Authors:Mtisunge Mandala, Wisdom Changadeya, Bosco Rusuwa, Sekeleghe Kayuni Pages: 1 - 16 Abstract: The impact of COVID-19 infections has been felt in Malawi since April 2020. Malawi readily benefited from the Coronavirus vaccine distribution program. While reagents were accessible for easy diagnosis, screening protocols kept changing. This paper assessed severity of symptoms among Coronavirus infected people as impacted by several factors in Zomba city. A cross-sectional study (n= 570) was conducted among patients accessing the University of Malawi COVID-19 clinic. Sex, age, disease outcome, vaccination status and underlying conditions data were collected. Log-linear multiple regression model was used for data analysis in R statistical analytical tool (Version 3.1). From July 2021 to October 2021, the clinic reported 179 (34.5%) third wave COVID-19 cases with a slightly higher males’ representation (54.8%) than females (45.2%). Significant variation of infection prevalence was represented by 71.1% and 3.2% in age groups 18-29 and 1-17 respectively (χ2 = 328.34, df = 4, p <.01). Majority of the infections were mild (90%) with few severe (5.1%) and asymptomatic (4.6%) cases (χ2 = 288.25, df = 2, p <.01). Underlying conditions (5.6%, n=197) were present among few infected individuals. Infection significantly varied according to vaccination status categories (χ2 = 284.63, df = 2, p <.01) with most of the un-immunized patients (89.8%), vaccinated with one dose (8.6%) and two doses (1.5%). A negative association of disease severity with underlying conditions [0.1(R: -0.4, p=.02)] and vaccination status (R: -0.4, p=.01) were observed. Coronavirus symptoms severity was positively associated with a vaccination status and age interaction (R: 0.01, p=0.01). Underlying conditions in consideration of age negatively determined severity (R: - 0.01, p=0.02). Further underlying conditions effect on severity assessment is needed to understand the relationship. Adherence to COVID-19 preventive and control measures i.e. vaccination, social distance and use of face masks reduce cases. PubDate: 2023-10-03 Issue No:Vol. 15, No. 1 (2023)
Authors:Yung-Ching Wang Pages: 17 - 34 Abstract: Extremely rapid weakening (ERW) is a form of abrupt intensity change of tropical cyclones (TCs) that has received scant scholarly attention. On the basis of worldwide TC records, this study identifies and presents 89 6-hourly periods in which a TC’s maximum sustained wind speed near center diminished by 40 kt (1 kt = 0.51 m/s) or more. The vast majority of these ERW periods occurred when powerful TCs made landfall (especially in mountains), but there are also exceptions in which ERW was the result of strong vertical windshear over open oceans. Madagascar Island, Luzon Island, Taiwan Island, west Mexico, US Gulf Coast, and Yucatan Peninsula are found to experience most ERW, while the incidence of such events has so far been zero at the Baja California Peninsula, the Korean Peninsula, and the coast of the Arabian Sea. PubDate: 2023-10-03 Issue No:Vol. 15, No. 1 (2023)
Authors:Sylvester Chikwana, Bosco Rusuwa, Wisdom Changadeya, Richard Zatha Pages: 35 - 54 Abstract: Species divergence under geographically varying selection across disparate habitats has intrigued ecologists for decades. The Lake Chilwa inland drainage basin in Malawi has historically undergone wild water-level oscillations, sometimes being split into various sub- basins. Hydrological regime shifts may drive morphological variance in fishes. Although many scientists have studied fishes of this basin, we know little about the potential effects of its stochasticity on its ichthyofauna. Traitbased approaches are useful for detecting phenotypic changes among different populations. We used morphometric analysis to assess morphological disparities among three allopatric populations of Enteromius paludinosus, a fisheries-dominant cyprinid of this basin. Specimens from its three inlet rivers were measured on 18 traits and the data analysed using principal component analysis, the Welch-F test and t-tests in the Palaeontological Statistics package. Two river populations were clearly separated along seven traits: post-anal distance II, post-dorsal distance I, post- dorsal distance II, post-anal distance I, pre-anal distance, pre-pelvic distance and predorsal. This divergence may be related to different abiotic selective pressures in their unique habitats, perhaps mediated by adaptive phenotype switching and incongruent growth trajectories. More eco-morphological studies in this basin may fully unravel the link between its wild hydrological fluctuations and the eco-evolutionary dynamics of its fishes. PubDate: 2023-10-03 Issue No:Vol. 15, No. 1 (2023)
Authors:Clara A. Majawa, Athumani M. Lupindu, Ginethon G. Mhamphi, Robert S. Machang’u, Abdul A.S. Katakweba Pages: 55 - 74 Abstract: Leptospirosis is a worldwide neglected bacterial zoonotic disease caused by pathogenic species of the genus Leptospira. Humans get leptospirosis through contact with an environment contaminated with bacteria from reservoir hosts, which are mainly rodents. A cross- sectional epidemiological study was carried out in Kibondo and Kakonko districts of Kigoma region, Tanzania, to determine the seroprevalence of Leptospira species in rodents and shrews. Blood sera were collected from rodents and shrews (n = 582) and tested for leptospiral antibodies using the Microscopic Agglutination Test (MAT) against five live serovars with titers ranging from 1:20 to 1:160 and a cut-off point of 1:160. The overall prevalence of leptospira antibodies was 11.9% with rodents showing 11.6% (95% CI 9.1% to 14.3%) and shrews having 0.3% (95% CI 0.1% to 1.1%). Number and prevalence per species (in brackets) were as follows; Aethomys kaiseri 16 (2.7%), Arvicanthis niloticus 1 (0.2%), Lemniscomys rosalia 2 (0.3%), Lemniscomys striatus 10 (1.7%), Lophuromys flavopunctatus 2 (0.3%), Mastomys natalensis 30 (5.2%), Rattus rattus 6 (1.0%) and Crocidura tansaniana 2 (0.3%). No antibodies were revealed in Grammomys dolichurus, Mus musculus, Praomys delectorum, and Tatera indica. In terms of prevalence, there was no significant variation with regard to sex or between rodents and shrews, but it was found across species (P<0.05). The most prevalent Leptospira serovar and titer were Lora (4%) and titer 1:40 respectively. Kakonko had a prevalence of 18 (3.1%) compared to Kibondo, 51 (8.8%). Fallow land was leading in the prevalence of leptospira antibodies in its captured rodents and shrews with a prevalence of 36 (6.2%), followed by farmland 16 (2.7%), indoor 11 (1.9%), grassland 4 (0.7%), forest 1 (0.2%) and wetland 1 (0.2%). The findings of this study denote a potential public health risk among the people of Kigoma region, Tanzania, and hence the need to raise awareness of the disease among the study population and the country as a whole. PubDate: 2023-10-03 Issue No:Vol. 15, No. 1 (2023)
Authors:Wasiu Agunbiade Lamidi, Mosobalaje Abdulsalam Murtadha, Tayo Babatunde Ojo, Grace Oluwaseun Olaniyi Pages: 75 - 94 Abstract: The average maize yield per hectare in Nigeria and other Sub-Sahara Africa is always less than in developed nation, hence, this research aimed to determine growth factors contributing to the yield performance of synthetic maize populations released for farming in Nigeria and rcommend most yielding variety.Ten synthetic maize varieties obtained from International Institute of Tropical Agriculture (IITA), Ibadan were sown at two seeds per hole in a two row per plot of 5 m length and a spacing of 50 cm intra-row and 75 cm inter-row. The experimental design was Randomized Complete Block (RCBD) of 10 x 3; ten varieties and three blocks. Data were collected from three plants in each row selected randomly from the block. The parameters measured were numbers of leaves per plant, plant heights (cm), stem girths (cm), ear heights (cm), leaf area, cm2 , days to 50% tasselling, days to 50% physiological maturity, cob’s length (cm), cob’s weight (g), number of grains per cob, number of cob and grain yield (t ha-1 ). Ambient temperatures and wind speeds and directions were measured at 10.00 h and 14.00 h daily. Both F2TWLY13124 and PVASYNHGACO had same values of 0.45 t ha-1 and 2.625 kg as grain yield and cob yield plant-1 respectively. However, F2SCA141336 had the highest mean number of leaf plant-1 , 12.20; this was 0.83% more than F2TWLY100121 that had 12.10 leaf plant-1 . F2TWLY13124 displayed higher number of grain cob-1 and longer cob length 778.50 and 20.59 cm respectively. Environmental factors decreased grain yield via decrease in number of leaf plant-1 , plant height and number of cob per plant (r= 70.13 to r = 92.31, p<0.05) for the ear height and the cobs’ parameters. F2TWLY13124 and PVASYNHGACO could be suitable, when used in planting, would improve the yield components and grain yield of maize in the study area and contribute significantly to increased production. PubDate: 2023-10-03 Issue No:Vol. 15, No. 1 (2023)
Authors:Francis James Ogbozige Pages: 95 - 104 Abstract: The health impacts of exposure to generator exhaust fumes have long been identified by researchers as a major factor contributing to igh morbidity and mortality rates in carcinogenic and cardiovascular related diseases. Notwithstanding, petrol and diesel generators are used frequently in augmenting the usual interrupted electric power supply experienced in most developing countries by individuals, institutions, and industries. Therefore, this research evaluated the quality of fume emitted by a diesel power plant and proffer solution for save dispersion in compliance with World Health Organisation (WHO) standards. This was achieved by employing the Gaussian plume dispersion model to design an effective stack height. The results showed that the existing stack height of the diesel power plants being 2.88m produced a maximum ground level SO2 concentration of 450.46 g/m3 at 150m downwind. This is 800% above the maximum WHO emission limit of 50 g/m3. However, an effective stack height of 12.0m with an internal diameter of 150mm was designed for the power plant based on information about the emission, and was noted that it will produce a maximum ground level SO2 concentration of 36.16 g/m3 during worst scenario at downwind distance of 650m thus, complying with WHO standard. Hence, it was concluded that the present installation of the diesel power plant with respect to stack height is a potential danger to the lives of humans and animals within the concerned area hence necessary recommendations were made. PubDate: 2023-10-03 Issue No:Vol. 15, No. 1 (2023)
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