Applied Science

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A Blockchain-based Patient Portal for Mental Health Management
(IEOM Society International, USA, 2024-04-23) Jhamba, P.; Ndlovu, B.; Dube, S.; Muduva, M.; Jacqueline, F.; Maguraushe, K.
Mental health is an important aspect of well-being as it encompasses emotional, psychological and social well-being. The use of patient portals in mental health care has gained attention as a potential tool to improve access to care for individuals with mental illness. Patient portals may be vulnerable to unauthorized access if appropriate security measures are not put in place. This study leverages blockchain technology to create tamper-proof patient records. The proposed solution uses an on-chain database that stores hashes and the actual medical record of a patient as well as an off-chain solution that handles encryption of each user’s medical record using their respective keys in a trustless manner before they are uploaded on-chain. A secure smart contract hosted on Ethereum and the Byzantine Fault Tolerance consensus algorithm was used to ensure patient privacy. The research employed the Comparative Analysis Research Methodology as the research methodology and the Kanban methodology as the software development methodology. The research project concludes that the proposed solution addresses the current security issues and data privacy concerns in patient data. The decentralized nature of blockchain ensures security, transparency, and tamper-proof storage of information. Further research is needed for future advancements, like integrating blockchain-based patient portals with wearable devices and IoT.
A Comparative Study of Transcranial Color-Coded Doppler (TCCD) and Transcranial Doppler (TCD) Ultrasonography Techniques in Assessing the Intracranial Cerebral Arteries Haemodynamics
(MDPI, 2024-02-10) Gunda, S.T.; Ng, T.K.V.; Liu, T.Y.; Chen, Z.; Han, X.; Chen, X.; Pang, M.Y.C.; Ying, M.T.C.
Cerebrovascular disease (CVD) poses a major public health and socio-economic burden worldwide due to its high morbidity and mortality rates. Accurate assessment of cerebral arteries’ haemodynamic plays a crucial role in the diagnosis and treatment management of CVD. The study compared a non-imaging transcranial Doppler ultrasound (TCD) and transcranial color-coded Doppler ultrasound (with (cTCCD) and without (ncTCCD)) angle correction in quantifying middle cerebral arteries (MCAs) haemodynamic parameters. A cross-sectional study involving 50 healthy adults aged ≥ 18 years was conducted. The bilateral MCAs were insonated via three trans-temporal windows (TTWs—anterior, middle, and posterior) using TCD, cTCCD, and ncTCCD techniques. The MCA peak systolic velocity (PSV) and mean flow velocity (MFV) were recorded at proximal and distal imaging depths that could be visualised on TCCD with a detectable spectral waveform. A total of 152 measurements were recorded in 41 (82%) subjects with at least one-sided open TTW across the three techniques. The mean PSVs measured using TCD, ncTCCD, and cTCCD were 83 ± 18 cm/s, 81 ± 19 cm/s, and 93 ± 21 cm/s, respectively. There was no significant difference in PSV between TCD and ncTCCD (bias = 2 cm/s, p = 1.000), whereas cTCCD yielded a significantly higher PSV than TCD and ncTCCD (bias = −10 cm/s, p < 0.001; bias = −12 cm/s, p ≤ 0.001, respectively). The bias in MFV between TCD and ncTCCD techniques was (bias = −0.5 cm/s; p = 1.000), whereas cTCCD demonstrated a higher MFV compared to TCD and ncTCCD (bias = −8 cm/s, p < 0.001; bias = −8 cm/s, p ≤ 0.001, respectively). TCCD is a practically applicable imaging technique in assessing MCA blood flow velocities. cTCCD is more accurate and tends to give higher MCA blood flow velocities than non-imaging TCD and ncTCCD techniques. ncTCCD is comparable to non-imaging TCD and should be considered in clinical cases where using both TCD and TCCD measurements is needed.
A feasibility study to assess Imbrasia belina (mopane worm) sensitisation and related respiratory health outcomes in a rural community in Gwanda district, Zimbabwe
(Springer Nature, 2021-02-22) Ndlovu, V.; Chimbari, M.; Sibanda, E.; Ndarukwa, P.
Background Allergic diseases are considered to be some of the fastest growing chronic conditions in Africa. Of concern is the paucity of knowledge about the local environment and its role in allergic disease development. In response to this, we explored whether Imbrasia belina, a popular indigenous edible insect commonly known as mopane worm, is a potential allergen of clinical and public health significance in Zimbabwe. This study was intended to assess the plausibility and feasibility of this hypothesis with a view to evaluate the insect’s health impact in a larger study. Methods The study participants included male and female villagers aged 10 years and above in Gwanda district, Zimbabwe. Eligible participants who completed the household questionnaire were referred to the local clinic for skin prick tests and to measure lung function and allergic airway inflammation. Allergen sensitisation patterns were evaluated using 10 different inhalant allergen extracts including an in-house preparation of mopane worm. Lung function was measured with a Koko Legend spirometer, and fractional exhaled nitric oxide levels (FeNO) (NIOX VERO) were measured in participants with at least one abnormal spirometric parameter. Data was analysed using Stata version 13 software. Results Of the 46 eligible participants that completed the household questionnaire, 17 went to the clinic giving a response rate of 37%. The majority who completed the questionnaire were adults (91%) and the children (9%) were all female. The prevalence of sensitisation to Imbrasia belina was 50%, and the prevalence ranged from 22 to 72% for the other allergens including cockroach, mosquito and house dust mites. The data collection tools were safe and well tolerated by participants with no adverse events reported. Self-reported respiratory symptoms, abnormal lung function and elevated FeNO were recorded amongst participants sensitised to mopane worm. Conclusion Pre-defined feasibility criteria were met with the exception of a lower than expected response rate for clinic data collection in this pilot study. For the main study, modifying the sampling strategy and applying more consistent community engagement will improve the response rates.
A Framework for Monitoring Stability of Tailings Dams in Realtime Using Digital Twin Simulation and Machine Learning
(Elsevier, 2024) Mwanza, J.; Mashumba, P.; Telukdarie, A.
Tailings dam failures cause catastrophic impact on the environment and surrounding communities. Incidences of failure in the recent past have caused industrialists and researchers to seek innovative ways for proactively managing their safety and disaster mitigation. Given Industry 4.0 technologies now available, researchers are looking to develop digital tools for cost-effective, realtime monitoring of tailings dams. However, published literature indicates that a reliable framework is still lacking. This paper proposes a framework for developing a data-driven system for monitoring tailings dam stability and early warning detection. The framework relies upon digital twin simulation and machine-learning (ML) techniques, and comprises four main components: realtime data collection, digital twin modelling, ML-based early detection and prediction, and intelligence-driven decision-support. Sensors gather real-time geophysical data from monitored structure, and the digital twin uses this data to simulate dam behaviour. ML algorithms analyse the data and simulations to enable early detection of instability and failure prediction. Literature suggests that digital twin and ML-based approaches may have advantages over traditional monitoring techniques and other AI-based methods. The paper concludes with a discussion of the framework's limitations, opportunities for improvement, and potential for application in mining and geotechnical engineering. The paper serves as a basis for model development and future research.
A mathematical model for bioconvection flow with activation energy for chemical reaction and microbial activity
(Indian Academy of Sciences, 2022-01-23) Dhlamini, M.; Mondal, H.; Sibanda, P.; Mosta, S.S.; Shaw, S.
In most of the industrial processes, it is of paramount importance to control the heat and mass transfer rates to ensure high-quality products. Using nanofluids instead of ordinary fluids and using motile micro-organisms are some of the techniques to control heat and mass transfer rates. In some recent studies of bioconvection flow, activation energy, Brownian motion and thermophoretic effects are considered only for the solute and not for the microbes. Our current study incorporates these effects for the motile micro-organisms too. Few, if any results of this nature exist in literature. A system of partial differential equations is formulated to incorporate the effects of these parameters. The system of equations are solved numerically using the spectral quasi-linearisation method to gain an insight into the influence of key parameters on the fluid and flow properties. The thermophoretic force, the Brownian motion and activation energy are significant contributors in the microbes’ dynamics. The concentration of microbes decreases with an increase in the thermophoretic force and increases with increasing microbe’s Brownian motion parameter. Based on our results, we conclude that increasing activation energy leads to a decrease in microbes’ velocity. The inclusion of the microbes’ Brownian motion proved to be significant as this was shown to have an impact on the temperature, solute concentration and microbes’ concentration in the boundary layer.
A Proportional Hazard model to establish factors that are significant in child survival.
(IOSR, 2014) Musizvingoza, R.; Mwembe, D.; Nyamugure, P.
This study addresses important issues affecting under-five mortality in Zimbabwe. The objective of this research is to establish factors that are significantly impacting on child survival and to determine the survival rate of children under the age of five years. Cox regression and Kaplan-Meier estimator were used for data analysis. Child survival was significantly influenced by two predictor variables, breastfeeding and immunisation status (p< 0.05). The Hazard ratios for variable breastfeeding and immunisation are 2.806 and 4.778 respectively. The survival functions for the children indicate a high survival rate especially in children who are well breastfed and those who are fully immunised. This study supports health policy interventions that enhance child survival. Immunisation and breastfeeding should be encouraged among mothers to enhance child survival.
A study of scavenging poultry gastrointestinal and ecto-parasites in rural areas of Matebeleland Province, Zimbabwe.
(Asian Network for Scientific Information, 2010) Dube, S.; Zindi, P.; Mbanga, J.; Dube, C.
A study was carried out to determine endo and ecto-parasites in Matebeleland North and South from free range chickens (Gallus domesticus). Only adult chickens were selected for determination of parasite. For intestinal parasites microscopic studies of eggs and faecal egg counts were done using the salt floatation technique. The endo parasites encountered in the study were Tetrameres americana, Acuaria hamulosa, Ascaridia galli, Heterakis gallinarum, H. dispar, Allodapa suctoria, Capillaria annulate, Raillietina echinobothrida and R. tetragona. A commercially prepared insecticide constituted as follows (0.02% Tetamethrin, 0.03% pramethrin and 0.034% Imiprothrin) was applied for 2 seconds and feathers were then gentle unruffled so that ectoparasites could be counted and identified. Ecto parasites recorded in this study were Menopon gallinae, Menacanthus stramineus, Dermanyssus gallinae, Argas persicus, Ornithonyssus bursa, Cnemidocoptes mutans, Echidnophaga gallinacean, Gonocoites gallinae and Gonocoites hologester.
A Survey of the University Students’ Perspectives about Using Digital Technologies in Education: Zimbabwean Case
(2017) Dube, S; Scott, E
This study investigated the perspectives of university students on the use of digital technologies as tools for teaching and learning. Digital technologies are an essential asset for academic institutions as they can support strategic teaching and learning objectives for education institutions. Studies have shown that limited use of digital technologies could lead to a second order digital divide. This problem negatively impacts the Government and university efforts and initiatives of increased technological investment. There is therefore a need to uncover and obtain a deeper insight into university students’ perspectives due to the sparse literature discussing this problem within the Zimbabwean context. Quantitative data on student perspectives was collected using 100 questionnaires administered to students at a single university of technology in Zimbabwe. Although the findings concur with existing literature that students highly value the integration of technology into their learning process, there were issues that appeared to be peculiar to the surveyed environment. For example, the surveyed students professed disappointment with the current traditional teaching methods despite the high availability and accessibility to digital technologies within the institution. They indicated their frustration emanating from the disconnection between commonly used teaching methods and the digital technologies effective for teaching and learning
Activities of glutamate dehydrogenase and aspartate and alanine aminotransferases in freshwater snails Helisoma duryi and Lymnaea natalensis exposed to copper.
(Biomarkers, 2003) Masola, B.; Chibi, M.; Naik, Yogeshkumar S.; Kandere, E.; Zaranyika, M.F.
In this paper we investigate the potential of glutamate dehydrogenase (GDH) and aspartate and alanine aminotransferases (AST and ALT) as biomarkers of water pollution due to copper in the freshwater snails Helisoma duryi and Lymnaea natalensis. Snails were dosed with copper(II) ion concentrations of 0.01, 0.1 and 1 mg kg(-1) breeding water for a period of 96 h, after which those surviving were shelled. The copper content in the breeding water, in whole snail tissue and in the snail shells was determined at the end of the period of exposure. For enzyme determinations, whole snail tissue was first homogenized and fractionated by centrifugation at 500 g to remove the nuclei. The resulting supernatant was then centrifuged at 10,000 g to give a pellet fraction representing the mitochondrial fraction and a supernatant representing the cytosolic fraction. Copper was very toxic to both snail species at concentrations above 0.2 mg l(-1), with only 3% of the Helisoma and 12% of the Lymnaea surviving at concentrations of approximately 1 mg l(-1). The copper content in the shells and tissues of snails rose with increasing copper concentration in the breeding water, and was 2.1- to 4.9-fold in snails exposed to copper ion at a dose of 1 mg kg(-1) water compared with undosed snails. Similarly, the activities of GDH and AST rose by up to 4.7-fold in the homogenate and the mitochondrial and cytosolic fractions with increasing concentrations of copper. These activities, however, fell at copper concentrations of approximately 1 mg l(-1), which coincided with massive death of snails. Mitochondrial ALT disappeared at copper ion concentrations of approximately 0.2 mg l(-1) for Lymnaea and 1 mg l(-1) for Helisoma, possibly indicating mitochondrial degeneration. These results show that GDH, AST and ALT have the potential to be biomarkers of sublethal copper pollution in these two snail species, since their activities were significantly altered by low copper concentrations.
Acute effects of beetroot juice ingestion on blood flow and blood pressure in diabetic patients with early-stage peripheral artery disease
(NUST, 2021) Tityiwe, J.S.; Crofts, G.; Newton-Hughes, A.; Azangwe, G.; Comfort, P.
The objective of the study was to determine the acute effects of beetroot juice ingestion on blood flow and blood pressure in diabetic patients with early-stage peripheral arterial disease compared to non-diabetic controls. In this quasi-experimental cohort study of 35 Black-African diabetic patients and 36 non-diabetic controls, peak systolic velocity (PSV), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were utilised to assess blood flow in the popliteal arteries (PA) basally, 90 minutes, 150 minutes, and 210 minutes-post-ingestion of beetroot juice both between and within groups. A two-way analysis of variance with Benferroni post-hoc analysis were performed to compare the two groups across 4-time points after the intake of beetroot juice. One sample and two-sample t-tests with Cohen’s d effects sizes were performed to determine whether any changes in dependant variables were significant and meaningful within and between groups. Within groups, PSV, SBP and DBP reduced significantly and meaningfully during baseline to 90 minutes and 150 minutes-210 minutes’ time points (P≤ 0.02; d≤ 1.70). However, no significant or meaningful change (P≤ 0.9; d≤ 0.29) occurred in PSV, SBP and DBP during the 90 minutes to 150 minutes’ time point. Between groups, PSV and DBP were significantly and meaningfully higher (P≤ 0.04; d≤ 1.95) in diabetic patients at baseline. At 90 minutes and 150 minutes PSV remained higher in diabetic patients (P≤ 0.04; d≤ 1.30) unlike SBP (P≤ 0.8; d≤ 0.34). At 210 minutes, PSV and SBP did not change significantly or meaningfully (P≤ 0.59; d≤ 0.18) between groups while DBP showed no significant or meaningful difference (P≤ 0.7; d≤ 0.33) between the groups at all the time points. The combined group effects were significant for PSV (diff≤ 20.0 cm/s; P< 0.0001) across all the time points except between 90 minutes to 150 minutes (diff= 0.4 cm/s; P= 1.0) The combined group effects were significant for SBP (diff≤ 22.01 mmHg; P< 0.0001) amongst all the time points except 90 minutes to 150 minutes time point (diff= 1.2 mmHg; P= 1.00) and finally the combined group effects for DBP were significant and meaningful (diff≤ 13.4 mmHg; P< 0.0001) amongst all the time points except 90 minutes to 150 minutes (diff= 1.34 mmHg; P= 1.00) after beetroot juice ingestions. The acute effects of beetroot juice on the blood flow of the popliteal artery were reflected as lowered PSV, SBP and DBP during the 150-210 minutes’ time point in both groups.
Adolescents and parents’ perceptions of condom distribution in selected secondary schools in the high density suburbs of Bulawayo, Zimbabwe
(2020) Mudonhi, N.,; Nunu, W.N.; Ndlovu, B.; Khumalo, N.; Dube, O.
Condoms have been highlighted as one of the most effective strategies to prevent the spread of HIV and AIDS. This study assessed how adolescents and parents perceive the condom distribution programme in selected secondary schools in the high density suburbs of Bulawayo. A concurrent mixed method survey was conducted on three selected secondary schools. Three hundred adolescents and three hundred parents responded to a pre tested semi structured questionnaire. Likert scales were developed to assess knowledge and attitude levels. The χ2 test and multiple logistic regression were used to associate different demographic characteristics with attitudes and levels of knowledge regarding condom distribution at schools using STATA Version 13. Practices and beliefs were assessed using unstructured interviews on purposively selected adolescents and parents. Qualitative data collected was thematically analysed on MAXQDA. The response rate was 100% and 81% for adolescents and parents/guardians respectively. There were more females than males in both response groups. About 67% of adolescents and 60% of parents/guardians were knowledgeable about condom usage and its implications on prevention of spread of sexually transmitted infections and pregnancies. A large proportion of parents/adolescents (72%) had good attitudes towards condom distribution in schools compared to adolescents (27%). Age was strongly associated with knowledge in adolescents, with older adolescent 102 times more likely to be knowledgeable compared to younger adolescents. Religion was the strongest predictor of attitudes in parents/guardians with Catholic having an odds of 227. The concerned sexual health institutions should increase awareness among adolescents, targeting their attitudes towards condom distribution and usage. Targeting attitudes will hopefully foster safe sexual practices.
Adsorption of Lead and Copper by Carbon Black and Sodium Bentonite Composite Material.
(Chemic Publishing Company, 2017-10-30) Chiririwa, H.; Matthews, T.; Nyoni, B; Majoni, Stephen; Naidoo, E.B
The efficiency of using a composite of carbon black and sodium bentonite in treating drinking water contaminated with lead and copper ions was analyzed. The effects of pH, contact time, concentration and adsorbent dosage using an adsorbent composite of 20 % sodium bentonite and 80 % carbon black were studied. The adsorption data was analyzed with respect to Langmuir, Freundlich and Temkin isotherms. The data fits well with the Langmuir isotherm model with high coefficients of determination for both metal ions adsorption. The adsorption kinetics follows a pseudo second-order model for both metal ions. The maximum metal ion uptake (qmax) of composite adsorbent is 7.69 and 0.80 mg/g for lead and copper, respectively.
Aflatoxin Carryover during Large Scale Peanut Butter Production.
(Scientific Research, 2011-04) Siwela, Andrew H.; Mukaro, Kudzayishe J.; Nziramasanga, Nozipho
Peanut butter was monitored for aflatoxin contamination at different stages during its large-scale production starting from raw shelled peanuts up to the final product. Twenty five samples, weighing 2 kg each, were taken from each of the following stages: roasting at 160°C, blanching/de-skinning and grinding. The sub-samples were ground, thoroughly mixed and further reduced by the quartering technique until a 1 kg sub-sample was obtained. This was then analyzed for aflatoxins using reverse phase HPLC incorporating pre-column trifluoroacetic acid derivatization. The results showed a total aflatoxin percentage reduction of 51% after roasting, 27% after blanching/de-skinning followed by a further 11% after grinding to make peanut butter. This meant that there was a cumulative total reduction of 89% of aflatoxin concentration during the production process of peanut butter. These results show that there is a significant reduction of aflatoxin levels at the roasting and blanching stages in the process of producing peanut butter.
Aflatoxin carryover during large scale peanut butter production.
(Scientific Research Publishing, 2011) Andrew H, S.; Kudzayishe J, M.; Nozipo, N.
Peanut butter was monitored for aflatoxin contamination at different stages during its large-scale production starting from raw shelled peanuts up to the final product. Twenty five samples, weighing 2 kg each, were taken from each of the following stages: roasting at 160?C, blanching/de-skinning and grinding. The sub-samples were ground, thoroughly mixed and further reduced by the quartering technique until a 1 kg sub-sample was obtained. This was then analyzed for aflatoxins using reverse phase HPLC incorporating pre-column trifluoroacetic acid derivatization. The results showed a total aflatoxin percentage reduction of 51% after roasting, 27% after blanching/de-skinning followed by a further 11% after grinding to make peanut butter. This meant that there was a cumulative total reduction of 89% of aflatoxin concentration during the production process of peanut butter. These results show that there is a significant reduction of aflatoxin levels at the roasting and blanching stages in the process of producing peanut butter.
Aflatoxin Contamination of Stored Groundnuts in Zimbabwe.
(ICRISA T (International Crops Research Institute for the Semi-Arid Tropics)., 1989) Siwela, Andrew H.; Caley, A.D.
Aflatoxins were analyzed in groundnuts stored for either local or export sales in the period 1982/83 to 1986/87. Four hundred and forty-one samples of seven groundnut varieties were collected for analysis. Sixty-eight percent of the samples had total concentrations of aIlatoxin BJ and OJ of up to 25 JIg kg-J. In the 1986/87 groundnut crop, the Flamingo and Makulu Red varieties, which constitute the bulk of export sales, had up to 25 JIgkg-J aIlatoxin BJin 79%of the samples, plus aIlatoxin OJ in 67% of the samples. Overall, the Egret variety was the most susceptible to aIlatoxin contamination during this period.
AI-based Drought Forecasting for Parametric Insurance
(IEOM Society International, USA, 2024-05-07) Mathende, M.T.; Ndlovu, B.; Dube, S.; Muduva, M.; Kiwa, F.J.
In drought-prone African countries like Zimbabwe, the uptake of parametric insurance has been low due to the absence of localized models. Guided by the CRISP-DM model, the present study proposes an AI-based approach to drought prediction in parametric insurance. The study’s paramount objectives are establishing trigger thresholds for drought events, assessing their significance, identifying the most effective machine learning models for drought modeling based on the Standardized Precipitation Index (SPI), and forecasting future drought occurrences and their magnitudes. Historical weather data, including temperature and rainfall, are utilized and a range of machine learning modelsneural networks, random forest, and support vector machines are employed for drought prediction. The performance of these models is evaluated based on accuracy, reliability, and interpretability, with continuous refinement based on feedback from stakeholders. The significance of this research lies in promoting data-driven decisions, incentivizing preparedness, enabling risk transfer, facilitating rapid insurance payouts, and enhancing financial stability. With accurate drought predictions driving parametric insurance, policyholders can make well-informed choices, adopt proactive measures, transfer the risk of drought-related losses, receive swift insurance payouts, and improve their financial resilience during drought events.
Alteration of some Hepatic Enzyme Activities by Gastrointestinal Helminth Parasites in Domesticated Ostritches.
(Society of Education, 2013-05-05) Siwela, Andrew H.; Motsi, Leonah R.; Dube, S.
Using the conventional methods for parasitological examinations of the salt floatation and direct smear, ten ostriches infected with internal parasites were identified. Ten birds that were without internal parasites were used as the controls. The metabolizing enzymes glutathione peroxidase (GPX), DT -diaphorase (DTD) and succinate dehydrogenase (SDH) were assayed accordingly using liver samples from the control and infected birds. Malondialdehyde (MDA), a marker of lipid peroxdation, was also assayed. Results showed that cestode eggs occurred at twice the amount of nematode eggs in the faeces of infected ostriches. Infected birds showed significantly higher DTD activity when compared to non-infected birds (Student’s t test, p < 0.05) whilst the activities of SDH and GPX were statistically not altered (Student’s t test p > 0.05). MDA levels were significantly elevated in infected birds compared to controls (Student’s t test, p < 0.001). These results suggest that infected birds are under oxidative stress due to the parasitic infection . Key words: Cestodes, nematodes, glutathione peroxidase, DT-diaphorase, Succinate dehydrogenase, malodialdehyde
Altered Esterase Activity Due To Pesticide Exposure In The Aquatic Snail Physa Acuta.
(2013-03-14) Maredza, Alice; Naik, Yogeshkumar S.
The effect ofpesticides on the xenobiotic metabolising enzymes of the aquatic snail Physa acuta was studied. Adult snails reared in the laboratory were exposed daily for three days to the following pesticides: 2,4-dichlorophenoxyacetic acid, deltamethrin, endosulphan, malathion and pirimiphos-methyl. Cytosolic fractions prepared from the snails showed that pesticide exposure had no effect on the glutathione or glutathione dependent enzyme activities. General esterase activity using two different substrates was reduced significantly by exposure to the organophosphate pesticides malathion and pirimiphos. Exposure to the other pesticides did not cause any substantial changes in the esterases activities. The nature of this inhibition is not yet apparent. It is likely, however, that the changes are due to a competitive type inhibition by the pesticides for the active site of the enzyme.
Altered esterase activity due to pesticide exposure in the aquatic snail Physa acuta.
(2013-09-24) Maredza, Alice; Naik, Yogeshkumar S.
The effect of pesticides on the xenobiotic metabolising enzymes of the aquatic snail Physa acuta was studied. Adult snails reared in the laboratory were exposed daily for three days to the following pesticides: 2,4-dichlorophenoxyacetic acid, deltamethrin, endosulphan,malathion and pirimiphos-methyl, Cytosolic fractions prepared from the snails showed that pesticide exposure had no effect on the glutathione or glutathione dependent enzyme activities. General esterase activity using two different substrates was reduced significantly by exposure to the organophosphate pesticides malathion and pirimiphos. Exposure to the other pesticides did not cause any substantial changes in the esterases activities. The nature of this inhibition is not yet apparent. It is likely, however, that the changes are due to a competitive type inhibition by the pesticides for the active site of the enzyme.
Amphistome Infection and Species Diversity of Freshwater Snails Collected from Selected Wildlife Drinking Water Sources in Matebeleland Region of Zimbabwe
(Vet. Sci., 2024-05-13) Sibula, M.S.; Malatji, M.P.; Nyahunda, C.; Mukaratirwa, S.
Simple Summary Amphistomes, also known as rumen flukes, are parasites of domestic and wild ruminants and occur globally. Adult parasites are found in the forestomach, and the young flukes are found in the small intestines, causing severe damage. The flukes are transmitted by various species of freshwater snails. While the disease is well documented in domestic ruminants, there are gaps in knowledge pertaining to wild ruminants with regard to the fluke species as well as the snail species which transmit them. Therefore, freshwater snails were surveyed from 19 water points that are frequented by wild ruminants in the Matebeleland region, Zimbabwe. Snails were found at nine sites, and eight species were identified and screened for rumen fluke DNA to determine the fluke species and prevalence of infection. Rumen fluke DNA was detected in 11.9% of the screened snails. Prevalence was high in the West Nicholson locality and in Bulinus globosus snail species. One rumen fluke species, i.e., Calicophoron microbothrium, was confirmed in one snail species and there were also mixed infections with lung fluke parasite, Paragonimus spp., in two snail species. This was the first study documenting the presence of this lung fluke in Zimbabwe. Abstract This study aimed at determining the identity of freshwater snails collected from selected water habitats frequented by wildlife as source of drinking water in the Matebeleland region of Zimbabwe and further screening the identified snails for natural infections with amphistomes using PCR. A total of 487 freshwater snails were collected from six areas in the Matebeleland region of Zimbabwe for identification and screening of amphistome infection. Eight freshwater snail species were morphologically identified and Biomphalaria pfeifferi, Bul. tropicus, Bul. truncatus, Bul. globosus, and L. (R.) natalensis were confirmed using the COI gene. Bulinus tropicus and Phy. acuta were the most abundant species at 33.9% (165/487) and 31.2% (155/487), respectively. DNA of amphistome was detected in 11.9% (58/487) of the collected snails. The highest infection rate was detected in Bul. globosus (44.4%). West Nicholson recorded the highest infection rate (33.9%), and infection was not detected in L. (R.) natalensis, Phy. acuta, and Bellamya spp. Amphistome DNA from M. tuberculata was successfully sequenced and identified as Calicophoron microbothrium. An additional band was detected in M. tuberculata, Bul. tropicus, and Bul. trancatus, which showed a 96.42% similarity to Paragonimus sp. sequence in the GenBank.

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