Fever Transmission Research Articles

Influence of environmental viral load, interpersonal contact and infected rodents on Lassa fever transmission dynamics: Perspectives from fractional-order dynamic modelling

<abstract><p>Lassa fever is a fatal zoonotic hemorrhagic disease caused by Lassa virus carried by multimammate rats, which are widely spread in West Africa. In this work, a fractional-order model for Lassa fever transmission dynamics is developed and analysed. The model involves transmissions from rodents-to-human, person-to-person, as well as from Lassa virus infested environment/surfaces. The basic properties of the model such as positivity of solutions, and local stability of the disease-free equilibrium are determined. The reproduction number, $ \mathcal{R}_0 $, of the model is determined using the next generation method and it is used to determine the suitable conditions for disease progression as well as its containment. In addition, we performed sensitivity analysis of the model parameters using the Latin Hypercube Sampling (LHS) scheme to determine the most influential processes on the disease threshold, and determined the key processes to be focused on if the infection is to be curtailed. Moreover, fixed point theory was used to prove the existence and uniqueness of non-trivial solutions of the model. We used the Adams-Bashforth Moulton method to solve the model system numerically for different orders of the fractional derivative. Our results show that using various interventions and control measures such as controlling environmental contamination, reducing rodents-to-humans transmission and interpersonal contact, can significantly help in curbing new infections. Morestill, we observe that an increase in the memory effect, i.e. dependence on future values of the model on the previous states predicts lower peak values of infection cases in the short term, but higher equilibrium values in the long term.</p></abstract>

Preventive practices by households against Lassa fever transmission in Ondo State, Southwest, Nigeria

continued transmission of Lassa fever has been recorded in 6 Local Government Areas (LGAs) of Ondo State in Southwest, Nigeria annually with high case fatality rates. Genomic analysis of the Lassa virus has indicated ongoing transmission from local rodents´ population to humans despite several public health interventions during the outbreak including risk communication on preventive practices against the disease. We assessed adherence to preventive practices by household against the spread of Lassa fever in these affected LGAs. a descriptive cross-sectional study was conducted among community members in the six affected Local Government Area (LGAs). A semi structured questionnaire was administered to 2992 consenting respondents to assess their reported preventive practice against Lassa fever while their observed practices was assessed using observation checklist. Data analysis was done using frequency, proportions, Chi-Square test and logistic regression of predictors of outcome variable with statistical significance set at p<0.05. a higher proportion of the respondents were females (51.2%) compared to males (48.8%) with mean age of 43.04±13.97 years. Majority of the respondents (88.2%) were married with at least secondary education (76.7%). Majority of the respondents (80.2%) reported washing their hands with soap and water regularly, 84.6% washed their utensils before and after use likewise. However, 10.6% of the respondents reported not storing their food items in lid-covered containers while 61.9% practiced open air drying of food items by the roadside. Also, 34.3% of the respondents were observed to spread food items outside their home in the open air. Overall, 32.6% of the respondent were observed to have poor preventive practices against Lassa fever with their level of education as a significant determinant. the poor preventive practices observed among the respondents in this study could sustain the transmission of the virus hence there is also the need to further intensify enforcement of public health control measures for Lassa fever through existing community structures and institutions to stop the current and prevent future Lassa fever and other related outbreaks in the State.

The Influence of Health Care Programs on Dengue Hemorrhagic Fever (DHF) Events at Cipamokolan Health Center In Bandung

Background: Dengue is a tropical disease that has become a major international problem in public health inrecent years. Currently an estimated 2.5-3 billion people live in dengue transmission zones.Objectives: The purpose of this study is to find out the effect of health care programs on the incidence of denguehemorrhagic fever.Method: The study used control case design. The case population is those who suffer from dengue hemorrhagicfever, while the control population is those who do not suffer from dengue hemorrhagic fever. The case samplein this study was 48 participants and the control group as many as 48 participants. Simple random samplingtechnique is used to determine research samples, Statistical tests used are chi square tests and odds ratiosResults: The results of the study that had an influence were health counseling (0.000), examination of the flick(0.014), administration of larvacide (0.013), and fogging (0.000).Conclusion: Health care programs that have been shown to affect the incidence of dengue hemorrhagic fever.are health counseling, larva examination, administration of larvacide, and fogging. To reduce the incidence ofdengue hemorrhagic fever needs to be done as early as possible by eradicating the vector of dengue hemorrhagicfever. Health extension activities need to be done to increase public knowledge of the importance of eradicatingmosquito nests in efforts to prevent dengue hemorrhagic fever transmission.

Mapping the prevalence of dengue fever in sragen regency Indonesia

Introduction: Dengue fever is a disease that is transmitted by vectors. The intermediary vector for dengue fever transmission is the Aedes Aegepty mosquito. Dengue fever cases occur in almost all districts in Indonesia, including the Sragen regency. From 2016 to 2019, the incidence of dengue fever was higher than the previous year. This unusual condition needs to be further monitored and studied. This study's purpose was to map the prevalence of dengue fever in the Sragen regency.Methods: A retrospective research design was performed using secondary data provided by the regency health office and the Central Bureau of statistics from the government of Sragen regency. A free and open-source software, namely Quantum Geographic Information System (QGIS), was utilized to produce maps and spatial figures. The results of this study are presented by map and prevalence.Results: The incidence of dengue fever in the Sragen regency in 2017-2019 fluctuated between 15.83 per 100,000 population and 33.54 per 100,000 population. The dengue fever case in Gemolong district is the highest in 2018 and 2019.Conclusion: The conclusion for this research is mapping the dengue fever prevalence helping to figure up the spatial pattern of the disease in Sragen regency.

Dengue fever awareness among patient presenting to tertiary care hospital, U.P (India)

Background: Dengue fever is widespread in India. Environmental changes and lack of awareness increase spread and increase dengue outbreaks. This study was conducted u.p (India),to build knowledge of dengue infection and dengue prevention activities among patients. Methods:A cross-sectional survey was performed in u.p, India. Study took place among 224 participants from May to October 2020. Organized patients sampling followed. A pre-tested, semi-structured questionnaire. Difference was calculated using Chi square test (qualitative variables). P was assumed to be p&lt;0.05. Results: 210 (93.7%) of participants understood dengue. Dengue fever symptoms responded 50% of participants correctly. 89% correctlyclaimed Aedes mosquito transmits dengue. About 40 % of participants had correct knowledge about Aedes mosquito’s breeding habitat and biting habit. In addition to avoiding mosquito bite, researchers use diverse strategies-mosquito spirals (53.7%), mosquito nets (14.7%). No mosquito bites prevention strategy followed by 15.1%. Conclusions: While most of the sample participants knew of dengue and dengue fever transmission mosquito signs, under half were conscious and 25% did not observe any mosquito bite avoidance procedure. Conclusions: Group consciousness plays an important part in improvising practices to avoid dengue.

Descriptive and Multivariate Analysis of the Pig Sector in North Macedonia and Its Implications for African Swine Fever Transmission.

North Macedonia, a country in the Balkan region of Europe, is currently bordered to the north and east by countries with active African swine fever (ASF) outbreaks. The predominantly traditional backyard pig farming sector in this country is under imminent threat of disease incursion. The characteristics and practices of such sectors have rarely been described, and thus the implications for these factors on disease introduction and spread are poorly understood. Using a semi-structured questionnaire, 457 pig producers were interviewed, providing information on 77.7% of the pig population in North Macedonia. In addition, a pilot study of 25 pig producers in Kosovo was performed. This study aimed to provide a detailed description of the North Macedonian pig sector, to make comparisons with nearby Kosovo, and to identify areas with high-risk practices for targeted mitigation. Descriptive data were summarized. Results of the questionnaire were used to identify farm-level risk factors for disease introduction. These factors were used in the calculation of a biosecurity risk score. Kernel density estimation methods were used to generate density maps highlighting areas where the risk of disease introduction was particularly concentrated. Multiple correspondence analysis with hierarchical clustering on principal components was used to explore patterns in farm practices. Results show that farms were predominantly small-scale with high rates of turnover. Pig movement was predominantly local. The highest biosecurity risk scores were localized in the eastern regions of North Macedonia, concerningly the same regions with the highest frequency of wild boar sightings. Veterinarians were highly regarded, regularly utilized, and trusted sources of information. Practices that should be targeted for improvement include isolation of new pigs, and consistent application of basic sanitary practices including washing hands, use of disinfection mats, and separation of clean and dirty areas. This study provides the most complete description of the North Macedonian pig sector currently available. It also identifies regions and practices that could be targeted to mitigate the risk of disease incursion and spread. These results represent the first steps to quantify biosecurity gaps and high-risk behaviors in North Macedonia, providing baseline information to design risk-based, more cost-effective, prevention, surveillance, and control strategies.

Association between climate variables and dengue incidence in Nakhon Si Thammarat Province, Thailand.

The tropical climate of Thailand encourages very high mosquito densities in certain areas and is ideal for dengue transmission, especially in the southern region where the province Nakhon Si Thammarat is located. It has the longest dengue fever transmission duration that is affected by some important climate predictors, such as rainfall, number of rainy days, temperature and humidity. We aimed to explore the relationship between weather variables and dengue and to analyse transmission hotspots and coldspots at the district-level. Poisson probability distribution of the generalized linear model (GLM) was used to examine the association between the monthly weather variable data and the reported number of dengue cases from January 2002 to December 2018 and geographic information system (GIS) for dengue hotspot analysis. Results showed a significant association between the environmental variables and dengue incidence when comparing the seasons. Temperature, sea-level pressure and wind speed had the highest coefficients, i.e. β=0.17, β= -0.12 and β= -0.11 (P<0.001), respectively. The risk of dengue incidence occurring during the rainy season was almost twice as high as that during monsoon. Statistically significant spatial clusters of dengue cases were observed all through the province in different years. Nabon was identified as a hotspot, while Pak Phanang was a coldspot for dengue fever incidence, explained by the fact that the former is a rubber-plantation hub, while the agricultural plains of the latter lend themselves to the practice of pisciculture combined with rice farming. This information is imminently important for planning apt sustainable control measures for dengue epidemics.

Modeling the dengue fever transmission in a periodic environment

A mathematical model for dengue fever transmission is analyzed, which incorporates relevant biological and ecological factors: vertical transmission and seasonality in the interaction between the vector (Aedes aegypti females) and the host (human). The existence and uniqueness of a positive disease-free periodic solution is proved; the global stability of the disease-free solution and the effect of periodic migrations of mosquitoes carrying the virus on the transmission of dengue are analyzed utilizing the mathematical definition of the Basic Reproductive Number in periodic environments; finally, it is numerically corroborated with the help of the Basic Reproductive Number that dengue cannot invade the disease-free state if it is less than one and can invade if it is greater than one, however, in both threshold conditions when vertical transmission occurs, the number of infected people and carrier vectors rises, representing a mechanism for the persistence of dengue cases in a community throughout a natural year.

Comparative study on the surveillance of Aedes albopictus by Breteau index and Mosq-ovitrap index in different habitats

Objective To compare Mosq-ovitrap index (MOI) and Breteau index (BI) of Aedes albopictus in two types of surveillance area through field experiments, and provide the basis for application and evaluation of two surveillance methods. Methods From April to December of 2020, Keqiao district with local transmission of dengue fever and Xinchang county without dengue fever transmission were selected as two surveillance areas in Shaoxing, Zhejiang Province. The density of Aedes albopictus larvae was monitored by BI and MOI at 10 day interval in a month, respectively. Results A total of 10 718 households were investigated, and 745 positive water containers were found, with a BI of 6.95. The BI in Keqiao district (6.98) was similar to that in Xinchang county (6.92). The peak value of BI was 11.28 in urban residential area in July, while 12.67 in rural residential area in May. A total of 11 837 mosq-ovitraps were placed around the BI investigated households, and the MOI was 1.62, while 189 mosq-ovitraps were found to be positive. The MOI was 2.37 in Keqiao district, higher than that in Xinchang county (MOI: 0.75). The MOI in urban residential area was 1.80, higher than that in rural residential area (MOI: 1.44). Pearson correlation analysis showed that there was a statistical correlation between BI and MOI Shaoxing (r=0.676, P=0.046), also in Xinchang county (r= 0.794, P=0.011) and urban residential areas (r=0.691, P=0.039). Conclusion Mosq-ovitrap and Breteau index were effective indicators in the monitoring of Aedes albopictus, but with different sensitivity in rural and urban residential areas.

Fractional Dynamics of Typhoid Fever Transmission Models with Mass Vaccination Perspectives

In this work, we formulate and mathematically study integer and fractional models of typhoid fever transmission dynamics. The models include vaccination as a control measure. After recalling some preliminary results for the integer model (determination of the epidemiological threshold denoted by Rc, asymptotic stability of the equilibrium point without disease whenever Rc&lt;1, the existence of an equilibrium point with disease whenever Rc&gt;1), we replace the integer derivative with the Caputo derivative. We perform a stability analysis of the disease-free equilibrium and prove the existence and uniqueness of the solution of the fractional model using fixed point theory. We construct the numerical scheme and prove its stability. Simulation results show that when the fractional-order η decreases, the peak of infected humans is delayed. To reduce the proliferation of the disease, mass vaccination combined with environmental sanitation is recommended. We then extend the previous model by replacing the mass action incidences with standard incidences. We compute the corresponding epidemiological threshold denoted by Rc⋆ and ensure the uniform stability of the disease-free equilibrium, for both new models, when Rc⋆&lt;1. A new calibration of the new model is conducted with real data of Mbandjock, Cameroon, to estimate Rc⋆=1.4348. We finally perform several numerical simulations that permit us to conclude that such diseases can possibly be tackled through vaccination combined with environmental sanitation.

Comparison of three Coxiella burnetii infectious routes in mice

ABSTRACT Evidence suggests that Coxiella burnetii, which is shed in the milk, urine, feces, and birth products of infected domestic ruminants, can lead to Q fever disease following consumption of unpasteurized dairy products; however, C. burnetii is not believed to be a major gastrointestinal pathogen. Most infections are associated with inhalation of aerosols generated from the excreta of domestic ruminants. We recently demonstrated that C. burnetii delivered by oral gavage (OG) resulted in dissemination and an immune response; however, it is unclear how infection via the oral route compares to other well-established routes. Therefore, we delivered three strains of C. burnetii (representing three pertinent sequence types in the United States, such as ST16, ST20, and ST8) to immunocompetent mice in four doses via aerosol challenge (AC), intraperitoneal injection (IP), or OG. Low dose (10^5) of ST16 by OG was insufficient to cause infection, yet doses 1,000- or 100-fold lower by IP or AC, respectively, induced a robust immune response and dissemination. Despite being able to induce an immune response in a dose-dependent manner, administration of C. burnetii via OG is the least efficient route tested. Not only were the immune responses and bacterial loads diminished in mice exposed by OG relative to AC or IP, the efficiency of transmission was also inferior. High doses (10^8) were not sufficient to ensure transmission to 100% of the ST20 or ST8 cohorts. These results may provide some basis for why ingestion of C. burnetii as a mode of Q fever transmission is not often reported.

Density Figure of Aedes Aegypti Larvae and Community Participation in Prevention of Dengue Hemorrhagic Fever (DHF)

The density of Aedes aegypti mosquito larvae is a risk factor for Dengue Hemorrhagic Fever transmission. Density Figure (DF) is a measurement to determine the success of Aedes aegypti control with four leading indicators (House Index/HI, Container Index/CI, Breteau Index/BI, and Larva Free Figure/ABJ). In addition, community participation, manifested in the Mosquito Nest Eradication Movement, is also essential to prevent and control DHF. This study determined the density figure of mosquito larvae and community participation in the DHF prevention in Oesapa Urban Village, Kupang City, in 2021. This research was a descriptive research type with a total sample of 99 households. Data univariably analysis on water container material, water container type, water container cover presence, and community participation. The results showed that most of the respondents used plastic water container material (57.51%), TPA container type (55.09%), and presented uncovered water container (63.05%). The DF of Aedes aegypti mosquito larvae was in the high category with HI (35.36%), CI (51.86%), BI (324.42%), and ABJ of 64.65%. Therefore, the community should be more aware and consistent to apply PSN-DHF, focusing on 3M Plus implementation to reduce the incidence of DHF.

Projections and fractional dynamics of the typhoid fever: A case study of Mbandjock in the Centre Region of Cameroon

In this work, we formulate a mathematical model with a non-integer order derivative to investigate typhoid fever transmission dynamics. To combat the spread of this disease in the human community, control measures like vaccination are included in the proposed model. We calculate the epidemiological threshold called the control reproduction number, Rc, and perform the asymptotic stability of the typhoid-free equilibrium point. We prove that the typhoid-free equilibrium for both integer and non-integer models is locally and globally asymptotically stable whenever Rc is less than one. We also prove that both models admit only one endemic equilibrium point which is globally asymptotically stable whenever Rc>1 and no endemic equilibrium point otherwise. This means that the backward bifurcation phenomenon does not occur. In absence of vaccination, Rc is equal to the basic reproduction number R0. We found out that Rc<R0 which means that vaccination can permit to decrease of the spread of typhoid fever in the human community. Using fixed point theory, we perform existence and uniqueness analysis of solutions of the fractional model. We use the Adams-Bashforth-Moulton method to construct a numerical scheme of the fractional model. We prove the stability of the proposed numerical scheme. To calibrate our model, we estimate model parameters on clinical data of Mbandjock District Hospital in the Centre Region of Cameroon, using the Non-linear Least-Square method. This permits us to find Rc=1.3722, which means that we are in an endemic state (since Rc>1), and then to predict new cases of typhoid fever per month at Mbandjock in the next new year. To determine model parameters that are responsible for disease spread in the human community, we perform sensitivity analysis (SA). This analysis shows that the vaccination rate, the human-bacteria contact rate, as well as the recovery rate, are the most important parameters in the disease spread. To validate our analytical results, and to see the impact of some control measures in the spread of typhoid fever in the human community, as well as the impact of the fractional-order on typhoid transmission dynamics, we perform several numerical simulations.

A seasonal model to assess intervention strategies for preventing periodic recurrence of Lassa fever

Lassa haemorrhagic fever is listed in WHO's Blueprint priority list of diseases and pathogens prioritized for research and development, affecting several hundreds of thousands of people each year. Lassa fever is spread via infected Natal multimammate mice and also through human-to-human contacts and it is a particular threat to pregnant women. Despite its importance, relatively few mathematical models have been established for modelling Lassa fever transmission up to now. We establish and study a new compartmental model for Lassa fever transmission including asymptomatic carriers, quarantine and periodic coefficients to model annual weather changes. We determine parameter values providing the best fit to data from Nigerian states Edo and Ondo from 2018–20. We perform uncertainty analysis and PRCC analysis to assess the importance of different parameters and numerical simulations to estimate the possible effects of control measures in eradicating the disease. The results suggest that the most important parameter which might be subject of control measures is death rate of mice, while mouse-to-human and human-to-human transmission rates also significantly influence the number of infected. However, decreasing the latter two parameters seems insufficient to eradicate the disease, while a parallel application of decreasing transmission rates and increasing mouse death rate might be able to stop the epidemic.

Mathematical modeling, forecasting, and optimal control of typhoid fever transmission dynamics

In this paper, we derive and analyze a model for the control of typhoid fever which takes into account an imperfect vaccine combined with protection, environment sanitation, and treatment as control mechanisms. The analysis of the autonomous model passes through the computation of the control reproduction number Rc, the proof of the local and global stability of the disease-free equilibrium whenever Rc is less than one using Lyapunov’s theory. When Rc is greater than one, we prove the local asymptotic stability of the unique endemic equilibrium through the Center Manifold Theory and we find that the model exhibits a forward bifurcation. Using clinical data from Mbandjock, a town in the Centre Region of Cameroon, we calibrate the model by estimating model parameters. We find that the control reproduction number is approximatively equal to 2.4750, which means that we are in an endemic state (Rc>1). We also performed a sensitivity analysis by calculating the Partial Rank Correlation Coefficient (PRCC) of Rc and of infected compartments classes. Then, we extend the model by reformulating it as an optimal control problem, with the use of three time-dependent controls, namely vaccination, individual protection/environment sanitation, and treatment. Optimal control theory is used to analyze our optimal control model. Numerical simulations and efficiency analysis are performed to show the impact of each control strategy on the decrease of the disease burden.

Gambaran Tingkat Pengetahuan Dan Perilaku Masyarakat Tentang Pemberantasan Sarang Nyamuk Di Banjar Dinas Dangin Pura Desa Panji Sukasada Buleleng

Background: Dengue hemorrhagic fever is one of the population's health issues in Indonesia, with an increasing number of sufferers as the disease spreads. The cases rose dramatically in Panji Village, with a significant spike in cases per year. Dengue hemorrhagic fever transmission is inextricably linked to the residents' experience and behavior. Mosquito Nest Eradication is the most reliable, safe, and cost-effective method of eliminating dengue fever vectors. The MNE Program must be complemented by increasing public awareness of dengue fever. Public awareness is needed since it is the first step in changing people's behavior. The aim of this study is to describe the community's level of knowledge and behavior regarding MNE in Panji Village.&#x0D; Method: This study is a descriptive study using univariate analysis. The overall selection of this study was 400 people from the community who were interviewed using a questionnaire. The inclusion criteria comprises any community member from Banjar Dinas Dangin Pura, who is 17 to 55 years old and can read and write. Meanwhile, people between the ages of 17 and 55 who are wandering, those with mental illnesses, and people with special needs are among the exclusion criteria.&#x0D; Results: The majority of the population in the Banjar Dinas Dangin Pura Panji Village was between the ages of 26 and 35 (46.7%), In terms of gender (224 people) (56%) were men, completed their high schools, with 229 people (57.3%), were working as farmers 158 individuals (39.4%). Most people in Banjar Dinas Dangin Pura Panji Village had inadequate knowledge as many as 249 individuals (62.3%), and had less behavior as many as 152 individuals (38%) towards MNE.&#x0D; Conclusion : The majority of people had a poor degree of awareness about MNE, and those on MNE had a poor degree of behavior.

Prevalence of Larval Breeding Sites and Seasonal Variations of Aedesaegypti Mosquitoes (Diptera: Culicidae) in Makkah Al-Mokarramah, Saudi Arabia.

Since 1994, dengue fever (DF) transmission rates have increased significantly in Saudi Arabia (KSA). Climatic, geographic, and demographic conditions make KSA especially suitable for DF’s spread. Still, there are insufficient strategies for controlling the Aedes species that transmit DF virus (DENV). To develop effective management strategies, it is necessary to identify Aedes species and the ecological habitat of larvae in Makkah Al-Mokarramah, KSA. We conducted a longitudinal survey of Aedes mosquitoes in 14 localities from January 2015 to December 2015. World Health Organization (WHO) inspection kits for larvae were used to detect and sample larvae, along with pictorial keys. A total of 42,981 potential Aedes larval breeding sites were surveyed. A total of 5403 (12.6%) sites had at least one water source positive for Aedes aegypti (Linnaeus) mosquitoes. Among the total of 15,133 water sources surveyed within the sampled sites, 1815 (12.0%) were positive for Aedes aegypti. Aedes aegypti was the only Aedes species identified in the course of the survey. The presence of such a large immature population may indicate an imminent outbreak of DF in the near future unless proper implementation of control and elimination of Aedes aegypti are undertaken. Additionally, the adaptation of Aedes aegypti to the arid climate of Makkah needs further investigation.

Is transportation a risk factor for African swine fever transmission in Australia: a review.

African swine fever (ASF) is a viral disease of the pigs that was first described in Africa during the early part of the twentieth century. The disease has periodically occurred outside of Africa, including an ongoing epidemic in Europe and Asia that started in 2007; the disease has never occurred in Australia or New Zealand. Once introduced into a country, spread can occur through direct and indirect routes of transmission. Infected feral pig populations have the potential to act as a long-term reservoir for the virus, making eradication difficult. Just before and throughout the period of clinical signs, ASF virus is shed in oronasal fluids, urine, faeces and blood. This results in contamination of the pig's environment, including flooring, equipment and vehicles. Transportation-related risk factors therefore are likely to play an important role in ASF spread, though evidence thus far has been largely anecdotal. In addition to the existing AUSVETPLAN ASF plan, efforts should be made to improve transportation biosecurity, from the time a pig leaves the farm to its destination. Collection of data that could quantify the capabilities and capacity of Australia to clean and disinfect livestock trucks would help to determine if private and/or public sector investment should be made in this area of biosecurity. No peer-reviewed research was identified that described a specific process for cleaning and disinfecting a livestock truck known to be contaminated with ASF virus, though literature suggests that transportation is an important route of transmission for moving the virus between farms and countries.

A Complete Model of Crimean-Congo Hemorrhagic Fever (CCHF) Transmission Cycle with Nonlocal Fractional Derivative

Crimean-Congo hemorrhagic fever is a common disease between humans and animals that is transmitted to humans through infected ticks, contact with infected animals, and infected humans. In this paper, we present a boxed model for the transmission of Crimean-Congo fever virus. With the help of the fixed-point theory, our proposed system model is investigated in detail to prove its unique solution. Given that the Caputo fractional-order derivative preserves the system’s historical memory, we use this fractional derivative in our modeling. The equilibrium points of the proposed system and their stability conditions are determined. Using the Euler method for the Caputo fractional-order derivative, we calculate the approximate solutions of the fractional system, and then, we present a numerical simulation for the transmission of Crimean-Congo hemorrhagic fever.

Comments on “The Solution of a Mathematical Model for Dengue Fever Transmission Using Differential Transformation Method: J. Nig. Soc. Phys. Sci. 1 (2019) 82-87”

The mathematical model for dengue fever transmission studied by [1], has been re-investigated. The differential transformation method (DTM) is used to compute the semi-analytical solutions of the non-linear differential equations of the compartment (SIR) model of dengue fever. This epidemiology problem is well-posed. The effect of treatment as a control measure is studied through the growth equations of exposed and infected humans. The inadvertent errors in the recurrence relations (DTM) of equations for dengue disease transmission including initial conditions have been removed. Furthermore, the semi-analytic solutions of the model are obtained and verified with the built-in function AsymptoticDSolveValue of Wolfram Mathematica. It has been found that results obtained from the DTM are valid only for small-time t (t &lt; 1.5), as t becomes large, the human population (exposed and recovered) and infected vector population become negative.