Journal Articles

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Validation of COVID 19 Spread Model by Early Cases from Spain
(Matrix Science Pharma, 2020) Kibona, Isack E.; Ruhere, Jeremiah J.; Saria, Violet G.
This article intends to illustrate the coronavirus disease 2019 (COVID-19) model if strict restriction is not enforced. Early COVID-19 cases from Spain have been considered an example. Thus, this article is for the estimation of specific parameter particularly to one of the most hit countries in April 2020. Our essence is the possibility to spot a natural model of COVID-19. The cases between March 1 and 15, 2020 have been taken to validate and estimate the parameter of the model. Parameters were estimated by a nlinfit function from MATLAB developed by Levenberg–Marquardt, and thus, so is the reproduction number (R0 ). R0 was found greater than the unit, which is catastrophic. Cases of COVID-19 between March 1 and 15 have been chosen to validate the model because in this earlier stage of the pandemic, Spain restrictions against the spread were assumed not enough to impede the pace of natural spread to the pandemic. Had it not been the lockdown that followed after the mentioned dates, by April 15, 2020, Spain would have been in a more catastrophic situation by >3,400,000 COVID-19 infection cases far worse from 180,695 cases that happened
Dynamical and Optimal Control Analysis of a Seasonal Trypanosoma Brucei Rhodesiense Model
(2020-02-27) Helikumi Mlyashimbi, Kgosimore Moatlhodi, Kuznetsov Dmitry and Mushayabasa Steady
The effects of seasonal variations on the epidemiology of Trypanosoma brucei rhodesiense disease is well documented. In particular, seasonal variations alter vector development rates and behaviour, thereby influencing the transmission dynamics of the disease. In this paper, a mathematical model for Trypanosoma brucei rhodesiense disease that incorporates seasonal effects is presented. Owing to the importance of understanding the effective ways of managing the spread of the disease, the impact of time dependent intervention strategies has been investigated. Two controls representing human awareness campaigns and insecticides use have been incorporated into the model. The main goal of introducing these controls is to minimize the number of infected host population at low implementation costs. Although insecticides usage is associated with adverse effects to the environment, in this study we have observed that by totally neglecting insecticide use, effective disease management may present a formidable challenge. However, if human awareness is combined with low insecticide usage then the disease can be effectively managed.
Uses, Constraints and Quality Characteristics of Juice Developed from a Wild Fruit- Baobab
(Mbeya University of Science and Technology, 2020-05-02) Ahmed,Amina; Tiisekwa,Bendantunguka P. M.
The investigation studied the uses, constraints and quality characteristics of juice developed from a wild fruit, Baobab. Desk review, observation and informal interviews with vendors, processors and consumers using open-ended questionnaire were conducted in Morogoro, Mbeya and Dodoma regions. Stepwise process was followed to develop baobab juice formulations with varied amount of pulp and sugar, colour and spice extracts and analyzed for titratable acidity, and sensory properties using 9-points hedonic scale. It was found that the pulp, leaf and bulk from the baobab tree are traditionally used as food and natural remedy for number of disease including malaria, anemia, vomiting, diarrhea and skin problems. Limited baobab products, mainly candy and ice cream were found in the local and super markets. Constraints to consumption of baobab and its products were limited processing knowledge and poor hygiene, and sensory qualities of the available products. The baobab pulp and sugar levels, colour and type of spice extract had significant effect on Total Titratable Acidity, Total Soluble Solids and sensory scores of the formulations. The titratable acidity ranged from 0.175 to 0.427% citric acid while Total Soluble Solids from 13 to 15°Brix. The final formulation scored high for sensory attributes of color, consistency, flavour, sweetness and overall acceptability. Therefore, juice prepared from baobab would increase the consumption of baobab fruit; hence promote uses of this valuable wild fruit for food and nutrition purpose.
Dengue Virus Infection and Associated Risk Factors in Africa: A Systematic Review and Meta Analysis
(MDPI, 2021) Mwanyika, Gaspary O.; Mboera, Leonard E. G.; Rugarabamu, Sima; Ngingo, Baraka; Sindato, Calvin; Lutwama, Julius J.; Paweska, Janusz T.; Misinzo, Gerald
Dengue contributes a significant burden on global public health and economies. In Africa, the burden of dengue virus (DENV) infection is not well described. This review was undertaken to determine the prevalence of dengue and associated risk factors. A literature search was done on PubMed/MEDLINE,Scopus,Embase, andGoogleScholar databases to identify articles published be tween 1960 and 2020. Meta-analysis was performed using a random-effect model at a 95% confidence interval, followed by subgroup meta-analysis to determine the overall prevalence. Between 1960 and 2020, 45 outbreaks were identified, of which 17 and 16 occurred in East and West Africa, respectively. Dengue virus serotype 1 (DENV-1) and DENV-2 were the dominant serotypes contributing to 60% of the epidemics. Of 2211 cases reported between 2009 and 2020; 1954 (88.4%) were reported during outbreaks. Overall, the prevalence of dengue was 29% (95% CI: 20–39%) and 3% (95% CI: 1–5%) during the outbreak and non-outbreak periods, respectively. Old age (6/21 studies), lack of mosquito control (6/21), urban residence (4/21), climate change (3/21), and recent history of travel (3/21) were the leading risk factors. This review reports a high burden of dengue and increased risk of severe disease in Africa. Our findings provide useful information for clinical practice and health policy decisions to implement effective interventions
Seroprevalence and Associated Risk Factors of Chikungunya, Dengue, and Zika in Eight Districts in Tanzania
(ELSEVIER, 2021) Mwanyika, Gaspary O.; Sindato, Calvin; Rugarabamu, Sima; Rumisha, Susan F.; Karimuribo, Esron D.; Misinzo, Gerald; Rweyemamu, Mark M.; Abdel Hamid, Muzamil M.; Haider, Najmul; Vairo, Francesco; Kock, Richard; Mboera, Leonard E.G.
Background: This study was conducted to determine the seroprevalence and risk factors of chikungunya (CHIKV), dengue (DENV), and Zika (ZIKV) viruses in Tanzania. Methods: The study covered the districts of Buhigwe, Kalambo, Kilindi, Kinondoni, Kondoa, Kyela, Mvomero, and Ukerewe in Tanzania. Blood samples were collected from individuals recruited from house- holds and healthcare facilities. An ELISA was used to screen for immunoglobulin G antibodies against CHIKV, DENV, and ZIKV. Results: A total of 1818 participants (median age 34 years) were recruited. The overall CHIKV, DENV, and ZIKV seroprevalence rates were 28.0%, 16.1%, and 6.8%, respectively. CHIKV prevalence was highest in Buhigwe (46.8%), DENV in Kinondoni (43.8%), and ZIKV in Ukerewe (10.6%) and Mvomero (10.6%). Increas- ing age and frequent mosquito bites were significantly associated with CHIKV and DENV seropositivity ( P < 0.05). Having piped water or the presence of stagnant water around the home ( P < 0.01) were as- sociated with higher odds of DENV seropositivity. Fever was significantly associated with increased odds of CHIKV seropositivity ( P < 0.001). Visiting mines had higher odds of ZIKV seropositivity ( P < 0.05). Conclusions: These findings indicate that DENV, CHIKV, and ZIKV are circulating in diverse ecological zones of Tanzania. There is a need to strengthen the control of mosquito-borne viral diseases in Tanzania. ©2021 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.
Estimating Risk of Introduction of Ebola Virus Disease from the Democratic Republic of Congo to Tanzania: A Qualitative Assessment
(MDPI, 2022) Rugarabamu, Sima; George, Janeth; Mbanzulu, Kennedy M.; Mwanyika, Gaspary O.; Misinzo, Gerald; Mboera, Leonard E. G.
Between April 2018 and November 2020, the Democratic Republic of Congo (DRC) experi- enced its 11th Ebola virus disease (EVD) outbreak. Tanzania’s cross-border interactions with DRC through regular visitors, traders, and refugees are of concern, given the potential for further spread to neighboring countries. This study aimed to estimate the risk of introducing EVD to Tanzania from DRC. National data for flights, boats, and car transport schedules from DRC to Tanzania covering the period of May 2018 to June 2019 were analyzed to describe population movement via land, port, and air travel and coupled with available surveillance data to model the risk of EVD entry. The land border crossing was considered the most frequently used means of travel and the most likely pathway of introducing EVD from DRC to Tanzania. High probabilities of introducing EVD from DRC to Tanzania through the assessed pathways were associated with the viability of the pathogen and low detection capacity at the ports of entry. This study provides important information regarding the elements contributing to the risk associated with the introduction of EBV in Tanzania. It also indicates that infected humans arriving via land are the most likely pathway of EBV entry, and therefore, mitigation strategies including land border surveillance should be strengthened.
Viral Haemorrhagic Fevers and Malaria Co-Infections Among Febrile Patients Seeking Health Care in Tanzania
(Open Access, 2022) Rugarabamu, Sima; Rumisha, Susan F.; Mwanyika, Gaspary O.; Sindato, Calvin; Lim, Hee‑Young; Misinzo, Gerald; Mboera, Leonard E. G
Background: In recent years there have been reports of viral haemorrhagic fever (VHF) epidemics in sub‑Saharan Africa where malaria is endemic. VHF and malaria have overlapping clinical presentations making differential diagno‑ sis a challenge. The objective of this study was to determine the prevalence of selected zoonotic VHFs and malaria co‑infections among febrile patients seeking health care in Tanzania. Methods: This facility‑based cross‑sectional study was carried out between June and November 2018 in Buhigwe, Kalambo, Kyela, Kilindi, Kinondoni, Kondoa, Mvomero, and Ukerewe districts in Tanzania. The study involved febrile patients seeking health care from primary healthcare facilities. Blood samples were collected and tested for infections due to malaria, Crimean‑Congo haemorrhagic fever (CCHF), Ebola virus disease (EVD), Marburg virus disease (MVD), Rift Valley fever (RVF) and yellow fever (YF). Malaria infections were tested using rapid diagnostics tests while exposure to VHFs was determined by screening for immunoglobulin M antibodies using commercial enzyme‑linked immuno‑ sorbent assays. The Chi‑square test was used to compare the proportions. Results: A total of 308 participants (mean age = 35 ± 19 years) were involved in the study. Of these, 54 (17.5%) had malaria infection and 15 (4.8%) were positive for IgM antibodies against VHFs (RVF = 8; CCHF = 2; EBV = 3; MBV = 1; YF = 1). Six (1.9%) individuals had both VHF (RVF = 2; CCHF = 1; EVD = 2; MVD = 1) and malaria infections. The highest co‑infection prevalence (0.6%) was observed among individuals aged 46‒60 years (P < 0.05). District was significantly associated with co‑infection (P < 0.05) with the highest prevalence recorded in Buhigwe (1.2%) followed by Kinondoni (0.9%) districts. Headache (100%) and muscle, bone, back and joint pains (83.3%) were the most significant complaints among those infected with both VHFs and malaria (P = 0.001). Conclusions: Co‑infections of VHF and malaria are prevalent in Tanzania and affect more the older than the younger population. Since the overlapping symptoms in co‑infected individuals may challenge accurate diagnosis, adequate laboratory diagnosis should be emphasized in the management of febrile illnesses
Dynamics of a Fractional-Order Chikungunya Model with Asymptomatic Infectious Class
(Hindawi, 2022) Helikumi, Mlyashimbi; Eustace, Gideon; Mushayabasa, Steady
In this paper, a nonlinear fractional-order chikungunya disease model that incorporates asymptomatic infectious individuals is proposed and analyzed. The main interest of this work is to investigate the role of memory effects on the dynamics of chikungunya. Qualitative analysis of the model’s equilibria showed that there exists a threshold quantity which governs persistence and extinction of the disease. Model parameters were estimated based on the 2015 weekly reported cases in Colombia. The Adams-Bashforth-Moulton method was used to numerically solve the proposed model. We investigated the role of asymptomatic infectious patients on short- and long-term dynamics of the diseases. We also determined threshold levels for the efficacy of preventative strategies that results in effective management of the disease. We believe that our model can provide invaluable insights for public health authorities to predict the effect of chikungunya transmission and analyze its underlying factors and to guide new control efforts.
Viral Haemorrhagic Fevers and Malaria Co-Infections Among Febrile Patients Seeking Health Care in Tanzania
(Infectious Diseases Of Poverty, 2022) Rugarabamu, Sima; Rumisha, Susan F.; Mwanyika, Gaspary O.; Sindato, Calvin; Lim, Hee Young; Mboera, Leonard E. G.; Misinzo, Gerald
Background: In recent years there have been reports of viral haemorrhagic fever (VHF) epidemics in sub Saharan Africa where malaria is endemic. VHF and malaria have overlapping clinical presentations making differential diagno sis a challenge. The objective of this study was to determine the prevalence of selected zoonotic VHFs and malaria co infections among febrile patients seeking health care in Tanzania. Methods: This facility based cross sectional study was carried out between June and November 2018 in Buhigwe, Kalambo, Kyela, Kilindi, Kinondoni, Kondoa, Mvomero, and Ukerewe districts in Tanzania. The study involved febrile patients seeking health care from primary healthcare facilities. Blood samples were collected and tested for infections due to malaria, Crimean Congo haemorrhagic fever (CCHF), Ebola virus disease (EVD), Marburg virus disease (MVD), Rift Valley fever (RVF) and yellow fever (YF). Malaria infections were tested using rapid diagnostics tests while exposure to VHFs was determined by screening for immunoglobulin M antibodies using commercial enzyme linked immuno sorbent assays. The Chi square test was used to compare the proportions. Results: A total of 308 participants (mean age = 35 ± 19 years) were involved in the study. Of these, 54 (17.5%) had malaria infection and 15 (4.8%) were positive for IgM antibodies against VHFs (RVF = 8; CCHF = 2; EBV = 3; MBV = 1; YF = 1). Six (1.9%) individuals had both VHF (RVF = 2; CCHF = 1; EVD = 2; MVD = 1) and malaria infections. The highest co infection prevalence (0.6%) was observed among individuals aged 46‒60 years (P < 0.05). District was significantly associated with co infection (P < 0.05) with the highest prevalence recorded in Buhigwe (1.2%) followed by Kinondoni (0.9%) districts. Headache (100%) and muscle, bone, back and joint pains (83.3%) were the most significant complaints among those infected with both VHFs and malaria (P = 0.001). Conclusions: Co infections of VHF and malaria are prevalent in Tanzania and affect more the older than the younger population. Since the overlapping symptoms in co infected individuals may challenge accurate diagnosis, adequate laboratory diagnosis should be emphasized in the management of febrile illnesses
Evaluation of Antibacterial Activity of Tanzanian Gooseberry (Physalis peruviana) Leaf Extract against Multi-Drug Resistance Escherichia coli and Salmonella typhi
(MJRD, 2024-12-05) Ngingo, Baraka; Magesa, Felista; Shebughe, Ramadhani; Rugumisa, Bernadether; Lwilla, Johnson; Mzena, Theopista; Ruhembe, Carolyne
This study was conducted to evaluate in-vitro antibacterial activities of methanolic leaf extract of Physalis peruviana growing in Dodoma, Tanzania, against multidrug-resistant bacteria (Escherichia coli and Salmonella typhi) using agar well diffusion and standard microdilution methods. Moreover, leaf extract was screened qualitatively for the presence of phytoconstituents using standard methods. Methanolicleaf extract of P. peruviana (from 0.2 mg/mL to 0.4 mg/mL concentrations) showed antibacterial activity against tested E. coli and S. typhi with zones of inhibition ranging from 19 to 21 mm and 17.7 to 22 mm, respectively. The micro-dilution method revealed the minimum inhibitory concentration of methanolic leaf extract of P. peruviana to be 10 µg/µL and 5 µg/µL for E. coli and S. typhi, respectively. Qualitative phytochemical analysis of methanolic leaf extract of P. peruviana identified the presence of tannins, cardiac glycosides, alkaloids, terpenoids, steroids, flavonoids, and phenols. Methanolic leaf extract of P. peruviana has antibacterial activity against multidrug-resistant bacteria (E. coli and S. typhi). This plant may be a promising new source of future antibiotics that potentially combat the existing problem of antimicrobial resistance.
Cerebral Death: Unraveling the Mystery of the Silent Mind
(MJRD, 2024-12-05) Akram, Muhammad; Ojija, Fredrick; Suke, Mary Nicholaus
The permanent loss of all brain stem functions, such as breathing, awareness, and cranial nerve reflexes, is known as brain stem death (BSD), and it presents a significant medical and ethical issue. While other bodily functions, such as heart activity and circulation, can be maintained with medical intervention, BSD is defined by the cessation of brain stem activity. The key characteristic that distinguishes BSD from other conditions, such as coma or a persistent vegetative state, is the complete and irreversible loss of brain stem function—a critical control centre for basic physiological processes. Diagnosing BSD requires strict clinical criteria and diagnostic testing to confirm the full and permanent nature of the condition. This typically involves a comprehensive neurological examination, assessment of cranial nerve reflexes, and confirmation through additional tests, such as cerebral blood flow studies or electroencephalography (EEG). A diagnosis of BSD carries significant ethical and legal implications, particularly in relation to organ donation, as it often plays a role in identifying potential donors. The ethical considerations surrounding BSD include its impact on families, the distinction between death and end-of-life care, and the challenges posed by varying legal and cultural perspectives. It highlights the importance of a clear diagnosis, obtaining informed consent, and adhering to established medical protocols to uphold human dignity and ethical standards. As medical technology advances and societal views evolve, the discussion around brain stem death continues to be a critical issue in both bioethics and modern medical practice.
Ecological Consequences of Antibiotics Pollution in Sub-Saharan Africa: Understanding Sources, Pathways, and Potential Implications
(ELSEVIER, 2025-01-23) Ripanda, Asha; Rwiza, Mwemezi J.; Nyanza, Elias Charles; Hossein, Miraji; Alfred, Mateso Said; Mahmoud, Alaa El Din; Murthy, H.C. Ananda; Bakari, Ramadhani; Vuai, Said Ali Hamad; Machunda, Revocatus L.
In Sub-Saharan Africa (SSA), the increasing use of antibiotics in human and veterinary medicine, combined with inadequate waste and water management systems, has intensified the problem of antibiotic pollution. Untreated or partially treated wastewater from industries, agricultural runoff, residential areas, and healthcare facilities is frequently discharged into the environment, often used for irrigation, contributing to antibiotic accumulation, the spread of resistance genes, and the rise of antibiotic resistance, posing serious threats to public health and environmental sustainability. The region's climatic conditions favour the survival and proliferation of microbial communities, including pathogens. Additionally, the high prevalence of infectious diseases such as HIV/AIDS, tuberculosis, and malaria, which often necessitate antibiotic use, further amplifies the issue. Systemic challenges, including poor waste management, inadequate or absent wastewater treatment infrastructure, weak regulatory enforcement, and the over-the-counter sale of antibiotics, exacerbate the crisis. Limited healthcare access often results in self-medication and improper antibiotic use, accelerating resistance spread. Evidence shows antibiotics in surface water, groundwater, effluents, food crops, environmental samples, and aquatic organisms, indicating their potential circulation through the food chain. However, a lack of comprehensive data on antibiotic pollution and its impacts on aquatic ecosystems in SSA hampers a thorough understanding of its scope and long-term effects. Addressing this crisis requires identifying contamination hotspots, evaluating ecological impacts, and establishing robust, region-specific regulatory frameworks to ensure environmental and public health safety.

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