Authors:Kazhila C. Chinsembu Pages: 1 - 4 Abstract: More than two years since the first case was reported in Africa, COVID-19 still lurks on the African continent, shattering the hopes and livelihoods of millions of people. Although Africans are accustomed to infectious disease outbreaks, COVID-19 seems unique in its aetiology and impacts. Assertions that Africans were ‘resistant’ to COVID-19 in the first wave were put forward, but data to support the accuracy of these claims are not available. More research data are required to explain COVID-19 prevalence and interventions in African settings. Control of COVID-19 should not just be left to medical doctors. All experts, working in multi-disciplinary, inter-disciplinary, intra-disciplinary and trans-disciplinary (MIIT) teams, should be involved in finding solutions to COVID-19 in Africa. We urge all our readers and contributors to get vaccinated against COVID-19. PubDate: 2022-01-31 Issue No:Vol. 15 (2022)
Authors:S Kanyemba, S Walter, A Iikasha, R Bock Pages: 5 - 15 Abstract: This study utilised the minimum inhibitory concentration (MIC) assay and the microtiter plate assay to investigate the antimicrobial and anti-biofilm activities of D. lycioides crude methanolic extracts against Staphylococcus aureus and Mycobacterium avium. Thin layer chromatography was used to qualitatively screen for the presence of phytochemical compounds in the plant methanol and aqueous extracts. Phytochemical analysis revealed the presence of all tested compounds in the methanol extracts, except for saponin. These included coumarin, triterpenoids, anthraquinone, tannins, alkaloids, steroids and flavonoids. On average steroids, tannins, triterpenoids and anthraquinones were the most abundant phytochemicals in both aqueous and methanol extracts, with the highest amounts observed in the methanol extracts. The minimum inhibitory concentration against M. avium occurred at 75mg/ml, 37.5mg/ml and 18.75mg/ml for the root, leaf and twig methanol extracts, respectively while for S. aureus all methanol extracts showed an MIC of 75mg/ml. The highest biofilm inhibition against S. aureus was due to the methanol extracts of D. lycioides leaves (57.2%) and roots (58.1%). However, the twig methanol extracts (57.8%) inhibited M. avium biofilm formation the most as compared to the leaf (25.6%) and root (35.3%) extracts. The leaf extracts (40.4%) were moderately active in eradicating S. aureus biofilms, whereas for M. avium the highest eradication activity was observed with the root extracts (35.6%). PubDate: 2022-01-31 Issue No:Vol. 15 (2022)
Authors:Opeoluwa F Oyedele, Anna-Lisa Shilongo Pages: 16 - 25 Abstract: Despite children not allowed to work by law in Namibia, child labour is still being practised in the country. In this paper, the multinomial logistic regression model was used to statistically examine the factors contributing to child labour in Namibia using the 2018 Namibia Labour Force Survey. Results showed that the children’s characteristics such as their residential area, region, age group, highest educational attainment, school attendance and the types of social grants received had a significant impact on the children’s engagement in child labour activities, while the sex of the children did not. In addition, economically inactive children aged 8-9 years, who already attained a pre-primary education and were currently attending school were more likely to engage in child labour activities, while employed children who were receiving special maintenance grants meant for disabled children, war veterans/ex-combatants grants and other types of social grants were less likely to. It is therefore recommended that the Namibian government and policy makers constantly engage and collaborate with community leaders to assist in the improvement of the standards of living through the creation of decent employment for the children’s parents/guardians, thereby providing decent income to cover at least the basic needs of the children’s households. PubDate: 2022-01-31 Issue No:Vol. 15 (2022)
Authors:N T Kapofi, J A Oyedele, S A Shimboyo, E Taapopi, G Uiseb Pages: 26 - 36 Abstract: The natural radioactivity and associated hazards in soil samples collected from ten geographical areas in the town of Otjiwarongo, Namibia, have been studied by gamma-ray spectroscopy with an HPGe detector. The mean activity concentrations of the primordial radionuclides ²³ᴽU, and ²³²Th, ⁴⁰K in the ten areas was found to vary from 37.6 ± 7.4 Bq/kg to 97.8 ± 46.2 Bq/kg for ²³ᴽU, from 81.9 ± 16.7 Bq/kg to 852.8 ± 533.0 Bq/kg for ²³²Th and from 498.7 ± 55.7 Bq/kg to 807.1 ± 94.5 Bq/kg for 40K. Most of these mean activity concentrations, especially those of ²³²Th, are much higher than the corresponding worldwide average values. In order to evaluate the associated health hazard, the activity concentrations were used to calculate different radiological parameters. The values obtained for the mean radium equivalent activity (ᴿᵃₑq) in some areas are above the maximum permissible limit. Also, the values obtained for the mean external hazard index (Hₑᵪ) in some areas are above the corresponding maximum permissible limit. However, the mean effective dose rates in the ten areas vary from 0.11 ± 0.01мSν y−¹ to 0.73 ± 0.43мSν y−¹ which are all below the maximum permissible limit of 1.0 mSv y−1 . These results imply that radiation hazard is negligible in the town of Otjiwarongo PubDate: 2022-01-31 Issue No:Vol. 15 (2022)
Authors:Emma Mazimba, Phillip O Y Nkunika, Miyanda N Moonga, James Nyirenda Pages: 37 - 49 Abstract: The aim of this research was to evaluate the efficacy of four commercially available biopesticide for[1]mulations, Azadirachtin indica, Beauveria bassiana, Metarhizium anisopliae and Verticillium lecanii in the management of Tuta Absoluta (Meyrick)(Lepidoptera: Gelechiidae) under laboratory and field conditions. Analysis of variance (ANOVA) using Fisher’s least significant difference test (α = 0.05) showed that the mean percent mortality ranged from 41.3±6.8% to 77.9±14.3%. A. indica caused the highest mortality of 77.9±14.3% while mortality due to B. bassiana, V. lecanii, and M. anisopliae was 48.3 ± 2.8%, 44.8 ± 4.8% and 41.3 ± 6.8%, respectively. The estimated LC50 for A. indica was 30.4 µL±0.4, while LC50 for B. bassiana, M. anisopliae, V. lecanii were 107.1 µL±0.4, 193 µL±0.4 and 118.7 µL ± 0.4, respectively. Biopesticide efficacy on larval mortality from highest to least was A. indica, B. bassiana, V. lecanii and M. anisopliae respectively. Percentage corrected mortality ranged from A. indica (69.8 ± 8.1 to 88.4 ± 41.9%), B. bassiana (32.6 ± 4.0% to 60.5 ± 16.3%), V. lecanii (30.2 ± 1.7% to 55.8 ± 14.6%) and M. anisopliae (32.6 ± 4.0% to 53.5 ± 5.4%) respectively. The selected biopesticides significantly (P < 0.001) reduced T. absoluta egg count compared with the untreated control. Performance ranged from A. indica (2.8 ± 1.1 and 10.7 ± 1.2), B. bassiana (3.0 ± 0.6 and 10.7 ± 1.9), V. lecanii (4.3 ± 1.2 and 11.7 ± 1.4) and M. anisopliae (6.8 ± 1.4 and 13.0 ± 1.6) for egg mortality, respectively. The study showed that selected biopesticides were effec[1]tive and should be used by farmers as an integral component of Integrated Pest management (IPM) in the control of T. absoluta in Zambia. Further research should evaluate the effectiveness of the selected biopesticides in other agroecological zones of Zambia PubDate: 2022-01-31 Issue No:Vol. 15 (2022)
Authors:N. K. Egun, I P Oboh Pages: 50 - 56 Abstract: The study examined the Ikpoba Reservoir water quality suitability as source water for aquaculture. Sixteen (16) water physico-chemical parameters were monitored for a duration of eighteen (18) months from February 2018 to July 2019, and analyzed according to standard methods. Concentration values were compared with the International Standard Water Quality Criteria for fisheries. Results showed that mean water temperature (27◦C), electrical conductivity (100.46 µS/cm), chloride (27.08 mg/L), potassium (3.40 mg/L), calcium (25.16 mg/L), magnesium (15.56 mg/L) values were favourable for aquaculture. While mean water pH (5.78), turbidity (24.59 NTU), total suspended solids (23.70 mg/L), dissolved oxygen (4.36 mg/L), biochemical oxygen demand (4.16 mg/L), nitrate (15.67 mg/L) and ammonium (1.63 mg/L), iron (0.95 mg/L), copper (1.37 mg/L) and zinc (1.23 mg/L) concentrations were unsatisfactory for the breeding and survival of fish. The unsatisfactory levels of several physico-chemical parameters and their attendant effects on the development of fishes makes the reservoir water source unsuitable for use in freshwater aquaculture. PubDate: 2022-01-31 Issue No:Vol. 15 (2022)
Authors:Nelson Mhlanga, Lloyd Shorai Pisa Pages: 57 - 68 Abstract: Post-colonial Zimbabwe has seen the implementation of agrarian reform policy. Through a case study of the Chimwara Community in Hwange District of Zimbabwe, It was the purpose of this research to investigate the resultant effects of associated resettlements to the edge of protected areas from the land redistribution processes on community livelihoods. Findings from the study show an increased influx and presence of women in the resettled communities and a diversification of livelihood sources from prior practiced ones, resettled households and farmers changed economic activity sources to suit the demands of the area including the presence of wildlife, with art and craft providing a new source of income for the resettled. 54% of participants shifted to crop production from a 49% prior practice and a slight decline in livestock farming was observed from 42% to 37% of survey respondents. The study highlights key issues pertinent in the promotion of human and wildlife coexistence practices and the need for diversification to alternative livelihood sources with the provision of key technical support for communities living proximal to protects areas with high wildlife densities being a priority need. PubDate: 2022-01-31 Issue No:Vol. 15 (2022)
Authors:Obemeata E. Oriakpono, Oluwatunmise Adetayo, Iris O Oriakpono Pages: 70 - 81 Abstract: The study was carried out to examine the biostimulatory effect of saw dust and cow blood on remediation of soil polluted with spent engine oil. A completely randomized design with four treatments and three replicates each were used; three rates of saw dust and 1 litre of blood was applied to crude oil polluted soils. The results for soil physicochemical parameters showed significant variations (P < 0.05) as the levels of total organic carbon, total petroleum hydrocarbon, polycyclic aromatic hydrocarbon and nitrogen increased 2 weeks after pollution but decreased 4weeks after remediation. The bacteria count at two weeks after pollution was (1.4 × 103 to 21.07 × 103) but increased at 4 weeks after remediation to (1.67 × 103 to 80.13 × 103 ). This study showed improved soil physicochemical properties after the application of saw dust and cow blood as biostimulatory agents on the soil polluted with spent engine oil. PubDate: 2022-01-31 Issue No:Vol. 15 (2022)
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