Phytoplankton community structure and cyanobacterial blooms in reservoirs in the semi-arid highlands of Tigray, Ethiopia

Ethiopia is the third largest country in Africa with an area of over one million km2. It is one of the most populous countries in Africa (probably second), with more than 80 million inhabitants. The Ethiopian highlands represent about 43% of the country but support about 88% of the population. The highlands account for 95% of the regularly cropped land, more that 70% of the livestock population, and 90% of the economic activities of the country. They are considered to be amongst the most degraded lands in Africa by some authors. Rain fed agriculture is the main stay for most farmers. The frequent rainfall anomalies suggest that there are recurrent periods of drought every 3- 5 years in the northern parts of Ethiopia and every 6-8 years over the whole country. Part of the variability in the seasonal and annual rainfall across time and space is known to be associated with the El Nino-Southern Oscillation (ENSO) phenomenon. The conditions in Tigray are worse. Extreme spatial and temporal variation in rainfall is characteristic for this region. To tackle the problem associated with the rain fall pattern, several small reservoirs have been constructed over the last two decades. Given the population intensity and long history of agriculture in the highlands of Ethiopia, massive erosion linked to land degradation is a prominent problem. This is expected to bring excessive nutrient to the reservoirs. And many of the reservoirs are expected to be characterized by high nutrient loads and phytoplankton blooms, including cyanobacteria blooms. This has indeed observed in a field survey of reservoirs, most of them suffer from heavy blooms of cyanobacteria. In this study we started with a field survey of a set of 32 shallow semi-arid sub-tropical reservoirs in the highlands of Tigray, Ethiopia. This survey was carried out in both the wet and dry season to capture seasonal variations of phytoplankton communities and associated environmental variables. We assessed seasonal variation Summary 240 in more details by monitoring eight selected reservoirs (sub sets of the 32 reservoirs) on a monthly basis during a whole year. We also carried out field enclosure experiments in an effort to better understand the trophic structure of the reservoirs and identify mechanisms that potentially lead to cyanobacterial blooms. First we tested the impact of fish on abiotic conditions in the water column as well as the dynamics of phytoplankton species composition and cyanobacteria biomass. In the second experiment we assessed the potential top-down effects of zooplankton on the phytoplankton communities including the toxic cyanobacteria. The studied reservoirs were characterized by high nutrient concentrations and high turbidity. Most of the reservoirs harbor the riverine fish Garra. Overall, the local phytoplankton richness was low with most reservoirs dominated by a single genus of cyanobacteria (mostly Microcystis), chlorophytes, euglenophytes, cryptophytes or dinophytes. Similarly the bacterial community richness in the studied reservoirs was also low. Lower bacterial taxon richness was encountered in reservoirs with Microcystis blooms than bacterial communities in reservoirs without blooms. High altitude reservoirs were more nutrient-rich and associated with high abundances of green algae, euglenophytes or cyanobacteria other than Microcystis. Microcystis was associated with high pH in the rainy and high conductivity in the dry season. Additional factors correlated with Microcystis biomass were Daphnia biomass and possibly altitude and fish biomass. Environmental factors explained the bacterial community composition differently among season. Percentage contribution of Microcystis to the total phytoplankton biomass and copepod biomass showed significant association with the bacterial community composition in the wet season whereas variation in bacterial community composition was associated with total nitrogen (TN), total phosphorus (TP), oxygen, the number of cattle frequenting the Summary 241 reservoir, and fish biomass in the dry season. Pronounced temporal variation was observed for both biotic and abiotic variables in our study systems. This variation involved both the intra-annual and interannual variations. For the intra-annual variation, the main limnological changes were associated with seasonal differences in rainfall, while also water temperature differed strongly between winter (sub-tropics) and the rest of the year. We observe two minima for phytoplankton biomass: one in winter and a more pronounced one during August. We also observed two main bloom periods for cyanobacteria: one in September-October and a more pronounced one in May-June. Seasonal variation in total phytoplankton and cyanobacterial biomass was, however, not significant. The first field enclosure experiment was the experiment with fish. The results of this experiment showed that the presence of Garra in general increased the amount of suspended matter, nutrient concentrations (total nitrogen and total phosphorus), phytoplankton and to some extent also Microcystis biomass (including the proportion of Microcystis in the phytoplankton community), and reduced water transparency. The second experiment was carried out to study the effect of zooplankton grazing on phytoplankton community structure, including the relative abundance of toxic cyanobacteria. From this experiment top-down regulation by zooplankton was observed for some of the phytoplankton taxa, including Anabaena, Euglenoids, Chlorophytes and Cryptomonads, whereas the impact of the presence of zooplankton on Microcystis and Peridinum biomass was limited. From the same experiment we observed negative correlation between Anabaena and calanoid copepods and Daphnia carinata. We also detected microcystin from all experimental units in the second experiment; and higher concentrations were detected in the treatment with than without zooplankton. Summary 242 We draw some important associations from the field observations and field enclosure experiments for Microcystis in our system. The results indicate an inter-play between bottom-up (possibility of Microcystis affecting the zooplankton composition) and top-down (zooplankton grazing) regulating the Microcystis. Negative association between Microcystis and Daphnia has been observed mainly from the field survey and to some extent the enclosure experiments with fish and fishless treatment demonstrated a top-down regulation. From these results we can conclude that the zooplankton grazing can not fully regulate Microcystis. But, the possibility remains, and is in fact quite realistic, that Daphnia also control Microcystis, mainly at lower biomasses of Microcystis until it reaches a certain biomass and Microcystis “escapes” potential control by zooplankton after which it may poison the major grazer zooplankton due to the high densities. Based on our results of the present study, we put some general suggestions and recommendations for sustainable utilization, maintaining the ecological integrity of the reservoirs and protecting water quality deterioration. The recommendations follow in the following statements. 1) Cyanobacterial monitoring and survey for hazardous effects to assess if the toxins of the organisms are translated into problems of animal or human health should be set-up. 2) Reduction of nutrient loading and sediment input to the reservoirs to curb the eutrophication of the reservoirs. Catchment treatment with reforestation and setting up of exclosures can serve the purpose. 3) Reduction of cattle trampling by restricting cattle access to the reservoirs at selected sites of the reservoir. 4) Reduction of fish (mainly Garra). Here we recommend the use of methods to reduce the riverine fish with a high level care to protect the reservoirs from unpredictable consequences like the introduction of exotic fish

Determination of Antimicrobial Activity and Phytochemical Screening of Selected Medicinal Plants in Tigray region of Northern Ethiopia

Present paper evaluates the antimicrobial activities and preliminary phytochemical screening of the extracts of Beciumgrandiflorum, Meriandrabengalensis, Tamarindusindica, Balanitesaegyptiaca and Otostegiaintegrifolia. Comparative study was made for the selected traditional medicinal plants. The results of phytochemical test indicate that the bioactive chemical components show presence of alkaloids, flavonoids, phenols, carbohydrates, saponins and terpenoids. The antimicrobial activities of aqueous and ethanol extracts of leaf and stem were determined on the selected bacteria strains. The results indicate that the aqueous and ethanol leaf extracts of Meriandrabengalensis show better antimicrobial activity against Staphylococcus aureus and Staphylococcus pneumonia with inhibition zone diameters of 15.97 ± 0.09 and 19.03 ± 0.15 mm respectively, significant at (P<0.05) compared to other extracts. From the phytochemical components tested, carbohydrate was present in Becium grandiflorum extract. The lowest inhibition zone (4.5 ± 0.29 mm) was achieved for the extract of Balanitesaegyptiaca. The phytochemical component saponinis significantly present in Meriandrabengalensis in the aqueous leaf extract. In the comparative study made for the extraction solvents aqueous and ethanol, the aqueous extraction had strong inhibition zone. Therefore, a study need to be done on the isolation, identification, and quantitative determination of antimicrobial components present in the Meriandrabengalensis for its application in both animal and human pharmaceutical industries. Keywords: Antimicrobial activities; Phytochemical screening; Extracts; Inhibition zone; Medicinal plants; Tigray; Ethiopia

Frequency of MTB and rifampicin resistance MTB using Xpert-MTB/RIF assay among adult presumptive tuberculosis patients in Tigray, Northern Ethiopia: A cross sectional study.

BackgroundMultidrug-resistant tuberculosis (MDR-TB) continues to be a global health problem. Data on rifampicin resistance MTB using Xpert- MTB/RIF assay in Ethiopia, particularly in the study area is limited. The aim of this study was to determine the frequency of MTB and rifampicin resistant-MTB among presumptive tuberculosis patients in Tigray, Northern Ethiopia.MethodsA multicenter retrospective study was conducted among presumptive TB patients from five governmental hospitals and one comprehensive specialized teaching hospital in Tigray regional state. Records of sputum sample results of presumptive MTB patients with Xpert-MTB/RIF assay from January 2016 to December 2019 were investigated. Data extraction tool was used to collect data from registration books and analyzed using SPSS ver.21 statistical software. Statistical significance was set at p-value ≤ 0.05.ResultsOf the 30,935 presumptive adult TB patients who have provided specimens for TB diagnosis from January 2016 to December 2019, 30,300 (98%) had complete data and were included in this study. More than half, 17,471 (57.7%) were males, and the age of the patients ranged from 18-112 years, with a median age of 40.65 (interquartile 29.4-56.5 years). Majority, 28,996 (95.7%) of the participants were treatment naïve, and 23,965 (79.1%) were with unknown HIV status. The overall frequency of MTB was 2,387 (7.9% (95% CI: 7.6-8.2%); of these, 215 (9% (95% CI: 7.9-10.2%) were rifampicin resistant-MTB. Age (18-29 years), HIV positive and previous TB treatment history were significantly associated with high MTB (p ConclusionFrequency of MTB among tuberculosis presumptive patients was low; however, the problem of rifampicin resistant-MTB among the tuberculosis confirmed patients was high. The high frequency of MTB and RR-MTB among previously treated and HIV positive patients highlights the need for more efforts in TB treatment and monitoring program in the study area

Prevalence, antimicrobial susceptibility test and associated factors of Salmonella and Shigella in ready-to-eat fruit juices and salads in Mekelle, northern Ethiopia

Abstract Background Food borne diseases is a challenging problem nowadays. Salmonella and Shigella species are great concern of food-born outbreaks. Thus, this study was aimed to assess the prevalence, antimicrobial susceptibility test and associated factors of Salmonella and Shigella species in fruit juices and salads. Methods A community based cross sectional study design was carried out on 50 juice houses from December to March 2020 in Mekelle. One hundred fifty samples were collected aseptically from the juice houses for laboratory analysis. Information related to risk factors was obtained using a structured questionnaire. In the laboratory, samples were homogenized using peptone water and incubated overnight for enrichment. Then, Salmonella and Shigella species were isolated on Salmonella-Shigella agar and Xylose Lysine Deoxycholate agar. Disc diffusion method was used to perform antimicrobial susceptibility test. Using SPSS (version 22) package, descriptive statistics and Chi square test (χ2) were used to analyze the data, and p < 0.05 was considered as statistically significant. Result The overall prevalence of Salmonella and Shigella species was 41/150 (27.33%; 95% CI: 20.20 – 34.46) with 33 (22%) Salmonella spp. and 8(5.33%) Shigella spp. Antimicrobial susceptibility tests of both Salmonella and Shigella spp.showed high resistance against ampicillin (100%), tetracycline (63.6 and 62.5%, respectively) and amoxicillin-clavulanic acid (100%). Accessibility of fruits to flies and dust had statistical association (p = 0.021) with occurrence of Salmonell a and/or Shigella spp. Conclusion The overall prevalence of Salmonella and Shigella spp. was found to be significant. The resistant rate of isolates against ampicillin, tetracycline and amoxicillin-clavulanic acid was high. Storage sites for fruits should be inaccessible to flies and dust. Therefore, routine monitoring of juice houses should be promoted and regular evaluation of bacterial resistance pattern should be done for selective antimicrobial therapy. Furthermore, consistent training of juice makers on food safety and hygiene should be implemented by the concerned body

Half of Pulmonary Tuberculosis Cases Were Left Undiagnosed in Prisons of the Tigray Region of Ethiopia: Implications for Tuberculosis Control

INTRODUCTION:Prison settings have been often identified as important but neglected reservoirs for TB. This study was designed to determine the prevalence of undiagnosed pulmonary TB and assess the potential risk factors for such TB cases in prisons of the Tigray region. METHOD:A cross-sectional study was conducted between August 2013 and February 2014 in nine prisons. A standardized symptom-based questionnaire was initially used to identify presumptive TB cases. From each, three consecutive sputum samples were collected for acid-fast bacilli (AFB) microscopy and culture. Blood samples were collected from consented participants for HIV testing. RESULT:Out of 809 presumptive TB cases with culture result, 4.0% (95% CI: 2.65-5.35) were confirmed to have undiagnosed TB. The overall estimated point prevalence of undiagnosed TB was found to be 505/100,000 prisoners (95% CI: 360-640). Together with the 27 patients who were already on treatment, the overall estimated point prevalence of TB would be 793/100,000 prisoners (95% CI: 610-970), about four times higher than in the general population. The ratio of active to passive case detection was 1.18:1. The prevalence of HIV was 4.4% (36/809) among presumptive TB cases and 6.3% (2/32) among undiagnosed TB cases. In a multivariate logistic regression analysis, chewing Khat (adjusted OR = 2.81; 95% CI: 1.02-7.75) and having had a close contact with a TB patient (adjusted OR = 2.18; 95% CI: 1.05-4.51) were found to be predictors of undiagnosed TB among presumptive TB cases. CONCLUSIONS:This study revealed that at least half of symptomatic pulmonary TB cases in Northern Ethiopian prisons remain undiagnosed and hence untreated. The prevalence of undiagnosed TB in the study prisons was more than two folds higher than in the general population of Tigray. This may indicate the need for more investment and commitment to improving TB case detection in the study prisons

Prevalence and Factors Associated with Multidrug-Resistant Tuberculosis (MDR-TB) among Presumptive MDR-TB Patients in Tigray Region, Northern Ethiopia

Background. Tuberculosis (TB) is one of the major public health problems. There are alarming reports of increasing multidrug-resistant tuberculosis (MTR-TB) from various parts of the globe, including Ethiopia. This study was designed to determine the prevalence and factors associated with MDR-TB among presumptive MDR-TB cases in Tigray Regional State, Ethiopia. Methods. A cross-sectional study was conducted in Tigray Regional State from 2015 to 2016. Two hundred sputum samples were collected, transported, processed using 2% N-acetyl-L-cysteine-sodium hydroxide, and cultured in LJ medium. Besides, the microscopic examination was performed after ZN staining. Moreover, drug susceptibility test was done using molecular line probe assay. Descriptive statistics and binary and multivariable logistic regression were done. A statistical test was regarded as significant when the P value was <0.05. Results. The prevalence of MDR-TB was found to be 18.5%. About one-fourth (26.5%) of the study participants had sputum smear positive for acid-fast bacilli (AFB). TB culture was positive in 37% of the samples, and rifampicin mono-resistant cases accounted for 3.5% of the presumptive MDR-TB cases. Three (1.5%) were new MDR-TB cases, while the rest had been treated previously for TB. Most (63.5%) of the MDR-TB cases were from 15 to 44 years of age. Age was associated with MDR-TB with a crude odds ratio of 1.06 (CI: 1.02–1.10) and adjusted odds ratio of 1.06 (CI: 1.00–1.11). Conclusions. The prevalence of MDR-TB was found to be high. Preventive measures should be taken to prevent the transmission of MDR-TB in the community

In silico approaches for the identification of potential allergens among hypothetical proteins from Alternaria alternata and its functional annotation

Abstract Direct exposure to the fungal species Alternaria alternata is a major risk factor for the development of asthma, allergic rhinitis, and inflammation. As of November 23rd 2020, the NCBI protein database showed 11,227 proteins from A. alternata genome as hypothetical proteins (HPs). Allergens are the main causative of several life-threatening diseases, especially in fungal infections. Therefore, the main aim of the study is to identify the potentially allergenic inducible proteins from the HPs in A. alternata and their associated functional assignment for the complete understanding of the complex biological systems at the molecular level. AlgPred and Structural Database of Allergenic Proteins (SDAP) were used for the prediction of potential allergens from the HPs of A. alternata. While analyzing the proteome data, 29 potential allergens were predicted by AlgPred and further screening in SDAP confirmed the allergic response of 10 proteins. Extensive bioinformatics tools including protein family classification, sequence-function relationship, protein motif discovery, pathway interactions, and intrinsic features from the amino acid sequence were used to successfully predict the probable functions of the 10 HPs. The functions of the HPs are characterized as chitin-binding, ribosomal protein P1, thaumatin, glycosyl hydrolase, and NOB1 proteins. The subcellular localization and signal peptide prediction of these 10 proteins has further provided additional information on localization and function. The allergens prediction and functional annotation of the 10 proteins may facilitate a better understanding of the allergenic mechanism of A. alternata in asthma and other diseases. The functional domain level insights and predicted structural features of the allergenic proteins help to understand the pathogenesis and host immune tolerance. The outcomes of the study would aid in the development of specific drugs to combat A. alternata infections

Densities of spotted hyaena (**Crocuta crocuta**) and African golden wolf (**Canis anthus**) increase with increasing anthropogenic influence

We report densities of spotted hyaena (Crocuta crocuta) and African golden wolf (Canis anthus) in Enderta district in northern Ethiopia with high human and low natural prey densities. We estimated spotted hyaena and African golden wolf abundance and characterized their spatial distribution with three methods: we surveyed four road-transects for 66 nights during dry (n=41) and wet (n=25) seasons, we used 34 calling stations and we mapped all active spotted hyaena dens at the time of the survey. The density of spotted hyaena and African golden wolf increased with proximity to towns where human density was higher. A total of 562 spotted hyaena and 63 African golden wolf responded to calling stations, leading to estimates of 1,145 spotted hyaena and 166 African golden wolf in Enderta district. This method also found a significantly higher spotted hyaena and African golden wolf abundance in high human density areas. Maximum response radius was 2.8 km for spotted hyaena and 2.5 km for African golden wolf, and response probability was 0.83 for spotted hyaena and 0.8 for African golden wolf, respectively. We found 40 active spotted hyaena dens with 1,507 remnants of prey, and the majority of the dens were located close to rivers and villages. Our findings show a positive relationship between spotted hyaena, African golden wolf and human concentrations that might demonstrate a case of exceptional coexistence of humans and carnivores, both at high densities. We suggest further investigations into co-adaptations between humans and predators in the study area

Spotted hyena (Crocuta crocuta) concentrate around urban waste dumps across Tigray, northern Ethiopia

Environmental Biolog

Risk factors for diarrhoea and malnutrition among children under the age of 5 years in the Tigray Region of Northern Ethiopia.

BACKGROUND:Diarrhoea and malnutrition are the leading cause of morbidity and mortality among children in areas with poor access to clean water, improved sanitation, and with low socioeconomic status. This study was designed to determine the prevalence of diarrhoea, malnutrition and risk factors among children aged 6-59 months in the Tigray Region of Northern Ethiopia. METHODS:A community based cross-sectional study design was conducted from June to August 2017 to assess the magnitude and factors associated with diarrhoea and malnutrition among children. A standardized questionnaire was used to collect data on diarrhoea, environmental, demographic and behavioural factors from 610 mother-child pairs. Anthropometric measurements were collected from the children. SPSS ver.21 statistical software was used for analysis. Factors associated with diarrhoea and nutritional status were identified using bivariate and multivariate logistic regression. A p-value ≤ 0.05 was considered statistically significant. RESULTS:Of the 610 children monitored in this study, the incidence of diarrhoea among 6-59 month-old children in the two weeks preceding the day of the interview day was 27.2% (95% CI: 23.6-31%). Specifically, 35.9%, 9.7%, and 1.8% had 1-2, 3-4 and 5-6 times of diarrhoea episodes in a one year of time, respectively. The prevalence of stunting, underweight, wasting, and acute under-nutrition were 36.1% (95% CI: 31-38.6%), 37% (95% CI: 32-39.6%), 7.9% (95% CI: 5.5-9.7%), and 5.4% (95% CI: 3.8-7.4%), respectively. In a multivariate logistic regression analysis, type of drinking water source [AOR = 3.69; 95% CI: 2.03-6.71], mothers not hand washing at critical times [AOR = 15.42; 95% CI: 2.02-117.78], improper solid waste disposal [AOR = 12.81; 95% CI: 2.50-65.62], and child age (36-47 months) [AOR = 2.57; 95% CI: 1.45-4.55] were found to be predictors of diarrhoea. Being within the age range of 12-23 months was a predictor for wasting [AOR = 4.38; 95% CI: 1.61-11.90] and being underweight [AOR = 4.4; 95% CI: 1.7-11.2]. Similarly, the age range of 36-47 months was associated with wasting [AOR = 2.3; 95% CI: 1.45-3.85] and stunting [AOR = 1.7; 95% CI: 1.03-2.67]. Family size (less than 4) [AOR = 0.56; 95% CI: 0.368-0.959] was inversely associated for wasting. CONCLUSIONS:Our study revealed that the problem of diarrhoea and malnutrition amongst 6-59 months children in the study area was significant. Access to clean water was the main problem in the study area. Hence, improving access to clean water and providing health education to mothers on personal and environmental hygiene, and proper waste disposal could improve diarrhoea in the study area. Intervention on children's nutrition should also be implemented to minimize the problem of malnutrition