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Item Quantifying the Public Health Effects of Vaccine Hesitancy and Delays in Screening Clinically Infected Patients: Insights From a COVID-19 Transmission Model(International Journal of Mathematical Sciences and Optimization, 2025-09-20) Lolika ,Paride O; Helikumi, Mlyashimbi,; Sube, Kenneth; Mushayabasa, SteadyMotivated by the recent COVID-19 outbreak, we develop a time delay infectious disease model that incorporates vaccination and screening of clinically infected patients and calibrate it using Chinese data to understand the quantitative implications of vaccine hesitancy and delay in the screening of clinically infected patients. Vaccine hesitancy refers to the denial or delay in acceptance of vaccines despite their availability. Understanding the implications of vaccine hesitancy is therefore essential for designing public health interventions. Analysis of the model revealed that whenever R0 ≤ 1, there exists a globally asymptotically disease-free equilibrium. However, whenever R0 > 1, there exists a unique endemic equilibrium which is globally asymptotically stable. In addition, results also show that vaccine hesitancy and delay in hospitalizing clinically infected patients have a stronger impact on the deaths toll and new infections generated [1,2]. Vaccine hesitancy and delayed screening of clinically infected patients lead to harmonic oscillations in deaths and new cases, which, however, die out over time. Our findings underscore the importance of including vaccine hesitancy and delay in hospitalizing clinically infected patients in the design of control strategies for infectious diseases.Item Impact of Health Education Interventions for Control of Taenia solium Cysticercosis/Taeniasis in Endemic Countries: A Systematic Review.(WILEY, 2025-10-08) Nyangi, Chacha; Martin, Ernatus; Helena, Mkupasi; Ngowi, Aminiel; Mahonge, ChristopherDespite some control efforts, Taenia solium cysticercosis/taeniasis (TSCT) remains widespread in many low-income countries across sub-Saharan Africa, Latin America and Asia. With increased global interaction, the risk of infection also rises in highincome countries (HICs) and middle-income countries (MICs). Community knowledge and awareness are crucial to influence behavioural change and thus aid in controlling the parasite. This systematic review examined the effectiveness of health education interventions in managing TSCT to inform future disease control strategies. Papers published up to June 2024 were searched through PubMed and Google search engines. Studies evaluating interventions involving health education aimed at improving knowledge, attitudes and practices (KAPs) to alter behavioural responses regarding TSCT were included. Initially, 392 studies were identified, with 21 publications ultimately included in this review. Although behavioural changes and reductions in disease prevalence were challenging to evaluate across the 21 studies, most concluded that health education, developed with community participation, enhanced KAPs, modified behaviour and reduced disease prevalence in the short term.Item Artificial Intelligence in determining optimal questions in assessing social socio-economic status of individuals for routine immunisation services in Tanzania(Tanzania Journal of Health Research, 2025-08-05) Mzurikwao, Deogratias; Edward, Mhamilawa Lwidiko; Simba, Daudi; Balandya, Belinda; Assenga , Evelyne; Okanda, Nyatega Evelyne; Zeramula, Jonathan; Wibonela, Seif; Mzurikwao, Zacharia; Sunguya, BrunoAccurate determination of socio-economic status (SES) is crucial for equitable access to immunization services. Existing SES assessment tools, like the DHS wealth index, are comprehensive but impractical for routine clinical settings due to their length. Objective: To identify the minimum number of questions that can validly determine SES using artificial intelligence (AI), and to assess their validity compared to the standard DHS wealth index. Methods: This study applied Principal Component Analysis (PCA), Convolutional Neural Networks (CNN), and Artificial Neural Networks (ANN) using the DHS wealth index as the gold standard. Data were collected from routine RCH clinics in Tanzania. CNN was used to extract weights for each question, and ANN was trained to validate different subsets of questions.Item Zero-valent Iron-aluminium Co-corrosion: A potential Comprehensive Low-cost Method for Water Defluoridation(Tanzania Journal of Agricultural Sciences, 2023) E.S. Lema; Mwakabona, H.T.Climate change coupled with population increase has forced communities in fluoride rich areas to turn to fluoride contaminated groundwater to fill in the water deficit created by drying of water sources and increasing water demand. Application of low-cost materials such as iron and aluminium hydroxides in the field is limited by expensive preparation steps involved. This study investigated the applicability of Fe and Al, in their metallic states, in water defluoridation by allowing simultaneous corrosion of zero-valent aluminium (ZVA) and iron (ZVI) to form in situ hydroxides. The effect of time, dose, concentration and pH was studied by varying one parameter at a time while controlling others. Findings reveal that, mixing the two materials in their metallic state have the same synergistic effect on their fluoride removal properties as their corresponding (hydr)oxides. Whereas in their pure metallic states, iron and aluminium lowered the concentration of fluoride from 15 - 13.09 mg/L and 15 - 14.9 mg/L respectively, their mixture lowered fluoride levels from 15 - 7.74 mg/L in the period of seven (7) days. Spiking the fluoride solution with Fe3+ ions was found to enhance fluoride removal by lowering Fluoride levels from 15 - 0.8 mg/L in the same period. This could imply that a fluoride removal mechanism in this process involves precipitation of fluoro-complexes of iron rather than those of aluminium. These findings, therefore, suggest that a step involving conversion of ZVA and ZVI into their (hydr)oxides can be skipped in water defluoridation without significantly affecting their fluoride removal capacities. Keywords: co-precipitation, zero-valent aluminium, zero-valent iron, defluoridationItem Modeling the Effects of Treatment Adherence Challenges on the Transmission Dynamics of Hepatitis C Virus(OPEN ACCESS, 2025-08-08) Mupedza, Tinashe Victor; Mhlanga, Laurette; Mamutse ,Dennis; Helikumi, Mlyashimbi; Oresto ,Lolika Paride; Tangakugara, Murambiwa Shingirai; Mhlanga, AdquateInfectious Disease Modeling is Crucial for Predicting Disease Progression Over Time And Helps Guide Decision Makers in Public Health Policy. Hepatitis C Virus (HCV) Prevalence is Still IncreasingiIn Zimbabwe, A Low-Middle-Income Country (LMIC), Despite The Avail- Ability of Effective Treatments, and the Reasons for this Increase Are Not Well Understood. Our Study Employed a Mathematical Model to Explain the Impact of Poor Treatment Adher- Ence on HCV Transmission Dynamics in Zimbabwe. we Computed The Basic Reproduc- Tion Number (R0), a Vital Metric of Disease Spread. Equilibrium States of the Model Were Determined, And Their Stability Was Investigated. The Study Demonstrated That An Adher- Ence Level Exceeding 52% Causes the Reproduction Number to Drop Below 1, Curtailing Further Spread. Our HCV Model Indicates that Variations in Re-Susceptibility Minimally Impact Outcomes, Suggesting that Re-Susceptibility Can Often be Excluded in Such Analy- Ses. Our Model Unraveled the Synergistic Impact of Simultaneously Enhancing the Recov- Ery Rate of Acutely Infected Individuals and Treatment Adherence on Reducing R0. the Study Underlines the Pressing Need for Stronger Health Interventions, Including Patient Education, Financial Assistance, and Rigorous Monitoring, To Improve Treatment Adher- Ence. These Interventions are Paramount in Curbing HCV Proliferation, Particularly in Lmics Like Zimbabwe, and Can Serve as aTemplate for Similar Settings GloballyItem Synergistic Effects and Chemical Interactions of Guava and Beetroot Extracts on Staphylococcus aureus(Sage, 2025-02-28) Mauya, Ester Vicent; Mwakabona, Hezron TimothyObjective: The rise of bacterial resistance presents significant challenges to the pharmaceutical industry. Researchers have focused on finding ways to counteract microbial resistance, with one approach being the exploration of synergistic effects from combining drugs or natural products. This study investigates the antibacterial effect of combining ethanolic extracts of guava leaves and beetroot against Staphylococcus aureus, and potential chemical interactions between the bioactive compounds. Methods: Using disk diffusion antibiotic sensitivity testing, the study compares the antibacterial activity of individual plant extracts with the combined extract. Additionally, the UV/Vis spectra of the individual and combined extracts were compared to assess chemical interactions. Results: Findings indicate that the combination of guava leaves, and beetroot extracts has a weak synergistic effect against S. aureus, with a Fractional Inhibitory Concentration (FIC) index of 0.25. The UV/Vis spectrum showed decreased absorbance at 245–280 nm and increased absorption at 365–400, 475, and 675 nm, suggesting the conversion of compounds and chemical inter actions between bioactive compounds in the combined extract. Conclusion: The study concludes that combining guava leaves and beetroot extracts results in a weak synergistic antibacterial effect against S. aureus, with bioactive compounds interacting to form derivatives that enhance activity. Further studies are, therefore, recommended to elucidate the mechanisms of these interactions and their effects against S. aureus.Item Determinants of COVID-19 Vaccine Readiness and Hesitancy Among Adults in Sub-Saharan Africa(PLOS Global Public Health, 2023-07-14) Abubakari, Sulemana W.; Workneh, Firehiwot; Asante, Kwaku P.; Hemler, Elena, C.; Madzorera, Isabel; Wang, Dongqing; Ismail, Abbas; Assefa, Nega; Azemraw, Temesgen; Lankoande, Bruno; Nuhu, Abdul R.; Chukwu, Angela; Mapendo, Frank; Millogo, Ourohire´; Olufemi, Adedokun A.; Okpara, Daniel; Boudo, Valentin; Mwanyika-Sando, Mary; Berhane, Yemane; Baernighausen, Till; Oduola, Ayoade; Vuai, Said; Sie, Ali; Soura, Abdramane; Killewo, Japhet; Tajudeen, Raji; Fawzi, Wafaie W.; Smith, Emily R.There is very limited data on the extent and determinants of COVID-19 vaccine hesitancy among adults living in sub-Saharan Africa since the global roll-out of vaccines began in 2021. This multi-country survey sought to investigate COVID-19 vaccine hesitancy and other predictors of readiness to get vaccinated. We conducted surveys among adults resid- ing in nine urban and rural areas in Burkina Faso, Ethiopia, Ghana, Nigeria, and Tanzania in late 2021. Log binomial regression models were used to identify prevalence and factors associated with vaccine hesitancy and beliefs around COVID-19 misinformation. We com- pleted a total of 2,833 interviews. Among all respondents, 9% had never heard of a COVID- 19 vaccine, 12% had been vaccinated, and 20% knew someone else who had been vacci- nated. The prevalence of vaccine hesitancy varied by country (Ethiopia 29%, Burkina Faso 33%, Nigeria 34%, Ghana 42%, Tanzania 65%), but not by rural or urban context. People who did not think the vaccine was safe or effective, or who were unsure about it, were more likely to be vaccine hesitant. Those who reported they did not have a trusted source of infor- mation about the vaccine (aPR: 1.25, 95% CI: 1.18,1.31) and those who thought the vaccine would not be made available to them within the year were more likely to be vaccine hesitant. Women were more likely to be vaccine hesitant (aPR: 1.31, 95% CI: 1.19,1.43) and believe COVID-19 falsehoods (aPR: 1.05, 95% CI: 1.02,1.08). The most commonly believed false- hoods were that the vaccine was developed too fast and that there was not enough informa- tion about whether the vaccine was effective or not. Educational campaigns targeted at misinformation and tailored to suit each country are recommended to build trust in COVID- 19 vaccines and reduce hesitancy.Item In Silico Study of the Inhibition of SARS-COV-2 Viral Cell Entry by Neem Tree Extracts(ROYAL SOCIETY OF CHEMISTRY, 2021-07-03) Shadrack, Daniel M.; Vuai, Said. A.H.; Sahini, Mtabazi G.; Onoka, IsaacThe outbreak of COVID-19, caused by SARS-COV-2, is responsible for higher mortality and morbidity rates across the globe. Until now, there is no specific treatment of the disease and hospitalized patients are treated according to the symptoms they develop. Efforts to identify drugs and/or vaccines are ongoing processes. Natural products have shown great promise in the treatment of many viral related diseases. In this work, using in silico methods, bioactive compounds from the neem tree were investigated for their ability to block viral cell entry as spike RBD-ACE2 inhibitors. Azadirachtin H, quentin and margocin were identified as potential compounds that demonstrated viral cell entry inhibition properties. The structural re-orientation of azadirachtin H was observed as the mechanism for viral cell entry inhibition. These compounds possessed good pharmacodynamic properties. The proposed molecules can serve as a starting point towards developing effective anti-SARS-COV-2 drugs targeting the inhibition of viral cell entry upon further in vitro and in vivo validation.Item An Overview of Maternity healthcare Monitoring in Developing Nations(Tanzania Journal of Engineering and Technology, 2024) Kyambille, Godphrey G.; Mvuma, Aloys N.; Machuve, DinaA healthcare monitoring arrangement is essential for frequently monitoring a patient's health status. Specifically, maternal healthcare systems for tracking are utilized to evaluate the clinical status and monitor any abnormal condition changes during all three trimesters. This paper's objective is to conduct an extensive literature review and acknowledge earlier initiatives and studies conducted previously in maternal health care monitoring. This review focuses on accumulating information from earlier work and presents a general overview of previous studies concerning maternal health care monitoring (MHCM). The paper focuses on the maternal healthcare systems in developing countries accessed by pregnant women during the antenatal period. Furthermore, this paper highlights the challenges in the maternal health sector that include inadequate work conditions for health workers, home-based birth practices, long distances to healthcare facilities, and long waiting times in health facilities. The paper indicates the potential opportunities to strengthen maternal healthcare services and allow effective access to maternal healthcare facilities by pregnant womenItem Determinants of acceptability of schistosomiasis mass drug administration among primary school children in Busega District, Northwestern Tanzania.(OPEN ACCESS, 2025-07-18) Yunzu Edward, Irene; Maritim, PatriciaSchistosomiasis is endemic in Tanzania, with a prevalence ranging between 12.7% to 87.6%. Mass drug administration (MDA) with praziquantel is the main recommended choice of preventive treatment for the disease. Low treatment coverage rates (46.6%) in Busega District, Northwestern Tanzania which are far less than the recommended effective coverage rates of ≥ 75% could indicate low acceptability and poor uptake of MDA. This study sought to establish factors associated with acceptability of schisto somiasis mass drug administration among primary school children in Busega District.Item Women's Satisfaction on Maternal Healthcare Services in Public Health Facilities: A Case of Meta Maternity Hospital(Tanzania Medical Journal, 2025-05-01) Kyambille, Godphrey; Mvuma, Aloys; Machuve, Dina; Rugumisa, Bernadether; Mang'ara, JL. RevocatusSatisfaction with healthcare services serves as a key measure of quality in healthcare systems. Although the Ministry of Health in Tanzania has introduced attentive and respectful health service, the satisfaction levels among pregnant women with delivery services at public hospitals remain inadequately addressed.Item Women's Barriers to Access Maternal Healthcare Services in Southern Highlands of Tanzania: A Case of Meta Maternity Hospital(EAST AFRICAN NATURE & SCIENCE ORGANIZATION, 2023-09-14) Kyambille, Godphrey G; Mvuma, Aloys,; Machuve,Dina; Rugumisa, Bernadether; Mang’ara, RevocatusThe improvement of maternal healthcare (MHC) is a global priority. However, barriers to accessing maternal healthcare services (MHCS) impede progress toward achieving sustainable Development Goals 4 and 5. The demand for maternal healthcare services (MHCS) is especially obvious in underdeveloped countries, where several obstacles restrict access to healthcare. This study aimed to identify obstacles to accessing maternal healthcare services. The primary objective of data collection questionnaires was to identify the variables influencing women's access to reproductive and maternal healthcare services. Between September 2022 and January 2023, 374 respondents' information was gathered and then thematically examined, the observed obstacles to using and obtaining maternal healthcare services were physical barriers, social obstacles, cultural obstacles, organization obstacles, and financial obstacles. The results of this study show that there must be a way to get around the problems listed above in order to improve access to maternal and reproductive health services.Item Dynamical Analysis of Mpox Disease with Environmental Effects(MDPI, 2025-05-29) Helikumi, Mlyashimbi; Ojija, Fredrick; Mhlanga, AdquateIn this study, we develop a fractional-order mathematical model for investigating the transmission dynamics of monkeypox (Mpox), accounting for interactions between humans, rodents, and environmental reservoirs. The model uniquely integrates two key control strategies—public health awareness and environmental sanitation—often over- looked in previous models. We analyze the model’s well-posedness by establishing the existence, uniqueness, and positivity of solutions using the fixed-point theorem. Using data from the Democratic Republic of Congo, we estimate the model parameters and demon- strate that the fractional-order model (φ = 0.5) fits real-world data more accurately than its integer-order counterpart (φ = 1). The sensitivity analysis using partial rank correlation coefficients highlights the key drivers of disease spread. Numerical simulations reveal that the memory effects inherent in fractional derivatives significantly influence the epidemic’s trajectory. Importantly, our results show that increasing awareness (ε) and sanitation efforts (η) can substantially reduce transmission, with sustained suppression of Mpox when both parameters exceed 90%. These findings highlight the synergistic impact of behavioral and environmental interventions in controlling emerging zoonotic diseases.Item GRAPEVNE - Graphical Analytical Pipeline Development Environment for Infectious Diseases(Wellcome Open Research, 2025-05-29) Brittain, John-Stuart; Inward, Rhys; Mwanyika, Gaspary; Tegally, Houriiyah; Githinji, George; Tsui , Joseph; Gutierrez, Bernardo; Huynh, Tuyen; Kifle Tessema, Sofonias; McCrone, John T.; Bhatt, Samir; Dasgupta, Abhishek; Ratcliffe, Stephen; Kraemer, Moritz U.G.The increase in volume and diversity of relevant data on infectious diseases and their drivers provides opportunities to generate new scientific insights that can support ‘real-time’ decision-making in public health across outbreak contexts and enhance pandemic preparedness. However, utilising the wide array of clinical, genomic, epidemiological, and spatial data collected globally is difficult due to differences in data preprocessing, data science capacity, and access to hardware and cloud resources. To facilitate large-scale and routine analyses of infectious disease data at the local level (i.e. without sharing data across borders), we developed GRAPEVNE (Graphical Analytical Pipeline Development Environment), a platform enabling the construction of modular pipelines designed for complex and repetitive data analysis workflows through an intuitive graphical interfaceItem 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. GBackground: 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 illnessesItem 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.Item Dynamics of a Fractional-Order Chikungunya Model with Asymptomatic Infectious Class(Hindawi, 2022) Helikumi, Mlyashimbi; Eustace, Gideon; Mushayabasa, SteadyIn 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.Item 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, GeraldDengue 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 interventionsItem 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 happenedItem 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.