Strongyloides Stercoralis Infection in Ethiopia: Systematic Review and Meta-analysis on Prevalence and Diagnostic Methods.

Strongyloides stercoralis is a helminthic intestinal parasite that causes the disease strongyloidiasis. Its prevalence is high in tropics and sub-tropics due to poor sanitation and hygiene. However, its true prevalence is not well known in Ethiopia as most health institutions use low sensitive diagnostic methods. This review aimed to determine the pooled prevalence of S. stercoralis at country, and regional state levels. Papers published on S. stercoralis in Ethiopia from 2010 to 2020 were collected from PubMed, Google Scholar and Science direct databases and Addis Ababa repository. Identification, screening, checking the eligibility, and inclusion of the relevant literatures were done. Articles with S. stercoralis positive results from Ethiopian populations were included. Articles which focused on Strongyloides infection in foreigners, and other than stool samples were excluded. The pooled prevalence of S. stercoralis and heterogeneity between studies and across regions were computed. From the 43 articles, the overall prevalence of S. stercoralis in Ethiopia was 1.82 %. Across regions, relatively high prevalence of S. stercoralis (8.78 %) was recorded in Addis Ababa city. High prevalence of S. stercoralis was found to be 44.02 % with a combination of formol ether concentration, Baermann concentration, and molecular methods. Low prevalence of 0.26 %, 0.31 %, and 1.20 % was evidenced respectively with Kato-Katz, direct saline microscopy, and formol ether concentration methods. Using random effect analysis, the pooled prevalence of S. stercoralis in Ethiopia, across regions and across diagnostic methods was 2.1 % (95 %CI: 1.20 - 3.60), 2.6 % (95 %CI: 0.80 - 8.20) and 3.7 % (95 %CI: 1.10 - 11.70), respectively. The heterogeneity was high (P<0.001). This review revealed that Strongyloides infection is probably underreported and its prevalence could be higher than the reported in Ethiopia. Therefore, a revision of the best combination of diagnostic methods could be advisable as it gives better diagnostic results in routine diagnosis of Strongyloides infection in Ethiopia.

Genomic diversity and transmission dynamics of M. tuberculosis in Africa: a systematic review and meta-analysis.

BACKGROUND: Mycobacterium tuberculosis complex (MTBC) and its human host are the most competent organisms with co-evolutionary trajectory. This review determined the phylogeography, clinical phenotype-related genotype and transmission dynamics of MTBC in Africa.METHODS: Spoligotyping and mycobacterial interspersed repetitive units-variable number tandem repeats (MIRU-VNTR) based articles from Africa published in the English language were included. Articles were retrieved from PubMed and Scopus on 12 May 2018.RESULTS: In Africa, respectively 92% and 7% of tuberculosis (TB) cases were caused by M. tuberculosis and M. africanum. Among M. tuberculosis lineages (L), L4 was the predominant, at 67%, followed by L3/Central Asian (CAS; 10%). L7/ETH1 and L5/6/Maf were restricted to the Horn and Western Africa, respectively. L4.6/SIT37, H37Rv like, L4.1.2/Haarlem and H3-Ural were proportionally more frequent among tuberculous lymphadenitis (TBLN) than among pulmonary tuberculosis (PTB) cases. On 24-locus MIRU-VNTR, clustering rate was 31%; the secondary case rate from a single primary source case was 20%.CONCLUSION: Africa in general, and the east-west pole of Africa in particular, harboured a genetically diverse population of MTBC, with characteristics of geographic segregation. Both generalist and specialist genotypes are circulating in the region. L4 is dominant across the continent, while M. bovis is rarely detected as a cause for human TB. The clinical significance of genetic diversity of MTBC in the different geographic and population groups of Africa is not fully understood. Both person-to-person transmission and reactivation mode of TB is significant in Africa. Prevention and control strategies should therefore envisage these two scenarios.

Trypanocidal and antileukaemic effects of the essential oils of Hagenia abyssinica, Leonotis ocymifolia, Moringa stenopetala, and their main individual constituents.

Essential oils from three Ethiopian medicinal plants; Hagenia abyssinica (Rosaceae), Leonotis ocymifolia (Lamiaceae), and Moringa stenopetala (Moringaceae) were investigated for their chemical composition, trypanocidal, and cytotoxic activities. Twenty components were identified from the essential oil of H. abyssinica female flowers, ledol (58.57%) being the principal volatile oil component. Sixty-eight components were identified from the essential oil of L. ocymifolia aerial part, caryophyllene oxide (12.06%) being the major component. The essential oil of M. stenopetala seeds was dominated by isothiocyanates; benzyl isothiocyanate (54.30%) and isobutyl isothiocyanate (16.37%) were the major components. The trypanocidal (Trypanosoma b. brucei) and antileukaemic (HL-60) effects of the three essential oils were studied. The oil of M. stenopetala seeds and its main compound, benzyl isothiocyanate showed the most potent trypanocidal activities with IC(50) values of 5.03 µg/ml and 1.20 µg/ml, respectively. The oils of H. abyssinica and L. ocymifolia exhibited trypanocidal activities with IC(50) values of 42.30 µg/ml and 15.41 µg/ml, respectively. Individual components (28 compounds) of the essential oils bearing different functional groups were also studied for their structure-activity relationships using trypanosomes and human leukaemia cells. Cinnamaldehyde (IC(50)=2.93 µg/ml) (a representative for aldehydes), nerolidol (IC(50)=15.78 µg/ml) (an alcohol), cedrene (IC(50)=4.07 µg/ml) (a hydrocarbon), benzyl isothiocyanate (IC(50)=1.20 µg/ml) (a representative for mustard oils), 1,8-cineole (IC(50)=83.15 µg/ml) (an ether), safrole (IC(50)=18.40 µg/ml) (aromatics with allyl and/or methoxy side chains), carvone (IC(50)=12.94µg/ml) (a ketone), styrene oxide (IC(50)=3.76 µg/ml) (an epoxide) and carvacrol (IC(50)=11.25 µg/ml) (a phenol) showed the most potent trypanocidal activities from their respective groups. Of all essential oil components tested, carvone (selectivity index (SI)=17.46) and styrene oxide (SI=19.92) showed good selective indices for the parasite with minimal toxicity on the human leukaemia cells. These compounds could therefore serve as lead structures for the development of trypanocidal agents with higher potency.

Chemical composition of the essential oils of two Citrus species and their biological activities.

Essential oils obtained by hydrodistillation of the fruit rinds of Citrus jambhiri Lush. (Rough lemon) and C. pyriformis Hassk (Ponderosa lemon) were analyzed by capillary gas chromatography (GLC/FID) and gas chromatography-mass spectrometry (GLC/MS). A total of 94 compounds were unambiguously identified from the oils and the (hexane/ether) extracts of the rind and juices representing 98.55% and 97.98% of the total oil composition. The main component of both oils was D-limonene (92.48% and 75.56% respectively). The antioxidant, anti-inflammatory, antitrypanosomal, antimicrobial and cytotoxic activities of the essential oils were evaluated. Whereas Citrus jambhiri and C. pyriformis have antioxidant activity with IC50 +/- SD 37.69 +/- 0.21 mg/ml and 28.91 +/- 0.09 mg/ml, respectively. Ascorbic acid a known potential inhibitor for DPPH free radical an commonly used antioxidant showed an antioxidant activity with an IC50 value of 16.32 +/- 0.161 g/mI. Both oils inhibited the activity of 5-lipoxygenase (5-LOX) with an IC50 of 40 +/- 1.63 and 38 +/- 0.82 microg/ml, respectively, and could be considered as interesting candidates for antiinflammatory agents. The essential oils of both species showed substantial antimicrobial activity against all tested Gram positive bacteria and yeasts. The essential oil of C. pyriformis showed higher cytotoxic activity against tested cell lines than that of C. jambhiri. The IC50 values were 374.36 +/- 43.95 microg/ml and 588.06 +/- 27.12 microg/ml in case of HepG2 cells and 213.87 +/- 18.50 microg/ml and 512.45 +/- 61.46 microg/ml in case of MIA-PaCa-2 cells, respectively.