followed by hookworm (13.8%), Schistosoma mansoni (10.3%), Entamoeba histolytica/dispar (5.9%), Hymenolepsis nana (4.2%), Taenia species (3%) and Ascaris lumbricoides (0.73%), in that order. Among the risk factors assessed, age, hand washing habit before meals, open field defecation habit, consistency of wearing shoes, habit of eating raw and unwashed vegetables, and finger nail cleanliness and trimming habit were found to be the most important predictors associated with high risk of IPIs (p < 0.05). High prevalence of IPIs among Jawi Primary school children demands improved health education on regular hand washing, latrine use, wearing shoes, cleaning finger nails, not crossing rivers with bare foot and avoiding eating raw vegetables.

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Prevalence of intestinal parasitic infections and associated risk factors among Jawi primary school children, Jawi town, north-west Ethiopia

Intestinal parasitic infections (IPIs) have been major public health burdens in low-income countries like Ethiopia. Studies in different areas of Ethiopia have shown a high prevalence of IPIs in poor families. A similar study has not been conducted in Sasiga District given that the area is possibly at high-risk of IPIs due to the prevailing risk factors. This study is aimed at assessing the prevalence of IPIs and associated risk factors among schoolchildren in Sasiga District, southwest Ethiopia. A school-based cross-sectional study was conducted from December 2018 to March 2019 to estimate the prevalence of IPIs and associated risk factors among the study participants. A total of 383 children were selected using resident-type and grade-level stratified systematic random sampling technique. Stool samples were examined microscopically using direct wet mount and formal-ether concentration techniques. A structured questionnaire was used to get information on the associated risk factors. Data were analyzed using SPSS version 20 and p value of ≤0.05 was taken as statistically significant. The overall prevalence of IPIs among the children was 62.4% (239/383). Single, double, and triple infections were 49.9%, 10.7%, and 1.83%, respectively. Residence, family income, place of defecation, source of drinking water, shoe-wearing habit, handwashing habit after toilet use, ways of waste disposal, and cleanliness of fingernail were the most important predictors of IPIs (p < 0.05). Ascaris lumbricoides (22.7% (87/383)) and hookworms (20.6% (79/383)) were the most prevalent parasites, followed by Entamoeba histolytica (8.1%), Trichuris trichiura (7.6%), Giardia intestinalis (6.5%), Hymenolepis nana (5.7%), and Schistosoma mansoni (4.4%), in that order. Sasiga District primary schoolchildren are likely at a high burden of IPIs. Intensive health education on personal hygiene and environmental sanitation is needed.

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Prevalence of Intestinal Parasitic Infections and Associated Risk Factors among the First-Cycle Primary Schoolchildren in Sasiga District, Southwest Ethiopia

The cost of nutrient media is the major challenge for biomass production of Spirulina. Although much effort has been made to use enriched seawater for the cultivation of this microalga, little attention has been given to the potential of water of soda lakes. In this study, growth (μ, day−1) and biomass production (B) of Arthrospira fusiformis cultivated using waters of the soda lakes Chitu and Shala with or without supplementation were evaluated. Comparable μ and B values were achieved in both Lake Chitu water-based media (CBM) and Lake Shala water-based media (SBM), with slightly higher values in the latter. Both CBM and SBM supplemented with the standard Spirulina medium (SM) by 25 % and 50 % supported considerably higher μ and B. The pH and salinity of the cultures showed significant variations (P < 0.05) among the media and had considerable effect on μ and B. The observed higher μ and B were probably associated with the reduction in pH and salinity of the supplemented media due to addition of bicarbonate–carbonates and dilution, and provision of the limiting nutrient nitrogen. The higher μ and B in SBM may have resulted from some of their aggregate chemical parameters, which were closer to those in the SM, and abundant PO4-P. This seems to suggest that Lake Shala water is more conducive to Arthrospira. We contend that 25 % and 50 % supplemented Lake Shala water can be preferably used to produce Arthrospira biomass, thereby reducing the cost of nutrients by 75 % and 50 %, respectively.

Evaluation of growth and biomass production of Arthrospira (Spirulina) fusiformis in laboratory cultures using waters from the Ethiopian soda lakes Chitu and Shala

Waterborne diseases continue to challenge communities in low-income countries like Ethiopia. Clinical information in Wegeda town showed that the prevalence of waterborne diseases was 58%. This study aimed to evaluate bacteriological and physicochemical drinking water quality in Wegeda town. This study will add valuable scientific data for future intervention. Water samples from protected and unprotected springs, hand-dug well, taps, and households' containers were collected from November 2018 to June 2019 for bacteriological and physicochemical analyses. Besides, information about the potential risk factors was collected using a structured questionnaire. A total of 120 water samples were collected and analyzed for total and fecal coliform counts using the multiple tube fermentation method (MPN). The presence of Escherichia coli was also checked from fecal coliform positive samples collected from households' containers. Selected physicochemical parameters were also determined using the standard methods. In all cases, the median values of total and fecal coliform counts ranged from 5 to 27 and 2 to 13 MPN/100 ml, respectively. Accordingly, all of the drinking water samples did not comply with the standards. Coliforms were significantly higher in the households' containers than in the sources (p < 0.05) and also significantly varied by water sources. The highest and lowest coliform counts were recorded in unprotected spring and taps, respectively. Besides, 18.33% of water samples collected from households' containers were tested positive for E. coli. Regarding physicochemical parameters, most values were within the acceptable limit values recommended by the WHO. However, water samples from unprotected spring and hand-dug well did not satisfy the turbidity limit value set by the WHO. Drinking water systems in Wegeda town were likely contaminated with pathogenic bacteria likely due to poor protection and sanitation practices. Providing the community with potable water, toilets, domestic and animal waste disposal systems, and intensive health education and sanitation practices for the community are highly recommended.

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Bacteriological and Physicochemical Quality of Drinking Water in Wegeda Town, Northwest Ethiopia.

Despite drinking water supply in Kobo town is from a borehole through pipes, a high incidence of waterborne diseases are frequently reported. Hence, this study aimed to assess the bacteriological and physicochemical drinking water quality in Kobo town. One hundred and twenty water samples were collected from four sampling sites (the source, reservoir, taps, and households’ containers) from February to April 2020. Total and fecal coliforms were counted from the water samples using membrane filtration while selected physicochemical parameters were determined using standard methods. The mean counts of total and fecal coliforms ranged from 3.9 to 22.9 and 1 to 13.6 CFU/100 mL, respectively. Hence, all water samples did not satisfy the WHO guidelines and national standards. There were statistically significant differences in the coliform counts between the different sampling sites, and the counts were significantly higher in the taps and households’ containers compared to the counts in the source and reservoir (p< 0.05). All physicochemical parameters, except for temperature, were within the recommended acceptable limits. High coliform count in the water system demands proper maintenance of the distribution line and good hygiene practices at household level to improve the microbiological quality of drinking water in Kobo town.

Baye Sitotaw

Papers

Prevalence of intestinal parasitic infections and associated risk factors among Jawi primary school children, Jawi town, north-west Ethiopia

Prevalence of Intestinal Parasitic Infections and Associated Risk Factors among the First-Cycle Primary Schoolchildren in Sasiga District, Southwest Ethiopia

Evaluation of growth and biomass production of Arthrospira (Spirulina) fusiformis in laboratory cultures using waters from the Ethiopian soda lakes Chitu and Shala

Bacteriological and Physicochemical Quality of Drinking Water in Wegeda Town, Northwest Ethiopia.

Bacteriological and physicochemical quality of drinking water in Kobo town, Northern Ethiopia